Traditional Leaded Light Construction

It’s not often that I construct a leaded light but having done so recently I thought I should share some notes with you. They may help you as a newcomer or give you some new ideas if it’s an activity you’re already familiar with.

I really cannot claim to be an expert so you might have different opinions and ideas and might even think I’m doing it all wrong. Use your own judgement and decide for yourself. Sharing the information is what’s important from my perspective.

Rather that write this blog as a tutorial, for which there are several to be found online and in books, I will break down my notes into short sections that broadly follow the construction steps but I will not concern myself with step-by-step instructions. Sorry if you find this results in a blog that is a little incoherent at times.

Two Schools

There are two schools of thought about what to do once a cartoon has been produced. The difference lies in the method by which a cartoon is translated into a set of glass pieces ready to assemble.

Incidentally, I use the word “cartoon” for a drawing of an intended design. You might be more familiar with “pattern”. I think there’s a subtle difference that makes “cartoon” more appropriate but we can beg to differ on this little matter.

The first school of thought is that you must make a copy of your cartoon and use scissors on the copy to make little templates that represent each of the pieces of glass. I find this time consuming and fiddly so only use this method when I am using opalescent glass or dark colours that I cannot see though.

The second school of thought is to use the cartoon to directly score the glass directly over the original cartoon. This is a quicker method, lazy some might say, because it requires no copy to be made and there is no scissor work. This is what I tend to do if I am using glass that I can see through. I also prefer this method because and there are no fiddly bits of paper getting in the way of glass cutter wheel and no little pieces of paper to lose. One might suppose that parallax error might make this method slightly less accurate because of the distance between the cutting wheel and the cartoon lines but for leaded light work this does not tend to be a problem.

As already mentioned in passing, I still sometimes have to use the first method when working with a dark cathedral or opalescent glass. In this situation I mark-out a copy of the pattern for individual glass pieces using tracing paper, cut-out the tracing paper and use this as the template. I then use a waterproof marker pen, or a white wax pencil, around the edge of the template to mark-out the perimeter onto the glass. I don’t stick the paper onto the glass and attempt to score around it as I find the outcome is worse score lines.

Whichever method you use, it can be a good idea to number the pieces of glass to match the number you’ve added to the cartoon (and maybe template pieces) so that you don’t forget where they go and indeed which way up the pieces of glass should be used. This is particularly important when the design is complicated and has many pieces of glass that are similar but not exactly the same.

DSCF3325 CartoonSomething extra that I do with leaded light cartoons is to pencil-in lines that represent the boundaries between the glass and leads. Whilst doing this I also consider how the pieces of leading will affect visual appeal, construction strength, how it will be assembled and so forth. So, in addition to marking-out where there will be leads I also mark how those leads should be cut and jointed as a reminder for later. Look at the picture for a better understanding of what I mean.

The thick black lines on the cartoon will be explained in the next section.

Can you see I stopped bothering to mark out the cames and joints in the lower part of the panel because it was the “easy and obvious” part? I find that marking-out the cames and joints is more important for the complicated or intricate areas than elsewhere so I sometimes allow myself to be lazy in the less critical parts of the design.

If you leave these assembly and jointing considerations until the assembly phase of the construction and try to do it “on the fly”, your mind and your eyes will tend focus on the immediate task at hand – which is to say the current piece of glass and lead came. This means you will tend to neglect the “bigger picture” and often forget any thoughts you had about what to cut, where to joint and so forth.

Another dividend is then repaid when assembling the panel because you instantly see whether or not each piece of the lead work is being placed exactly in the correct position and is the expected shape. This in turn means construction problems are caught early and can be addressed immediately. You don’t have to wait until the panel has been fully assembled to realise that lots of subtle little errors have produced a wonky distorted panel that’s not quite the size it was meant to be.

Cutting the pieces of glass to the “right size” is important and the “right size” depends on the construction method and materials being used.

If you simply score along the cartoon pattern lines your will end up with glass pieces that are too large because no allowance has been made for the thickness of the lead between pieces of glass in a leaded light. A different allowance must also be made for the a double-thickness of copper foil (and a little solder) when using the copper-foiled method. So, the “right size” is a little smaller than the size on your nicely drawn cartoon drawing.

Commercially available pattern shears are available that will automatically cut on each side of the cartoon’s lines to help you with this task but I do not use them. One kind of shears is for copper-foiled work and the other is for leaded lights. The only difference between them is the amount of size-trimming that they perform. But there is a simpler method that is not only cheaper but is, at least in my opinion, more effective…

Look back at the previous picture and notice the thick black lines. Then read on…

Mark out all the glass boundary lines in your cartoon design with a felt tipped marker pen that produces lines about 2mm thick if it is going to be a leaded light. If you intend to use the copper-foiling method then a finer marker pen that produces lines no more than 1mm wide is appropriate.

You will then score along the edges of these marker pen lines, not the middles of them.

Thus, the thick marker-pen lines represent the channels inside your lead cames. Because 2mm is slightly more than the thickness of lead in the channel we can be sure the pieces of glass will not only fit but should rattle slightly.

The reason we should aim for slightly under-sizing the glass pieces is to ensure that the panel as a whole can be constructed exactly as the cartoon design intended, which is to say the final product will not contain distortions and can be made to exactly the correct dimensions. Although there will be some rattling of glass pieces around the constructed panel it will be entirely resolved by the waterproofing and strengthening stage of construction. But, there is a difference between being “a little too small” and “too small” and it depends on the width of the lead cames you are using. Wide leaves (flanges) of chunky cames means you’re allowed more latitude. Narrower cames demand more careful cutting!

