Canopy help please

[freeswimmingfis]

I am in the planning stages of a new canopy for my standard 90g to house my new MH lights/reflectors. My plan right now is for it to be 18" high. I want to use oak plywood to match the Oceanic oak/cherry stained stand. Is it OK to use the oak plywood for the face frame as well as the sides and top? I plan to have two 12" tall x 20" wide doors on the front (ordered from www.cabinetdoorsandhardware.com). Other canopies I have made have only had a top that lifts open, but, due to the height this will be the first with doors on the front. It might have a top that opens, or be clam shell style, but the doors on front are a must.
How would I seal the (ply) edges to keep them from separating or swelling from absorption?
Is 18" too high? The 2 reflectors are 7" tall (homemade Lumenarc III Mini). Assuming I mounted them at the top of the canopy, this would put the bottom of the SE bulb 5" from the top, or 11" from the top of tank or about 12" from the water surface (subtract 2" for overhang). I have considered mounting the reflectors on an aluminum frame that could be raised or lowered.
If I make it clam shell style, Is it OK to use oak planks, grain vertical? The rear section would be 12" x 18", the front section would be 8" x 18". How would I keep the light from "spilling" from between the 2 sections?

Thanks
Joe

[Chris27]

A couple of coats of polyurethane should eliminate your moisture intrusion worries.

[sirreal63]

Since you are in the planning stages...this is what I did on my old 125 and it was perfect, easy access and looked good too.
Click pic for full size

Instead of doors, I had 2' panels that slid up and down, I could remove a panel for tank work and had full access.
http://img.photobucket.com/albums/v362/sirreal63/125/th_canopyup.jpg (http://img.photobucket.com/albums/v362/sirreal63/125/canopyup.jpg)

When panels were in place no light escaped
http://img.photobucket.com/albums/v362/sirreal63/125/th_canopydown.jpg (http://img.photobucket.com/albums/v362/sirreal63/125/canopydown.jpg)

When front and side panels were off I had extreme access to all of the tank.
http://img.photobucket.com/albums/v362/sirreal63/125/th_125lumenarcs.jpg (http://img.photobucket.com/albums/v362/sirreal63/125/125lumenarcs.jpg)

Hard to see in the pic but the lights were hung from a couple of laminated 1x2 hard rock maple and the height was adjusted on the ends by raising or twisting the maple. Lights were raised by twisting in the attached pic.
http://img.photobucket.com/albums/v362/sirreal63/125/th_125vho2.jpg (http://img.photobucket.com/albums/v362/sirreal63/125/125vho2.jpg)

The frame was made from 2x2 clear cedar and 2x2 treated in the back and where it did not show. This was the best and most versatile canopy I ever made. There was no top on it but one could be made for it. It took a long time to route the H channels that the slider panels fit in but it was worth it. Oak is a good choice, just be sure and seal the edges and inside. I used cedar because of the rot resistance and weight and being a porous wood it breathed without becoming saturated with moisture.

Whatever you do, make the lights adjustable, it just makes it so much easier.

[freeswimmingfis]

I like the idea of polyurethane to seal the edges. And having the light rack adjustable just makes sense the mor I think about it.
I dont think the removable panels will work for me, since it will be a match to my stand. Those would not go with the Oceanic stand at all.

[sirreal63]

The panels were a solution for me, back then I had my hands in the tank a lot and my wood selection was unique, Tigerwood because I distributed it and it was very cheap and a hardwood. I started the plan with oak but considered how heavy a 6' canopy would be and chose a different way.

Be sure and snap some pics as you are building it.

[freeswimmingfis]

Will do, thanks for the info. I think I may have a better option. There is a furniture builder on my street, he gave me a quote that is pretty sweet!! Once he looks at the stand and I give him my plans, I will have a better idea of a "real" price.