I have thought of doing this...using the rubber to seal the glass on the inside and silicone on the outside. Should I put a layer or two of sealer down then the glass or put the glass directly on the wood, then seal it?
First attempt
- Thread starter specialized002
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I just read all 29 pages of Joeys build 
Great tank and I would like to model mine after this. Only concern I have is how long is the rubber coat going to last? It's not been time tested yet, has it? Also, I would like to make the tank a little more structuraly strong (piece of mind) Someone mentioned car body bondo in the corners? What is another good waterproofer that silicone will stick to and is proven...in case I decide not to use the rubber coat. I got all my tank pieces sanded down today, sorry no pics yet. I will when I make some real progress
Great tank and I would like to model mine after this. Only concern I have is how long is the rubber coat going to last? It's not been time tested yet, has it? Also, I would like to make the tank a little more structuraly strong (piece of mind) Someone mentioned car body bondo in the corners? What is another good waterproofer that silicone will stick to and is proven...in case I decide not to use the rubber coat. I got all my tank pieces sanded down today, sorry no pics yet. I will when I make some real progress
I spoke to the distributor of Pond Coat in Texas. He told me that you can use Pond Coat over silicone as long as you keep the bead small. That way it bridges from one side of the silicone to the other. Kind of like how a band-aid sticks to your skin on both sides of your cut, but the center piece doesn't stick to the cut. He said Pond Coat sticks to just about anything, so I'm guessing that even though nothing bonds to silicone that it will stick to it sufficiently for our purposes.
That said, you don't need to silicone the corners if you use Pond Coat. You put a coat of it down, put mesh tape over it, then put another coat over the tape. You do this while the first coat is still wet.
That said, you don't need to silicone the corners if you use Pond Coat. You put a coat of it down, put mesh tape over it, then put another coat over the tape. You do this while the first coat is still wet.
specialized002;3825269; said:I just read all 29 pages of Joeys build
So remind me (us) how Joey attached the glass in his build?
I'm the one who mentioned bondo or thickened epoxy to fillet the interior corners. This is not so much for structural integrity as it is to allow for a more gradual curve for your fiberglass reinforcement or for your sealer. Not something that's required by any means.
And if you do go this route, thickened epoxy is stronger and more flexible than Bondo.
If you're looking for sealers that silicone will stick to, the tried and true are polyester resin (with isophthalic being "better" than orthphthalic), vinyl ester resin and epoxy resin.
Closely related to these are the solvent based epoxy paints like Sweetwater.
When I say "tried and true", understand this is mostly due to the fact that they've been around for a long time. So when you hear of 30 year old plywood tanks sealed with these products, the above resins or epoxy paints were all that were available, so of course they're going to be tried and true. This does not necessarily mean they are better than other options available today.
When considering a plywood tank sealer, there are five main things to consider, IMO. In no particular order:
1) ease of application
2) long term durability
3) repairability
4) silicone adhesion
5) cost, factoring in the total thickness a particular product requires to waterproof wood.
Which of these are most important to you is something only you can decide.
Joey siliconed his view window to the rubber sealer. Claimed he did a test run on a sheet of plywood and when he pulled the silicone up part of the plywood came with it. I'm looking for easy application, and long term reliability. When you say mesh tape...kinda like drywall tape?
specialized002;3826167; said:
I don't recall saying mesh tape but yes, mesh drywall tape is a type of fiberglass mesh tape. There are many types of fiberglass mesh tapes.
I have not used the Permadri product the the brushable/rollable product they carry sounds about as easy to apply as anything. Obviously I can't comment on long term reliability as the patent on the product isn't even as old as some resin sealed tanks. But it sounds like it will be fine.
Solvent based epoxy paints are very easy to work with and obviously have long term reliability on their side. But a wearing a respirator and applying it in a well ventilated area is a must. Odor aside, very easy to work with.
Epoxy resins are a bit more difficult to work with. But they don't have the odor of epoxy paints and end up being a bit cheaper due to the high solids. I have heard that West Systems with the 207 hardener is very easy to work with, similar to epoxy paints. Any epoxy can be made easier to work with by thinning with solvent and/or by heating up both the resin/hardener as well as the substate it is being applied to. But this shortens the working time.
A little update of the build...wood screwed and glued. Now just need to figure out what I'm going to use to seal it 
and pick up a piece of glass
and pick up a piece of glass