And by the way, if you have the habit of using waterproof marker pens to mark-out the glass cutting lines then a smear of something like petroleum jelly (eg Vaseline) will help to stop the lines washing off when subsequently grinding. An alternative is wax pencils. A lazy third alternative is to place a sheet of clear acetate over the cartoon to protect it from water, then repetitively grind and check the piece of glass against the cartoon.

Obtaining and Storing Lead Cames

Lead cames are produced in straight lengths and that’s how you should try to obtain them. Avoid buying lead cames that have been coiled-up because it requires more effort to straighten them and increases the chances of physical damage. If this means you need to visit a stained glass supplies shop one per year rather than have it posted to you in coils then do so.

Once bought, give some thought to transporting and storing your lead cames straight and flat. Some possibilities are a long sturdy cardboard postal tube, a piece of plastic drainpipe or even a piece of plastic guttering. You glass supplier receives the lead cames in crates – maybe they are kindly folk and have one spare that you can have.

If you live in a damp environment, or your work area gets damp, try not to buy more lead came than you need as it will deteriorate through oxidation and become harder to solder. If you live and work in a nice dry environment then this is less of a problem so buying in greater bulk is more viable.

I have in the past been “donated” really old lead cames that had lain unused for many years. They had almost turned to black and were an absolute swine to solder and it was (in practical terms) impossible to “brighten” the leads where I intended to solder. So, if someone approaches you with a fist full of twisty mangled ancient lead cames, politely decline the offer even if they are free!

I should perhaps briefly describe some common forms of lead came, particularly for novice readers. What you choose comes down to artistic necessity, suitability and experience.

H-section cames are what you will mostly use so I will talk mostly about them. You will notice they have 5mm wide channels into which the glass pieces fit. The overhanging leaves (flanges) will keep the glass in place even before you’re waterproofed and strengthened your masterpiece.

But why not a 3mm channel for the glass we tend to use? The answer is easy. Think about the effect of surface patterns and the thickness variation of hand-blow glass. The extra 2mm is needed to accommodate such situations!

Another aspect of H-section cames is that the leaves “overhang” the glass by differing amounts. In this regard it is like choosing between thin or fat copper foil – part of the choice relates to the visual effect but there are also underlying practical consequences. A consequence of choosing H-section cames with wide leaves is that there is more latitude for error in the glass cutting and a stronger layout at the expense of a “chunky” appearance to the finished piece. Finer cames demand more accurate glass cutting just as using skinny copper foil only looks good if you cut the glass accurately.

H-section cames are available with “leaves” that are may have flat or curved outer surfaces, or both. In practise it doesn’t matter whether the leaves are flat or curved, and you will not really notice the difference except in one situation – accidentally mix them up in the same piece and it looks shabby with both flat and curved surfaces on the same side. I’ve accidentally done this in the past so trust me!

There is no reason why you cannot mix-and-match different types of H-section came in the same piece. For example, if your design contains a nice traditional stylised flower (not unusual!) you might choose a “fatter” came below to represent a stem for that flower.

U-section came and C-section came need special attention because their names are often confused. U-section came isn’t just C-section came turned on its side! They have different cross-sections but more to the point, they have very different purposes.

C-section came might have curved or squared-off outer profiles when viewed in cross-section and tend to be used to form a framing edge for a panel or inside a wooden frame (eg a cabinet door). Consequently they are often used for a standalone piece such as a suncatcher and sometimes have a narrow channel that is around 3mm rather than 5mm so be careful before your buy such cames. Incidentally, I hate the term “suncatcher” because they don’t catch the sun and they’re not necessarily hung in a window and it explains why I tend to use the word “panel” instead. But again we can agree to differ!

C Section Came UseU-section came is interesting. When you find some to look at, notice the heavy-duty curved outer profile in cross-section. The reason for such a sturdy curved profile is because U-section intended to be used as the upper edge of a large panel section that will have another panel section resting on top. To understand what I mean, think of a massive stained glass window in a church which has, by necessity been constructed in sections. Now look at my rubbish little diagram to understand how the H-came (in red) and C-came below (in blue) are being used. Over time the H-section presses down under the weight of the upper panel and the H-section’s leaves will splay and form a nice neat seal over the C-section curve below. Rainwater will remain outside and not be drawn into the panel. A simple solution to making a massive glass window panels waterproof wherever they meet. Our ancestors were not so primitive as we sometimes assume!

And finally, remember there are other forms of lead came for special situations. Some cames are for forming a right-angle joint. There are others designed to be the perimeter of a piece that makes it easier to mount into a frame. Visit your stained glass shop or look at a web site and ask what they are intended for. Nice people like to share their knowledge and experience.

Stretching Lead Came

Lead came needs to be stretched a little before use, not only to remove kinks but also to make the structural properties of the lead change. Somehow a stretched came seems to be a little stronger.

Stretching ought to be done only once per came, so to avoid confusion don’t stretch a came until you need it and store leftovers in a different place from un-stretched cames.

Two people holding each end of a length of lead came with pliers (or a similar tool) can perform the stretching. If there is nobody to help you then a lead vice will be needed and the vice must be screwed to a table top or clamped into a sturdy vice. Don’t attach the lead vice to your best table and don’t trap one end of the lead came into a door frame – these are both effective ways to damage woodwork!

