Ah, summertime. On these sweltering days there's nothing quite like hanging out at the lake with a nice cold beer in your hand. On the other hand, there's nothing quite like standing over the ribbon burner with a hot stick of glass in your hand either. But rather than just shutting down for the summer and heading for the mountains, let's look at some ways to cut down on the amount of time you have to spend standing in front of the ribbon burner.
One option is to use some type of form to bend the glass around. We've all heard of people using relatively complex versions with compressed air to blow the bends out that are making complete "E" s in a single heat, but the time it takes to get everything right doesn't make their stuff very useful to the average neon shop. However, a simple form to cut down on the number of heats or simply reduce the level of concentration can make a job a lot easier. And in many cases the form can be whipped out in just a few minutes.
For the sake of this article lets define a couple of terms;
jigs: surface mounted patterns with little or no "outside" to bends, simply a mold to draw the glass around;
forms: patterns that appear to have been routed, having complete " inside" and "outside" for each bend and for each straight section that joins the bends.
Although there are many similarities in construction and use between jigs and forms, in this article we are going to concentrate on jigs which are more suited to the average neon shop.
Most tube benders have tried wrapping some kind of pattern cloth - Transbestos kind of stuff - over wood to make a simple jig and have been less than thrilled with the results: the cloth falls off, the wood burns, the size of the jig was difficult to get right, and so forth. What is needed is a solid material that won't burn, has a very low thermal conductivity so that it won't lead to stress in the glass, is easy to cut and shape with tools around the shop, lasts a reasonable length of time, and is affordable.
I've tried materials from high temperature plastics (which wouldn't quite take the heat) to glass fiber reinforced concrete (too high thermal conductivity and very hard to shape) and the best results come from a couple of materials that are pretty similar. It is important to point out here the fact that there is a direct relationship between density and thermal conductivity; the stronger and long lasting the jig is, the more stress it is going to impart in your glass due to the amount of heat the mold sucks out of the glass.
One option is available through stained glass supply outlets and is referred to as work surface. It is available in small quanities at reasonable prices (2' x 3' for about $30.00 in 3/8 inch), but it's right at the upper end of densities in my humble opinion. The material I feel most comfortable working with comes from BNZ Materials Inc. (303-978-1199 can get you in touch with your regional distributor) and is available in three hardneses:
All of these materials (including work surface) can benefit a little from a coat of graphite (Wale Apparatus, 215-838-7047) after the jig or form is finished to make the glass slide a little better.
So now that we have the material, how do we go about shaping the jig? This is the easiest method that I know of:
1) make a photo copy off the paper pattern of the letter to be used
2) using some aerosol adhesive (like photo spray mount), stick the copied letter to the Maronite (or whatever material you're using)
3) cut the Maronite slightly larger than the copied pattern. A band saw or scroll saw works well; if you don't have either, it's pretty easy to fake it with a coping or hack saw. Use a wood rasp or sandpaper to smooth out the rough spots.
4) if the jig is large and simple enough, a weight can be used to hold the rough jig in place for a quick test run; if this won't work use a hot glue gun. Remember the piece you just cut goes upside down just like any neon pattern.
5) check the test piece against the original paper pattern. Adjust the mold as needed with a wood rasp - it's easier to methodically work the jig down to shape than add material back or start over.
The completed jig can now be used by weighting it down if it is large and simple, or fixing it to a backboard of the same material. A hot glue gun will usually hold for few heats, but for long term use either screw the pieces together or use silicone adhesive (I prefer the silicone as it gives you the option of taking the jig apart and reusing the unmarred pieces when the jig is no longer needed).
Here are a couple of examples:
Note: Apologies no photos available yet,
The universal 10 inch OPEN. Here we show a simple jig for the "P" that both reduces heats and concentration. We also use jigs for the "O" and part of the "E". Note the marks for the double back and right angle bends. This jig has been used for around 400 pieces.
The "e" in "the extra mile". This letter is only 3.5 inches tall and is made out of 12 mm glass. It makes a big difference in the final appearance of the sign that all three "e"s look exactly the same. Using a jig ensures that they are. Here is the original, the photo copy of the letter we're going to make, and the completed jig.
The heat. Note the marks for the next bends. (photo 4)
The completed letter
Simple, right? With these jig making basics you should be able to be saving time in no time.