bluebuds said:shady if it dosnt have to be perfectly round, the craft shops sell glass to go around candles and lanterns. they may be a little bigger on one end or fatter in the middle but im sure they will work the same. -bluebuds
DiscoDuck said:Thanks greenhead. Hang in there, as you said it didn't make things worse. Add a computer fan to "blow" the heat directly off the bulb and off the canopy. The fan doesn't cool the heat, it just mixes with the cooler air below the canopy and drops the temps a couple of degrees. If your intake is correctly tuned, the heated air should be exhausted before it makes an issue.
Try this for starters:
Open the door(s) of your box with the exhaust fan running. Listen to the speed of the fan closely, then shut the door(s). Does the fan speed increase? If so, the exhaust is attempting to expel the heated air while the intake isn't replacing that air fast enough, slowing down the whole process and heating the box. A negative pressure environment is what you want here but you don't want significant negative air so much that it causes your fan to overwork.
If you shut the door(s) and don't hear a noticeable difference in the exhaust fan speed, you're intake is probably ok.
Several other things to consider: (please forgive if being redundant)
Heat = rise
Cool = sink
It's not uncommon for air circulation to mix and overheat your cool air intake. Cool air is at the floor level so it's convenient to cut intakes on the floor or near the floor, ex. bottom panel or bottom of back panel. Heated air is best expelled through the top of the box or the upper part of the back panel.
My box doesn't have much headroom. Even though my intake and exhaust are separated as far as possible from each other, it's still possible for the intake to "suck" some of the heated exhaust air wafting out of the box.
I made a glorified manifold (half a shoe box) out of thin veneer. I attached the half box over the exhaust vent, this directs the heated exhaust up and away from the potential influence of the intakes.
Another potential band aid is to duct your intake to a cooler area if possible. Do you have any dark colors inside the box? White paint on surfaces seems to keep things cooler than darker colors. Good luck!
Duck