300gal plywood paludarium project

the_deeb

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Ok, time for some more updates.

Here's the bottom installed:



The bottom is glued to the sides and to the lower bracing with thickened epoxy. It is also screwed into the bottom bracing with screws every 2" and also screwed to the sides with pocket holes (staggered relative to the pocket holes in the bottom bracing).

You might recall I mentioned near the start how I discovered that "3/4" ply isn't actually 3/4" (more like 11/16"). Because the sides are joined with miters and my bottom piece is inset into the sides, this meant that the bottom was 1/8" too small. To deal with this I cut some 1/8" slivers from some scrap poplar and epoxied them into the gap. The pocket holes are actually driven through some of these poplar shims. I think this has addressed the problem quite well.



I filled all remaining screw holes and gaps in the bottom with wood putty, sanded and them painted with 3 coats of Drylok. Here's how it looks:



For those of you know don't know, Drylok isn't smooth like paint. It's filled with bits of sand. This means the resulting finish is quite rough and can't really be sanded for a smooth finish. Here's a closeup:



I didn't know this to begin with and this wasn't the effect I was going for. Ultimately, it doesn't really matter since its the tank bottom and is just going to be sitting on styrofoam. I was initially going to use Drylok for the top of the tank and the inside of my stand but after seeing how it looks I think I'm going to use Kilz instead for a smooth finish.
 

the_deeb

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Ok, so I'm wondering whether to use Pond Armor instead of Pond Coat to seal the tank. I like the flexibility of the Pond Coat, but it's going to involve more work sealing the windows and extra work/cost getting the background to be black when submerged. Pond Armor is an epoxy so silicone will stick to it and it will stay black underwater without any additional treatments. Plus, Pond Armor is available locally from a place just a couple of miles away from me.

Unfortunately, I'm worried that because I don't have any external bracing there's going to be too much flex in my structure for Pond Armor. But admittedly, my water depth is only going to be around 15", so the pressure shouldn't be too high. What do you guys think? Will Pond Armor be flexible enough?
 

the_deeb

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So no one has any thoughts to contribute? I guess this build isn't really "monster" enough to garner much attention on this site. Anyway, here are some updates.

I had some extra West Systems 105/206 left over so I decided to fiberglass the seams on the submerged part of the tank for good measure. I'm glad I did - now they're strong, completely sealed and should resist the formation of any potential stress cracks. I've never worked with fiberglass before so, as with everything else about this build, it was a learning experience and I got better as a I went along. Here's how I did it worked once I had the whole process figured out.

First I tilted the tank at an angle so that all residual epoxy resin would pool into the seams, deeply penetrating them and effectively creating a fillet. This was a little cumbersome because I had to reposition the tank for every seam, but it worked out very well.



I coated the seams with an initial layer of epoxy to saturate the wood and provide an initial barrier coating. I also dripped a little extra epoxy into the seams to make a slightly thicker fillet.



After this first layer had dried and was no longer tacky, but not completely cured, I layed out a strip of fiberglass cloth into the corner. I just used the cheap, lightweight Elmer's brand cloth from Lowes since I figured it would be adequate for my purposes.



Here's the strip wetted out with epoxy. After brushing it on I used the flat end of a stir stick to really push it into the seams and force out any air bubbles. Make sure to work out the air bubbles while it's wet and you still can. Then I dripped a little extra epoxy on to really get a nice thick layer in the seams.



After waiting a few hours for the epoxy to gel (but not harden) I used my trusty paring knife to trim off the excess cloth to get a nice clean edges. I found that you musn't try to trim the cloth before it sets up or you'll pull it out of place and introduce air bubbles. Similarly, if you wait until it's completely cured it becomes too hard, making it difficult and dangerous to cut. Do it when it's tacky and rubbery.



And there you have the finished, reinforced seam. I'm also planning on adding an extra 4" strip of plywood running horizontally across the rear of the tank about half way up (just above the level of the water). This will add some extra rigidity to the long back panel and hopefully reduce any flex caused by the water pressure. I think that with these reinforcements I should be able to safely used Pond Armor to seal the tank and not worry about delamination or stress cracks forming in the seams.
 

mike huntley

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mate, this is really interesting to me, i have only just found your thread and not had much time to read through it as yet, but it looks great and is coming along nicely. Pond armor should be strong enough for sure, especially as you say the depth won't be much. what are you going to stock it with ( you've probably posted that already, im just lazy! :grinno: )
 

pengu13

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I just about finished up my build with pond armor (pond shield) it was interesting to work with i had to thin it out alot to get the coverage i needed. The directions call for a 1/4 cup of alcohol per half can but i ended up using 1 cup per half can. it made it more workable and so i could get two coats out of it which i need, lots of little holes to fix. I used it over epoxy, i used a good auto body prep spray like suggested but i think i just didn't get it clean enough on the bottom and thats why it fish eyed on me. thats what i can think of plus that is were i put it on as directed with the 1/4 cup mix after that i thinned it right out.

Here is a pic of what i'm calling fish eye in the epoxy. Oya save some till the end there will still be spots.

P7160006.JPG
 

Burko

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Hey deeb

As for your question...

"When you left the T unfixed did you experience any leaks? Any tricks to seal it while still allowing movement? Did you ultimately glue it once you had the water level set? Finally, are you happy overall with this style of overflow? Anything you would change if you were doing it again."

I'll post a picture.



As you can see the 'Tee' and the 'still' unfixed pipe are quite high so only a little pressure and no leaks. The sump is directly below the pipes so any dripping would have been no concern.

The drain below needed fixing, so I'd suggest the answer is entirley depth dependent.

If I did it again I would lower it to half way for 50% water changes. But other than that it suits my purpose well.

Fish 3 080.jpg

Fish 3 081.jpg
 

pengu13

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yes i did cover another epoxy with the pond shield. i prep sanded all surfaces with 60 grit vacuumed then wiped with wet rag then sprayed and wiped it down with a automotive body prep spray like the directions say. i add the extra alcohol when i realized i would only have enough for one coat the way things were going the back and sides were thinned and didn't show nearly as much fish eying on the first coat as the bottom. the second coat coverd most of the holes then went back a third time to patch any spots i could see wood . now i'm waiting on the silicone to dry so i can see if it worked.
 

the_deeb

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Thanks guys.

Mike - I'm not sure of stock yet. My goal for this build is primarily to create a nice planted display and will then choose inhabitants to fit the display. I'll probably move in my clown loaches from my current tank and may get some other kinds of loaches. I'm going to have to think about what fish would look good in a shallow tank. Rays would be awesome but I don't think it's big enough. A single male hystrix might work. For the emersed portion I was thinking dart frogs, but my wife is really against the idea of breeding fruit flies in our apartment. When this thing is finally ready for inhabitants I'll post for suggestions.

longliveledzep - I'm planning a bentonite clay dripwall for the emersed part but would like the submerged part to just have a plain black background. I'm carving styrofoam tree roots that will take up part of the background (both emersed and submerged).

Burko - thanks for the pics. It makes sense that the leaking is pressure/depth dependent. Hopefully it means I can leave my upper T unfixed to allow for some height adjustment like you did. I'm still trying to decide whether I want to include the lower ball valve for water changes. It's a nice idea but I'm not likely to be able make use of it based on the layout of my current apartment. I'm not sure if I should include one anyway in case I can make use of it in the future.

Pengu - thanks for the info. So it sounds like the "fisheyeing" isn't really a problem as long as you have enough pond shield left over to go over again. I hadn't heard about using the auto body prep spray. I was planning on just wiping down with alcohol after sanding.
 
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