# DIY plywood terrarium questions.



## thedudeabides (Mar 3, 2015)

I am researching building a terrarium out of plywood. If I did this would be several years down the road so I have some time to think about this and work out any kinks. I have a few questions regarding sealing the tank and making a background.

1. If I used an epoxy coating to seal the wood could either GS or silicon adhere to it once dry?

2. Is there anything I can do to make that happen. Like add sand to the epoxy when it is drying to increase texture. Or use a sponge while drying for the same effect?

3. If that wont work could I use silicon to seal the tank where the background will be? How expensive would that be if this tank was relatively big? (I am thinking somewhere in the 4' X 2' X 4' neighborhood)

Thanks in advance


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## Kalle (May 14, 2010)

I was just watching a few good tutorials on plywood tanks the last few days on "the king of DIY" on YouTube. He built aquariums but the same principle applies to vivariums. 

HOW TO BUILD Aquariums: http://www.youtube.com/playlist?list=PLcWeEm9w62maxRP9hUzeWSR2NsoCK0prQ


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## Grimsrude (Apr 6, 2017)

Another source I've been looking at is http://www.garf.org/tank/BuildTank.asp.

Not watched the videos Kalle posted - at work haha. Will likely look later though. But I imagine it's much of the same information just in text format. 

I'm not entirely sure about the biggest concern you have which is adhering the background. I've not worked with silicon + wood anytime recently (and if I have in the past, it was by accident working in construction), but I don't think silicon adheres to wood terribly well. For the background, you might honestly be better off making a background outside of the enclosure and using something like liquid nails to adhere it to the plyboard on the back, and then use epoxy to seal the edges to keep it safe - and I know from experience silicon doensn't bond too well to epoxy, but since you've sealed what should be just the edges with epoxy, you could go over that with silicon and then coco coir / background substrate for aesthetics, as it shouldn't be too bad as long as the rest of the background is solidly in place.


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## Kalle (May 14, 2010)

I was on my phone earlier so I just threw up the link to the playlist. 

Here's the links to the two builds with plywood:

First one with a glass front viewing panel:





Then one with four sides of glass and a bottom of plywood:





Joey silicones the glass to the epoxied plywood. Don't know how strong the bond is but in his cases the water is pushing the glass towards the wood so there's no big forces involved. Personally I think silicone would be able to hold up a background on an epoxied surface.


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## kimcmich (Jan 17, 2016)

@thedude,

My previous terrarium was an epoxied plywood build. I used both West System epoxy and a Sherwin Williams potable-water-safe epoxy paint.

Both silicone and GS adhered just fine to the epoxy. I used silicone to mount spyra panels and GS to fill-in voids in my background. When I disassembled that viv last month, the siliconed and GS'd items were still firmly attached.

Note: Neither GS nor silicone adhere well to acrylic or polycarb plastic. In both cases, they adhere while wet but once dry the bond is not strong and can fail suddenly. In the case of silicone, it peels off like a decal once dry.


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## thedudeabides (Mar 3, 2015)

Thanks for the responses everyone! 

That is a good point that the glass is siliconed to the epoxy. I am toying with the idea of doing a paludarium since this build would be such a monster. I am such the force of the water probably helps but I would think it would have to be a strong bond regardless or it wouldn't be done. 

@ kimcmich thank you exacally what I was looking for! Do you happen to have pictures of the set up? How long did you have it set up for?


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## kimcmich (Jan 17, 2016)

@thedude,

The post about the older viv is here.

The viv was in-service for about 1 year before I upgraded and the silicone and GS were still very firmly attached when I broke it down.


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## thedudeabides (Mar 3, 2015)

kimcmich said:


> @thedude,
> 
> The post about the older viv is here.
> 
> The viv was in-service for about 1 year before I upgraded and the silicone and GS were still very firmly attached when I broke it down.


Wow that is an awesome build! Never thought of using shower doors. Now something else to consider. I was planning on using sliding glass doors, how did you find using the shower doors worked out?


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## kimcmich (Jan 17, 2016)

The shower doors worked great - I have zero complaints about their performance. I was able to use clear plastic edge protectors to create a bug-tight seal between the doors.

In my newer build I went with flat glass panes and side-pivot hinges. This was cheaper than the shower doors and very easy to mount.


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## Pumilo (Sep 4, 2010)

Grimsrude said:


> Another source I've been looking at is http://www.garf.org/tank/BuildTank.asp.


