Using epoxy and window sealant

[nikirushka]

*** UK ***

Come summer, I'm planning to renovate my two year old 800g plywood and 4x2 tropical pond. I've got a viewing window I want to fit, and I want to replace the liner to get the light blue color I wanted originally but couldn't afford at the time.

I'm looking at pond paints for the colour, but I'm also seeing bad reviews re. cracking after time.

Is that still an issue with an indoor pond and if so, what's a better (but not hideously expensive) option? I really, really do not want a black pond anymore, many of my fish just vanish against it. But being indoors of course it needs to hold up over time!

Once that's sorted, what's the best sealant to install the window with? It's second hand, the previous owner used HA6 but I don't know how their pond was built as they'd already gotten rid when I got the window.

 

[jjohnwm]

Well, I have used various epoxies on probably close to two dozen plywood tanks over the past few decades, mostly mine but a number of them that I built with and for friends. I have always used black, and loved it. The last two I built were done in blue, which I began to regret almost immediately; I even covered the interior of one of those with black pond liner when I had the time, material and the required excuse, i.e. a damaged epoxy bottom made a refinish job necessary.

I know a lot of folks don't like a black interior, but with proper lighting, I think that fish stand out against black better than any other colour.

Pond Shield/Pond Armor is an easy epoxy to apply, has minimal VOC's and stands up very well. It was my go-to for years, but more recently I have used an epoxy made by Interseal. Comes in plenty of colours...including black!...and is very easy to use and apply...and, in Canada at least, is just about the least expensive I have ever tried. My oldest Interseal tank is only about 8 years old, so not exactly a long-term test, but it's still completely waterproof and perfect.

There are plenty of other quality epoxies available that are non-toxic when cured, so it shouldn't be difficult to find one to suit. What's more important is the proper preparation and application of the product. Read the manufacturer's instructions...and then follow them! No deviations. The surface being sealed must be clean and dust-free, and then you must pay attention to temperature, to proper mixing ratios, to application procedures and methods, to the number of coats required, to the thickness of the coats, to the drying time required between coats, to the final curing time. No shortcuts; if you want the product to work as intended, it must be used as intended. Don't think you know better than the chemists who formulated the stuff; you don't. And don't think their recommendations are not necessary or important; they are.

I have always used plain old GE Silicone I to adhere my front glass windows in my tanks. The glass panes sit on top of either the tank bottom or an interior ledge along the bottom. The silicone therefore isn't required to support the actual weight of the glass, but merely to adhere it to the epoxy and to create and maintain a perfect seal. The water pressure is pushing the glass against the inside of the front frame. Silicone I works like a dream for me. There are other silicones which create stronger joints, and which would be preferable for some applications such as those where the glass is unsupported and held in place strictly by the adhesive. Guys like thebiggerthebetter , M M1A1 , Backfromthedead , wednesday13 and others will be better sources of info on this point.

Good luck, and keep us posted.