I have been asked to make some props that look like a bed of coral for a VBS. I want it to be kid friendly rather than exactly match.
This is the real thing.
I decided to use some great stuf foam. I started by rolling up a piece of card stock paper and taping it closed.
I put a piece of paper towel in the bottom and pushed it about halfway up the tube so I wouldn't waste the foam.
I filled the tube with about 2 inches of foam. It will expand and come out the top so no need to waste it. And I found out that if it is colder it doesn't rise as much.
The foam expanded out of the top of the cardstock tube. This is what I wanted. because I want to make a ring of coral around the top.
I pushed the top of the foam back inside. I had to wait until the foam was hard enough to touch without getting sticky, but not fully cured. It takes about 45 minutes or so. If you wait until the foam is fully cured it doesn't work.
While I was waiting for the foam to cure, I took a scrap piece of styrofoam. Mostly I use 2 inch foam. You can get a 4x8 sheet of 2 inch foam for around $12-$15 at Home Depot. It is available at Lowes, but the sheets I found had a silver backing on it, and it was almost twice the price.
I also found that furniture stores have thicker pieces, and they are happy to get rid of it since it fills up their dumpsters. They are not in sheets but they are great if you need a bigger piece, and you can't beat free! This piece is about 3 inches thick and about 5-6 inches square.
Next I used a heat gun to melt the foam to make it look like a rock. If you are going to do any type of styrofoam work I would strongly recommend getting a heat gun. You can get them at a hardware store, usually in the wallpaper dept. There are other tutorials out there that say to use spray paint. This will work, but if you don't use the same color spray paint it will show through. Plus it always smells like spray paint.
Then I put a wooden skewer in the bottom. (You can find these usually around the barbecue stuff in the grocery store.) I broke it off so now it is about 6 inches long.
Then I stuck it into the styrofoam "rock."
I did this several times, and sprayed the great stuff in spirals around the tube and let it dry.
This is the final part.
Next I painted the rock brown. Then (unpictured. I forgot to take pictures of it until after I was finished.) I painted the coral a purple color. I just used a brush and some Apple Barrel paint.
I then mixed a little of the purple and some light blue together and just lightly brushed it on, trying to only hit the raised areas.
Then I mixed a little white with the new blue/purple color and brushed it on a few of the more outstanding areas.