Now there is a blast from the past. Garf is the Geo Aquathermal Research Foundation. Leroy and Sally Jo Hedley are great people, who have given so incredibly much to the coral reef hobby. 
I had the honor and pleasure of attending one of their coral farming seminars, wow, must have been about 18 years ago. It's one of the few events I can remember as if it were yesterday. Who would have ever thought that a 3 day trip to Idaho, would be my dream vacation? A couple of the highlights were supplying their genetic stock with around half a dozen unique, new corals, taking home a flourescent green Nepthea coral, which was later spread heavily throughout the hobby, and finally, smoking a cigar with Albert Thiel. I had a blast and wouldn't change that experience for anything this world has to offer.
Google, "Garf farming Doug Hollister", sometime, for a little blurb that has nothing whatsoever, to do with frogs.

Anyway, sorry for the sideline, back to business. While I haven't looked them over, I know the plans from Garf would be quite solid. They had a big contest to see who could build the best plywood tank, open to any and all. As I understand it, their plans would be from the best submission. I don't know how they judged, but they are good people, and I know they put their due diligence into making sure it was safe, before releasing plans.

Your seams are everything. They can not flex at all, or it will snap a seam right through the inner coating, and blow out. Of course you won't have as much pressure on a viv, as they do with their plywood reefs, but you could still develop leaks, rather than a 200 gallon blowout. Ever seen a 200 gallon reef tank blow out? I have.


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## Grimsrude (Apr 6, 2017)

Haha, glad to have given you a nice chunk of nostalgia Pumilo, and nice to know they have a good reputation as well! 

Sent from my LG-H910 using Tapatalk


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## cam1941 (Jan 16, 2014)

West System is truly a great product. You can make anything with this stuff. Truly a pleasure to work with but get the perfect pour pumps. You buy them separately but they are so worth it and make the epoxy a dream to work with. Barely any waste if any.

You have to mix the epoxy at a ratio of 3:1. With the properly sized pumps the ratios are achieved perfectly with one pump from each part. Just screw them to the top of each can. Makes a nice small amount each time so you always have plenty of time to apply. 

Once dry everything turns into a hard plastic. This stuff is like an analog 3D printer, you can make anything. 



kimcmich said:


> I used both West System epoxy and a Sherwin Williams potable-water-safe epoxy paint.


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## kimcmich (Jan 17, 2016)

@cam1941,

For clarity: The resin-to-hardener ratio may be 3:1 _pumps_ but that is not the actual ratio, by volume, of resin to hardener. The mixing ratio by volume is *5:1*. I hope no one goes by discussion group rather than the directions on the label - but just in case...

I don't use pumps since they don't support mixing small batches. For that, I use graduated plastic mixing cups I got from the boating supply shop where I got the epoxy (they have them at paint shops too)...


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## cam1941 (Jan 16, 2014)

I was giving you props for your recommendation but now I have to wonder if you even used it LoL



The directions for the West System Epoxy I have clearly state *3:1* so your wrong about that unfortunately. Most importantly you're wrong about the pumps. Have you used them?

The point of my post was that the pumps make this stuff a dream to use. Its actually fun because its so easy and the base amount is small as I wrote in my first post LoL

Mixing with cups makes epoxy an intimidating mess and its harder to mix small batches. Way more waste. With the pumps there is no waste other then what remains on the brush.





kimcmich said:


> @cam1941,
> 
> For clarity: The resin-to-hardener ratio may be 3:1 _pumps_ but that is not the actual ratio, by volume, of resin to hardener. The mixing ratio by volume is *5:1*. I hope no one goes by discussion group rather than the directions on the label - but just in case...
> 
> I don't use pumps since they don't support mixing small batches. For that, I use graduated plastic mixing cups I got from the boating supply shop where I got the epoxy (they have them at paint shops too)...


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## kimcmich (Jan 17, 2016)

@Cam1941,

We are talking about 2 different West System epoxy products (but thanks for suggesting twice in your response that I might just be lying instead).

I have not used the pumps, that's why I said they 'may' be 3:1. 

Without the pumps, I have used West epoxy with both the Fast (205) and Slow (206) hardners. _Both of these hardeners are mixed 5:1_. I checked the website before my original response.

The Clear hardener (207) is indeed a 3:1 mix ratio (_Clearly_ I have not used this hardener!) The minipumps you posted are specifically for the 207 hardener. I'm not sure if they make mini pumps for the other hardeners - the pumps I have seen are fairly large for 205/6.

