# Plywood Tank Questions



## BigDaddyK (Nov 6, 2006)

I have been planning an 800g+ tank for about 4 weeks now. I am thinking that before I take on that project I need to try a smaller version. I'm going to build a 240 using the glass out of my 135.

I plan to use West Systems to seal both tanks but I have a question. I'm not sure when to mount the glass. Logic (albeit mine thus not necessarily logical) tells me that I should seal the entire aquarium, then attach glass. I can't seem to find information on how silicone will seal to the west systems.

Can anyone offer some experience based thoughts?

Thanks!!


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## Rhinox (Sep 10, 2009)

> Can anyone offer some experience based thoughts?


No, but I can offer you some research based thoughts 

From what I've researched with some big tanks, if the silicone doesn't bond well, then braces are used to hold the glass until the water is in, and then the water pressure holds the glass in place, with the silicone actiong as a gasket.

But I would think, if the epoxy (thats what west systems is) is scuffed up and clean, the silicone should bond to it. I guess you could always make a test sample, take a small square of plywood, cover it with the epoxy, and try to stick a small piece of glass to it and see how well it holds. Its well worth the time and would only cost pennies.

What you're doing is exactly what I plan to do when I build my big tank some day.


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## BigDaddyK (Nov 6, 2006)

Hey Rhinox,

Thanks for the feed back. I've done a lot of research too. I'm not a fan of the "just put water on it to hold it in place" idea. I appreciate what you are saying but for my own sanity it will have to make a good bond on it's own. I like your test it out idea much better 

I will have to make that happen.

anyone else with experience? ? ?


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## Dieselfool (Aug 11, 2010)

MFK has lots of DIY plywood/epoxy builds. Go check'em out.


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## BigDaddyK (Nov 6, 2006)

I've been looking there... I haven't seen anyone actually state when they add the glass and if it's adhering directly to wood or epoxy


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## Dieselfool (Aug 11, 2010)

I belive some of them said they applied the epoxy 1st, then the calking on top. I only seem to remember this cause one or two of them mentioned roughing up the epoxy with sandpaper to give the calking something to grab onto. I belive this is how I'm going to do mine, unless of course I find something better.


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## 98dak83cam (Jan 16, 2006)

I built a 1000 gallon tank a few years ago and it is still running strong, no leaks at all. I used epoxy from US composites in Florida, much cheaper and just as good as west systems. I let the water pressure hold my glass, and it is about 100" long and 45" tall. I used GE I silicone.

Here is the complete step by step to building it - http://www.cichlid-forum.com/phpBB/viewtopic.php?t=148215


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## BigDaddyK (Nov 6, 2006)

Thank you for the link and the response.


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## auratum (Jul 6, 2006)

BigDaddyK said:


> Can anyone offer some experience based thoughts?


I just finished my plywood tanks. Go ahead and seal it all with epoxy first. Once the whole thing is sealed I lightly sanded the surface where the glass was to adhear to. This worked just fine. Mine (420, 225, 150) have been holding water now for around 6 weeks - not as long as others on here. http://www.cichlid-forum.com/phpBB/view ... &&start=90

I wouldn't spend top dollar on the West system - there are cheaper options. I bought material from Progressive Epoxies - http://www.epoxyproducts.com/. Their web site is a little complicated but there is tons of info on epoxy products.

Good luck and keep us posted.


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## BigDaddyK (Nov 6, 2006)

This is excellent information. I can now build a 240 and then just house my fish temporarily while i cut up the 135 and silicone the glass in place. The main reason for West systems is proximity. There is a dealer within 10 minutes of where I live. I appreciate the website provided and I'm not 100% sold on West but I think I'll probably go that route to avoid shipping costs and potential border hold ups.


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## Dieselfool (Aug 11, 2010)

BDK, where you at? I'm in Barrie and I'm going to be starting my build as soon as this winter thing starts to break. No garage to work in so I'll have to do the epoxy thing outside.


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## BigDaddyK (Nov 6, 2006)

I'm in Niagara Falls Area. Thats another reason I'm likely using West Systems. Fumes. From what I've read it's not too bad. I might do a 240 outside but I will not have that luxury should I move forward on my 870 build.


