How long for mortar to cure before removing foam?

hey guys! oven build is going great so far.

my finish is going to be stucco. I am planning to close off part of the front w/ firebrick, ceramic blanket, lathe/stucco. I would like to do all the insulation/lathe at once, meaning I have to remove the foam beforehand(so I can close part of the front off.) my question is, how long for the high-temp mortar to cure before I can safely remove the foam? (and any tips on removing the foam?) thanks!

Glad to hear your build is going great! I removed the foam 3 days after setting the brick. As for removing it… i had not done the back wall. I tried pushing, pulling, rubber mallet ended up using sawzall. I have read posts where the foam has come out easy, but I would bet most of us have struggled :slightly_smiling_face: . Can’t wait to see your oven pictures.

Great news, Steve!

What Norm said concerning the mortar vs. foam. Note that high-temp mortar will get hard pretty quickly, but will not cure until it is fired. That’s when it achieves a rock-hard, durable form.

Here’s a link with tips about removing the foam. It is an art that is learned and lost pretty quickly unless you plan to make a lot of ovens, but you will feel better knowing we all struggle with it!

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Side grinder with the guard removed and a wire wheel. It’s a snow storm of styrofoam! BE CAREFUL!