# Great Stuff foam noob



## flyingSquirrel (Aug 22, 2011)

At some point in the near future I will be doing a GS background in a 29 gallon paludarium. I have literally never used Great Stuff for anything, ever! I do plan on coating the back glass with a thin layer of silicone before applying the foam, as I read it's good insurance to make sure the background doesn't fall off. Not likely but it has happened to some people.

- What is the best way to apply the foam? Do I go in zigzags? Crosshatch? Random? Clumps?

- How much does it expand?

- How thick can I / should I apply the wet foam?

- How fast does it skin up AND does the entire background have to be done all at once? Or can you apply GS on top of GS?

- Any other tips?

Thanks everybody!


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## freaky_tah (Jan 21, 2009)

WEAR GLOVES!!!

The easiest way to see how much it expands it to just do a test on a piece of paper/cardboard. When I apply it, I do it going back and forth, working my way down, but don't make it too thick or it won't cure properly. It will get tacky pretty quickly, and should have a hard skin in an hour or so but it won't be fully cured. If you're planning on making any areas thicker, you'll want to let it cure and then add another coat. You can certainly add great stuff on top of great stuff! Once it's totally cured grab a knife and carve away


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## Feelin Froggy (May 12, 2011)

It's actually very easy to carve it up. I like to coat it really heavy. Make sure you get the edges really good... The foam will expand towards the center of the tank. If you need to fill small holes and gaps let it rest 8 hrs or so until its totally dry and hard. Then you can put GS on top of GS. When you go to apply the silicone try to carve all the surfaces at list a little bit. The silicone sticks better to it that way.


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## flyingSquirrel (Aug 22, 2011)

Thanks for the tips so far! I will try a practice run on some cardboard as recommended. I am not sure how much foam I'll need for my 29 gallon, I am doing the back and sides. I have 2 cans of foam, hopefully that will be enough.

Once the straw is attached and you do some foam (say for example to do a practice run with just a little bit), how do I prevent the straw and can outlet from clogging up? Or is it like once you start spraying you have to use the whole can?

Just thought of another question..I'm sure this has been asked before...
I was thinking I might want to have the great stuff actually extending into the underwater part of the paludarium. I have some DryLok and acrylic paints. I would probably let the foam completely cure, carve it, coat it with some drylok and acrylic paint so it looks like rock. Do you suppose this would be safe to have submerged underwater? I am hoping somebody here has had experience with doing something crazy like that 

thanks again! 

btw the build thread is here (not a lot going on yet though) http://www.dendroboard.com/forum/pa...m-build-post-i-go-details-very-pic-heavy.html


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## Steve88W (Jan 21, 2011)

Read the labels as some foam expands a LOT while others fill in small cracks. The commonly used foam comes out yellow but there is a pond foam that comes in black.

You can use it under water but make sure it is sealed first.  I wouldn't carve the foam that goes under water as the foam 'skin' is much less porous than the rest.


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## Bowser (Jul 4, 2011)

Detach the straw and pour acetone down the straw. It'll clear it up. Do the same for the place where the straw goes, and you're set. that's what i did, but if you don't have acetone i don't know how you would clean it besides water. My family owns a nail salon so i have access to it


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## mordoria (Jan 28, 2011)

GS will expand more then you think it will. Dont over pull the trigger either. Zigzag from end to end or try and add depth so your frogs have some ledges. Try and do a nice thin application, at first. Itll puff up a bunch. Dont put it on thick!! it will melt into a sticky mess. You should also wait for it to dry before you add more. 2 cans will cover the back and some sides of a 29g, if you put it on thin. You can also get a lower expanding stuff. There is Great Stuff, GS door and window, and GS Big gap filler. Go for the door and window, it expands less


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## DANdroBATES (Aug 30, 2011)

When I use GS and I don't finish the can, I've found that usually just the end of the straw cures. So when I use it again, I just cut the end with scissors and then it works fine.


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## jband (Aug 16, 2011)

Yes use silicone to help stick gs to glass this will insure a good bond. Make sure u reinforce your acrylic in your tank that you are using for your pond. GS could bend and warp that if it comes in contact with it. It has great strength when expanding.


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## B-NICE (Jul 15, 2011)

Main tip use gloves and old clothes. That stuff is really sticky and will take days to remove. I would use GS Pond & Stone for the sides and the bottom of the tank. You dont want any silcone on the front glass of your viv. With the GS pnd & stone you dont have to silcone it you can just leave it as is, because its black and it looks like actual rock. Its kind of hard to get in those 2 front cracks. Pond and stone is aquarium safe too.


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## Judy S (Aug 29, 2010)

Nail polish remover is acetone...Great Stuff is just Gorilla Glue under pressure...they can be successfully combined. I've had problems in the past because the GS sags if applied too heavily...and the bubbles formed are just big air pockets. One of the backgrounds I did was to lay the egg crate material on a flat surface on one of the heavy duty large black plastic trashbags..I applied the GS across it and let it dry that way...and when I picked it up, cut away the excess behind the eggcrate. That way I had a removable background and it made it easier to "carve", etc. Another post somewhere mentioned making a more dilute silicone, peat & toulene solution to "paint" on the backgrounds...sounded like a good idea since silicone can be so stiff. The use of toulene is very, very tricky--so if you do intend to use it...outdoors...well ventilated, mask, etc. Very strong solvent...read up on it, but sounds like a good way to get authentic looking vines, etc. And the vapors are the "bad' component so it becomes inert after curing from the silicone...


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