Science and art aren’t in opposition, so in this posting I will tell you about what I know as the borax bead test from my days studying science and from what little I know about ceramics. The twist is that I apply it to stained glass crafts.
Borax is a household cleaning product that has been used for many years, although it is becoming increasingly difficult to buy it over the counter because the EU have recently classified it as a product that can do harm to the unborn child. I don’t have ovaries so it is unlikely to be a problem for me. Given that borax has been used as a household cleaning product for many years without concern until now I am rather baffled to understand why, if it is harmful, that nobody has noticed until now. But I digress.
I have read that borax has also been used for many years as a glaze in ceramics. I know nothing more about borax in this context.
The borax bead test was certainly well-developed in the field of chemistry in the past but I was not taught it at school. Only by accident did I encounter it whilst hunting around on the Internet. I have not found much use for this test in chemistry but it’s fun and entertaining to try it and, more to the point, I think it is a really useful technique for use in stained glass crafts to produce small glassy blobs on the ends of wires – such as you might otherwise do with a blob of solder on the end of a wire to make something that resembles the antennae on insects or stamens on flowers.
You, like me, may be more familiar with the flame test in chemistry, where you dissolve a small sample of a chemical in water and then burn it over a flame to see what colour is produced. Similar chemistry relates to the colours produced in fireworks and also with the borax bead test. We’re talking colour chemistry.
How do you do the borax bead test in a form that is useful for the stained glass artist? Let’s find out…
You will see from the first picture that I have laid out all the things you will need. There is a small spirit burner (any flame will do), some matches to light the flame, a ceramic bowl containing borax, a few lengths of wire with a loop at the end, a wooden peg and some copper sulphate solution in a little plastic container.
The wire loops are mostly nichrome wire, but the one on the wooden peg is plated copper wire. I deliberately use two kinds of wire to show that the type of wire is not important in terms of producing borax beads. For use with Tiffany style copper foiling projects you will find the plated copper wire easier to solder. I’ve not tried putting a borax bead into a kiln but will be interested to hear what happens – in theory it should work because ceramic workers use borax as a glaze.
The copper sulphate solution is what you might better know as the blue solution you use on lead and solder to produce a copper-coloured patination. You can also use copper sulphate crystals instead. The original purpose of the borax bead test is to find out what a particular chemical contains so by implication it’s not just copper sulphate you can do this borax bead test with. I find it easier (and safer) to use dry powders than solutions.
So, onto the test itself… how to make your beads…
Light your burner and, hold the looped-end of a wire in the flame until it is red hot. Using a peg will stop you from burning your fingers.
When the loop is red hot dip it into the borax powder and then return the loaded loop back into the flame. You will observe a fascinating bubbling as the water of hydration is boiled out of the borax. When the bubbling and writhing cease you are left with a glassy blob within the loop of the wire. If the blob is too small warm up the loop and load more borax and heat it in the flame again. This is the part of the process I enjoy the most and you’ll know why when you try it for yourself.
At this point you will have created a glassy but somewhat opaque blob at the end of the wire. This is perhaps all you need for your stained glass creation, but if you want it coloured the original purpose of the borax bead text becomes of important interest. From the perspective of a ceramics worker you’ve just glazed the end of a piece of wire. From the perspective of a glass producer it’s little different than getting ready to dose a pot melt with metal oxides to produce the colourful glass we know and love to use!
To colour the borax bead to a particular colour requires a reasonable knowledge of the borax bead test (search the internet!) or other allied areas such as ceramics and glass production, and maybe the chemistry of fireworks, but careful experimentation is also allowed because you’re only dealing with tiny quantities of chemicals. But as it’s likely you’ll already have some copper sulphate in the form of copper patina solution, that’s what I’ll illustrate next.
To colour the borax bead you need to heat the borax bead in the flame again and then dab it onto your powdered chemical sample if it is in a dry form. A little of the chemical then attaches to the bead. Re-heating the “contaminated” bead in the flame one more time will cause the bead to change to a characteristic colour that depends on the chemical contamination as it disperses into the bead.
But maybe you only have copper sulphate in a liquid solution form – in which case don’t heat the bead too much before you dip it into the solution or you’ll make a mess or cause the bead to shatter when the hot bead meets cold liquid! Just a gentle warming and then dip into the solution. You may need to repeat this to get a colour change.
You don’t need a lot of the “contamination” to produce coloured beads and, in fact, you’ll see that the two coloured beads I produce have deliberately been over-done.
You will need to do some experimenting to get the bead sizes right, to get the colouring right and indeed to figure out which chemicals are useful. This is where the fun lies – especially the part when you’re heating the borax over the flame and watching it bubble and writhe around the loop.
To finish off my posting I’ve attached a photo of the completed borax bead wires. Not a great picture but it gives you some idea of what you’ll be producing.
The plated copper wire loop is to the left. The two in the middle are “unadulterated” on nichrome wire. The two on the right are also nichrome wire but have been coloured by the copper sulphate so many times that they are a completely different colour.
Have fun. Try the borax bead test!