side wall construction

[wingrydr57]

Hello all! Wow what a great web site for a noob like me. Its a great time sucker for sure lol. Anyway I want to build my TD as light as possible, and was wondering if I could use 1/4 inch say birch plywood on the outside with the rigid foam insulation ( the pink stuff) in the middle and say some 1/4 inch paneling of some sort for the inside. The plans I have call for 3/4 inch birch plywood but the stuff is heavy. to conserve on weight all my cabinets will be pine with a high gloss finish.I am going to build on a 4x8 HF trailer. Oh and what would be best for glueing the panels to the foam?

Thanks everyone for the help, Steve W.

[Corwin C]

Welcome to the discussion. I'm considering a very similar construction technique (pre-finished flooring/foam/canvas-paint). The Foamy section has lots of ideas concerning adhesives and etc. I would recommend spending some time there. I think that the two biggest concerns with adhesives are #1 doesn't melt foam and #2 doesn't require air to "dry" (as sheet goods restrict air to the adhesive.) A curing adhesive such as gorilla glue or epoxy seems to be the best, but there are many alternatives as well.

[Larry C]

Hello all! Wow what a great web site for a noob like me. Its a great time sucker for sure lol. Anyway I want to build my TD as light as possible, and was wondering if I could use 1/4 inch say birch plywood on the outside with the rigid foam insulation ( the pink stuff) in the middle and say some 1/4 inch paneling of some sort for the inside. The plans I have call for 3/4 inch birch plywood but the stuff is heavy. to conserve on weight all my cabinets will be pine with a high gloss finish.I am going to build on a 4x8 HF trailer. Oh and what would be best for glueing the panels to the foam?

Thanks everyone for the help, Steve W.

Welcome aboard!
Your plan should work fine. I am doing similar, but using 1/8" skins, and epoxy for the glue.

Larry C

[wingrydr57]

Thanks guys Larry what kind of epoxy are you using? I have a 2 part resin and hardener left over from when I built a cedar strip canoe would that work?

Clear skies, Steve W.

[IndyTom]

You are still going to have 1/2" of plywood in that sidewall, so with the weight of the foam added in, I am not sure you a saving a great deal of weight. That being said, you WILL have a wall with much better insulating properties.

Tom

[Larry C]

Thanks guys Larry what kind of epoxy are you using? I have a 2 part resin and hardener left over from when I built a cedar strip canoe would that work?

Clear skies, Steve W.

Steve, If your using 1/4" plywood skins the weight savings after gluing everything together is going to be negligible. If you truly want to build no heavier than 500#, your almost half way there with the HF trailer!! I too want a TD in the 500# range, but even using 1/8" skins over foam it is going to be difficult to achieve, and my chassis will be 1/2 the weight of the HF trailer.

I am using Raka Epoxy, but the brand doesn't make a difference. You could also use PL premium construction adhesive to glue the skins over the foam as many have done.

There are many different ideas on building light weight. I am working with what I already know from previous experience. You may want to also look at the "Foamies" that are being built, if you want seriously light weight.

Keep your ideas and questions coming, there is a wealth of knowledge, ideas, and of course "opinions" here....

Larry C

[Oldragbaggers]

Larry, what kind of foam are you using? I have seen resin eat foam before so I am just curious.

[Larry C]

Larry, what kind of foam are you using? I have seen resin eat foam before so I am just curious.

It's just the blue foam from Lowes. I think it's polystyrene. I am using epoxy resin/hardener, not polyester resin which probably would eat the foam. The reason I used epoxy instead of PL was my floor is 5" x 7'+ and the epoxy gave my more work time than trying to apply the PL over that large of surface before it tacked up.

Larry C

[Oldragbaggers]

Larry, what kind of foam are you using? I have seen resin eat foam before so I am just curious.

It's just the blue foam from Lowes. I think it's polystyrene. I am using epoxy resin/hardener, not polyester resin which probably would eat the foam. The reason I used epoxy instead of PL was my floor is 5" x 7'+ and the epoxy gave my more work time than trying to apply the PL over that large of surface before it tacked up.

Larry C

Sounds great. And I was going to use epoxy to apply the skins to my plywood wall frame for the same reason. I just couldn't see how I was going to get all that glued up without the glue starting to set up before I got the skin on. Besides, you get a really good water tight seal in the process.

I am very interested in these lightweight builds and would like to tackle one for my next project, if I have a next project, so I will be watching yours!!

Thank you for answering my question.

[Larry C]

Larry, what kind of foam are you using? I have seen resin eat foam before so I am just curious.

It's just the blue foam from Lowes. I think it's polystyrene. I am using epoxy resin/hardener, not polyester resin which probably would eat the foam. The reason I used epoxy instead of PL was my floor is 5" x 7'+ and the epoxy gave my more work time than trying to apply the PL over that large of surface before it tacked up.

Larry C

Sounds great. And I was going to use epoxy to apply the skins to my plywood wall frame for the same reason. I just couldn't see how I was going to get all that glued up without the glue starting to set up before I got the skin on. Besides, you get a really good water tight seal in the process.

I am very interested in these lightweight builds and would like to tackle one for my next project, if I have a next project, so I will be watching yours!!

Thank you for answering my question.

On my side walls, I may try a hybrid approach by gluing all wood members with epoxy, and use PL spread with a notched trowel for the foam.

[SteveW]

I'm also scouring this site and others looking for the best possibilities for lightweight designs. So many design possibilities, at times I'm having paralysis of analysis.

I'd love to do a foam build w/ a fiberglass shell, but think that will have to wait until at least build 2, as I just don't think I have the skills for that just yet. For now I think the best option for me seems to be foam sandwiched between 1/8 ply with some pine blocks placed inside for anchor points. With that in mind, I have pretty much the same question about adhesives to bond all the different parts together. Wood/wood I think I have covered, but not sure about the foam. Is this the PL that is referenced in the previous posts? I've never used this or epoxy, so what should I expect when using either of these products? Pros/cons?

[linuxmanxxx]

Look at my post on this floor thread in this section and it applies to how I have built my walls and roof all in a single post. Details what glue to use and what to frame with and just simple 1/8" luan on skins and it is massively strong. http://tnttt.com/viewtopic.php?f=21&t=48712#p911552

[Wolfgang92025]

Is this the PL that is referenced in the previous posts? I've never used this or epoxy, so what should I expect when using either of these products? Pros/cons?

Steve, yes it is. That is what I used to glue the inside and outside skin on my trailer. Used a notched trowel for coverage on the foam panel. You have to work quick, but it can be done with a little planning. Start with smaller job first to get the hang of it if possible. Make sure you dry fit everything and lay out all tools etc. Before you start and make sure you are not working in the direct sun. PL is pretty cheap, comes in several different sizes. And it is tough. Had to make a couple corrections and the wood gave out before the glue. Also works real well in places were you might have a small air gap. once cured, you pretty much have to cut it apart.

hope this helps.....

[SteveW]

That's exactly what I was hoping to hear. Looks like my ideas for floor and walls (and possibly ceiling) are now in order. Time to start the official drawings!