Let’s Heat bend Foam … Please !!! No more kerfing ...

[GPW]

I’m sure once we all work out the technicalities , heat bending foam will become “common” and very useful as we can make any shape of trailer we want … Heat blankets , heat guns , hot water … several methods to try.

The best thing about the process is there is no messy kerfing which weakens the foam , and once the foam is bent , it stays like that , no stresses …

[twisted lines]

I have done a bit of plexiglass,
My big attempt would be, Build a form and a trip to a powdercoater’s oven.

[DaddyJeep]

I built this oven to use as a warming oven for my BBQ business a few years back. It is just big enough to fit my radius pieces inside. This is going to happen tomorrow. There will be video. Since I will have the big smoker out anyway I might as well throw some ribs or chicken on the other side huh? Yes, the smoker side is completely separate from the warming oven with potentially toxic foam outgassing.





I will add some luan to the lower form that I showed earlier and probably drill a bunch of holes in it to allow heat to get through better. I am also going to build an upper form so I can add some weight.

[Socal Tom]

After reading the thread and watching the video I have a couple of suggestions.
1) consider clamping the foam between 2 pieces of plywood. By covering the sections you don’t want bent with wood you create a “heat break” that will help control the bend. You could also build mounts for the heat gun on the plywood to cut back on the hands needed.
2) taking this a step further, if you put a couple of movable arm you could add a cross piece and make a bending arm that should make a more uniform bend ( picture a wide pipe bender/ sheet metal brake.

[GPW]

Found this … What you can do with a piece of curved Foam … https://www.youtube.com/watch?v=7-wCS_S ... &index=124

Just something to consider …

[DaddyJeep]

Here it is guys..... the long anticipated (at least by me) video all about heat forming XPS foam. Some challenges along the way, but it all worked out in the end.

https://youtu.be/qzFQxbxrOjE

[QueticoBill]

For a typical teardrop roof - like a 4' or 5' wide - am I the only one that thinks kerfing makes more sense?

[ghcoe]

For a typical teardrop roof - like a 4' or 5' wide - am I the only one that thinks kerfing makes more sense?

I will still be kerfing my builds.

Kerfing in my opinion is so much easier and takes less time. Of course I do have a hot wire jig that makes it simple.

[twisted lines]

I found a easy way and thought it would be a lot messier
1 inch spacing 5/8" deep I could see lines still.

[ghcoe]

I could see lines still too, but they usually are easy to sand out.

If you live in Jefferson you may live close to me. George.

[GPW]

Daddy’ Jeep has it now !!! Nice to have a choice … Kerf or heat bend , all what YOU want to do !!!

[Socal Tom]

I like daddy Jeep’s idea, but I think I would have hearted the foam flat, then pulled it out and put it in the mold.

[Pmullen503]

The problem with heat forming foam, and I've done a lot of it, is the temperature that foam becomes flexible is very close to the temperature that it collapses. That and the need to let the heat "soak" in means you need good temperature control and the ability to hold it there for a long time.

I've been able to heat form foam for RC planes into complex curves but I'm typically working with foam only 1/4" thick. I think I could do 1/2" with the right time and temperature settings. At that point you could laminate several layers to get a usable thickness.

The equipment to do this is more than most one-off builders would want to invest in, but it could be done.

[DaddyJeep]

The problem with heat forming foam, and I've done a lot of it, is the temperature that foam becomes flexible is very close to the temperature that it collapses. That and the need to let the heat "soak" in means you need good temperature control and the ability to hold it there for a long time.

I've been able to heat form foam for RC planes into complex curves but I'm typically working with foam only 1/4" thick. I think I could do 1/2" with the right time and temperature settings. At that point you could laminate several layers to get a usable thickness.

The equipment to do this is more than most one-off builders would want to invest in, but it could be done.

So here is what I found concerning melting the foam.... If the temp stays around 200 it seems to be very stable and it can be in the heat for a very long time. I had pieces at 200 for 30 minutes or more with no melting. Once I got over 220 or 230 is where I started seeing melting.

The biggest issue with my process is that most people don't have access to a controlled oven of an appropriate scale to do camper work. Mode airplane stuff can be done in a toaster oven. An insulated box could be built out of foam and wood, maybe drywall or steel, within a reasonable budget. A propane burner could be used for a controllable heat source.

[DaddyJeep]

For a typical teardrop roof - like a 4' or 5' wide - am I the only one that thinks kerfing makes more sense?

I will still be kerfing my builds.

Kerfing in my opinion is so much easier and takes less time. Of course I do have a hot wire jig that makes it simple.

In many cases that is probably true. My camper has so many radii that I needed a different solution. I will have a total of around 30 pieces of 21" wide foam that will be bent and I wanted these to be as structural as possible. I didn't want a bunch of seams that would potentially weaken it. I can just throw a piece in the oven and work on something else for 15 minutes.