Over the years I've built many ponds, including several indoor, and I've got a couple suggestions for placing and sealing your liner.
1. Lay the liner in place
2. Fill with water, adjusting and smoothing as you fill
3. Secure liner
4. Trim excess with sharp razor blade
5. Drain water
Don't drill a hole in the liner, the saw will catch and pull at the liner, sharp razor blades work best.
1. Place your bulkhead on the liner where you will install it
2. Use a sharpie to trace the outline of the bulkhead on the liner
3. Cut the circle out of the liner with a sharp razor blade.
4. Hole saw through the wood below the bulkhead
5. Silicone the bulkhead seals and tighten down onto liner
6. If you can, secure the PVC pipe close to the bulkhead to help provide support at the seal
I was also going to say to use a razor blade and not a hole saw to cut the liner. Then use the hole saw or boring bit to drill through the wood.
Lowe's sells Pipe clamp supports that use threaded rod to tightly secure the piping. I used them on my overflow drain pipes. I painted the galvanized clamps after the first set started corroding. I also used stainless threaded rod and cut it to length with a cutoff wheel.
After some consideration including some earlier advice (p1 or p2), I have decided against the pond liner. I kept reading reviews, and there's a consistent group of reviews on any brand liner that said either it leaked immediately, or within a short (<year) period of time. (thanks for weighing in on that as well)
After some research, I think I found my material, liquid rubber. The company's website shows building an aquarium with it, so the company definitely stands behind its performance in this specific use.
I think my material cost is about 180 on amazon, going to shoot off the order. I am ordering the 5 gallon so I will have plenty to over kill it.
Disappointed as I have to wait and order, but I will try to get the door built for it over the long weekend.
You could see if you can use pieces of acrylic sheet on the inside of the tanks at those mounting points I'm not sure how feasible it'll be to get the sheet sealed in. But if you can do it you'll have a nice flat surface for the gaskets on the bulkheads and still have the ability to maintain/repair them in the future because you wouldn't need to glue them in place.
Okay, I received the liquid rubber, and the geo tape stuff they recommend.
First, I needed to work on the wood itself. The tanks were built with the idea that the pond liner would be in them, so I never finished the wood or did anything about any small gaps. So i had to putty it up, and sand it down
I felt it necessary to fill in screw holes etc because I was worried that a surface with holes might allow me to miss a tiny spot, and end up with a major problem down the road.
After it was sanded down, I spent some time wiping all the surfaces down so i had as clean a surface as possible to start with first thing in the morning
Liquidrubber recommends the geotextile cloth at joints or corners to add strength to areas which might see a little movement. I watched the video on this, and found it to be a little more difficult to do than they made it look but not too bad. I did stop on each step of this process and anywhere i would have a little overlap in the cloth, i made sure to go ahead and put some more liquidrubber on it so I didn't end up with a dry spot in the cloth.
From there, i got the roller out, and went to town. I will say that it tends to bubble a pretty good bit. Not sure what's going to happen during the curing over night but i imagine I wont have a super smooth surface, but it should be fine either way. Note that the liquid rubber rolls on a deep brown, and dries to black. I have read that when submerged it will still appear brown but under actinic lighting you wont be able to tell anyways.
The top portion is only getting the one coat, where the inside of the tank will get at least 5 more coats throughout the next week. (one a day)
After that, it will rest for a week. Liquid rubber then recommends a water curing process. I am to fill it up with water, let it sit for 24 hours, and then drain it, let it sit for 24 hours. I think I am to repeat that one or twice.
Overall, I am pretty happy with the way it looks, just glad to finally be rolling foward with the tanks.
Turns out Anit called it dead on. I mounted my overflow bulkheads, and they aren't sitting flush due to the rough texture of the liquid rubber. I cranked it as hard as I could by hand as I don't have a pipe wrench and it's got a bit of a gap.
So I am going to pick up some 3m 5200 i saw works well with liquid rubber, and fill in the gap, span it out some, and then give it two more coats over with liquid rubber. it should be just fine.
So if anyone reads this planning a liquid rubber tank, be aware of problems mounting the bulkheads. I suppose if I had to do it over again, I would have mounted them right after the first coat, let it dry, and then seal with with 3M, then continue on with the coatings.
Apologies to Anit, I read your post as a suggest about being able to remove the bulkheads for maintenance down the road, and glossed over you pointing out that it would give a good seal. Still I think plexi would offer distinct challenges of it's own, but props for being able to visualize that issue the way you did
Okay, I installed the plumbing necessary to shut off the overflow.
Then got to filling it up. Scary
Zero leaks, not even so much as a creak from the wood.
The tanks are filled up about an inch more than they will normally be, I wanted to stress test it some, and submerge the bulkhead connection to ensure no issues.
Pretty big milestone, Now tomorrow I have to drain it again, and then fill it up again. Will do this a few times total, Liquidrubber says it's necessary to strengthen the seal though I honesty don't know how that would work. I imagine it's also necessary to remove any contaminants.
As it stands right now, looking like saltwater next weekend.
it has a bit of maybe a petrolium smell? it definitely doesn't smell reef safe, but they insist it's safe. After a month or two, I am actually going to send in one of those fancy tests and we will find out definitively what it does to the water.
That's not as bad as I thought then. I was worried about sulphur. Maybe a very tiny amount of dish soap in one of the middle fills. The surfactant of the soap should be mild enough to pull way any residue that flashed to the surface and you'll still filling and rinsing a few more times.
So it developed in a few spots. it formed these large soft bubbles under the coating. I wrote liquid rubber, and they think it's a pin hole leak.
What I think happened was that I had areas that had too much liquid rubber on my final coat, and those areas failed to fully cure. when water was added, it was able to get in between the last layer and the one before it, creating bubbles. i do not have any leaks, but for the sake of my sanity, im draining the tanks so i can scrape those bubbles, and apply new coats to them. it sucks, because this is going to set me back at least a week and a half, but better for the long term
Tip to anyone thinking of using liquid rubber: the side walls aren't so much of a concern, but pay close attention to pooling at corners and make sure that you brush it out flat or you could see curing problems.
On my lunch i went down there, got them drained and dried out. I ripped into one of the bubbles and found that it was indeed my last coat. They really should have warned about a coat that's too thick (even though it's pretty obvious). My assumption that liquid rubber didn't cure completely, and water got into the layer was correct. Under each bubble was a mixture of water and uncured liquid rubber. When i peeled back that layer there's still plenty of liquid rubber underneath which explained why it didn't leak. This is the best case outcome of this issue. I actually considered just moving forward anyways, but ultimately thought against it because i was afraid that uncured liquid rubber would be leeching into my tank.
so I ordered another gallon of liquid rubber to be here on sunday. i will hit it with another layer or two in the spots where it failed, and it should be good. Also going to get a dehumidifier setup in there asap to promote stronger curing.
if i had it to do over again, I would have done 10 coats, with really thin layers, and very likely hand brushed it instead of rolling it.
BTW, i was looking and I can't believe I did this in a tank thread, when it really should be in DIY, can you move it over to there?