Alternate bending method? Answered
I recently wired my entire 2-car garage with plastic conduit, which required many custom bends. Heat guns are good for small bends, and the sand trick is OK for short lengths. I often needed to soften a couple feet or more of the pipe at one section of a long length. My solution was a propane radiant catalytic heater, the kind you often buy for camping or similar uses. Mine was fairly small, and I used it on the low setting. It fastens securely to a standard 20 lb. bottle, which makes it very stable. Most important, it puts out a large volume of heat, which will warm a long length of the pipe.
To use, light it and feel around for the heat flow. Although it does glow red and radiates heat, mine had a nice convection column rising from several inches in front of the catalytic face. Once you've located the best heat source, just move the whole length you want to soften back and forth through it, fairly quickly, and rotating a little with each pass. Use patience, and in a couple minutes, it will start to sag. Let it get nice and droopy, then move it to your installed location and hold in place while it cools. More patience, or a partner with clamps ready, gets you a nice, smooth bend.
And if you need to put a bend near the end, which must go into a fitting, you want to be sure the end stays round and does not deform. Before heating, slip on a cap or other fitting. As long as you don't put heat right on the fitting, it will hold your pipe round even as you soften the pipe just a couple inches away. After it cools, tap off the fitting, cut accurately to length, and make the connection.