Working With Styrofoam

10 Jun , 2011,
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Styrofoam is an effective material for crafting lots of props and armor pieces. I use styrofoam balls almost exclusively as the base of my shoulderpads, and it’s not entirely unheard of for cosplayers to shave styrofoam to the correct shape and size for weapons ornaments and frills, or to use expanding foam to craft the same.

While styrofoam’s fairly easy to cut and shape (all you need is a heated blade and a firm hand), applying a coat of paint to the styrofoam, or even sticking it to another piece with glue can be a real hassle. The composition of styrofoam precludes the use of conventional methods, and here’s a little science lesson why.

Styrofoam is composed of polystyrene, which is easily soluble in most chemical solvents. The propellants in spray paint cans, as well as the compounds of most liquid based paints (such as glass paint) will eat through styrofoam faster than you can say “cosplayer”. Same goes for most conventional glue products, which contain chemical solvents that prevent the glue from drying up, but has a rather nasty side effect on styrofoam.

Tough luck, you might think, but here are some ┬ámethods I’ve used, and items that have proven to be great workarounds.

1. Apply Liquid Varnish

Varnish, for the win.

You can prevent paint from eating into your styrofoam prop by covering it with several layers of liquid varnish. Personally, I prefer Amsterdam Matt Varnish, which goes for about $10 at Art Friend and most major craft stores. Brush on three coats of liquid varnish – one coat at a time, and allowing intervals for the varnish to dry.

If you’ve done this correctly, your prop should be protected by a thin, yet durable sheen that can be spray painted or glued on without hassle.

2. Use Acrylic Paint

Daler-Rowney's Cryla label is ideal for painting cosplay props.

The best way to get around using aerosol paints is to stick with good, old fashioned acrylic. I normally use Daler-Rowney’s Cryla label, which has a great finish, some really neat color combinations, and most importantly, is fairly affordable. What’s more, Cryla paints are great to use with the Dry Brush method of painting, which leaves a polished, aged look on your armor and weapon pieces.

Apply acrylic over a single coat of varnish, then varnish over when dry for best results.

3. Shellac it up

If you can get your hands on shellac (it’s available in most hardware stores), it functions the same way as liquid varnish, except you only really need a single coat to inure your styrofoam prop against the dangers of acetone and other solvents. You can also do the same with clear nail polish (couple dollars in SaSa and Daiso).

Now on to glue selection.

4. Glue as you know it

There’s only really two types of glue you can use reasonably well with styrofoam. One’s the UHU Por glue, which is foam friendly. I can’t count the number of times it’s actually saved my Warlock shoulderpads, replete with foam spikes and skulls, from falling to pieces. You can get a stick at Art Friend (about $5) or any reliable craft store.


UHU Por, and a very well used stick at that. XD

PVA - The alternative.

The other label is PVA Craft Glue, which is purchaseable from Spotlight for $7. Personally, I prefer UHU Por, but PVA tends to dry faster.

And there you have it.

Until next time, cosplay friends. Cheerio!