In some parts of the world it gets cold during the winter. Well its started here, been in the 20's f at night. Needless to say epoxy isn't a fan of cold, so before I can really go any further a heater box is in order. My old one fell apart in the move, so I built a new one and stuck some light-bulbs in it (it got me through the summer), but at these temps and with the slow and medium epoxy I use, more heat is necessary. I started out by sticking my jet heater into the box, but even on low it was way to hot (350 melt foam hot) and it eats propane, so wouldn't be something I would want to use very often. Needed to try something else. I thought 185f would be a decent temp to hone in on, and I really want some good convection for when I start messing with LTM prepregs. I figured space heaters would be a good way of getting there.
Cheap Gonzo Convection Oven:
Step 1: Steal the guts out of a couple 1500w heaters.
step 2: bypass the low temp thermostat and install in a capped 8'' to 7'' reducer, cut some vents in the cap and rig a little switch box.
*note. don't bypass the high/low switch, because in the summer you'll want to use the low setting since the fresh air intake temp will be higher.
Step 3: Install the heaters in the cure box, then install a "T" in the middle of the box and stretch some flex duct over to the heaters. Don't cover the intake more than 1/2 way or you'll run too hot (keep it below 200f) hotter and you'll blow up the fan motor, which will spike the heater coil, which will melt all the wiring. (don't ask me how I know....... I ran it at 230f for about 1/2 an hour, then the fan went and bad, smelly things started to happen. Lucky they are cheap little heaters)
I'll be cookin this weekend.
It ran great and stayed between 185 and 190 (measured at the exhaust T) for 6 hours. Seems to be working. So that's how I made a 14ft convection oven for less than $200.
****yes, I know exhaust is spelled wrong on the drawing. My spelling is terrible.
