Is 1/2" ply good enough for 6' canopy?

[ambaratur]

My stand is finished and the 125g tank is on it - but now I need to build the canopy.

I have never built one before but I think I have most of it figured out. My question however is if 1/2" plywood is going to be good enough for the main pieces.

It will only be about 7" tall because I intend to use T5 lighting. I will finish the inside with a good primer and several coats of exterior grade semi-gloss paint. (Same paint I used inside the stand.) The exterior will be sealed and painted black.

Will the 6' run of plywood be protected from warping if I make sure it is sealed well?

Thanks for any input.

-Amb

[smcdonn]

I don't know if I would use plywood but that is just me. A 6' span of plywood I feel is sure to warp with the water and the heat no matter how well you seal it. Cheers

[ambaratur]

Then would you recommend a solid piece of 3/4 pine or something?

[drauka99]

you could "rib" the underside of the plywood to help keep it from warping. I would prob go for the solid pine but if $ is an issue then do the ribing and it should be ok

[ambaratur]

Money is not the issue - and pine boards are not terribly expensive. For some reason I was thinking the solid wood would be more likely to warp than the plywood.

[bassnman11]

I use 3/4 oak plywood for my hoods. I edge band the plywood with solid oak. I use kilz and gloss white exterior enamel on the interior and minwax poly on the outside. Your other option is build a skeleton of pine and cover with 1/4 plywood.

[ambaratur]

Wow - that seems like the canopy would weigh a ton if done with 3/4. Does the tank support that much weight. I do have a glass tank.

[20 20]

Here's a thread I put together detailing a hood I made for my 125 gallon that's similar to the one you want to build, T5 lighting, 1/2" plywood, 7" high, etc:

http://www.reefcentral.com/forums/showthread.php?s=&threadid=877954


Still no water in the tank, so take that for what it's worth. :p

[ambaratur]

Thanks for the link. I like your build.

Have you had your canopy over water yet? My main concern is if it warps or not. Did you choose birch for strength or just looks?

Thanks!

-Amb

[20 20]

Nope, haven't had the canopy over water yet. I guess warping is a possibility, but I'm not worried about it. Yet. :p I choose birch for the looks, it was the best looking stuff I could find in 1/2" thickness at Home Depot or Lowes. Basically, it was the default choice because all the other 1/2" stuff looked like crap.

[ambaratur]

Gotcha - I think you and I think alike. heh heh heh

Thanks for the info - and I subscribed to your thread to see how things go.

Best of luck!

[hllywd]

Ambaratur,

There are some misconceptions going on here concerning plywood. Plywood is actually very much less likely to "warp" in any circumstance due to the layers or veneers which make up the core. 1/2" should be structural enough when the canopy is completed not to sag or bend in a 72" span when supported by the tank. I built my kitchen drawers using 1/2" baltic birch which has 9 total layers of veneer and few voids, the edges can be routed for a finished look if you don't want to edge band. The bottoms are constructed of 1/4" birch because it's cheaper than 1/2" and looks good, except that the slides are rated for 100lbs I wouldn't be afraid to stand in them. If you want to use 3/4" the tank will support it and it will be heavier, however in my opinion not completely necessary

I have built a couple of hoods basically like an upside-down drawer the longest being 48" of edge banded 1/2" with very good success.

FYI Species of wood doesn't matter too much birch, oak, walnut, cherry, mahogany are what the face veneers are, the core veneers will be composed of a less expensive species or possibly even MDF. These types of plywood will not be available at HD or Lowes. I get mine from Toledo Plywood in Toledo, Ohio.

Hope that helps,
Tim:cool:

[ambaratur]

Wow, thanks hllywd that is very helpful! Following your recommendations I would be able to continue with my original plan. Warping was my main concern - and if I seal the wood good it sounds like I will be OK with the 1/2" ply that I was planning originally.

Thanks again for your input!

-Amb

[don954]

you might also want to look at marine plywood, its made for boats, and i used it on several boats i built. You can get it in many surface veneers (including my fav teak), and the bonding agent is a waterproof epoxy that will probably outlast your tank... ;)

[ambaratur]

<a href=showthread.php?s=&postid=7998185#post7998185 target=_blank>Originally posted</a> by don954
you might also want to look at marine plywood, its made for boats, and i used it on several boats i built. You can get it in many surface veneers (including my fav teak), and the bonding agent is a waterproof epoxy that will probably outlast your tank... ;)

Yea marine plywood would be nice, but us landlubbers here in northern Arizona have no access to that type of material unfortunately.

[don954]

that sucks... anytime your more than 1 hour drive to the ocean your too far inland i sayz.... :P

[speartheman]

I used roofing grade plywood it did not warp

[wigo]

My canopy has 3/4 ply and it has warped up in the middle. Someone else built I and I bought the setup that way. I have tried to undo the warping but to na avail so am planning on build ing a new one. I would go with nothing less than 3/4 plane and I like the idea of the 1/4 with a pine frame. The only thing is make sure the grain is in the right direction. Meaining if you took a 2X4 use it on the 4" side and not the 2" side because it would definitly warp.

[wigo]

The other benifit to the 1/4 plan is you could screw it down every few inches so it would not warp plus it should be lighter even using 2X4 construction.

[SteveOhh]

<a href=showthread.php?s=&postid=7998213#post7998213 target=_blank>Originally posted</a> by ambaratur
Yea marine plywood would be nice, but us landlubbers here in northern Arizona have no access to that type of material unfortunately.

I'm sure plenty of places in Havasu & Parker carry marine grade plywood..................... :)

Steve :D