Can I coat Crayola Model Magic with a spray rubber (e.g. Flex Seal) to prevent it from cracking?


New Member
Hi all- I have worked many times before with Crayola Model Magic to make prop heads for Halloween and haunt stuff, sculpting on top of styrofoam heads. Most of the time, I end up covering its surface with something like paper mache in order to prevent it from falling apart. Would coating it with a decently thick coat of a spray rubber sealant like Flex Seal keep the clay intact? I might allow it to dry somewhat first, possibly patch big cracks with more model magic as well. Will a spray rubber coat create a sealed homogeneous surface? It's not often I use kinda cheap materials like this, but for my current project I am on a very tight budget and schedule lol


Well-Known Member
The deal with Model Magic is that it shrinks a lot when it dries. Because you've got it on a styrofoam head, the outseide of your sculpt is shrinking, but the inside is unable to do so without cracking around the solid head form. Sealing it can help a little, but doesn't stop that fundamental problem. Best I've found is to be able to remove it from the core so that the outside and inside can shrink at the same rate.

Here's a video I did on the subject: