I am a little obsessed with “melting” styrofoam lately. It is fun and crazy science and when you mix it with a little creativity you can make some interesting stuff. It does take awhile to harden but once it does you have a lightweight sturdy shape that floats in water.
I am cringing a little as I think of all the times I have thrown away my take out containers and other foam packaging. But now that I know I can make hard plastic from it I will never have to do that again.
It is a simple process to “melt” the foam into a gooey substance using acetone but before you dissolve the foam you need a form to shape it. I have not tried a silicone mold and I don’t know if it would work as the acetone does melt some other plastics. Don’t ask me how I know this. 🙂
I have made the molds for my projects from cardboard boxes partly because I wanted to make my own shapes and partly because I like to re-use the boxes.
To make a cardboard mold start with a template. Trace the template on the a piece of cardboard.
Cut strips of cardboard and use hot glue to attach the sides of the mold. Be sure to keep the glue on the outside of the mold so it does not interfere with the finished shape.
Once the mold is completed it is time to dissolve the foam. Use pure acetone available from home improvement stores to dissolve the foam into a plastic goo.
Place the plastic substance in the mold and allow time to harden. (This shape and thickness took a couple of weeks.)
Once the shape is hardened it is time to remove the cardboard. This is not very easy and does take some scraping, filing, soaking in water and scrubbing.
(To be completely honest after all that I still didn’t get all the remnants of cardboard off but since I decided to paint the letters with a faux metal finish I figured it would be OK.)
For the faux metal finish I used silver spray paint.
To finish the antique look a small amount of black paint was brushed on and then dabbed off with paper towel.
For more details, you can see the whole process here on a smaller project that I made a few weeks ago.
Just in case you didn’t think I was serious about my foam obsession, I made a second letter just for fun.