How far to stretch the cames is a matter of judgement. What you are aiming for is the removal of kinks plus just a little more. Do not pull too hard or stretch too far as the lead will start to lose its strength and become softer. Worse still is if you pull too hard and the lead breaks (usually at the pliers) because you will find yourself flying backwards uncontrollably!

Although kinks can be removed from a lead came by stretching, nicks and most crush-damage can not. A problem with lead is that it is very soft and therefore very prone to damage especially on the leaves. At best you might be able to use a lead knife blade or an All Nova tool to “flatten out” some of the damaged areas but, of course, you will be cutting up the cames in various lengths so you can plan to cut pieces between the points of damage, or if you’re sneaky you can ensure damaged areas are soldered over at joints. Constructing a panel from damaged leads, visible for all to see, reflects badly on your commitment to excellence so don’t do it. Hiding little areas of damage under soldered joints is another matter entirely!

From all this you’ll understand why it’s not a good idea to buy coiled-up lead cames and why it’s sensible to transport and store them tidy and flat. I’ve previously suggested cardboard tubes, drainpipes and gutters as suitable storage containers.

If you don’t have space to store your cames in full-lengths then you might try cutting them in half but this will limit the maximum size of panel that you can make. Another reason to cut cames into half lengths is when you’re not a strong athletic person or you’re on your own – it’s easier to pull a shorter length of lead came single-handedly.

Use an All Nova Tool

The All Nova tool is inexpensive and replicates the functions of traditional tools such as the lathekin, fid, oyster tool and others besides for burnishing, flattening and spreading came. Unusually for “multi-function” tools, which tend to do many things badly, this one is well-designed and does all the tasks asked of it properly. I think it’s an essential tool for anyone who does copper-foiling or leaded light work. Not really useful for fused glass work though.

I’ve never seen any “formal” instructions on what the various parts of an AllNova tool are designed for so here’s my take on what I’ve read and discovered for myself and I also attach a picture that also includes a few horseshoe nails and a few scraps of lead came (the purpose for which will become apparent later).

DSCF3326 AllNova ToolThe outside curve of the flat face at the flat end of the AllNova tool can be used for burnishing copper foiled work or to completely close the lead came channel gap around the peripheral edge of a leaded light.

The very end of the flat end of the All Nova tool can pushed into the channel of a lead came and gentle “pulled along” the channel to open-out a kink in the leaves of a lead came, or the flat face can be used on the outside of the lead came to close-up a kink in the leaves of a lead came. Although this flat end of the tool is useful for dealing with kinks and opening-up the channels, see below for how the heel at the “pointy end” can also be used to widen the channel down a full-length of a lead came in one simple action.

Another use for the end of the flat side of the tool, when inserted into the heart of a lead came channel, is to help push and shape the lead came around the profile of an adjacent piece of glass. This avoids the kinds of damage that your hands or some other tool might do when pushing against the structurally weak leaves of the cames.

And yet another use for the flat end is to gently open up the “crushing damage” that can and often does occur when cutting a lead came. Insert the flat end into the channel just behind the damage and pull through to the end of the came. The little crushed area at the end will be pushed back into shape. I sometimes also use of the flat-side of a lead knife to “finish off” the damage repair.

An All Nova tool can be used to widen the channel of a lead came if glass is too thick to be inserted into the channel easily, or if the channel is slightly closed. The heel area at the “pointy end” is a splaying tool. Hold the came end that’s nearest to you and put the ‘heel’ of the AllNova tool into the lead came channel nearest to you. Then gently push down the heel into the channel and push away from you. The amount of pressure downwards into the channel will affect how much you splay the leaves of the came so take care. Ideally, practise first on a pieces of scrap came to get the technique right. You will see the channel widen by an amount determined by the downward pressure being applied. If the channel is still not wide enough for your glass then you can try to pull back with the ‘toe’ of the All Nova Tool (remembering to now hold the came at the far end!). To be honest, I’ve never needed to use the toe-end of the tool as the heel seems to do enough of a widening job for my purposes.

A traditional oyster tool (long thin U-shaped blade with a handle) is another possibility for widening the channel of a lead came. There’s not much point in owning one if you already have an AllNova tool.

If you’ve used the heel to widen a came and it’s now too wide then the flat end of the AllNova tool can be used to reverse the over-enthusiasm. Press the flat side down and slide gently along the came to close-up the gap. A sort of gentle burnishing action you might say.

The pointed end can be used as a “picking tool”, for which the most obvious task is to remove excess cement after waterproofing a leaded light. Despite this suggestion, I tend to use matchsticks because they can be then thrown away. The pointed end could also be used for back-scratching and nose-picking. Well, that’s what I tell kids. Some believe me.

And finally, what’s the little hole for? To be honest I have no idea.

Preparing for Construction

Place your paper cartoon design onto a wooden base and firmly fix a batten along of the main (longest) edge of the design so that the design cannot move and you have an accurate straight edge to work from. Of course, this assumes you have at least one straight edge in the cartoon design.

Ideally I would add another batten at 90 degrees (or whatever angle is required) to form the second edge of the panel to ensure at least two side can be constructed with absolute accuracy. This also gives you a firm and well-defined corner out of which you assemble the panel. Get the angle wrong and the resulting panel will also be wrong!

I tend to leave a little gap between these two battens so that a lead came can “poke out” of the corner if necessary.

Masking tape is not very reliable to hold a cartoon design firmly, nor will it ensure that two sides of the design are accurately placed, but it is better than nothing.

