My 315G Plywood Tank Build

[BadOleRoss]

Do you know if anyone ever glued the glass first with silicone and let it cure then. Paint over it.

Maybe we should try putting pond coat with drywall mesh. The same way you sealed the corners of the plywood

The first time I put the glass in I siliconed it in place, ran a bead of silicone around the edge of the glass and then PCed from the tank, over the silicone, to the glass. The PC did not adhere to the silicone or the glass. Adding drywall mesh to the PC would just give me a strip of PC with the mesh imbedded that didn't stick.

Is it not just s cheep to buy this set-up as it is to build it?

Possibly, but where is the fun in that?

 

[GermanRam]

True........but a $200.00 dollar broken glass would be hard to take, OUCH.
I will keep checking in to see how it's going. I hope you keep up what the tank cost minus the first glass and let us know the finnel cost. I grabbed a 7'x41"x1/2 the other day for free but I'm not sure if the tank build is for me.

 

[BadOleRoss]

While I have waiting on the replacement glass to arrive and trying to figure out how to get a seal on the viewing window, I have been working on the hood. I used an 8' T-8 light fixture from Lowe's that holds 4-48" bulbs. I have also wired in 7 receptacles that will hold what are essentially night lights with blue LED bulbs. The night lights actually have 4 different colored bulbs (red, blue, yellow and clear) but I am using them for moon lights so they will remain blue. Both lights are on separate power cords so they can go on timers. Today I will start working on filling the holes, putty, sanding, priming and painting. I also set up several test pallets to see if PC will stick to fiberglass resin, if sanding the glass helps the PC bond, if silicone sticks to fiberglass resin. When cleaning up the broken glass I found places where the PC bonded very well to the glass so there is something going on here.....just gotta figure out what!

 

[GermanRam]

Love the moon light idea! That is going to be something to see...

 

[BadOleRoss]

Testing, testing and more testing. After my first fail getting PC/silicone to seal my viewing window and breaking a $200 piece of glass I was determined to come up with a solution to sealing this tank. The test were pretty simple and were as follows:

1. Properly prepare a piece of glass and partially sand and area of the glass, apply pond coat to the glass over the sanded and unsanded area and allow it to throughly dry! Then soak it in the bathtub for several hours and see if the pond coat adheres to the glass.

2. Cover a piece of plywood in waterproof fiberglass resin. When the resin has dried, apply pond coat to the board over a large portion of the fiberglass resin. Using silicone, bond a piece of acrylic to the resin to see if silicone sticks! Allow to dry and then stick it in the tub!

The results: Pond coat did not stick to the glass at all. The glass was clean and part of it was lightly sanded and the pond coat did not stick to glass. As you can see in the pictures, it comes right off leaving no residue! Pond coat stuck like a champ to the fiberglass resin! Silicone bonded great to the fiberglass resin.

Tomorrow, I will be reworking my frame a little and then coating the inside of the frame with a couple coats of waterproof fiberglass resin. When the resin has throughly dried, I will silicone the viewing window into the frame bonding it to the resin. After the silicone has dried, I will apply pond coat over the frame up to the edge of the silicone. I am confident this will work and will leave very little, if any, resin exposed in the tank.

 

[greenterra]

It just peels off the glass like Laytex. Good to see someone actually test it. I would be using a decent marine epoxy to seal around the glass frame. Even though the pond coat will be covering the majority of it, the fact that it wont stick to glass or silicone will mean there will still be that fine edge between the 2 mediums for water to get too. I hope you get it sorted in the end.

 

[BadOleRoss]

My fiberglass resin area is going to be pretty broad. There will be a good overlap of PC and resin to prevent leaks. That one of the reasons I am reworking the frame tomorrow, to increase that bonding area.

 

[CJH]

Tomorrow, I will be reworking my frame a little and then coating the inside of the frame with a couple coats of waterproof fiberglass resin. When the resin has throughly dried, I will silicone the viewing window into the frame bonding it to the resin. After the silicone has dried, I will apply pond coat over the frame up to the edge of the silicone. I am confident this will work and will leave very little, if any, resin exposed in the tank.

If you search all of my posts you'll find a recommendation I have made involving a small amount of epoxy resin, polyurethane caulk (instead of silicone) and Pond Coat. I did something very similar to this for a few zoo exhibits years ago and it worked well. I suspect it would work with polyester resin but if it were me I'd order a small kit of epoxy or see if you can find one at a local hobby store or something.

Basically I recommend putting down a narrow strip of resin in the area you will be putting the caulk down for the glass. Make sure it's wider so you have caulk attached to glass and sealed wood only and not to bare wood.

The Pond Coat will adhere to the fully cured polyurethane caulk so that way and adhesion issues with the glass will have no effect on water holding ability.

I know you've expressed concerns about the flexibility of epoxy previously. While I think it's much ado about nothing, for certain polyester is much more brittle than epoxy resin so I want you to keep that in mind.

One of the Pond Coat distributors recommended something similar but specifically suggested a "fast cure" polyurethane caulk vs. a regular polyurethane caulk. I think a poster here on MFK posted this recommendation or even pasted the distributors email outlining this into his reply. It might take a bit of digging but I would try to find that post. I have never used a fast cure polyurethane much less in an aquarium so I can't comment further than that. I don't believe the recommendation included the narrow strip of resin but I think it's a good idea due to the viscosity of silicone or polyurethane caulk. Essentially it can't fill the tiny pores on the surface of the wood so any water than penetrates can slowly work it's way underneath silicone or polyurethane caulk.

Assuming a good bond between the Pond Coat and polyurethane caulk in theory this won't matter but I know I'd include it if I were sealing a plywood tank with Pond Coat or another product that silicone cannot be used with.

 

[CJH]

It might take a bit of digging but I would try to find that post.

Never mind. I did a search and found it.

http://www.monsterfishkeepers.com/forums/showpost.php?p=3699251&postcount=27

I still think a narrow band of epoxy is a good idea. Polyester would be further down the list but better than bare wood, IMO.

 

[greengiant]

when I spoke to a rep from Liquid Rubber they suggested using Butyl Rubber Caulking to seal the glass then PC over it. I haven't tried it or even looked at Butyl yet but passing it on. I'm waiting to get my hands on my PC so I can do some trials