Steam box for bending wood

[Prashun Patel]

I need to make a new steam box. The plywood one I made has delaminated after several years. If I make a new one from wood, it will be solid. However, I really like the idea of a PVC steam tube. Unfortunately, the Schedule 40 one I made melted and sagged very quickly.

I've read that Sch 80 is better, and even Peter Galbert seems to have used one. However, the melt temperatures of all pvc appears to be under 180 degrees, so won't it all melt?

Any advice appreciated.

[Doug Garson]

How about metal ducting? Make the ends from wood and wrap with insulation.

[lou Brava]

How about the orange fire sprinkler pipe ? https://www.plumbers-supply-co.com/2.../spears-cp-010

[Richard Coers]

From what I've seen, you just need to support the schedule 80 more so it doesn't sag. If you are steaming thick pieces of wood over a long time, wood will work better. Just don't the door a flush mount as it could get stuck from movement. Lots of videos on YouTube showing PVC steam boxes.

[Lee Schierer]

Depending upon the size of pieces you are wishing to steam, you could use the spiral air duct material with a solid wood cap at each end you will need to slope the pipe so the condensate will drain and have a small vent at the opposite end from where the steam is introduced. It would be better to inject the stem at the mid point and have vents at each end for more rapid and uniform steaming. A steam generator can be a metal gas can with a length of rubber automotive hose stuck in the spout and the input port to your chamber. Use a Coleman stove or hot plate for a heat source. Insulating the metal pipe would improve performance and reduce steam generation capacity.

[Jamie Buxton]

Yeah, my PVC steaming pipe looked neat until the steam hit it. I went back to wood. Wood's nice stuff, y'know? Solid lumber does a good job. Or you can use cheap plywood, and figure on replacing it every once in a while.

[Kevin Jenness]

Try using a 6mil poly bag. https://www.youtube.com/watch?v=50uXPPt8-VI

[Bill Dufour]

ABS pipe is 221F.

[Thomas McCurnin]

I have used plywood, properly sealed inside and out for years. Add a drip drain and some holes for a brass grate to support the pieces and an exit pipe for the steam.

[Warren Lake]

Chuck Norris does not need a steam bender he just uses his hands.

[Kevin Jenness]

I've used galvanized steel ducting in the past. Eventually it will rust but if the stock is supported on wooden rods that's ok, and it is lighter than plywood, I'm not kidding about using bags though, you can get them in any length and roll them up for storage, and you can bend a large piece around your form while still in the bag and still putting steam to it.

[Mike King]

Was you steam box made with marine plywood? Mine is out of MDO but it is only a few months old. Seems to work pretty well. Michael Fortune recommends using marine plywood.

[Jay Houghton]

I took a steam bending class with Michael Fortune one time and he builds his out of exterior grade plywood. He claims they last a long time and just don't paint it so it can dry out after use. I have yet to build one so no personal experience.
Jay

[Bradley Gray]

I use a wooden box insulated with rigid fiberglass but the bag idea is interesting. How would I insulate? Steaming while on the form would be a big plus.

[Kevin Jenness]

You could throw a blanket over the setup. Whether you need to depends on your steam generating capacity. I stumbled on the technique in several of Lou Sauzedde's videos https://www.youtube.com/watch?v=50uXPPt8-VI&t=8s https://www.youtube.com/watch?v=RORoex0TTfY&t=45s