Cutting Lead Came

There are different kinds of commercially available lead knife that are commonly used. The traditional ‘Don Carlos’ lead knife seems to be more expensive and in my experience works no better than a more modern lead knife.

Modern lead knives have a curved blade on one end (with a pointed end on one side) and metal cap at the other end of the handle. The metal cap is intended to be used as a hammer and is useful for driving horseshoe/glazing nails into the base board. It is a boon for lazy people because it means you don’t have to repeatedly swap between a lead knife and a hammer. Take care not to cut or stab yourself with the lead knife blade when hammering the horseshoe/glazing nails – enthusiastic hammering is a bad idea with a blade not far from your face!

An inexpensive alternative to the “proper” lead knives are putty knife or a cut-down wallpaper scraper which has been sharpened on a grinding stone (of the kind you would sharpen a chisel for example). Be sure the blade is strong and does not flex.

Later I have included a picture containing an improvised and a modern lead knife.

Just as the secret of a good steak is a sharp knife, so it is true for cutting leads. A blunt lead knife is harder to use than a sharp blade so sharpen the blade regularly. I use my kitchen knife sharpener for this purpose and it seems to work well enough.

There is something of an art to the act of cutting a lead. To begin with, place your H-section lead with leaves top and bottom and the channels to the side. Then, with the lead knife correctly placed above, use a gentle side-to-side rocking motion whilst pressing downwards. The wiggly rocking motion helps to work through the considerable amount of lead in the top leaves of the came. When you’re about to get through the top leaves, reduce your downward pressure because relatively little is then needed to push down through the channel part. And finally, increase the downward pressure to push through the lower leave of the came. If you can keep your knife vertical (except for the initial “wobbling” action) throughout this process you will get a nice exact 90 degree vertical cut. A nice vertical cut ensures the lead work is equally precise on both sides.

Practise makes perfect but sometimes some trimming may be needed to get the piece of lead to fit exactly in the panel. Hold the lead came in the same way and pare away at the end of the came until the exact length and angle is achieved. If necessary, flip it over and repeat from the other side. Wipe away the little pieces of scrap because they can damage a came if you subsequently try to “work” on top of one of them.

Once cut and trimmed to size there may be some crushing damage to the ends of the leaves. In addition to using the flat end of an AllNova tool to “pull though” the end of the channel I also use the pointed end of the lead knife to deal with any residual damage to the corners of the came. Crushing damage becomes an unavoidable problem when cutting the cames at shallow joint angles.

Remember that it is easier to cut the stretched came into smaller pieces to work with than a full length but it will mean a little more waste. Shorter lengths of came are also less likely to get twisted or damaged when they accidentally knock into other things nearby.

Use of a mitred or butted joint corners are equally acceptable. The choice depends on circumstances and generally butted joints are quicker and easier. Remember that the joint will be soldered so how you form the joint will not be visible. All that remains visible is the quality of your soldering!

Assembly

Glass cutting errors are not so critical for leaded lights when compared with copper foiling.  Actually we should be aiming for just a hint of “rattle” in an assembled leaded light because it tells you there are no “pressure points” that might cause stress fractures later.

Ideally you should strive for a situation in which you rarely need to use a glass grinder to finish off pieces of glass for leaded lights. Pause for a moment to think about the glass workers of times past when electric glass grinders were not available. Getting it right first time was important because all you had was grozing tool with which to “nibble” the glass and a scythe stone. So, let the “leaves” (flanges) of the lead came be your friend as they hide a multitude of sins, such as slightly mis-shaped pieces.

Assemble from the longest side of your piece first. It is usual to start the assembly in a corner that will at the base, working piece by piece away from the corner and up the side and across. Pieces of came will need to be cut enclose each successive piece of glass that is to be added.

Although it’s a rather vacuous statement, remember to pause from time to time as you assemble the piece to review progress and plan what needs to be done next. For example, sometimes you may find that you need to build a whole “sub-assembly” and add it as a whole rather than add pieces one part at a time. Remember that you are aiming to make the pieces fit accurately over the cartoon design as well as constructing a strong panel that will look good when soldered. This is not a trivial matter so that’s why I try to plan and record my cutting and jointing intentions directly onto the cartoon in the design stage.

To a significant degree your cartoon design ought to address many of the visual appeal and strength issues but there remains the matter of how you cut and connect those pieces of lead came. For example, running single continuous lengths along the outside of each edge of the whole piece is good for the strength of the panel. But what about a circle within the design – are you going to have a single piece of lead coiled all the way around? Where will you “make the join”? Try to think before cutting and fitting the leads. Better still, do it in the design stage!

To stop the assembly from slipping and falling apart you will find it useful to strategically hammer horseshoe/glazing nails around the edge of the part-constructed panel wherever they are needed to stabilise the panel. A dozen of these horseshoe nails is adequate for a modest sized panel.

Before you start hammering those nails into your baseboard and against the leads I remind you that horseshoe nails are made from harder metal than lead and can therefore damage the leads. I therefore recommend you place a piece of scrap came between the cames of your panel and the horseshoe nails as a softer protective spacer.

DSCF3281 LeadedAt this point I think I need to relieve your boredom with a picture. So, to illustrate what I have been talking about, look at the picture of the assembled panel. Notice how the circular area containing the rosebud has been pre-assembled before insertion. Notice also the little mistake on the right-hand leaf where I’ve inserted a little fillet of lead to “fill the gap”. I’ll talk more about this “bodging” when I chatter about soldering. Notice also the use of horseshoe nails with little scraps of lead to hold the assembly firmly in place. And finally, you might want to compare how I cut the leads with how I planned to do it against the cartooned design.

