An overview of the Unimold pattern method

The Unimold lamp system has many innovative tools - such as slumping molds where the bent glass fits on the construction molds - and lamp levelers for level soldering. These tools and methods speed up the lamp building process. And the corresponding slumping molds introduce a variety of new possibilities by easily incorporating slumped and fused glass into lamp building.

These advanced ideas have the potential to give stained glass lamp building a wealth of possibilities. However there are two - very simple and very important - innovations that give advantages to the Unimold method without purchasing anything but the mold itself.

The first advantage is obvious from the pictures of the molds. They are translucent with a grid line imbedded into the form itself.

It is easier to manufacture an opaque fiberglass mold because the gelcoated finish will hide small bubbles on the surface of the mold that are unavoidable in manufacturing. Gelcoat gives the mold a more uniform higher quality look.

Having manufactured fiberglass a long time - at first I struggled with this manufacturing compromise. But the reality is that once a light is placed inside the mold - deciding how to place the glass by using the streaks and swirls of stained glass is so much better - that as an artist I had to go with the translucent mold.

The second innovation is the way the glass is held onto the fiberglass mold. Those that have used the Warden or Odyssey systems know about pins and double stick tape and tacky wax.

Without going into any detail about these methods I will say I do make a polyester mold that will not melt from solder and is the same size as the fiberglass molds. This allows someone who desires a mold that pins can be stuck into - will still be able to use the Unimold shapes by ordering this type of mold.

The method of how the glass is held on the fiberglass mold is consciously designed for teachers and students. Those of us that have taken or taught a stained glass class know how difficult it is for the student to transport a simple flat panel home - so they can work on it during the week - let alone a complex many piece lamp. This is where the Unimold method of holding the glass to the mold is a real advantage.

A complete pattern set consists of the drawing on the mold - a Mylar pattern that is the shape that each piece of glass is cut from - and a flat pattern that the glass can be laid out on so the glass pieces can be kept track of. Ideally all these patterns will have a number that identifies the location of the glass.

The simple but powerful innovation of the Unimold method is that a “glob” or “leg” of putty is put on the backside of the glass and the glass piece is stuck to its proper location right on the mold. This holds the glass in place so well that the mold can be picked up, moved, and even held upside down. This makes it easy to put the mold - with the project on it - in the car seat and barring throwing something on the mold or a traffic accident on the way home - the pieces will be right where they are supposed to be when you get there. Yet the glass can be easily removed and replaced as often as required during construction of the lamp.

Suppose a student cuts the glass out and grinds the pieces at class or perhaps during the extra time the studio usually gives with the class. This is good because of the extra help available with experienced people around. The student cuts and grinds their glass and lays it out on the flat reference pattern. At this point – because of the hassle of transporting the project - they may simply leave the project in their assigned cubby hole.

But suppose when it is time to go they feel comfortable enough to foil at home - but even if they used a marker to number their glass it is still takes time to scoop up the pieces and then to lay out the pieces on the flat pattern again. Not too bad if you have a couple of dozen pieces but Tiffany style lamps can have hundreds of pieces.

With the Unimold method the cut and ground glass is pasted in the proper position on the mold with putty - making the project easily transported. Once at home the student removes one piece of glass at a time - foils it - and replaces it so its location is not lost. This same procedure is used if the glass is only cut but not ground - but as I'm sure you're aware the rough edges of the glass will not allow the glass to set exactly where the lines are on the mold. However at this point that is OK because the desire is to transport the glass and mold without having to read each number and lay out everything again. It is relatively simple to remove and re-place the glass as many times as desired.

There are two major reasons for this “glob” or “leg” method of putting the glass on the mold. One is as discussed - to keep the glass organized for transportation - and the other is to hold the glass in place with putty “legs” while the lamp is tack soldered or tinned together. It is best to use different materials for these different steps.

One of the most versatile, inexpensive, and readily available materials for “gobs” or “legs” is a material called plumbers putty. This substance is used when the plumber installs the drain in a sink. Nearly any hardware store or building supply will have a plastic container of it for less then two dollars. If you keep the lid closed and if you take the putty off the glass and put it back in the container - this amount will last you literally for years.