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## Dieselfool (Aug 11, 2010)

870!!!!!! Wow! Very cool. I believe I've setteled on 350 8'. Already have my glass (86"X24"X10mm tempered), just waiting on the weather. I went and checked out my local W. Systems dealer here in Barrie and WOW! That stuff's a bit pricey. I believe I'm going to be finnishing mine with Zavlar, so I'm not too worried about toxins, so I may just try to find an alternative to W.S. epoxy I'm gonna be keeping an eye on your build, so I hope you post lots of pics. Good luck.
Al.


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## BigDaddyK (Nov 6, 2006)

I haven't really priced it out. I'm curious on what you've found ?? maybe I will consider alternatives LOL

There is a window where I plan to build the 870 so I could setup a fan and just keep the air as fresh as possible.

Good luck to you too.. I figure the 240 will be a nice "small scale" for me LOL


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## auratum (Jul 6, 2006)

The Epoxy you choose should be solventless - that is what makes the fumes. I did my entire build in my basement and there was almost no smell. My wife is very sensitive to smells and she never once complained. The epoxy systems that use solvents do so to dilute them and cut the cost to make them (more money in their pockets). The only time you would need one with a solvent is if you are trying to repair rotted wood and you need a penetrating epoxy.


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## Dieselfool (Aug 11, 2010)

auratum said:


> The Epoxy you choose should be solventless - that is what makes the fumes. I did my entire build in my basement and there was almost no smell.
> 
> The only time you would need one with a solvent is if you are trying to repair rotted wood and you need a penetrating epoxy.


Good to hear there are alterntives.

But would it not be good to have the 1st. coat of epoxy nice and thin, to penatrate the wood for exta sealent? Then to put 2 or 3 coats on top?

Sorry BDK, not trying to hi-jack your thread.
Al.


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## auratum (Jul 6, 2006)

Dieselfool said:


> auratum said:
> 
> 
> > The Epoxy you choose should be solventless - that is what makes the fumes. I did my entire build in my basement and there was almost no smell.
> ...


I had thought the same thing, but newfisher on here coached me otherwise and it was great advice. New wood is sound enough and the epoxy will stick to it and penetrate sufficiently to seal it. The epoxy I used turned rock hard after it cured and is so durable I have no worries about this stuff lasting. As I learned, the key to epoxy is to put it on in rapid succession while the previous layer is still tacky. It binds better to itself when wet and it avoids you having to sand. Another key is to use non-blushing epoxy - the amine blush will mess with bonding between layers. The higher the humidity the worse epoxy can blush, but better epoxies are formulated to not blush as badly. If you read pages 4 & 5 of my build thread, there was some great advice from *newfisher* on how to work with epoxy!


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## BigDaddyK (Nov 6, 2006)

Hi-Jack away!! I am learning here not trying to make sure only my questions are answered. You thought of something I hadn't I'm glad to see your point of view and get an answer for a question I wouldn't have considered.


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## auratum (Jul 6, 2006)

By the way - you want to plan on at least 3 coats. Base coat to wet the wood that you then put the glass cloth on immediately while still wet. The second coat you put on immediately after the glass cloth to "wet it out". The last/top coat is where I added the pigment - again you would like to apply this while the previous coat is still wet. You don't have to add pigment, but that is what I wanted to do. A little pigment goes a long way but follow the directions on the can. I bought my pigment from US Composites.


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## BigDaddyK (Nov 6, 2006)

excellent information auratum... I've been trying to understand the wetout step... it's logical but you never know until you find someone that's done it or find good driections. I definitely want pigment... i'd like a slate grey but black would work as well


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## Dieselfool (Aug 11, 2010)

Hey BDK, is the epoxy going to be your finished coat. This is what I planned on doing because like you, I wanted a nice color (black for me) and the W.S. guy said I could just use the pigment to color it. Then I read some threads about epoxy cracking over time. One thread on MFK in particular showed pics of the bottom seams all cracked and rusting screwheads showing through after a couple of years. This kinda worries me cause of flexing when I drain it down to move to a new house (with a bigass garage/shop) :drooling: This is why I'm planning on sealing with Zavlar, even though I know it will turn a brown color after exposed to water. I saw some pics of a Zavlar finished tank and it looked pretty good, not as nice as black, but I think I'd sleep better at night. LOL.
Any thoughts Auratum?
Al.