The outer perimeter of the panel does not need to be cut to exactly the right size to begin with but will need trimming when you have finished. This is why I mentioned that I often leave a little “gap” between the battens earlier on in my chatter.

But you may be wondering, especially as a novice, how to remove at least some of the guesswork from cutting the pieces of lead came accurately. Am I right?

Well, it depends on the situation as to how to proceed, but one extra useful hint is that a scrap of came can be used to “represent” what has not yet been fitted. It’s easier to show you than write it down but I’ll try…

Imagine you have a single piece of glass in your hand and that it’s a quarter of a circle. You want to cut the curved piece of lead but realise that the two straight sides of the quarter circle will also have leading. So, either the curved piece of lead needs to be slightly shorter than the length of the curved edge or the straight pieces need to be slightly shorter than the straight sides. Aaargh! This is partly why I think about the cutting plan at the design stage.

Let us assume the straight sides of the quarter circle will have full-length pieces of lead came and that the curve must fit in the remaining space. We therefore want the curved piece to be slightly shorter than the length of the curve of the glass piece. But how much shorter?

To remove guess work from cutting this curved came piece accurately,  first apply your piece of came to the curve and push it into shape along the curve. You could use the flat end of an AllNova tool to help you do this without damaging the lead came. Allow this length of came to overlap the ends of the curve at each end. We know we need to cut “something” off each end so need to figure out where exactly to cut the ends in order for them to both butt-up accurately onto cames running along the adjacent straight edges.

With the overlapping curved came still in place, lay short lengths of scrap came just next to the overlapping ends of the curves on each of the adjacent straight sides. These two scraps shows you where the real straight cames will fit. So, lightly mark the curved piece of came at each end with your lead knife with lines that extend the inside edges of the two scraps.

With the curved came marked, remove it, put it on a nice clean work surface, then cut through the came at the required angles at each end. The quarter circle of glass and the curved came are now ready to be added to the panel. If necessary hold them in place with a horseshoe nail and protective lead scrap.

DSCF3329 CuttingThe picture you now see is an illustration of what I’ve just been talking about and also includes of a lead knife made from a cheap wall scraper and a “proper” modern lead knife. If you click on the picture it will display in greater detail in another window.

Incidentally, I’ve deliberately used old lead cames for this picture so that you can see what happens after several years of storage in a relatively dry environment. Notice they are looking distinctly grey.

The upper-right area of the glass piece illustrates how a scrap piece of lead can be used (across the top) to gauge and mark where to cut the long curved piece of lead (on the right). The lower-left area of the glass piece shows the next step, where the lead has been cut and you should immediately notice that the curved lead does not reach the end of the curve. Notice also that when you follow the straight piece of lead on the left, downwards along the inner edge, it leads you neatly past the end of the curved piece. This illustrates what you’re trying to achieve with each pieces of lead came in the assembly.

But what happens when you later find that you have an assembled panel ready for soldering and discover that one of the leads was 1mm or maybe 2mm too short? Such accidents do happen but don’t despair. By all means investigate to understand how the problem happened, and learn from the mistake, but don’t dismantle the panel to re-make that piece of lead came because there’s a sneaky trick you can use and it’s another use for little pieces of scrap H-section came…

Although this trick may seem to relate to soldering, I’ve put it here because really it’s more about dealing with an assembly problem caused by mis-cut leads.

To fill in a rather-too-big gap easily and invisibly, first cut a suitable short length of the H-came that will nicely fit into the gap above and below. Then, use your lead knife to chop out one side of the H so that you end up with a T and an I piece (or two stubby T pieces if you prefer). These two pieces can now fill the gaps on each side of the panel.

When you are ready for soldering, insert the T-shaped portion to bridge the gap and solder as normal. The solder flows over the insertion and your trickery then is hidden behind the solder joint.

Later, when soldering the back of the panel, use the remaining I shaped piece but be careful you don’t lose it in the meantime. No, actually it doesn’t matter if you lose it as you can easily make another!

Defects larger than 2mm can also be dealt with in the same way, provided they are shorter than the size of the soldered joint to be produced. But, if you’ve got a gap larger than about 3mm you should start to wonder how you’ve managed to cut a piece of lead so badly wrong and not notice it before!

This trick is not needed for tiny sub-millimetre joint defects because solder will happily bridge small gaps.

If you refer back to the picture-before-last, you’ll remember I filled a little gap with a fillet of lead at the end of a rose bud leaf. On this occasion the fault was only on one side of the panel so I could simply bridge the gap on one side. Again, this becomes an invisible mend because it will soon be covered with solder.

Soldering Lead Came

If you are a novice with leaded light construction you will discover that soldering a leaded light is not the same as soldering copper-foiled work. For this reason I recommend you do lots of practise joints until you can confidently and reliably solder lead cames.

What I describe works for me but to be brutally honest I ought to practise my leaded light soldering more often because is “a bit dodgy” sometimes. Ask around and watch other people soldering and they will reveal subtly different techniques. With time you will find a technique that works reliably for you.

The key to successful soldering is preparation. With copper-foiled work your “safety flux” removes oxidised copper and this helps the solder flow and bond nicely. The situation with lead cames is subtly different because a different flux is used and oxidation must be removed before the flux and solder are applied.

