[IdealDrug]

Attempted my first GS foam background with Cork bark. Last night I trimmed up the foam and this morning the back wall was separating. I scrapped the whole thing. What are the most common reasons for this failure? I siliconed the the sides and back before I started foaming. I let that cure roughly 36 hours. Humidity has been high and it has been hot. I kept it in my garage for this whole process. Do I need to completely clean the tank to start over? will the silicone allover the sides and back be compromised by me pulling the foam off? If I need to clean it, please let me know how.

 

[khaku2]

Apply black silicon (they sell it in tubes) on the back glass wall before applying the black colored great stuff foam. It won't detach after that.

 

[rmingers]

Did you clean the glass with rubbing alcohol before you put on the silicone? If there was a bunch of dust and crap on it, it may have prevented good adhesion.

 

[Encyclia]

Is it black (dark gray, really) pond Great Stuff or the yellow? I have found the yellow stuff to stick a lot better to the glass than the black. You can also silicone the pieces of cork to the back glass before using the Great Stuff to add some extra adhesive to the process.

Mark

 

[bssknox]

Did you clean the glass with rubbing alcohol before you put on the silicone? If there was a bunch of dust and crap on it, it may have prevented good adhesion.

Recommend doing this^. I've never put silicone on the glass before adding Great Stuff, just foam to glass.

 

[dmb5245]

Bummer, but better now than later! The silicone you added *should* have helped the GS stick, so I wouldn't spend time removing it. But you should probably wipe it down with alcohol before adding foam again (I assume the silicone is sticking to the glass fine). It can also help to silicone in something like egg-crate scraps to give the foam something extra to grab on to. Also, Dow's website says that GS cures faster with humidity, so maybe your hot humid garage made it cure too fast, leading to the failure.

The exact cause is anyone's guess, but I think you should do the minor fixes and give it another shot.

 

[IdealDrug]

The silicone seems fine for the most part. Now the problem is all of the foam in the curves of the cork bark. I have no idea how to get it out other than handpicking at it. It seems like that will take hours. I hate foaming it again and having it raise even more than it already was. And ideas?

 

[DPfarr]

Pressure wash it out.

 

[rmingers]

The silicone seems fine for the most part. Now the problem is all of the foam in the curves of the cork bark. I have no idea how to get it out other than handpicking at it. It seems like that will take hours. I hate foaming it again and having it raise even more than it already was. And ideas?

I would think a rasp (curved file) would make pretty quick work of the foam. I don't know if I'd use a pressure washer, it seems like it would break the edges and possibly split it in two.

 

[DPfarr]

If it’s the cambium side of the cork, it should be fine. I pressure wash my ghostwood to get foam off so it can be autoclaved and reused.

 

[Herbaliser]

I have found working onto sheets of polystyrene easier. Cut the sheets to size for the back and sides, arrange cork then use the expanding foam.

It is much easier to trim the foam after it has cured then to add the silicone and coconut fibre while the panels are outside the tank.

I put the panels in place after carving and before adding the silicone and cocofibre to check the corners fit nicely, and carve a bit more if needed.

You then just need to silicone the panels to the glass once everything is cured.

The disadvantage is that you lose an inch or so depth and an inch either side of width but in a 2ft wide Exo Terra you don't really notice.

 

[Cakers]

If I use any silicone for background prep its just a ribbon to allow GS foam to hang onto. I have had GS retract and not cure if the silicone is not completely dry. Usually I do not use any silicone before I apply GS. Same goes for Titebond 3 if the GS is not completely cured Titebond will cause GS to retract and not cure. I use titebond 3 instead of silicone to adhere coco fiber or tree fern.

 

[Kinstrome]

I'm curious, what do yall use to disguise GS foam and other unattractive substances in clear-glass vivs? If you use anything at all, that is.

 

[BRLegend]

To cover the GS in the tank I use silicone spread on the GS and then covered with coconut coir. For the outside, I wipe the glass down with alcohol and then paint the glass with Folk Art Enamel Paint. I use flat black but there are many colors available.