Plywood frag tank construction

Please don't try to make a woody out of MDF. I have yet to see one work made from MDF.

If you want some good reading, click on my 193g DIY plywood epoxy reef tank build. A link is in my signature.

 

Ply wood will rot just like mdf, it just takes longer. I have several sheets of mdf might as well use them. And trust me when I say there will be no spots missed lol. I am completely anal about things like this, so it will have to be perfect, or else I will just trash it.

As for the size versus money part, it's a frag tank. I would much radther have 20 gallons with 500 sqare inches of space to place coral than the same volume but half the space to place coral. the larger tank will give me 90 gallons, but a working area of 2300ish square inches. The other reason for custom building these tanks is so they can be shallow water. They are specifically going to be used for coral frags...so I can use fewer lights with the shallow depth.

Everything is also going to be built so it is easy to work inside the tanks. As stated before, its going to be strictly for fragging corals...so ease of use will deffinately be kept in mind during the building process. I am not going to give away all my ideas at this point, but in this tank there will be a couple different "stations" I geuss you could call it, that will serve different purposes.

It will deffinately be interesting, and knowing myself I'm sure there will be plenty of excitement

 

In the words of mi madre, never say never lol.

I have read your thread, and your a big part of the inspiration for my build.

Just curious, what were the failures when MDF was used?

 

I guess, but I would rather spend a few dollars and get a decent grade of plywood to make sure it works. You don't need to use the 40 dollar a sheet stuff I did.

I am glad you waded through my build thread. There is a ton of info in it, but I need to make a condensed version so people can buzz through it quicker to see if they want to undertake such a task, or for simply an overview. The detailed version is for the kooks like me that attempt to hold a couple hundred gallons of SW back with plywood and epoxy. LOL

Well, one issue is that the screws won't hold well, and the other issue is that the mdf can break easily, unlike plywood.


What epoxy will you be using? As stated before, the price of a woody gets easier to swallow if the tank is pretty big. Are you puttinga glass pane on the front? or is it a look down only? If it is a look down only, then I can see a woody frag tank that small being a little better on the pocketbook.

My epoxy resin was about 100 dollars, and shipping is pricey because of what it is.

Now if you can get epoxy resin for a boat builder locally, that might make it more palatable. The other thing is, while I assume that most epoxies are reef safe when dry, I wanted to use a product I knew was reef safe.



Honestly, you could make this frag tank out of wood and the epoxy paint alone, with silicon sealing the edges, kinda like GARF does it. That epoxy paint is not cheap either, but if you were to do it this way, you would definitely not want to use mdf.

 

Check out glasscages.com, they have really nice frag tanks for very reasonable prices. There is a 29 gallon tank thats 30" long x 12.5" wide x 6" tall and its only $30 + shipping.

~Will.

 

Well after lots of pondering today, I am deffinately sticking with MDF. I know I know, I'm hard headed. After many long years of building custom speaker enclosures out of both FG and MDF, I am very confident in its strenght, especially since my side walls are only gonna be 9" high.

I checked out that site, very cool equipment! But I am still going to build this tank DIY. I love custom fabricating things, just so fullfilling.

Todays update: Did lots of woodworking....but not on the tank.
I have 3 ladders and a pike pole from a 1948 Ahrens-Fox fire truck that have to be completely re-finished, BY NEXT FRIDAY so looks like this tank will be on hold till after mardi gras:-/

 

This is probably getting annoying, but I agree on MDF being a bad idea. I have a few years of experience in custom woodworking of all kinds. Have you ever seen what happens when MDF gets wet? I just don't see the cost of some plywood being worth the risks here.

Aside from that what type of corals are you thinking of fragging in it? One of the LFS here has a sweet long surge frag tank. Basically they have a water tank sitting above one end of the tank. A pump in the sump fills it with water and when it gets to capacity a toilet valve in the bottom releases dumping the water into the tank. While your building maybe you could build something like this also. It would be awesome for SPS.

 

Hahaha its ok, I dont get annoyed easily. That is a pretty neat idea, although i had something else in mind for flow. Think of an oval race track, but with baffles to interupt flow. If I keep getting posts about not using MDF, I'm liable to use plywood. Hopefully a couple speaker boxes will need built and then I will go out and buy plywood lol.

Keep the cool ideas coming, I always love hearing about other peoples setups

 

just a question from a curious onlooker - although i am sure it is not the most cost effective - but would something like Marine Grade plywood make sense for these types of projects?

I know it comes in several grades, thicknesses and either MDO or HDO. I was very impressed with Horkn's build. I do not recall if that was marine grade plywood or not in that build - but its a very impressive tank for sure!

I totally understand the need to be creative and just make something yourself for the sheer joy, challenge, and self satisfaction it can give you - albeit cost efficent or not. You cannot put a true price on those benefits.

Best of luck with this project! I look forward to seeing your progress!

 

Well since you don't get annoyed, I'll keep going than. The biggest problem I see with MDF is it's too dense. If when you move the tank into place you make the tiniest scratch and even a drop of water gets in, the fibers in the MDF will swell. This will cause more cracking to the point the tank is a soggy mess. I was transporting some MDF work once awhile ago when it started raining. Within about 1/2 hour the 3/4 MDF was about 1" thick and flaking apart. The company I worked for built a valet station that had to sit out in the weather. Needless to say we used plywood and it still stands to this day.

MDF is also very very brittle. I'm sure during using it you've noticed that it does not flex. Simple as that. If you push it to the point it wants to flex it snaps right in half.

It's also way heavier than plywood.

It also makes for very good insulation. You may be able to leak some light temp out of the plywood, but there is no chance of that with MDF.

As others said, it doesn't hold screws very well. Not only that, but the screws that hold are very unpredictable. They can look to be in and grabbing well only to fail later.

I do se one advantage of MDF though. It doesn't burn;D

Either way, good luck.