I have used the pink or blue foam many times. Depending on what you are making you can gule the pices together with liqiud nails or a scenic glue. Foam can be coated with textureing products (rosco makes some good ones) and painted. Spray paint will eat away at the foam leaving a rough surface, it will also produce a toxic gas so try this outside! I am sure there will be more advice about using foam to come!

good luck, if you let me know what you are making I might be able to help more.

I love this stuff! It is light weight and you can do ANYTHING with it. I have no idea what I would do with out it.

Liquid nails is great for gluing it together. I imagine elmers might work too. Don't think I have ever tried it.

You can get the "foam cutter" at any hooby supply store (Michael's, Hobby Lobby, etc)  Some use batteries, or you can by them that plug in. You get very smooth edges.

I reccommend gluing soem pieces to gether, then , after completely dried you can "sculpt" it to your liking.

If you did not want to make all that food, those same hobby stores sell fake food! Depends on your time and of course the budget!

Paints well, just do not use spray paint, it'll melt...not pretty at all.

The downside to useing this is is not all that durable. During rehearsals and production it will take a beating. (Depending on your actors abuse)

Best of luck and have fun!

 The portable hot knife are not that complicated to make, but as suggested! It is much better to purchase a proprietary brand tool, which are cheap enough & readily available, therefore you don?t have to mess about making it!
I?m sure the tool will come with all the usual health & safety warnings.
The main thing you have to remember is use it in a well ventilated area when cutting the styrofoam. You will find it cuts like butter & it gives a smooth finish to the cut surface, which I can never seem to achieve using a hand saw!
Possibly with an electric band saw or dado profile cutter, the heat generated from the friction of the blade, is possibly enough to smooth out the surface that?s cut, I?ll just have to try & hand saw faster?
If I may suggest & point out, styrofoam heated or melted in anyway, gives off toxic odours. All so in a fire situation, if it is subjected to flames, it will melt & perpetuate it?s own flame. Making it extremely difficult to extinguish.
Try it outside.
{Disclaimer never try this unless under adult or parental supervision!}
Hang a piece of styrofoam on a on a small safe structure off the ground, like a steel pole or something similar. In a clear open sandy location. Then set fire to it with a blow torch or something similar, then evacuate quickly to a safe distance, ensuring it is not windy.
After a few moments the of flame the foam will return to it?s original liquid form & molten fire ball droplets will be observed hitting the ground spreading & continuing to flame, giving off black toxic smoke.
It is quite spectacular & completely deadly!
Image if this was to happen on a stage set, besides the molten drops, igniting everything that this flaming petro chemical liquid comes in contact with, the black smoke will certainly suffocate anyone caught in an enclosed area, in less than 90 seconds!
Don?t take my word for it, ask your fire Marshall or have a look at a fire prevention & cause video.
I see that here, they are starting finally, to restrict the sale of styrofoam & other petro chemical based products in building materials.
I don?t know about your school fire policy, but here in the state school system, there are no fire extinguishers installed in any school buildings, as they do not want any teacher or student to become a hero or a pseudo fire fighter. In the case of a fire, their sole duty of care is to evacuate everyone, as buildings are easily replaced. Which in my view is a sensible attitude, all so it helps in still a sense of thinking health ?n safety. Which can be an oxymoron in it?s self, with a few that I know!
Not wanting to be an alarmist old chook!
But you only have to look around your home To find petro chemical products & materiel everywhere, even the PC your using right now!    

 
Go for it Joan!
A cigarette lighter works a lot fast and easier than using matches!
I have seen some of those foam cups, they use to hold candles on vigils or carols by candlelight. Flame up if the candle falls over, without going out & melting the styrofoam, than catching fire. But in those case the person holding it just drops it on the ground & it is not a problem!
We mainly use Gyprock plaster & fibre glass insulation.
However what might work, as you suggested, is to use a jesso type covering on the styrofoam!
I?d still carry on skip diving for the waste foam & just be judicial in it?s application.
Possibly using unbleached calico as a jesso type covering & with fire retardant added!


 

Tjelvar.... I am guest directing at a theater near by and was amazed at their technique for moulding. They just send it throught their table saw (no special balde or anything..) it cut like butter.  Very straight and no problems. Then they put on Moulding blades and they too worked great! They had quarter rounded tops, tri grooves. They had even used a technique where they sent the stock through at an angle and created a cove.  I know how I'm doing moulding from now on.  Blades may cost a little to start, but doing an entire room for one sheet of foam vs 10,15 or 20 bucks a board... wow..