Use this putty for holding the glass to the mold for transpiration and to keep the glass organized. The one big drawback to this type of putty is that it can contaminate the soldering process. I usually use a giant “glob” of the stuff when I paste glass to the mold when the glass isn't foiled.

But after the glass is foiled I use a small thin “leg” of putty making sure the putty doesn't squish under the foil. If a little does get under the foil it isn't fatal – it's just during soldering the putty will sometimes bubble out and stay in a little crater it makes. The putty can be wire brushed out - but this takes time and it's much better if this doesn't happen.

So when I'm ready to solder I make putty out of a mixture of paraffin, bees wax, and gum arabic. This wax melts and if it gets into the solder it will not harm the soldering process.

(For your information Odyssey's tacky wax - although sometimes a little too tacky - will work just fine. Just be sure you don't put it on the mold the way they say but roll a piece between your fingers into a small cylinder about 1/16 inch in diameter. Then pinch off a1/4 to 3/8 inch “leg” and use one, two, or even three “legs” depending on the glass size).

An important part of Unimold patterns is that they are actually made to a larger radius then the mold itself. This allows for the extra distance the putty adds between the glass and the mold.

There is another advantage to having the pattern at a slightly larger radius and putting putty under the glass raising it up to the pattern radius. Often different types of glass have different thickness - especially if you are a ripple lover like me. By using a longer length of “legs” under the thin glass and shorter “legs” when the glass is thick - it is possible to give the outside surface of the lamp an extraordinarily even and smooth surface.

Eventually I would love to have dozens of complete pre-made patterns as the other mold manufactures have. But on the other hand my mold system - with the slumping and fusing molds - naturally lends itself to creative one-of-a-kind lamps that are not made again - let alone repeatable patterns.

However many people would like a pattern and if I do supply a complete pre-made pattern I want it fit perfectly. This would require building at least one lamp and perhaps two - to make sure everything is perfect. This is plainly too large of an undertaking - and I am unable to do this alone - so for now I have computer drawn pattern templates that will help the lamp maker get started.

These template patterns are made so the main bulk of the pattern is given but the pieces that have to be altered to fit the curve of the lamp are not all exact. And the reality is that the Unimold method of using putty under glass has so many advantages that simplify pattern making that filling in missing pieces is pretty easy. (I'll go into template patterns in a separate section).

Let's see - now that I've given all this detail - I wonder if I can repeat it in somewhat orderly steps.

First the original pattern is drawn on the mold. If you have one of my template patterns place the pattern on the inside of the mold and trace the lines of the pattern on the mold surface. Sanding the surface of the mold with 80 grit sand paper will give the fiberglass “tooth” so a pencil will leave a nice line. If you don't sand the mold a Sharpie type pen will work but the lines will tend to rub off so I strongly recommend that you take the time and at least scuff up the mold some. It is also good if a matching number is also put on the mold - although this isn't mandatory - it may save time later.

Cut some of the different colors of the glass and using plumbers putty paste the glass on the translucent mold. You will notice the glass colors are changed and darkened somewhat by the light traveling through the fiberglass first. Always pick the colors by putting them on a light table or looking at them with a light bulb behind them. (Use a light bulb because even daylight will make the colors look different then an incandescent bulb). However the variations in the streaks and swirls of the stained glass and the various densities of color will show up nicely – it's just the lamp will look even more colorful once off the mold. (Unimold does make a mold - called a viewing mold - with holes in the mold for accurate color representation while the lamp is being constructed on the mold - but that is rarely needed).

All the glass can be cut and put on the mold at once - even if the pattern is a repeating one. However I would rather make panels - if the lamp is a repeating pattern. There is a Unimold tool to line up the panel edges but the imbedded grid line makes it possible to get the edge of the panel straight.

Now at this point all glass of one panel - or all the pieces - if the whole lamp method is used - are cut, ground, foiled and ready to solder.

If the foiled glass is laying on the flat reference pattern find a critical design element - such as a line that should be straight or the edge of a panel - then roll out a small cylinder of wax putty, pinch off a 1/4 inch or so “leg” put it on the back of the glass and stick the glass in its position. Don't push it down too hard because it is easier to push the glass farther down then raise it up. (To raise the glass it is usually necessary to remove the glass and roll out the “leg” of putty and place the glass again).

