Weight difference of foam vs plywood

[atahoekid]

I vote for plywood.

I built the foamie standie to learn about the pros and cons of foam.

And while there are a lot of benefits, I keep hitting a brick wall when it comes to finishing foam.

you probably should have a generous radius on the sharp corners. But I'm really struggling with how to get the canvas to lay flat on those radii.

Mike...

Because of my concern about a smooth finish, I decided to use a light fiberglass cloth instead of canvas. Since the weave has a bit of give I'm able to wrap the radiused corners pretty easily.

[SteveW]

I'm in pretty much the same position as the OP. Building my first TD and looking to go as light as possible, without sacrificing the integrity of the trailer. My brain is swimming with all the various alternative materials available, but of course as soon as I find something with merit, I look at the pricetag and scratch that idea off the list.

We just had a sunroom and porch cover added to our house a couple years ago, and the ceiling and lower walls are 2" foam sandwiched between what appears to be a thin aluminum skin with some powdercoating outside. I was skeptical about it until the installer had me hit it with a hammer and not even a dent. The panels themselves came in sheets of 4' x >12'. I was amazed to see the installers standing on the panels as they installed the roof, with only a crossbeam at the peak. Extremely solid stuff with no flexing. While I didn't test how heavy it was, they definitely weren't fighting with it to get it up.

I'm considering using something like this for my build, but of course it will need an aluminum frame. I'm a lot more confident in my skills working with wood than I am with aluminum and foam. Regardless, I'll be putting in a call to them later this week to get some input/info.

With that said, I'm withholding voting until I can add some more valuable input.

[S. Heisley]

not sure about a woody trailer, but my foamie is approx 500lb total, with mattress. that includes the frame, which is 265lbs.

Louella, I'm assuming your trailer is a 4x8'?

Back in 2009, before anybody had tried building foamies, I took all the information that I could find from two threads and combined it. Based on that, there was one trailer that came in at 450 and one, at 585. Taking the provided weights of the 14 plywood or sandwiched plywood trailers in the 4x8' category, the average weight was 785.7 pounds. Based on this information, I would say that it is possible to build a plywood trailer that is as light as a foamie but most people don't build that way.

Which is better? I'd like to see an experiment where three scrap walls were built and finished: a foamie style, a 1/8"ply/foam sandwich style; and a 1/4" plywood style. Then, I'd like to have an 8 year old little leaguer pitch a ball into each one, at the same approximate speed. That might give us the answer to which is better....maybe.

[wagondude]

not sure about a woody trailer, but my foamie is approx 500lb total, with mattress. that includes the frame, which is 265lbs.

Louella, I'm assuming your trailer is a 4x8'?

Back in 2009, before anybody had tried building foamies, I took all the information that I could find from two threads and combined it. Based on that, there was one trailer that came in at 450 and one, at 585. Taking the provided weights of the 14 plywood or sandwiched plywood trailers in the 4x8' category, the average weight was 785.7 pounds. Based on this information, I would say that it is possible to build a plywood trailer that is as light as a foamie but most people don't build that way.

Which is better? I'd like to see an experiment where three scrap walls were built and finished: a foamie style, a 1/8"ply/foam sandwich style; and a 1/4" plywood style. Then, I'd like to have an 8 year old little leaguer pitch a ball into each one, at the same approximate speed. That might give us the answer to which is better....maybe.

I guess we may need to submit to the Mythbusters to find out. Although, I think a proper test would require the construction of a complete cabin of each method as just a wall would not have the same structural characteristics. Who knows, they might do it. They already have the bird cannon.

Bill

[GPW]

I’d bet a frozen Turkey would reduce a plywood TD to a mass of splinters instantly ... Unrepairable ... Foam is a Lot stronger than you think , but in a different way than plywood ... Damage would only be localized and patchable ...

So when you’re towing down the Hwy. be sure to look out for the “Frozen Turkeyâ€

[eaglesdare]

i'm sorry, i thought i put the measurement in there. my trailer is a 5x8, not a 4x8.

