1/2 & 1/2 Foamie

[TerryB89]

would it be weird to build a half foamie and half ply to cut down on some weight? 1/2 inch ply front and back walls and foam end walls and roof then all covered by PMF? not planning on this just popped into my head, wondered if anyone has done this

[John61CT]

the points where heavier ply are supported by just foam would get a lot of stress at highway speed

The whole foam unibody flexes a lot in those conditions, all sides having the same properties may be a big reason it all hangs together

[TerryB89]

Makes sense

[GPW]

TB , Foamies now are like a “System” … after all these years we know how to build them and what works …

Consider this … Plywood is 57 lb. per cubic foot … Foam is two lbs per cubic foot …

[RJ Howell]

Your question leads me to believe you may be questioning the structural integrity of foam built. Much as I did when I came here. I was also looking to reduce weight of my potential build.

I did incorporate other structural elements in my build where I felt it necessary. I routed in 3/8" plywood over my windows/door. I do wish I had also along the roof edge to mount a awning. I also added aluminum bracing at the roof seam. So, added elements other than foam can be done, I just don't see the need to mix complete walls of different.
By adding where and as you feel it's required you'll keep the over-all weight down. Many 'frame' with wood/plywood/etc around openings, a few have built skeletons of plywood and foamed over or routed in.

Design your trailer and look at where you feel you require 'extra' support. The ways of doing this is pretty much limit-less with foam. The strength will surprise you, it did me!

[tony.latham]

The whole foam unibody flexes a lot in those conditions, all sides having the same properties may be a big reason it all hangs together

John: Do you see this with your trailer?



T

[ghcoe]

I really don't think the foam flexes at all. It is a pretty strong unibody once completed if competed well. I suggest when installing a door in the sides to allow at least 2" of foam below the door to the floor. I believe this really helps in the strength of the body. I also install a 2"x2" square tube from the hitch to the rear bumper to stiffen and strengthen the Harbor Freight trailer, more for the off road usage that I use my trailer for. So far all is working good and I am beating on it harder than I think most will. This is my latest video of my trailer being used in harsh conditions.

[GPW]

Wow !!! Great Video George !!! That about says it all eh !!!

[ghcoe]

Wow !!! Great Video George !!! That about says it all eh !!!

Thanks! Yes! It says it all to me!

I think the biggest thing people have to wrap their head around is that a trailer does not have the structural stress that a vehicle has. The easiest way I can explain it is like using a 4 or 3 footed stool on a rough surface. Which one has less stress applied to the legs when you step on it? Like a car that has 4 wheels, even with suspension, forces start to load up onto the frame and body as soon as you get into rough situations. A trailer only has 3 points of contact. The hitch and two wheels, in most cases. When you get into rough situations the forces do not load up onto the frame and body because there is no resistance to the movement. The most it has to overcome is inertia. I think the body and frame are plenty strong enough to overcome those forces. I have airborned this trailer more than once and it it has stood up to that kind of inertia jarring just fine.

One of the reasons I post up these videos is so that people can see how durable a foamie is. I have been beating on this trailer for over a year now with no ill effect as of yet. Another year of trips planned for next year so stay tuned for more. George

[GPW]

Your astute observations are Most Appreciated !!!