Some people may tell you to use a fine-grade wire wool to remove lead oxides (ie “make it shiny”) in preparation for soldering. I have tried this method and although it works I have two objections to it. One is that it produces a lot of dust from the wire wool breaking down into fine iron particles. The second is that the rubbing process produces a lot of lead dust, some of which will become airborne whilst rubbing and also when cleaning-up afterwards. Lead is nasty when it gets into your body so, for your own health, don’t make lead dust when there is an equally effective alternative method that doesn’t!

The alternative to using wire wool is to lightly roughen the area around an intended solder joint with the point of a lead knife or a horseshoe or glazing nail or, in truth, anything else that’s sharp, pointy and can be used to scrape the surface of a lead came. You only need to get the surface shiny around the exact area where you will be soldering. This is simple, it’s effective and it’s not going to harm your health.

Now that you have some lead prepared and ready to solder, there’s an extra step I suggest, if you have the patience…

Take a moment to pack a small piece of cardboard or folded paper between the glass and lead came in the area where the joint is to be soldered. This preserves the gap, protects the glass and perhaps more importantly, it eliminates solder bead drops which may ultimately cause a stress fracture in the distant future.

Next is the application of the soldering flux. For leaded lights the flux is tallow and the form commonly used looks like a candle minus a wick. The tallow should be rubbed around the surface of the area to be soldered.

The method of soldering is also different from copper-foiled work. First feed a little solder onto your soldering iron so that it holds a molten bead.

If you’ve read my chatter about choosing the right solder then you know you ought to be using a 40:60 solder rather than a 60:40 solder and should understand why. But I digress…

The aim is now to transfer the solder bead from the soldering iron to the joint without melting the lead around the joint. Much practise is needed to achieve consistently good results and the most important thing to understand is that a confident and quick technique is the key to success.

Slowly bring down the soldering iron tip (with the solder bead), but try to stop when the iron’s tip is a millimetre or so above the lead came. At this point the solder will “find” the lead and begin to spread out by itself. Oh for the joy of surface tension!

You can then deftly move the soldering iron around (still trying to hover) to help the solder flow around to where you want it do go. The aim is not to touch the underlying lead with the soldering iron because you don’t want to directly transfer heat from the soldering iron into the leads and cause them to heat up and melt more quickly. I suppose this technique could be likened to rolling a blob of sticky glue around – the objective is rolling, not squashing.

The reason you need to act quickly and deftly is that the lead cames and the solder melt at similar temperatures and it does not take long for the heat in the solder to conduct into the lead, heating it up to melting point. This also explains why we don’t want the leads being heated up more quickly by being in direct contact with the soldering iron. So, speed and accuracy is important. Starting the process with cold lead is also important.

In my experience “fiddling around” trying to “fix” a bad joint rarely achieved more than melting the underlying lead and make a crisis out of a disaster. If you really must “fix” the joint, leave it alone and do not attempt to fix the problem until the joint has become stone-cold. I repeat this warning in different words to stress this point: do not be tempted to “fiddle around” when the lead is still hot because it’s nearly ready to melt!

Let us assume you’ve dropped your blob of solder, hovered with the soldering iron and have and wiggled and rolled the solder around to the point where it has satisfactorily covered the whole area of the joint. You must immediately  pull away the soldering iron because you don’t want the leads to melt.

And finally, an opportunity to clean-up as you go. As soon as the soldering iron has been removed, count a “slow 5” to give the solder enough time to become solid but not long enough to allow the tallow flux to solidify. It is now safe to wipe the soldered joint with a paper towel or a clean rag. This will remove excess tallow and save you a lot of difficult cleaning work later.

If you forget to wipe away after your “slow 5” then don’t worry. Bring your soldering iron reasonably close to the joint for just long enough to re-melt the tallow then remove the soldering iron and wipe away. Your objective is to gently melt the tallow and not to re-melt the solder!

Remember to remove your little piece of cardboard (or paper).

Waterproofing and Strengthening

In this section please notice that I do not use the word “putty” because it is the wrong word and the wrong product to be using when we concern ourselves with the waterproofing and strengthening our freshly soldered leaded panels.

Leaded light cement smells a little like ordinary glazing putty but looks different. Leaded light cement is usually dark coloured and always has a sloppier consistency. Both smell of linseed oil but leaded light cement smells more of turpentine (or substitutes). Another difference is that putty stays soft for many months, if not years, whereas the cement dries and sets within days. So, dear reader, there really is a difference between putty and leaded light cement.

If you’re not doing much leaded light work then remember that the leaded light cement will slowly “settle out” in the tin over the course of a year or two into a hard lump of solids underneath an oily top layer. Despite this, I have found that even after a few years of settling it can be “revived” and made usable again, but it is time-consuming process poking, mixing and squidging the solid and liquid portions back into something usable. This may be useful to remember if you’re short of funds but have plenty of spare time.

It is also a hint that you should not buy more than you need. Or, as an alternative, perhaps we should make our own, storing the dry and wet portions separately, then mixing only what’s needed when it’s needed. Oh dear. The formulation of leaded light cement. It’s another area I’ve yet to chatter about.

For the moment, I just warn you not to blindly follow the recipes that some people are publishing on the Internet. As you might expect, some are sensible but some of them are well-intentioned but reveal themselves to be ill-conceived on closer inspection. If some lengthy chatter about formulations for leaded light cement is important to you, please prompt me to do this sooner rather than later.