If after foiling the glass - you have put the glass back on the mold with the wax putty - take each piece of glass off and roll out the wax legs and place the glass back in position - without pushing it down to far.

As you get more of the glass pieces in place you can start pushing the glass down closer to its proper depth. You will notice that the glass can be slid around and pushed together to make the lines look as good as possable.

For example if the glass is cut is too small the distance between the glass on one side of the small piece and the glass on the other side can be split and this will at least help keep the lines the same size - even if the lines would be better thinner. In addition if some pieces are too large - and some to small - the glass is pushed around until the gaps fill as best as possable and lines look the best.

Remember that background grids need to be straight and even as possible. So place those pieces first and squish the other pieces around. If necessary - push everything nice and tight - then find one or two pieces of glass that don't fit and re-cut those pieces.

Take a piece of the scrap Mylar - place it over the hole left by the removed piece - take a pencil and trace the hole shape and size. Cut the piece of Mylar out - put a “leg” of putty on it - and put it in place as you would the glass. This will tell you if you need to alter the Mylar shape.

Remember the foil will take up some space and the Mylar should be pushed down to the bottom of the glass pieces. (When I grind for a lamp I always bevel the grinding a little so the edge of the glass angled and the bottom of the glass is slightly smaller then the top - this lets the glass slide closer together and makes the solder lines thinner).

If the glass piece is too large - take the Mylar pattern and cut it to fit - you'll have to cut another piece of glass if it is too small. Look over the panel (or complete lamp) making sure all lines are straight and as even as possible. Glass pieces can be moved slightly by using a knife or razor blade in-between the foiled pieces - carefully prying the lines into shape. Also - being careful not to push too hard - you can push the glass down a little so the different thickness of glass are as even as possible.

You will also notice that as you push the glass closer to the mold the radius is smaller and this will move the glass pieces closer together - minimizing line thickness. Just be careful not to push all the glass pieces down to the mold surface. Perhaps a large or long piece of glass will actually touch the mold at its middle - but the edges should still be above the mold at the height of the other glass pieces with “legs”.

Although this may sound complicated - it actually is quit easy to arrange any reasonably cut glass pieces so the lamp looks good.

Once the glass is as even as possible - and if it's a panel the edges are straight - tack solder or tin the glass together. Then carefully push sideways on the edge of the panel to break the wax free from the mold. Don't try to pull the panel straight off or up. If the whole lamp is made pull up - gently - up on the border to remove the tinned glass.

Odyssey's tacky wax is made to hold the glass without “legs” and is very sticky so if you have used it then push very slowly and carefully because the wax sticks very well. If you seem to be pushing too hard or have made the whole lamp on the mold you may have to heat the lamp and mold according to their instructions.

Now remove the wax “legs” by scraping them off with you fingernail. Roll them all up in a ball and put the ball in a plastic bag if you want. If your lamp is whole you can now use the Unimold lamp leveler or solder the inside as you normally do. (Cardboard box - wadded up newspaper - some of you know the drill)!

I scrape as much of the wax as I can off the glass before soldering but as you solder the remaining wax will melt and pertty much boil away. If you end up with what you feel is too much wax on the inside of the lamp there are wax removers but I've never found wax a problem after I've cleaned the lamp with soap to make sure I've removed all the flux.

After the inside is soldered, then bead up the solder on the outside, clean, and patina. Presto you're done!

If you have made the lamp in panels (like I usually do) then remove the one panel you have made and lay it aside without soldering the inside. There is a Unimold device for panel holding or it can be put in the lamp leveler. Or - I like I used to do with Warden - place the panel on wadded up newspapers to help keep its shape. I don't solder the back of the panel now so it will still be flexible.

Make all the panels and be sure to have removed all the wax “legs”. Then put a small number of “legs” maybe seven or eight on the back of the panel and re-place it on the mold. Do this to all the panels - line up the edges of the panels carefully by pushing and squishing things around - and put any bridge pieces in. Tin everything together and proceed as described above. And once again – presto you're done!

I hope this has explained this part of the Unimolds concept of lamp construction. Above are the drawings and condensed information. I would be more then glad to answer any questions or fill in any blank spots I may have skipped over. I can be reached at dlp@unimolds.com or survey@unimolds.com .