making a cool tube

Or you could hook up a thermostat to a ac. That is a cool contraption you got there I have never seen that.

how much do those plugs go for

$65 us

Get out your slide rule and do the math again guys. You are way off base here and are missing the basic science. There is a point where the bulb reaches max temperature and then just radiates heat and the excess heat as a by-product is what you are cooling not the true internal temperature of the bulb. You are using dry air to cool the bulb so you are not affecting the inside of the bulb.

In fact I believe you are helping the bulb to work even more effect by maintaining a better working temperature so the bulb can put more energy into producing lumens. (that part is only observation)

You can buy Pyrex Bake-A-Round tubes on ebay and jury rig them as cooltubes, for $20-$30. You can also buy cooltubes from bghydro.com, or whatever store you prefer. If you buy a real one, get one with an internal reflector (reflector inside the tube). They're a fair bit more efficient when run that way, since the light only has to pass through the glass one time, compared to as many as 3 times with an external reflector (three would be: once going upward through the glass, hitting the reflector, coming back down, hitting the top of the tube, then hitting the bottom of the tube on the way down). Every pass through the glass eats up some of your light, so minimizing the number of passes maximizes your light output.

Working with Zandor's input, and Karmaxul's... I'm thinking...

Ok, does ANYBODY have a cool to the touch cool tube? Or experience with such a setup?

I had 1st a 6", 90CFM fart fan, running one 400W MH.
Warm air out, hot (if touched) cool tube. Hot, right under the bulb... not "near" it.

2nd, I installed a 550CFM Dayton axial 10" fan... same 400W MH.
Too much air out to know if it's "warm" or not.
But cool tube? Same as 90CFM... hot right under the bulb, not in the areas sorrounding the bulb.

I'm just wondering, does anybody have a "cool to the touch" cool tube?

Just felt mine (400 watt HPS), and the tube is warm. I put my hand right on it for 30 seconds (right under where the bulb is), and it got no hotter than just warm. That's a 6" diameter, 18" length tube, 400 watt HPS, and a 440 CFM 6" inline centrifugal fan about 2.5 feet worth of ducting away. (The fan is dialed way down speed-wise though, because my carbon filter is only rated for 250 CFM, and my box isn't large enough to need the full 440 CFM anyway.)

I doubt there are any that are actually cool, but I guess 'cool' is a subjective term anyway. Obviously, the tube would never be cooler than the temperature of the intake air, but mine is definitely warmer than that, at least right under the bulb. I have read about liquid cooled lights, but...liquid + electricity seems scary to me. :)

Mine was cool up to about the 3" mark but if you touched the glass it was still well over 100 deg and would burn your hand. It did allow me to get my light to with in 6" of the top of the plants and that improved light penetration and bud production of the lower portions of the plant that would not get light before.

i have found a glass tube 4 inch diameter, but i dont know if it will break with the heat, i sat it on a gas fire all night and it didnt break but was to hot to pick up, now can any one tell me the best method to attach the duct fittings i dont want to tape them on as i dont want the tape to burn , and thanks guys for all the input nearly there lol

dont know but thats How i did it... Oh go and check out the link I sent u before on this thread for turtle