Right, back to topic of waterproofing and strengthening…

The general plan of attack in this stage of construction is to force the leaded light cement into gaps between the lead cames and the glass pieces. With the gaps filled we achieve a single solid structure. Over the course of a few days the leaded light cement hardens and therefore stabilises the panel and increases its strength. Once hardened the cement also forms a waterproof barrier.

The best warning I can give you is to not get too enthusiastic, trying to force too much into the gaps, because it’s only going to start oozing out of the other side of the panel. All you’re aiming to start with is to fill the gaps on the “upper” side of the panel. Once the whole process of waterproofing and strengthening is complete on one side, you can then flip the panel over and repeat on the “other” side. The elapsed time is days, not hours!

DSCF3286 WaterproofingHere is a picture to illustrate what I’m now talking about.

Waterproofing is a messy process so use plenty of newspaper under your work. Cheap throwaway toothbrushes and nail brushes are recommended for forcing the cement into the gaps. It is better to use throwaway items than buying and cleaning expensive brushes because the hardened cement renders the brushes useless. Can you see how messy the little nail brush is in the picture?

Another tip is that you can also use a piece of glass to ‘push’ the compound into gaps but I don’t tend to do this.

I should also mention that leaded light cement is fantastic at finding its way into the smallest cracks, crazes, and deep recesses of textured glass surfaces. Never forget that the cement can destroy the visual appeal of the most gorgeous piece of “unsmooth” glass with a patchwork of mucky marks that are impossible to remove. Protect the surface of any glass that has such surface imperfections by whatever means are available to you so that the leaded light cement can not find its way into these defects in the glass. An adhesive plastic film should work nicely, maybe even self-adhesive labels.

If you’re careful and don’t randomly slosh the cement everywhere then it’s going to be easier to “clean up” later. To this end, try to keep the cement close to the filled-gaps and do your best to not get the cement on the tops of the lead cames. Look at the picture to see how I try not to make too much of a mess but wasn’t entirely successful.

When you have cemented one side of the leaded panel it’s time to add whiting (see below).

Be aware that the volatile ‘drying agents’ in the cement are smelly so ventilation is suggested. It’s not that these vapours are toxic, it’s that their smell can be quite intense and last for days.

Once the whiting has been added, leave the panel overnight, clean-up that side of the panel then attend to the other side of the panel.

Whiting

Whiting is nothing more exciting than chalk powder and it needs to be sprinkled over areas where leaded light cement has been applied. An alternative to whiting is to use fine sawdust or fine wood shavings. Whatever you use, just remember that the aim is to “draw out” the oily part of leaded light cement.

Plaster of Paris and patching plaster have also been suggested as an alternative to whiting but I’d be wary of them because any hint of dampness may cause them to solidify on the surface of your glass, making the cleanup process harder. Let me know if you’ve tried these alternatives as I haven’t.

DSCF3288 WhitingHere’s a picture of a panel that has just had whiting added. It still looks nice and white but in a few hours it will start to look rather mucky. Notice that I’ve tried to put more whiting where there’s more leaded light cement and less where there’s (hopefully) only glass. Notice also that there’s whiting on top of the leads because there’s cementing “mess” to be dealt with on top of the lead work.

So, don’t be mean-minded with the whiting. Use as much as is needed. As a minimum at least try to get most of the whiting where there’s cement. In addition to drawing out the oily part of the cement, whiting also helps to clump together particles of excess cement and as such is really helpful in the “cleaning up” activities.

After a few hours the whiting starts to clump and look mucky. Now you may clear excess whiting off the glass surface carefully with a soft brush or a cloth but stay away from the leaded areas as they have not hardened sufficiently. Try and leave decent border (at least 2mm) around the leaded areas completely untouched. Carefully removing cementing compound from the tops of the lead cames is another task that can be started. Adding more whiting or shuffling “unused” whiting to where it’s still needed can also be done. So, at this stage our aim is to remove the worst of the mess without compromising the quality of the waterproofing or strengthening.

On the next day, no sooner, remove the 2mm borders carefully with a wooden stick, matchsticks, an All Nova tool or similar. This is where I mostly use used matchsticks. If you used enough whiting then the cement will have set sufficiently and this becomes quite an easy job. The clean-up process is all done when all the gaps between glass and lead are filled with cement and there are no stray lumps of cement on the lead cames or on the glass. Try not to under-cut the cames when cleaning away the excess cement because all it achieves is little water collection areas which are ideal micro-habitats that encourage algal growth especially in damper climates.

Once cleaned up, it will still take a few days for the remaining “drying agents” to evaporate out of the cement. As time passes the stink slowly subsides.

Finishing

Some people suggest that soldered joints should be darkened to match the lead work. Zebrite is a commercial product that can be used to blacken the lead and solder and is normally used to blacken stoves. Zebo is an equivalent product that is no longer made.

My experience is that these products don’t really work very well, except on stoves. They hardly take to solder and aren’t much better with fresh lead. So an alternative suggestion is to patinate (ie use patina) these areas first.

Better still, in my view, is to not bother with this step. Allow the lead and solder to do their darkening naturally.

Miscellany

Here are a few miscellaneous things that I couldn’t sensibly put anywhere else:

An alternative to using a grinding stone or grinder to remove a burr from glass is to run a piece of scrap glass down the edge of the cut edge. Quick and good enough for leaded light work. Another handy trick from the days before electric grinders.

