Geocel 4500 sealant?

[fishdance]

Wherever a viewing panel needs to be water sealed against a flexible liner, I recommend using a fixing frame which can be tightened into a gasket seal. So the silicone (or PU) isn't used as adhesive but as sealant.

Something as simple as a wood frame would suffice. Add your sealant thickly, screw down your frame enough to form a smooth flattened surface on sealant but leaving several screw thread seals to go. Wait for a week (depending on width and thickness of your sealant) then when fully cured, finish tightening the screws. The spacing interval between screws will depend on the rigidity of your tank wall - rigidity of fixing frame and the viewing panel material type and panel thickness (glass is stiffer than acrylic which is stiffer than polycarbonate).

Send me an email if you need photos or better explanations.

 

[jjohnwm]

Wherever a viewing panel needs to be water sealed against a flexible liner, I recommend using a fixing frame which can be tightened into a gasket seal. So the silicone (or PU) isn't used as adhesive but as sealant.

That would be my plan if I were building a tank. In this case, however, the tank is already complete, with glass already firmly installed. If I use a liner...which is seeming less and less likely...I would be attempting to adhere the liner to the inside of the glass, not the other way around. I am trying to avoid the necessity to remove the glass.

At the moment I am leaning towards painting the entire interior with liquid rubber. Seems like the easiest way by far.

Bear in mind, this is just a smallish tank on which I am experimenting. I built it as an experiment out of remainders and scraps, using a slightly different technique than I normally employ. Learned a lesson...still learning another now...

 

[jjohnwm]

Just when you think it's safe to sit back and watch your fish...

Went into town yesterday, and one of my stops was at a general-store/gas-station/grocery/post-office/liquor-store/courier-depot/hardware/second-hand shop. I was there to avail myself of most of their services and the owner spotted me and pulled me aside; she had something that "I think you might be able to use".

It was an EPDM pond liner, still in the original packaging, 8 x 10 feet in size. I felt my left eyebrow twitch. She said "Whadayya think? $20 and you take it away."

I forced that errant eyebrow back into position with an effort that probably made me look as though I were passing gas. "Sold!"

So last night I was absent-mindedly doing some cipherin'...I realized that this liner could easily be utilized to waterproof both the leaking tank mentioned earlier...and also a 240-gallon that I have been silently mulling over, to fit into a specific spot in my basement. I don't like the idea of just building a box and then folding and shoehorning a flat liner into it, and in any case this liner is too short for that type of application. But it is plenty large enough to cut it into individual pieces sized and intended for the various surfaces in the tanks, with lots to spare for other future projects.

The only catch is sealing the seams, which will be numerous. The Gold Seal adhesive mentioned earlier is just not to be had in Canuckistan; 5200 is only slightly less impossible to source, and stupidly expensive. What to do, what to do...?

Well, the thing to do is apparently to visit the site of a Canadian online retailer from who I have ordered numerous items in the past. I was looking for a few oddball plumbing bits...but what I found was the Geocel 4500 that was the subject of this thread. Dang...if only I could be certain that it would work with glass...

...and then my computer dinged. I had mail! And it turned out to be mail from the makers of Geocel products, answering that specific question. They cautioned me that the product might change colour under prolonged exposure to water, but would work very nicely to seal EPDM to EPDM...and to glass!

I'm not superstitious...but if all this doesn't mean that the finger of Fate is pointing at me, while the air shakes with a deep voice intoning "Build that tank!"...then I will eat my apurensis jelly cat!

A case of Geocel 4500 is heading my way as I type. With any luck I can get this done before the cold weather hits, so I can keep the basement windows open to prevent suspicious smells from reaching the nostrils of SWMBO...until it's too late for her to stop me...

wednesday13 , I could have sworn that you wrote something sometime somewhere about a spray adhesive that could be used to adhere an EPDM liner to the interior of the plywood tank...or am I delusional...well, more delusional than usual...?

 

[wednesday13]

Just when you think it's safe to sit back and watch your fish...

Went into town yesterday, and one of my stops was at a general-store/gas-station/grocery/post-office/liquor-store/courier-depot/hardware/second-hand shop. I was there to avail myself of most of their services and the owner spotted me and pulled me aside; she had something that "I think you might be able to use".

It was an EPDM pond liner, still in the original packaging, 8 x 10 feet in size. I felt my left eyebrow twitch. She said "Whadayya think? $20 and you take it away."

I forced that errant eyebrow back into position with an effort that probably made me look as though I were passing gas. "Sold!"

So last night I was absent-mindedly doing some cipherin'...I realized that this liner could easily be utilized to waterproof both the leaking tank mentioned earlier...and also a 240-gallon that I have been silently mulling over, to fit into a specific spot in my basement. I don't like the idea of just building a box and then folding and shoehorning a flat liner into it, and in any case this liner is too short for that type of application. But it is plenty large enough to cut it into individual pieces sized and intended for the various surfaces in the tanks, with lots to spare for other future projects.

The only catch is sealing the seams, which will be numerous. The Gold Seal adhesive mentioned earlier is just not to be had in Canuckistan; 5200 is only slightly less impossible to source, and stupidly expensive. What to do, what to do...?

Well, the thing to do is apparently to visit the site of a Canadian online retailer from who I have ordered numerous items in the past. I was looking for a few oddball plumbing bits...but what I found was the Geocel 4500 that was the subject of this thread. Dang...if only I could be certain that it would work with glass...

