The Foam/rock Projects Here Thread

Has anyone ever try to coat/cover the foam with dryloc its like a concret patch for waterproofing basements its also used in ponds pools ect i have used it on foam backgrounds when i had reptiles never had any problems also for people how are afraid about build up behind the rock wall you can cut a sheet of the thinner pink foam or the thick foam and carve the foam quick tip use a tourch or a heat gun over the foam when your done carving it makes looks like rock and cut it so it fits super tight then put the eggcrate on that so there is no build up of nasty stuff also u can use magnets to hold the background in place instead of sealing it to the back glass with glue ect..
 
so how is the wall attached to the glass without creating any dead spots for crap to build up?
Also, any negative effects by having the foam adhere to the silicone seams? Like if you ever have to remove the wall would the foam rip up the silicone requiring the tank to be re-sealed?
 
hey, ive got one question. once you apply the resin, and you put sand on it, and it hardens/cures, does coraline actually grow on the sand that is on the foam?

thanks in advance
 
Hi Whacked -- sorry for the delay -- wasn't sure who you were asking. I think we all do things a little differently.

I mounted my wall on flat egg-crate and made sure the foam came through the holes on the egg-crate. I then sanded the foam away and also epoxy coated that backing. I then used a complete cover of reef-safe silicone to attach the structure. Very, very little water gets behind the wall. On the downside ... it ain't comin' out in a real hurry either.

In reply to 'is_that_a_fish"

Yes the coraline most certainly does attach to the sand that is stuck on with the epoxy resin. The epoxy coatings (I did 4 coats all up starting with sifted fine sand and then generally increasing the coarseness) gives the foam a really hard exterior and will help keep anything from boring into it over time.

Don't skimp on the epoxy ... try to make sure you cover ALL of the black foam.

Any spillage or over run onto the dead coral rock, I used a dremel to sand off when it was all cured.
 
ok, sweet. thats what i thought, but i didnt want all my hard work to be ruined when all the rocks are purple, and the sand would be white.

thanks for the quick and useful advice! cant wait to do it!
 
one more question, i just tried this, using "great stuff" and Bondo brand fiberglass resin, and the foam shrinked after i applied the resin. is this because i didnt wait long enough for the foam to cure? i only waited about 5 hours... i was anxious. lol besides, it was a test, small scale, just to see how it would turn out.

any help is appreciated.
 
Don't use fibreglass resin ... steer clear from any kind of polyester resin. I would hunt down epoxy resin with a hardener as opposed to a resin using a catalyst.

You will be left with all kinds of residual chemicals with the polyester resins ...

And possibly... the shrinkage may have been because you didnd't let the foam cure completely. I don't know the brand 'Great Stuff" ... its hard to say whether there's been a chemical reaction or whether the foam wasn't cured.
 
is_that_a_fish -- Deep in this post the brand Great Stuff was talked about and was deemed ok. The problem is it will breakdown because of UV light. Others recommend Beckett "Pond Foam" which is black, protects against UV, and can be found at Home Depot, etc. I found mine in the outside section along with the pond building supplies.

I would also not recommend the poly based resin as it could leech into your system. There is alot of talk about that earlier in the thread. I, and many others used a 2 part epoxy found at Hobbytown type stores. Steps: mix epoxy, apply to fully hardened foam, while epoxy is still wet apply the sand. Make sure all the foam is covered to get a uniform look.

Hope this helps, here is a link to our local thread (it has a pic of the epoxy. Foam/Rock build
 
ok, i understand. i went to home depot to look for the pond foam, and they didnt have it, thats why i picked up great stuff.

well, there goes $20 down the drain.

but thanks for saving my tank all the trouble.

about how much does the epoxy from the hobbytown store run you?
 
is_that_a_fish, you can still use the yellow colored great stuff its just that you need to 100% cover all of the foam with epoxy/sand to prevent breakdown.

How much great stuff did you buy? Did you already make the wall? I hope the $20 wasnt for just 1 can. That is $2-3 a can in NE. On the other hand, the pond foam I bought from HD was $12 a can.

The epoxy was roughly $10??? I bought 2 and used only 1 set. Buy a bunch of the little hobby brushes, I think they are $0.10 a piece?
 
Polyurethane Resin

Polyurethane Resin

Great thread by the way:)

I was just wondering if anybody has used polyurethane casting resin to make rock?

I was thinking to make a foam scape, take a mould using paint on latex and fill this mould with a mix or resin and coral sand, gravel and rock chips.

Its supposed to be inert like the foam - just wondering if mixing in sand would mess this up?

Cheers anyhow :D
 
I cant answer about poly resin. I did ask a couple months ago about Gorilla Glue (polyurethane glue) and someone said not to use it, didnt see the MDS though.

Hopefully someone will chime in with a definitive answer.
 
oh no, the great stuff was about 3 bucks, but the fiberglass resin was 15, so with tax it was about 20. good to know i can still use great stuff tho.

and my wall hasnt been constructed yet, although it will be shortly
 
hey, what if i used some portland cement to cover the great stuff? im sure that it would work, i dont see why not, right? i would just have to cure it....

any info is appreciated. i saw a while back someone did it in this thread, im gonna go look for it...
 
Not sure if someone used portland to cover the foam?? Maybe they did, this thread is long. I would suggest one or the other. It really isnt that labor intensive it is more time consuming. Plus the cure time for the foam/epoxy is shorter than curing cement rock.

My suggestion:
Do the foam wall with eggcrate backing
Use some large ganule rock salt to imbed the foam will still tacky
Place some rock rubble into the foam while still tacky
Day goes by fill any gaps missed the first time with foam.

Start coating with epoxy/sand add crushed coral to your liking
continue coating with epoxy/sand until all is covered. Let cure and viola!!
 
I went ahead and bought the more expensive becketts.I cant locate the tried and true Z poxy anywhere locally. I'm not to sure about the other stuff people are using and prefer a bit more cautious route.

So, i'd rather spend a few bucks more on the becketts and skip the epoxy step entirely.
 
Whacked, you have a Hobbytown a little ways from you.

2221 N Tracy Blvd
Tracy, CA 95376-2425
(209) 221-6391

They will have the epoxy I used. I was cautious too, but this epoxy was not something I came up with, rather it was mentioned earlier in this thread.

I tried to sprinkle some sand/crushed coral onto the foam before it dried and it didnt turn out very well, looked like dusty foam. The epoxy is also used to keep little critters from picking at your foam wall as well as adhering a substate for algae growth.

Keep asking questions and posting thoughts, maybe some of the OGs who started the thread will comment.
 
Hobbytown Epoxy

Hobbytown Epoxy

I used the Hobbytown epoxy and it turned out great!!!

It sets in about 10 min and starts to dry in 30 min full cures in 8hrs.

Cost me 11.99 for the setup, real easy to mix also.

I will post pics in a few hours.
 
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