Just a thawt… spend more time on the design. use the minimal amount of light wood and panel possible, yet keep it strong and stable. its no fun placing or moving a 200 pound hood. and pay particular attention to passive air flow. passive cooling is much nicer than having to blow a bunch of fans . i made my VHO hoods so that they are half and inch larger inside around the tank. and open across the back. that way cooller room air can flow up around the front and sides between the tank and hood sides , over the bulbs, and up and out the back by chimney effect. no fans.
and i made the front hinged to flop down for feeding, so as i didnt have to always prop the top up on its hinges with the lights on it. when its real hot i can also leave the front flap open down too.
dont make an air tight toaster oven. lots of people do that. think passive air flow for cooling. the heat of the lamps will move the air if there is good flow path. like smoke up a chimney.
[quote=“kaptken, post:21, topic:4645”]
Just a thawt… spend more time on the design. use the minimal amount of light wood and panel possible, yet keep it strong and stable. its no fun placing or moving a 200 pound hood. and pay particular attention to passive air flow. passive cooling is much nicer than having to blow a bunch of fans . i made my VHO hoods so that they are half and inch larger inside around the tank. and open across the back. that way cooller room air can flow up around the front and sides between the tank and hood sides , over the bulbs, and up and out the back by chimney effect. no fans.
and i made the front hinged to flop down for feeding, so as i didnt have to always prop the top up on its hinges with the lights on it. when its real hot i can also leave the front flap open down too.
dont make an air tight toaster oven. lots of people do that. think passive air flow for cooling. the heat of the lamps will move the air if there is good flow path. like smoke up a chimney.[/quote]
Thanks for the advice Ken. I was hoping to make it 74" Long as the tank is 72.5". I need the extra room anyway if i am going to have my light fixture and the canopy sit on the tank at the same time. My light fixture is 72" long on the nose so i need the extra room anyway. 74" also matches my stand so i think it will work. I am hoping to have the canopy rest on all four corners of the tank instead of the entire perimeter.
That is exactly how i built my two. if the outer length of the tank is 72.5 hope you mean the inside dimension of the hood will be 74. that will give you a nice 3/4 inch gap. similar with front to back. I support mine at the 4 corners too. i just cut some 2x4 to height and screw into the corners of the hood frame. they also support the front corners of the full lenght lid that hinges up with the lights. i set them so that the hood sits a little lower over the black plastic tank top frame, so light doesnt spill out in my eyes.
and , very important, shim the hood to maintain the air gap around the tank , and so that it wont slide off the tank, front or back. that would crush your lights and it falls down on the glass. with an open back side, it makes fro a nice passive cooling system. you can also make the top hood out of 1x3’s spaced about half inch apart, that lets the hot air goe straight up. I did that for my hanging MH 4 foot pendant light hood.
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