400 gallon plywood aquarium. 600+ gallon system

[Mr_Stian]

It's been a very productive weekend. On Friday i managed to cut all the plywood and on Saturday and Sunday it was all screwed and glued in place. Today i hope to sand down some of the corners as they were not 100% aligned and i will start applying the first coat of Pond Shield.
Both the front and side panels have double layers of plywood. And the rear has 6 extra vertical 10cm strips. But as AlexG had some issues with his tank i will reinforce the tank with horizontal beams once it is placed on the stand.
Hoping to glue the glass early next week. After this there will be added a top brace of 2"x4" beams with three 3x10mm aluminium braces across. This aluminium brace will be glued and screwed into slots on the top bracing.

So to some pictures:

Main panels in place

Had to secure the front panel before screwing the bottom in place so that this was straight.

Before adding glue to the bottom panel

Finished with all panels!

Pre drilled holes for the bulkheads in the top sheet. Will be drilled all the way through later today.

Since i do not have a double bottom i added a extra internal support consisting of a 2"x2" beam screwed from the outside.

Hopefully the inside will be black later today!

 

[Mr_Stian]

First coat of pond Armour applied. I have read that this stuff is supposed to be almost smell free. It is not! Not as bad as regular epoxy but it still smells quite bad. Same level as a smelly wall paint.

Anyway, it came on quite nice. Easy to apply and easy to mix. Tomorrow I will do the seams with fiberglass cloth.

 

[andrewkw]

Looks good so far!

 

[Muttley000]

How many coats are you planning? Did you apply with any special device?

 

[Mr_Stian]

I will do a minimum of 3 coats. Maybe more depending on how much pond armor i have.

I used a small paint roller to apply, and a small paint brush for the corners.

 

[SPR1968]

Great pictures and thanks for sharing it with us in such detail, very nice!

 

[Mr_Stian]

Today I did the corners with fiberglass mats. A real pain in the butt to do. I found out early that I had mixed too much to apply good in a half an hour so I had to rush it. So it is not the nicest finish, but it will work.

Next step will be to apply coat 2 and 3 on the rest of the tank. Hopefully I will manage this in one day so that I don't have to sand between the layers.

Just a quick picture of the result:

 

[Pntbll687]

Looks good!

It should blend in nicely with the next couple of coats.

And these plywood builds amaze me. I'm nervous to drill a tank on my own and you guys are building your own tanks! Consider me impressed

 

[Muttley000]

Looks great! What weight of cloth did you use?

 

[DCR]

I don't have any experience with plywood tanks, but I think you may be underestimating the amount of structural bracing that is going to be required for that span and depth - especially on the front and back. I fear you are going to get significant bowing. I will defer to someone with more structural expertise, but I would be surprised if you can get by with less than something like 2x6's or even 2x8's laid perpendicular to the panels. I would also be concerned about how well those seems are going to withstand the pressure.

 

[Mr_Stian]

I don't have any experience with plywood tanks, but I think you may be underestimating the amount of structural bracing that is going to be required for that span and depth - especially on the front and back. I fear you are going to get significant bowing. I will defer to someone with more structural expertise, but I would be surprised if you can get by with less than something like 2x6's or even 2x8's laid perpendicular to the panels. I would also be concerned about how well those seems are going to withstand the pressure.

Thanks for the input. But i am confident that the structure will be good once i have put the 2"x4" beams onto this. There is a guy here in Norway that has built quite a few plywood aquariums and he says that a 15mm sheet of plywood of 90cmx207cm will bow out 2-3cm with only one 2"x2" beam. He says that one 2"x4" was enough to keep this from happening.

My tank is made of 18mm plywood, and it is double on most areas. So after the added support from the 2"x4" beams i think there will be little to none bowing.

Regarding the seams this is made in the same way as all the other plywood aquariums. i only added the 2"x2" to support them. The strip of fiberglass (which i think was 200gr) is as recommended by Pond Armor.
This morning i found out that i had made a rookie mistake and there were some air bubbles in the cloth. So i will sand these down and put new cloth on.

 

[Cabinetman]

I built a 96x30x29 plywood tank about 6 years ago and only made it out of 1" plywood glued and screwed together then fiberglassed in the corners and then epoxied inside. I then put a 1x3" frame around the top with cross braces every 2 ft and that tank is still going. There wasn't any noticeable bowing

 

[Mr_Stian]

I built a 96x30x29 plywood tank about 6 years ago and only made it out of 1" plywood glued and screwed together then fiberglassed in the corners and then epoxied inside. I then put a 1x3" frame around the top with cross braces every 2 ft and that tank is still going. There wasn't any noticeable bowing

Thanks for the input. Even though mine is about 6" taller i think the 2"x4" on edge horizontal brace will be enough to keep it from bowing.

 

[Mr_Stian]

Dilemma dilemma! I have now done 3 coats, but I would really like to do one more coat. But I don not have enough to do this and waterproof the top brace! After coat 2 some small parts where still slightly transparent. After coat 3 I could not see anything of the plywood, but I would really like to have a last coat!

The problem is that it will take many weeks to get more pond armor through the normal channels.

Do anybody here have any contacts somewhere where I can get one more kit of pond armor delivered fast? Amazon do not ship to Norway so when I got the first kit I got some US friends to ship to me!

 

[Mr_Stian]

Managed to get a hold of a kit of Pond Shield from the UK. So hopefully this wont delay the build too much.

This morning when i inspected the last coat it looked actually quite good. But there are some imprefections, and some debrees from the roller i used that got stuck in the paint (did not know i needed a roller that was made for thick 2-component paint). So i want to give it a light sand and put one extra coat on. Then i will be happy with the overall thickness.

So the progress for the next few days will be to sand down the tank, fix a few issues on the seams, one last coat of Pond Sheild and then get it ready for glass installation. After this i still have to make the top brace before i need more Pond Shield.

 

[Mr_Stian]

I am glad that I decided to take the time to add another coat of pond shield. I hade to repair a few minor things on one of the seams, but I am very happy with the final result on the sides.
A small advice to others that are using pond shield, use a paint roller that is supposed to be used with two component paint or epoxy. The rollers that are for normal paint will leave stuff from the roller in the epoxy...

Happy with the progress so far. I am planning on installing the glass on Monday. Until then I will fill the screw holes and prepair the front for final paint.

A quick picture of the finnished waterproofing.

 

[Muttley000]

It looks great! When is the glass install?

 

[Mr_Stian]

I seems to be on Monday. I will keep you posted!

 

[Dsnakes]

This is so cool! I’m glad I found your build thread. I’m looking forward to the glass install

 

[Mr_Stian]

This is so cool! I’m glad I found your build thread. I’m looking forward to the glass install

Always nice to get such feedback

Since this build is taking so much time, the aquarium that is up and running doesn't get much attention. But today I had to do some maintanace on the refugium. As the picture below shows!

This had been left to grow for about a month or so. So it was about time to remove some.

Regarding the build it looks like I am ready for glass installation tomorrow. During the weekend I have focused on the Finnish of the front panel. I have filled all the screw holes and some minor defects and painted it. I had missed a few spots so I had to fill again today. I have also rounded the edges to make a nice finish to the front.

Since there are still a lot of spots of unsanded filler I forgot to take a picture this time.

Hopefully a new update tomorrow with the glass installed!