Teardrops n Tiny Travel Trailers

We’ve mentioned this for a long time as an alternative to messy kerfing … Here’s a couple videos of modelers bending 1/4” foam with Heat … we just have to do it on a bigger scale ….
Let’s see if this provokes any ideas … https://www.rcgroups.com/forums/showthr ... aling-iron
https://www.youtube.com/watch?v=Zd9ie5vA-Jg

My initial thought is that the heat transfer characteristics of the foam are such that it's gonna take for-friggin'-ever to get the foam warm enough, far enough through for a good clean bend, without getting impatient and overheating the surface. I mean, after all, it IS insulation, for crying out loud!

1/4" foam has an R value of what? 1.2? And 2" foam has an R value of 10. The progression of the heat through the foam is going to be geometric, not linear, as it has to fight through more insulation the further it goes.

I suspect kerfing is going to wind up being more economical time-wise. Not all of us have the patience of a buzzard watching healthy, young prey

Very big microwave oven might heat through.

1/2 inch glued with liquid nails and curved while adhesive was still wet.

Time and material to build a mold form?

Those free form bending pics and/or tight bends using a stretcher are always impressive, but don't ever seem to address the issue of bending to a prescribed profile.

KCStudly wrote:Time and material to build a mold form?

Those free form bending pics and/or tight bends using a stretcher are always impressive, but don't ever seem to address the issue of bending to a prescribed profile.

A couple of pieces of plywood and some masonite will make a form. If you used your pre built cabinet as a form then time and material are already included.
As Mr. GPW advocates, try it and we will see if it works.

There’s a big advantage with bent foam rather than kerfed … the kerfing leaves only a small bit of original material on the outside of the bend …that is unless the kerfs are cut exact according to formula and then all glued solid ( the math) … The heat bent foam is One piece solid all the way through , and when cooled the foam STAYS in that shape , no stresses , no springback … That and the rolled shape makes it very strong
Obviously a heat blanket or hot water tank would be a good heat source , and building forms to bend around gives you an exact shape , but those things are only really good for production run of foamie trailers , not really practical for just one trailer … But if we put our heads together I’m sure we can all come up with a simple practical way for “home garage” use …

Now as far as the bending , the only surfaces you really have to heat is the inner and outer surfaces… the inside core is pretty neutral and will follow the outsides which stretch ( tension on the outer curve) and compress ( the inner surface of the curve) . How do I know this … I’ve been heat bending thinner foams for years now , very successfully … Just need to bump it up to a bigger scale … Remember you don’t want any heat hotter than boiling water or you’ll melt the surfaces ( not good ) …

For you folks living out west , just put the foam in the Sun , that should get it soft enough to bend slowly ... Been a HOT summer already …!!!

GPW wrote:For you folks living out west , just put the foam in the Sun , that should get it soft enough to bend slowly ... Been a HOT summer already …!!!

So GPW, it is a little warm here in Arizona right now, my intention is to build a foamy but am I going to come out one morning and find a wobbly blobbly draped over the trailer instead of the foamy it was yesterday ???

Only if it gets over 250 F … Given the circumstances lately … schmaybe ‘ ???

Seriously , the Foam won’t melt away unless you exceed a temperature waaay beyond what we could tolerate … but i suspect even lower temperatures over time would allow a flat piece to bend ( under constant pressure) … One idea might be paint the foam flat black on the outside ( or cover with a black or dark canvas ) put it over some rudimentary “form” and let the Sun and gravity do the work …

Trust me , if we can get this to work on this larger scale , we can really make unlimited designs without a lot of labor and Mess… and trailer “cores” with better integrity, even stronger … We’ve been bending thinner foams for many years , and we know well the advantages … https://www.rcgroups.com/forums/showthr ... ndFoam+gpw

I always dream of a Teardrop made with continuously bent foam pieces for front-roof-back … Put two sides on and Bob’s your ….

Edit: If you go to the BendFoam site above ^ , it gets OT real quick , just read past that …