Concrete Form of XPS

[beniblasnok]

Hi. I'm planning to make a mold by cutting the shape into an XPS board, which I then glue or clamp together with a whole board that I have as a base. Is there anything I can treat the cut sides with to avoid all the small pores and irregularities in the XPS board and to ensure it releases easily? Grateful for any advice!

 

[Allmänobildad]

Cover the mold with plastic, polyethylene, or polypropylene, which definitely won't stick to concrete. For example, building foil, to keep the cost down. Otherwise, it might work to wax the surface of the styrofoam or spray with Teflon/silicone spray.

 

[beniblasnok]

Thank you so much for the tips!! I think I'll try using silikon spray

 

[beniblasnok]

Would plasti dip work, you think? Do you think it will stick to the XPS or will it come off and stick to the concrete when removing the mold?

 

[Rabbithole]

Spray putty and wax?

 

[danne_08]

Duct tape or packing tape if the shape isn't so tall that there are very many seams.