Monday, May 12, 2014

The Putty Party

A few years ago I learned a great shortcut. But first, dramatic tension!

I've wanted to try and make thumb wax for a long time. There is a recipe in Elskus and another in Isenberg ("How to Work in Stained Glass", third edition, my modern glass bible). Thumb wax is used to hold glass pieces onto a glass easel or lightbox for test viewing or while painting.

Elskus' recipe is simple: a quarter pound of beeswax and a teaspoon of venice turpentine. The one given in Isenberg is considerably more complicated, calling for a significant amount of beesewax, a pound of cornstrach, "sweet oil" (olive oil), venice turpentine, and resin. The recipe given, below, must make enough for Tiffany's studio at it's most productive. I cut everything into a 1/6 proportion and still ended up with a lot of thumb wax.

Thumb wax (from Anita/Seymour Isenberg's How to Work in Stained Glass, 3rd edition, P. 188)
1 pound beeswax
1 pound cornstarch
4 ounces resin
7 ounces venice turpentine
1-3/4 ounce sweet oil (olive oil).

Melt the beeswax in double boiler, add the cornstarch one spoonful at a time. Then add resin, venice turps, and oil. Mix thoroughly.

Note that the above is the original recipe, not my reduced portions!

I asked my chef mother about setting up a double boiler. She suggested a good plastic bowl. Being a professional she has high grade bowls. I settled for gladware....

Hey, it doesn't melt...

I made Elskus' recipe first, beeswax and rosin. It's nice and simple to be sure.

The molten thumb wax, in it's cooling bowl

It took a small laboratories worth of scales and calculators to get some of those numbers converted and reduced. Here are the ingredients I used for the Isenbergs' recipe:

The mix being cooked

The two waxes finished, Isenberg on the left (the cornstarch makes it much lighter)

The waxes smell amazing. Beeswax gives off a honey scent when warmed. Venice turpentine is drawn from pine trees, and that is another favorite smell of mine. I also used pine resin. 

If you've never worked with venice turps, it's very messy. It gets on your hands and it wears off within an hour or two. Washing it off was impossible, though I probably don't have the right solvents.

The waxes, after being poured, are very solid. You rip out a chunk and start kneading it with your fingers and it becomes pliable. Unfortunately it leaves a definite coating of turps on your fingers as you use it. Elskus' recipe is much harder and takes more to make it pliable. Once it is warmed up, both seem to react similarly. I immediately had a suspicion that the wax would leave behind residue on the glass, if it's leaving it behind on my fingers. This is probably fine for glass you are going to fire (the wax will run or burn off) and should be fine for leaded glass, but I think this will be completely unacceptable for copper foil:

 Click the pictures to enlarge them. You will see on each piece or pieces a distinct residue of thumb wax.

This leads to my personal favorite thumb wax, something that seemed obvious to me when, in a pinch, I needed something to hold glass to my lightbox.


Ever since I was little I've loved Silly Putty. My parents have made it a point to give me an egg or two of it every Christmas as a gag gift.

I grabbed a handy egg one January when I needed to hold glass to my lightbox while I aggressively blended some matt paint. It worked wonderfully. No residue, easy to clean up, it's sat on top of one bottle or another in my studio for years.

I needed to trace a few bevels to make an accurate pattern of the gaps between. I turned to my silly putty to hold everything together.

There are two other alternatives that need to be discussed: Non-thumb wax (usually beeswax, kept in a crockpot-type thing and applied with an eyedropper). I didn't test it because I don't have room on my benches for a small potpourri pot to keep the wax hot and don't want to deal with clean up. I suspect it would be much more easily cleaned up but I question whether the wax would leave the glass clean. Beeswax is used to... well, wax a lot of things and it applies itself avidly.

I once tried plain candle wax. I don't recommend it. While melting a candle has a lot of benefits for ambiance and seems like it would be a good source, I found it very difficult to clean up; after scraping a lot of it off I had to soak the bevels in hot water and wipe them clean with a rag.

So, for my time and money, silly putty is where it's at. It's not going to hold pieces to a vertical easel, if that's how you choose to paint, but if you work on a lightbox like I do it's a great choice.

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