Smooth side outside and textured inside is the old general rule for glazing leaded lights. This is simply because single-glazed windows get dirtier outside than inside. However, this becomes questionable when the panel is part of a double-glazed window pane or embedded into a triple-glazed window pane. For indoor decorative pieces it’s a matter of design because you might deliberately want people to touch and experience the different surface textures.

Installation

I do not tend to get involved with the installation of leaded lights so only have a couple of thoughts to pass on.

Using glazing putty to mount a leaded light panel into a window frame has been a standard practise for many years. It works and there are no nasty side-effects. Our ancestors knew what they were doing.

By contrast modern squirty plastic “caulk” type fixatives should be treated with caution as I have learned from personal experience. By “caulk” I am thinking of the kinds of product that you would use to seal the gaps around door frames or around a bath or sink. Take care with these products and check the labelling to see what happens when they “cure”. If the product produces a vinegar smell as it “cures” a consequence is that it will be prone to provoke a white powdery surface patina of lead acetate on nearby cames. Lead acetate is a far greater risk to your health than the lead of the cames.

Sometimes a leaded light panel is added as an indoor secondary panel against an existing window. I have seen double-sided sticky black butyl tape being used to attach the perimeter of a leaded panel to the perimeter of the pre-existing glazing. A typical location might be the window pane adjacent to a door.

Health & Safety

Last but not least is the dreaded Health and Safety section. It’s a must because we’re working with lead.

Working with lead cames to produce leaded lights raises a number of heath and safety issues and some of them I’ve already alluded to. I will now elaborate.

A guiding principle in health and safety is that the elimination of a hazard is always preferred to doing something that reduces the effects of a hazard which in turn is preferred to the use of protective equipment to “hide” from the hazard.

Lead cames and particles of lead are not, in themselves, toxic. It is the compounds of lead that are what we should be most worried about. It is biological and chemical actions that turn lead into compounds of lead that you need to be most wary of.

Already mentioned is lead acetate from “caulk” that may arise when mounting and installing a panel. Lead acetate is a compound of lead. It is a white powderly “bloom” and easily inhaled or injested if you don’t take care.

Another source of lead compounds is through the action of sweat on our fingers reacting with lead when we handle lead came or solder. So, although touching lead is not very much of a hazard to your health, the ingestion of lead compounds produced by the sweat on our fingers is bad news. The transfer route that leads to ingestion tends to be lead came to fingers to mouth. So, before you try eating, drinking and smoking, stop working with the lead and wash your hands first.

Ingestion of particulate lead and lead compounds can be caused by airborne particles and I’ve already explained why I do not use wire wool on lead cames. So, rather than waste time and money using cheap ineffective face masks, eliminate the creation of particular lead by not using wire wood to clean up lead cames.

Although not directly lead-related, remember horseshoe nails and modern lead cutters that double-up as a hammer. Here you need to be careful not to cause puncture wounds and cuts. Puncture wounds and cuts must be covered with sticking plasters when working with lead or other toxic chemicals. Cuts and wounds are a fast and efficient entry point into your body.

If you’re a bit paranoid, you might consider using some rubber or nitrile gloves to minimise your contact with lead. But don’t let these gloves lull yourself into a false sense of security – remember to wash your hands after you take them off.

Lead poisoning is one of the oldest occupational hazards due to lead mining over many centuries so a word about exposure limits is perhaps needed. The first point to make is that different nations have different legislation so I can only generalise.

Lead exposure limits are unlikely to be exceeded if you’re an occasional hobbyist. The trouble is that workers only occasional exposed to lead, and hobbyists, are not really in a position to measure lead exposure without outside help. If you are in the least worried, try talking to your medical doctor, or your employer’s occupational health service (if you have one).

The group at risk is full-time workers who spend a lot of their time working with lead and traditional lead-based solders.  If you are an employee in a company where working with lead is a significant part of your job then your employer ought to be monitoring your lead exposure routinely through periodic medical assessments. I say “ought” rather than “will” or “should” because theory and reality are rarely the same.

The world is full of experts in Health and Safety and unfortunately a lot of health and safety is about subjective opinion rather than reasoned facts. Unfortunately this leads to experts that are, to varying degrees, ill-informed, paranoid, obsessive, irrational, deliberately biased or downright dim-witted. Somewhere amongst the cacophony of mixed messages is a reasonable and rational basis on which to live our lives!

If you think I should do a blog on Health and Safety that identifies some of the hazards and risks of our activities and translates them into advice that is hopefully more balanced, rational and helpfully practical then please tell me that it’s something you want sooner rather than later.

A Topical Postscript

And finally, on the subject of Health and Safety, you may already be aware of what’s happing in Oregon in the USA.

I note with concern that “the authorities” in Oregon are behaving irrationally and badly towards glass producers Bullseye and Uroboros. You will find more information in the news releases section at the Bullseye web site. It makes interesting reading because it relates to to toxic metal emissions from furnaces.

The recent announcement by Spectrum that they are shutting down makes this even more worrisome for our chosen career or hobby.

This health and safety madness in Oregon reminds me of a quote attributed to Voltaire:

It is dangerous to be right when those in power are wrong.

Or perhaps this one from the painter John Constable:

We see nothing until we understand it.

Bye for now, dear reader. Thank you for visiting my blog.

 

 

 

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About chatterglass

Maker of stained glass frippery.
This entry was posted in Cartoon design, Flux, Glass Cutter, Lead cutter, leaded light, Leaded light cement, Putty, Solder, Soldering, tallow, Whiting and tagged , , , , , , , , , , , , , , , . Bookmark the permalink.

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