One of my most and least favourite materials to work in is polystyrene. its very versatile and incredibly light but it also creates a nightmarish amount of dust and needs a papier mache coat to avoid breaking down.
The best way I've found to work with polystyrene is to cut it roughly to shape (laminating pieces together if needs be -- I've done quite a lot of laminating for this show!) and then refine it with electric tools such as a belt sander or dremel before hand sanding to achieve a smooth, natural finish. For more unnatural puppets, such as robots, this final sand is less necessary.
The best glue to use with polystyrene is Gorilla Glue. Much like a Gremlin, the key is to make sure you don't get it wet (until you want to use it). They do a range but the one you want is the water-curing variety -- most other glues will melt right through the polystyrene! Never dip an applicator in the pot as any liquid might set off the curing process and ruin the whole pot.
The brilliant Catherine Thomas introduced me to Gorilla Glue, as well as the best technique for using it. Always, always wear gloves -- as well as being a bit of an irritant, Gorilla Glue stays around for ages -- I got a tiny bit on one of my fingers yesterday and there are still traces of it a day (and a shower and countless washes) later. Instead of dampening both surfaces, use a spray bottle on one surface, then apply the glue thinly, then spray water on top of the glue. That should be enough to cure it. Tape and/or clamp it and leave it overnight to cure. It will expand and become a light yellow solid foam so don't use it anywhere you want it to be discrete!
It's carcinogenic if I recall correctly, so use it in a ventilated area! But it's great stuff.
After it's dry, it's around the same texture as polystyrene and can be cut and sanded the same way.
The final thing you need to do is add a layer or two of papier mache -- depending on the finish I use brown paper, tissue paper or a combination of the two. This will stop the polystyrene from degrading and provide a surface for painting. You can also sand it.
I find it easiest to do this all with paintbrushes -- you can immerse the paper in glue and then smooth it on but it's a bit messy. I add water to the glue (about half and half), then using a rubbish paintbrush I paint on a patch of glue, then apply the dry paper. I then paint another layer of glue on top. Continue as long as you like but don't add too many layers at once.
I say a rubbish paintbrush because this can trash a brush very easily and it's not worth risking something fancy!
Tomorrow, more progress on the puppets for the show. And tonnes and tonnes of polystyrene dust all over everything.
Making and Production Blog