P.S. I believe the thread in question on MFK was titled, A Cautionary Tale, or something like that.


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## BigDaddyK (Nov 6, 2006)

I do plan on using Epoxy for the final coat. I will be looking up that thread on MFK if you find it pls link it here.

I really want to have greyish black or black for the background. I think it's very important to follow the directions on the mixing of the hardener. I can't say as I haven't read the thread but I used to work in an autobody shop and I know if you put too much hardener in you are going to have a cracked finish.


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## auratum (Jul 6, 2006)

I hadn't seen the thread on MFK, but I just looked it up. The issue this guy had is that he didn't use glass cloth. All he did was put on lots of coats of epoxy. The strength comes from the glass cloth, the sealing comes from the epoxy resin - you need both if you want this thing to last. He also mentions he used polyester resin on another tank. Polyester resin is not waterproof so you would need to coat it with something that holds water.

For my build, I put glass cloth on the bottom first with it overlapping the corners, the I put it on the sides overlapping the bottom. So every inside corner had two layers of glass cloth with the corners having 3 layers. I also built it so there were no internal screws or through holes other than for the glass or the bulkheads. I also put a layer of epoxy & glass on the outside edge of all seams to reinforce them. I used ~9 oz glass cloth. I bought the cloth from here: http://thayercraft.com/ I bought both the wide cloth and the glass tape. The tape was only used on the outside corners and could be skipped it you didn't do that part. I recommend buying cloth wide enough to overlap edges by at least 2".

The biggest issue with epoxy resin is that it is not UV resistant - this should not be a problem unless you are building a boat in which case you then need to paint it with UV protectant paint.


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## auratum (Jul 6, 2006)

BigDaddyK said:


> excellent information auratum... I've been trying to understand the wetout step... it's logical but you never know until you find someone that's done it or find good driections. I definitely want pigment... i'd like a slate grey but black would work as well


Here is the pigment section for US composites: http://www.uscomposites.com/pigments.html

Looks like you have some options for gray. You may want to blend black & gray if you want it darker than what they offer. I used the Indigo blue and I love the color - it is very hard to photograph the true color.


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## BigDaddyK (Nov 6, 2006)

What you described for the edges is pretty much what I imagined i'd need/want to do. a lot of great information. I think I need to secure some epoxy and cloth and give this a try!!


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## Coln (Dec 17, 2007)

Hope this helps a bit, plywood the way to go but def a learning curve

http://www.cichlid-forum.com/phpBB/view ... c&&start=0


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## auratum (Jul 6, 2006)

Your build is sweet Coln. Agreed on the learning curve comment. I would have no qualms about doing another though, now that I have done one.


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## BigDaddyK (Nov 6, 2006)

Hey Coln, I read your thread start to finish not to long ago. It provided a lot of ideas for me. Thanks for the link so I don't have to go searching again LOL


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## Dieselfool (Aug 11, 2010)

opcorn:


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## Guest (Feb 23, 2011)

Curious about the age of some of your builds here. I built a plywood tank and sealed with epoxy back in the early 70's and while it would still hold water now I had to take it out of service as the epoxy started to get small hairline cracks and I was afraid the wood would begin to take on water and swell and then leak. The idea of using glass clothe back then was not thought of so not done. The glass panels were siliconed to the epoxy and the corners were siliconed just like a glass tank. It all worked fine for many, many years. I think that over time UV from the sun through windows and perhaps even enough from the lights got to the epoxy and caused it to deteriorate. As a side note this tank had a wood bottom,back and half sides. The front and half way back on the sides were glass. I don't have a pic site so I can't post a picture, but I have one with some discus I kept from the 70's. The reason I question the age is because of what happened to the epoxy on the tank and I had a fiberglass canoe that did the same thing after sitting out a decade or so back then.


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## auratum (Jul 6, 2006)

If I get 40 yrs out of my build I would be happy! Not sure what the expectations are from others from a plywood tank. Even all glass tanks require maintenance - I have had to reseal old glass tanks where the seams failed.


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## BigDaddyK (Nov 6, 2006)

I understand completely that UV is not friendly to an Epoxied (is that a word) Tank. That Said I'm quite happy with 40 yrs and only hair lines... Heck I'm 36 and I have more damage than hair lines :lol:


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