I like the propane weed burner idea. Most of the plastic conduit I bent during my shop build would not have fit in the oven or grill. I bent lots of 1" and 2.5". I used a heat gun on the 1" and a propane torch on the 2.5". A weed burner would have made the 2.5" much easier. The trick is to heat the conduit gently and evenly without melting it. If using a propane torch or weed burner, you don't want to get the flame too close and you always want to keep it moving along the conduit, never stopping in one place or you will melt that section. It should not be discolored or blackened. Another tip is to not heat or try to bend at the end of a section. Heat and bend 1 foot or so from the end and if you need the bend closer to the end, wait until it cools completely and then cut to length. By not heating right to the end you help maintain the round shape. Also heat a slightly longer section than you actually need to bend, as you'll find that it's less pliable near where you stopped heating. If you try to bend it and it's starting to kink, stop, it's not hot enough or not heated completely through yet. I'd practice on a couple pieces before working on the critical one you need. Using one of these methods takes a little time and patience but it can be done. I usually try to set it on a large workbench with a form set up to the correct angle. Then when holding it on the form (with welding gloves) I blow compressed air through it to cool it faster. Once it's holding it's shape I stop the air and let it cool to ambient before trying to cut it.
If you are doing a lot of bends, there are professional tools designed for this task. They are a tube shaped oven that the conduit slips through that evenly heats the conduit all around.
Brian
