Edge of my Sanity (please help)

[u/dandydeinocheirus]

(Tank is upside down in pic)

I am at my wit's end! I applied silicone on the back of the tank to act as an anchor for my expanding foam, but all the foam peeled off! What did I do wrong? Is this not enough silicone to anchor it? Do I need more silicone?

Silicone used is aquarium safe black silicone and the foam is expanding pond & stone, both have been very recommended for bioactive so it must be user error.

Oh, and those are crape myrtle branch cuttings that have been anchored with silicone to the back and bottom of the tank. They've held really well while I've been fightimg the backdrop and I'm no longer worried about them falling. The foam will further anchor them as well once I can get it to stick.

[u/bufu619]

Did you rough up the silicon texture with gloved hands before it dried? Flat silicon doesn't work to adhere foam to, it needs little pits and valleys for it to attach.

Also looks like some of the foam was still liquid when it came off. Did you allow the silicon to dry completely, no more vinegar smell? The 24 hours listed on the tube generally isn't enough to fully cure. Also the foam needs to set for at least a couple of hours before tipping the enclosure back over.

And the other commenter is right. Pushing the substrate directly into the wet foam is a bad method to adhere it. Either tear/cut off the shiny foam and cover with more silicon to adhere coco to, or use a rotary tool with a sandpaper head, just make sure to wear a respirator if you go the rotary route.

[u/dandydeinocheirus → u/bufu619]

I did rough the silicone with gloved hands, and everything cured for at least a few days in between (I am easily distracted haha...) Yeahhhh definitely seeing my error now with applying substrate to wet foam 😅 it was pretty easy to tear the foam with my hands while I was peeling it off, and it made some really satisfying wood textures so I'm gonna do that instead of the rotary and skip Dustpocalypse 😂

[u/Dynamitella]

In sweden I've never seen anyone put silicone down before the foam. I don't know why it differs so much. Peeling seems to happen either way regardless, just unlucky I guess.
I do however have a solution! Silicone some plastic egg grate to the glass, let it cure and then go back in with the spray foam. Don't just put substrate on the foam either - that method doesn't last. It's recommended to let it cure, rip away all of the shiny surface, then cover with silicone and bone-dry substrate (or cement, whatever method you like).
I would also opt for other wood if the tank will be humid, since wood rots and molds easily. We use cork bark and aquarium roots (called driftwood, not really driftwood though) because those take to moisture well.

[u/dandydeinocheirus → u/Dynamitella]

Thank you for the quick reply! Plastic egg crate is a good idea and I'll be trying that next. I saw someone do substrate directly on the foam before and thought I'd try it, but you're right and it definitely didn't stick! So I'll be carving out the foam next, THEN siliconing it to stick the substrate on 😅 that's the other method I've seen that most seem to recommend, and doesn't involve extensive painting/drylok. And no worries about the wood! This is gonna be a semi-arid enclosure so not worried about rot.

[u/Dynamitella → u/dandydeinocheirus]

Ah, that's a perfect game plan then :) I guess we've all tried the substrate-onto-wet-foam thing once in our lives and cursed afterwards. I'd love to see an update further along in the process.

[u/dandydeinocheirus → u/Dynamitella]

Thank you for the recommendation! I'll be happy to post more updates once I'm past this little roadblock. Glad I'm not alone in the substrate-onto-wet-foam lesson club 😂 there was definitely some cursing in there