I did my background on a piece of plastic to be put in after it cured. It warped like crazy. Any fixing it or should I just do it over directly on the glass? Any suggestions would be greatly appreciated. Thanks.
1. I sprayed gs directly on a piece of cardboard and let it dry. Once it dried I removed the cardboard (which wasn't easy) with patience and a box cutter. It was by far the straightest piece of gs with the smoothest back.
2. I used another piece of cardboard but covered it with plastic wrap before spraying the gs. After 8-12 hrs I simply lifted the foam and plastic wrap off the cardboard. Then you have to turn the foam over and remove the plastic because the gs underneath is still wet. Now that nothing is restraint the gs it will expand a bit from the back.
#1 creates a more uniform background but removing the cardboard isn't fun. #2 is much easier and doesnt end up too bad. I prefer option 2 but the decision is your. Keep in mind that with any method you will still have to shave, cut or sand depending on the expansion. Hope this helped
Next time you can use that 'pink' insulation foam to put your Great Stuff on and easy to trim the edges if it goes over. I did this with my 18" cube Exo-Terras and worked out real well. The warped piece, you're just going to have to place it in your vivarium or scrap it. It may look nice with the added depth of warping.
The warped piece is definitely too warped to use. It would take up way too much space. I guess I'm just going to have to try again. I'm probable going to try the cardboard method because it seems like it will take up less space and be a little more cost effective. The great stuff won't make the cardboard warp? I didn't think it would warp the plastic I used but boy oh boy did it. Thanks for the help guys.
I only tried to do one background outside the tank and it warped like crazy for me. I made it on the pink foam and I was determined to add it to the tank so with much effort and many pieces to push the great stuff back forcing it to stretch flat (I'm surprised we didn't crack the tank glass), we siliconed it to the glass. I will never do that again. If you insist on making them outside the tank I would suggest egg crate as well. Or once I did a very small piece to be used for a waterfall on a piece of glass. I just added vaseline to the glass before adding great stuff. That might work for you. It wasn't very smooth on the back but flat.