[katozzi]

Nice one S. Heisley! OR I think we could send two comparable trailers through a road course, like the ones they use to test new vehicles with all the bumps in the road! I have traveled through a lot of states, but haven't found any frozen turkey crossings yet. Maybe I need to travel more through canada!?


But I am convinced that the foam would indeed be lighter. We have thought that what we could do is sandwich the foam with 1/8'' birch?
Also, one crazy idea we had, would be to make a section of roof "convertible" style. By that we mean paneling with a lexan or plexiglass with a vent hole cut out so we can get a good view of the wyoming stars at night!

But ultimately, we like the finished look wood, but without the weight. Are we crazy? Yes, sometimes we are, but let us know what yall think.

[GPW]

Canada !!!

There’s always a “Faux “ wood finish ... sometimes looking Better than the wood ...

[S. Heisley]

i'm sorry, i thought i put the measurement in there. my trailer is a 5x8, not a 4x8.

That makes more sense. I only had six 5x8' trailers that reported their weight. The two lowest were 580 and 625 pounds; but, the average was 862.5.

[linuxmanxxx]

If you keep the size down and don't put a lot of runners in the walls using 1/8" panelling on interior and a mesh/water epoxy coating on exterior I think those weights can be shattered Heisley. The real test is killing off the weight at the trailer side right off the bat. I think the first help would be going to the short L shaped torsion axles dropping a lot of overall axle weight from the build right off the bat and giving a smoother ride. That would have to be a good 50 pounds or more dropped right away maybe even close to a hundred.

[crumbruiser]

Nice one S. Heisley! OR I think we could send two comparable trailers through a road course, like the ones they use to test new vehicles with all the bumps in the road! I have traveled through a lot of states, but haven't found any frozen turkey crossings yet. Maybe I need to travel more through canada!?


But I am convinced that the foam would indeed be lighter. We have thought that what we could do is sandwich the foam with 1/8'' birch?
Also, one crazy idea we had, would be to make a section of roof "convertible" style. By that we mean paneling with a lexan or plexiglass with a vent hole cut out so we can get a good view of the wyoming stars at night!

But ultimately, we like the finished look wood, but without the weight. Are we crazy? Yes, sometimes we are, but let us know what yall think.

This is the build I'm thinking of. I like the look of wood and foam is a very good insulater. I may even do 1/8 luan inside and lamenating with latex paint and old sheets from the thrift store.
Frank

[loaderman]

I agree torsion axles are usually lighter.
Also reducing frame weight is key. Incorporate the frame into your floor and walls.

[myoung]

The best material for the intended purpose. For me that meant plywood for the floor, 3mm plywood for all other sides over 3/4-inch foam in a mostly 1 and 1/2 inch by 3/4 inch poplar frame.

Total weight for a TTT 11 by 6 by 5.5 feet with all the toys is 1,400 pounds. Can't image getting the same structural integrity with any other construction except perhaps aluminum tubing and skins with foam insulation.

[linuxmanxxx]

Now there is a key word in this whole weight loss drive is structural integrity. If you had a foot of snow fall on your foam structure can it withstand the added weight on top of it? DOT and OSHA standards are in place for many reasons and safety being the number one thing. That's why on the exterior shell surface is where my greatest concerns lie for stiffness and strength of the overall structure. If a person couldn't lay or walk on the roof of the camper, I'd sure not be very comforted sleeping in it. What if a storm blew through and took a tree limb onto the structure? Lots of things to ponder more than light and cheap in life.

[loaderman]

I agree structural integrity is key. By using unibody principles, stress skin panels, torsion box, etc. we can have light weight and strength.

I am a carpenter by trade, we used to use 2x10's for floor joists. Now we use engineered I-joists 3/8 osb with a 2x3 top and bottom. Way lighter. 2 of us easily carry 30 foot I-joists and they span further.