4" PVC is good for thin strips but it will deform if steamed for too long. It was a while ago, but I think it was 'schedule 80' pipe I used - it has a really thick wall.
I used an electric hotplate and a stock pot from the thrift store. The best way I found to keep the water boiling was to wrap the pot in fiberglass batt and secure it with baling (mechanic's) wire, otherwise the hotplate was running full bore all the time and took a while to boil again after loading the strips in.
I cut an oval hole in the lid and slid the pipe in at an angle so the vapor that condensed would run back into the pot. When I do it again, I'll probably try a length of exhaust hose or some such between the pvc and the pot.
One trick I found was to keep the air moving through the pipe, otherwise the steam cools before it gets all the way to the end and then the strips won't bend evenly. A 1/4" hole in the far end worked for me - watch for a consistent plume of steam coming out.
A glue-in threaded bushing and a threaded cap handle inserting and remopving strips but be VERY careful of the steam when opening it up. BBQ tongs work pretty well if the cap isn't screwed in tight.