...and then my computer dinged. I had mail! And it turned out to be mail from the makers of Geocel products, answering that specific question. They cautioned me that the product might change colour under prolonged exposure to water, but would work very nicely to seal EPDM to EPDM...and to glass!

I'm not superstitious...but if all this doesn't mean that the finger of Fate is pointing at me, while the air shakes with a deep voice intoning "Build that tank!"...then I will eat my apurensis jelly cat!

A case of Geocel 4500 is heading my way as I type. With any luck I can get this done before the cold weather hits, so I can keep the basement windows open to prevent suspicious smells from reaching the nostrils of SWMBO...until it's too late for her to stop me...

wednesday13 , I could have sworn that you wrote something sometime somewhere about a spray adhesive that could be used to adhere an EPDM liner to the interior of the plywood tank...or am I delusional...well, more delusional than usual...?

yup, not delusional lol ??…u can get spray adhesive or roll on type adhesive for laminates/veneer that should work well. When used “properly” ie coating both surfaces, let dry, then apply them together… its a very strong bond. Regular old rubber cement works excellent in this fashion also not sure if the “construction” grades made for veneer would b a stronger bond to the wood itself tho. I used rubber cement to attach my liner to steel. Its 12 yrs and still adhered well to the steel.

 

[jjohnwm]

Just wanted to briefly update this "project".

The leaky 70-gal plywood build turned out to be an easy repair with liquid rubber. I used a razor blade to carefully and completely scrape all the existing exposed silicone off of the interior surfaces, taking care to completely clean the interior glass as this was the source of my original leak. Ran coarse sandpiper over the surfaces to roughen them up a bit, and applied a thin strip of the Liquid Rubber tape all around the edge of the glass, then put on 4 reasonably thick coats of the Liquid Rubber, completely covering both edges of the tape and running well up onto the glass. It's been running for close to 8 months now without issues.

It's my first and, truth to tell, probably last experiment with Liquid Rubber. While the stuff has the huge advantage of being locally available in stock...I just didn't enjoy using it. However, it seems to work...will continue to watch it carefully...and it's a good addition to one's bag of tricks in case of an "in case..." situation.

Ah, but the Geocel 4500? I think I might love this stuff.

I have already been forced to make one repair in my 360 plywood tank, after an incident where some heavy stuff bristling with cutting edges dropped inside onto the bottom the last time I had it emptied. I put a few nice holes in the epoxy...and if you have worked with epoxy, you know how tough it is!... and patched them up with silicone. I wasn't happy with this...and I have regretted my choice of blue epoxy since the day I finished the build...and the tank was now almost devoid of fish, since most were moved outside over a week ago...so...

Within 8 hours, the remaining fish were moved out, the decor removed, water drained, and the interior cleaned up. The 8x10 EPDM liner was carefully measured and cut into panels. I then sat back, cracked a beer, viewed the carnage...and smiled. Duke wagged his tail and looked approvingly on...but he always does that, so...

The next day I spent installing the pre-cut panels of EPDM into the tank, using contact cement. Some panels are adhered over their entire surfaces; others are cut large enough to overlap the edges of adjacent panels, and those are left without adhesive for about 4 inches on the overlapping sides. This was a pretty easy-going day, since most of the time was spent waiting for contact cement to dry before laying the EPDM. More beer was expended on this day than usual. I admit to an error of over-confidence: the largest single sheet of EPDM was almost 96 inches long by 60 inches wide. The idea was to cover the entire bottom and the entire back of the tank with a continuous piece that overlapped the front glass a few inches and also wrapped around the top rear brace and onto the upper surface of the tank. I was trying to create as few seams as possible. This piece needed to be adhered in stages, applying contact cement to large swathes of both surfaces, letting it dry and then adhering the piece to the plywood base before moving on to the next section. Unfortunately, while sitting on the perfectly-smooth perfectly-applied bottom, I found it difficult to unroll the 8-foot-wide liner up the back wall; I ended up with a few wrinkles and folds that were permanently contact-cemented in place. Much profanity ensued; Duke squirmed uncomfortably on his bed, watching closely and cheering me silently on. By day's end, all the liner was adhered in place, but all seams were still loose and unsealed.

I left the sealing of seams until the next day, as I wanted to apply all the Geocel sealant at the same time. I still don't know if Geocel shares silicone's unfortunate trait of not bonding to itself when applying new over old, and didn't want to take chances. Geocel redefines the term "sticky"; I had to work with nitrile gloves the whole time. I used it to attach together all the seams, and applied generous seals over top of any suspicious-looking gaps or edges, as well as all along the edges where the liner overlapped the front glass. That day saw me using a lot of beer and a lot of gloves, but ended without significant stress.

I gave the Geocel 5 days to cure (manufacturer calls for one). Two days ago, I filled the tank, and that's where the project sits right now. It's not really an experiment; I have used it in the past to adhere a couple of little 4x6 patches to an EPDM pondliner outdoors, and a couple of preliminary tests this past winter have confirmed what the manufacturer told me, i.e. it sticks to glass very well. This was just a much larger-scale project than I have tackled with it before. The unfortunate wrinkles are not as obvious as I had feared, as the black liner just fades from view in a front-lit tank. I'll let it sit for a week or so, drain and re-fill, and then...well, I'll be where I was a year ago, except my tank will now have a black interior (bonus!) and I will be enjoying the undeniably greater confidence level in my tank that the liner construction has provided me.

Might even possibly build one more tank...