The 205 and 206 hardeners are the most commonly available in my experience (ie they are stocked by local shops that carry the poxy) and both are cheaper than the clear hardener. 205 works in the widest range of temperatures and both 205 & 206 cure to full strength in 1/2 the time of the clear hardener.

Regarding cups vs pumps - I think it's largely a matter of preference but both can be used with "zero waste".

In my case, I use small, graduated plastic cups I bought from the epoxy supplier. You pour the resin and hardener into the same cup - using the bars to measure the right ratio. When the epoxy dries, it peels off of the cup so you can re-use the same cup again and again.


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## jgragg (Nov 23, 2009)

Right off the bat, I'm not a mod, just a community member. This has been a very interesting thread from a technical and aesthetic standpoint. I think this is a good point to take stock of where we're at with the OP's questions, and the useful answers & contextual info s/he's gotten, and maybe see if we're done. If anybody's got anything to work out 1:1, by all means go for it. Like that, I mean - 1:1. Thanks for keeping it nice here.

cheers


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## thedudeabides (Mar 3, 2015)

Nothing wrong with a little healthy debate. I think I got the answer I needed for the original ? in that silicon and GS will stick to dried epoxy (unless someone else can say otherwise). I do appreciate the additional comments as they are all things I will need to consider down the line. The pumps do sound easy and may be a little less intimidating for my first plywood build. One of the reasons I want to do a terrarium or paludarium for my first project with plywood is the fact I do not want 200 gals of water on my basement floor (although if I go paludarium I will probably have ~ 100 gal so whats an extra 100 on the floor )


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## Pumilo (Sep 4, 2010)

I know silicone inside and out, having used thousands of tubes in my career as a glazier. I would sand it rough first, and degrease it with a solvent that is epoxy friendly, but silicone should bond just fine to dried epoxy, but of course you know to do all your silicone work at once. You won't be able to get new silicone, to stick to old, cured silicone, or even silicone you put on 20 minutes ago. Silicone is what all the reef tank people are using on plywood and epoxy tanks.
Fresh, wet silicone gives a good bond with most surfaces. It simply hates many or most plastics.
Silicone's weak point comes in after it dries. After it dries, pretty much nothing will stick to it, including paint, fresh silicone, and other adhesives.

Great stuff I can only make an educated guess. I think great stuff would probably bond better to your epoxy, than it does to glass or silicone.


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## kimcmich (Jan 17, 2016)

"I would sand it rough first, and degrease it with a solvent that is epoxy friendly" 

Pumilo makes an important point. Epoxy can cure with an invisible surface deposit called "amine blush" which can prevent anything (including more epoxy) from adhering. The blush is easy to remove with soap and water but a mild solvent like rubbing alcohol will clean even better. I skipped a surface clean in a small area of my new build and I see yellowing from the amine blush now. In this case it is only cosmetic and out-of-sight - but in a more vulnerable or visible spot is could have been a problem.


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## OllieNZ (Apr 6, 2012)

If you're not using fiber reinforcement for the whole thing I'd use a at least a 2" strip around the seams. You can buy it as a tape on rolls. When the resin is combined with fibre reinforcement it's more flexible and less prone to cracking, meaning you could have a little bit of flex and not crack open to seal in the corners.


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## npaull (May 8, 2005)

Go with System Three Silver Tip epoxy!

https://www.systemthree.com/products/silvertip-laminating-epoxy-resin

I've used it for several plywood tanks now (one currently in the works) and I like it MUCH more than West Systems or any other epoxy I've tried (I've built many plywood/epoxy tanks).

The 2:1 mix ratio makes life WAY easier, and you're much less likely to get slow or incomplete cures due to slightly-off mix ratios. There is no amine blush, it bonds beautifully to all sorts of stuff (including glass btw), has a nice pot-life but a pretty quick dry-time. They have a bunch of other products that are super useful too for vivarium building, (such as EZ-filet).

It's by far my favorite epoxy for this application.


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## npaull (May 8, 2005)

> great stuff would probably bond better to your epoxy, than it does to glass or silicone.


Great stuff bonds ok to epoxy in my experience. Well enough so that if the GS structure isn't too heavy you probably don't need extra reinforcement. I always epoxy or otherwise cover my GS when it's attached to epoxy though. You CAN peel the great stuff off of epoxy, it just takes some pull. For what it's worth, I think it bonds better to epoxy than it does to glass. But usually when I'm making a plywood/epoxy tank, it's pretty big compared to glass, so the background has more downward/pulling force, so it's kind of a wash...


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