Expanding Foam

[scott_n06]

I was thinking of working on a diy 3d background today and had a question.

If I were to spray expanding foam directly onto the glass will it adhere to it and not float when I add water or do I need to make it separate from the tank and glue it in?


Thanks

 

[joe jaskot]

Pond waterfall foam will adhere to glass, but not to silicone. I have no idea if it will float, but I doubt that it will.

 

[ChewyFlipper]

any experience i have had using spray foam, it expands and is full of tiny air pockets. all those foam product were originaly used for insulation. and its the air pockets that make the insulation value so high. but then it went into being using for decorations, fake rocks, movie sets. ext.
so yes it will float. ( no experience with pond waterfall foam ). but that stuff if it is sprayed directly onto the glass will bond to it. sticks to everything and if it does come off usually the part that bonded to the material will still be there. the weak part is the foam its self. only way i could see it float and tearing off is if there was a large amount of foam extended from the glass. but pretty sure thats not the look your going for.
i wouldnt worry.

 

[ShaneOSullivan]

I'd suggest making it on some kind of base, and using velcro to stick it to the back wall. But I don't see why you would need to. The pressure from the water should hold it onto the back wall of the tank.

 

[skjl47]

I'd suggest making it on some kind of base, and using velcro to stick it to the back wall. But I don't see why you would need to. The pressure from the water should hold it onto the back wall of the tank.

Hello; The water will likely find it's way behind the base and equalize the pressure causing the base to dislodge. The spray foam will be very bouyant and may overpower the velcro.
There are at least two kinds of expanding foam that i know of. One is called closed cell foam and is used for insulation and in cavities in boats for flotation. This foam makes sealed bubbles. The other is open cell foam and I believe that it can become water soaked over time. The sponge used with aquarium sponge filters is an open cell type, although I suspect it may be an entirely different material than the expanding foam you can buy in a can. If it can be found, the open cell type foam will not float up on you after it becomes soaked. Not sure if the trapped water in the foam might cause problems over time.
I have used the expanding foam from cans as insulation around houses. It sticks to most things and has to be scrapped off . It should stick to the glass strongly enough to not float off.

 

[broken]

You could always take some pvc pipe and fill it with sand and place it up against the tank wall before spraying the foam to make it heavier therefore it will not float if it dislodges.