Picture of foam sandblasted sign
This instructable will show you how to make a small sandblasted looking sign from simple and easily obtainable materials.

Step 1: The Materials and Tools

Picture of The Materials and Tools
Styrofoam: any type will do, beaded white (thats what I'm using here), or the pink, blue or grey extruded type of polystyrene. urethane foam will not work for this project. The colored foam is usually sold under the name foamular and is found at most building supply yards as foundation insulation, they also carry the white beaded foam and you can find it in some craft stores also.

Stencil material: I'm using sign vinyl that I cut on my Summa plotter using Coreldraw, but, you can use contact shelf paper handcut with an exacto knife. or even cutout stencils using chipboard or other materials, be creative.

Sandblast: For this project you could use a sandblaster (very quickly) but because of the polystyrene we are going to use spray paint any brand will do as long as it's not water based, solvents in a spray can will also do, experiment.
reinlar5 years ago
What reasonably cheap (and readily available) liquid type finish could you dip or spray onto your sign, to make it HARD and more durable and long-lasting than painted foam. I guess clear fiber glass resin & hardener would eat the foam wouldn't it???

I used to know a commercial sign maker who cut letters out of pink construction insulation type foam (from Home Depot) and he dipped them into something which hard-coated them for durability against the outdoor elements, but can't remember what it was. It would be perfect for making this sign technique durable enough to use outdoors. Anybody know what he used.????
peterman921 (author)  reinlar5 years ago
I doubt it was cheap. you can use epoxy resins without melting the foam, polyester resins are too hot. there are two part urethane coatings available, try set design websites, foam coatings, hardcoat, props, etc. http://www.sculpturalarts.com/ http://www.demandproducts.com/Signage-items/
Thanks for the links, but I think the stuff I'm talking about was (1) component, non-toxic, 24 hr cure, and cleaned up with water. The guy didn't even wear gloves when he dipped his signage into it. I'll track him down in the next few weeks and post his links. He may have even had a formula for self-mixing the stuff. It looked like white latex paint but thicker, dry to touch in an hour and in 5 days it was pretty dogone hard. Felt like plastic, but flexed enough so it didn't crack if you hit it. I know it was only guaranteed to remain intact for 3 years. He got repeat business, because his signs were good, and cheap. I also remember he attached plain roofing nails to the back of his signs and pushed them into holes with blue anchor plugs for mounting. Very simple, cheap and quick. His signs never got damaged, except during hurricanes of course. He made a ton of money traveling around Florida in April-August.
peterman921 (author)  reinlar4 years ago
it occurred to me a few weeks ago it might be snow seal roof coating. it's white and I believe waterbased, I'll have to go get some for my roof anyway, I'll try it out
v. good man; any other works pics.
peterman921 (author)  adel_sebaey15 years ago
yeah, check out my website and my facebook http://home.budget.net/~signjon/Home.htm http://www.facebook.com/home.php?sk=lf#!/pages/Grants-Pass-OR/JP-Graphics-Artistry-and-Design/230729986988
Mig Welder5 years ago
cool! that's tiny drill press!
penumbra_5 years ago
So you can paint over the initial spray paint coat with acrylic paint? Not acrylic primer? I wasn't sure how well acrylic paint would adhere to the enamel, but if you could skip a primer coat that would be nice.
uguy6 years ago
You could use some of the 2 part Faux Stone paint and make it really look like sand blasted stone. We did this at a vinyl sign shop I worked at. Looks Great, Great ible, thanks for sharing.
scavanger6 years ago
Great idea I always knew paint did this to foam, but never thought to use it to my advantage!
peterman921 (author) 6 years ago
And some more at my flickr photostream the coolcat job was just done 2 months ago.

peterman921 (author) 6 years ago
more of my work here some is foamular and some is urethane foam

Cool! I've never thought that this property of Styrofoam could be anything but a nuisance.
PS1186 years ago
I'm with the others. Very cool idea melting the foam on purpose to make designs. I bet you could use this to create molds for concrete or other materials. Also, wonder how far a person could take this. CNC / Reverse stereo lith machine, anybody?
peterman921 (author)  PS1186 years ago
well there is also lost foam casting that I have done using my cnc mill to make the parts in foam bury them in dry sand with a foam runner coming up to the surface and pore in your molten aluminum, let cool and out comes your aluminum part ready for finishing. I'll make my web page into an instructable
jeff-o6 years ago
Wow, that looks really good! I like how you've turned a nuisance (melting foam) into something useful.
webman38026 years ago
This also works great for making tombstones for Halloween. You can apply a stencil that will only etch the "RIP" or other letting, and use this technique once or twice (allowing to "dry" between sprays) to carve out the letters. Then, remove the stencil and apply a light dusting of spray to the entire tombstone to give it an overall grainy texture. For added details, you can chip out cracks and "crumbles" with the tip of a knife before or after spraying (this probably wouldn't work as well with the beaded white foam). When painting, after the main color, a dark wash of thinned-out black or brown will show off the details nicely.
webman38026 years ago
I accidentally discovered this technique while making a blue foam King Tut mask for a sarcophagus I made for Halloween one year. I knew it would melt the foam, so I used one coat of water-based latex (brush-on) primer. Not enough, obviously, but instead of pitting the the foam, only a little of the solvents leaked through the primer, giving it a wavy, dented look in some areas. It worked well for aging the mask, even though I wasn't expecting the effect. You can also use a hobby knife to slice shallow cuts into the foam before spraying. More of the solvents will leech into the cuts than the surrounding area, and you will end up with slight grooves in the etched surface.
craig36 years ago
if you use blue spray paint will the melted foam turn blue?
peterman921 (author)  craig36 years ago
yes, you can use any color you like but you still have to prime and paint especially if its going outdoors, so it doesn't matter what color you use to blast with.
rimar20006 years ago
Very smart, good work.
courtney6 years ago
nice! I used a similar technique to faux finish some Styrofoam volcanic rocks for an art project, but never thought of making a sign that way. cool!
gmjhowe6 years ago
Nice work, alot simpler than i first thought!
ChrysN6 years ago
That looks really nice!
CameronSS6 years ago
Very nice! It looks great!
foobear6 years ago
interesting idea!