i found this on the web so not my idea but will make one thought it was worth sharing if u like please add some rep thanks Clean and Easy Cool Tube This is a detailed tutorial on how to put together your very own cool tube. You can assemble one of these in about 20 minutes. This is based on a 150 watt HPS, but may be adapted as needed. What You Need: 1 x Pyrex Bake-A-Round tube (long discontinued, but available readily on EBay and in classifieds, Flea markets etc surprisingly common) - $10-15 1 x pair of Café Rod brackets (hardware store, where window fittings are located) - $1.50 1 x Ceramic medium or mogul lamp base with standard mounting hole - $0.99 1 x 1-1.5 (approx) hose clamp - $0.80 1 x 3.5-4 (approx) hose clamp - $1.00 2 x 4.5-5 (approx) hose clamps - $2.50 1 x roll of self adhesive insulting foam for hot water pipes. - $2.50 1 x #6 32 x 3/8 (machine screws with nuts) - $0.99 1 x multipurpose (including glass) glue or epoxy (optional) - $3.00 1 x 400°F small tube of silicone sealant - $2.50 Your HPS/4 duct system N/A Step 1: Collect your café rod brackets, lamp base, and screws. Remove one of the café rods and bend into roughly the shape illustrated in the next photo (you may need a something to help such as a pair of pliers). Attach the café rod to the lamp sockets mounting hole using a screw and nut. Connect the wires from your power source line to the lamp socket. The white wire should connect to the silver screw, and the black wire to the brass / darker screw (this is standard color coding). I used a little bit of solder for good measure. Leave the ground wire (green) unconnected for now, ideally left a little longer than the others. Cut and bend the remaining café rod into three pieces with tabs on the end as shown. The longest/middle section should measure 1&1/8 on each (medium) or 7/8" (mogul). The other sections are of negligible length, but around ½ is good. These are your spacers. Fasten the spacers to the lamp socket as shown. Use your epoxy or glue if desired in addition to the clamp to make sure everything is firmly in place. Step 2: Hang your bulb assembly over the end of the Bake-a-Round. You will notice that there is a slight bit of play between the spacers attached to the socket, and the inner walls of the tube (if you measured correctly and dont have an oddly sized socket). This is deliberate and is to account for possible thermal expansion in the metal. Fitting the spacers firmly could result in a cracked or broken tube! Place the bulb in the socket and clamp the hook hanging over the side of the glass tube with the ~4 Clamp. Tack the hook and clamp with epoxy/glue for added strength (The glued clamp can still be popped off, so dont worry too much about how you will change the bulb). Step 3: Wrap self adhesive insulating foam around each end on the tube as shown (or only one if you are using exhaust only). This will allow 4 duct to fit very snugly to the tube (which its self is 3 ¾ O.D.), and will also act as a gasket/seal when clamped. Thread wiring through the ducting, attach the ducting to the tube, and clamp in place. Finish with silicone sealant if desired. Connect the ground to the duct or the café rod hook. Add an optional reflector made from unclosed rigid duct (you can find this in your hardware store its a piece of sheet metal with a snap together seam that hasnt been connected). Simply cut to length, cut flanges a half inch from the ends, and clamp those to the duct/tube. Hang your lamp with light chain available from your hardware store by the foot. The chain attaches under the clamps on the duct. Youre done!