FRP instead of Plywood for Outer Skin and Hatch

[Dan P-TNT]

Greetings!

I searched high and low through the forums and couldn't find the answer I was looking for, so here goes. I am about to skin my TD and was hoping to use FRP exclusively for the outside skin and the galley hatch (inside & out). Wondering if this is a good or bad idea and if others have had success with it. If so, anyone know the best way to bond it to the spars/insulation? I plan on putting trim around the perimeter/edges so I should be good there. Any help would be appreciated.

Dan

 

[Tony Latham]

and was hoping to use FRP

How's it do in the sunlight?



Tony

 

[Pmullen503]

It would really depend on how it's framed underneath. The framing needed for plywood is much less because the plywood adds most of the rigidity needed for a hatch. With a flexible skin, the frame has to do most of the work and must be designed accordingly.

It can work, there are fabric covered airplanes still flying today.

 

[Dan P-TNT]

and was hoping to use FRP

How's it do in the sunlight?



Tony

Hey Tony, not sure about the sunlight aspect, which is why its great to hear from experienced builder such as yourself. I do plan on using a UV paint on the outside. Not sure if your reply was aimed at UV protection or temperature/humidity fluctuation in general. Trying to find thin plywood is not easy; at least hasn't been for me.

 

[Dan P-TNT]

It would really depend on how it's framed underneath. The framing needed for plywood is much less because the plywood adds most of the rigidity needed for a hatch. With a flexible skin, the frame has to do most of the work and must be designed accordingly.

It can work, there are fabric covered airplanes still flying today.

My build design is based of off the Steve Frederick's build. So the hatch will be very close to what he advises. The only vertical support is the sides with 1x3 or 2x2's going horizontal. I only have the sides completed at this time, so its not fully assembled yet. I am constantly rethinking (as any DIYer does) but finding the right skin seems to be my biggest challenge. Especially for my first build that is 62 inches wide

 

[Tony Latham]

I do plan on using a UV paint on the outside.

That's what I was referring to. Good luck with your build.



Tony

 

[PhilipE-SKO]

Do some pricing between FRP and filon. Both will require a plywood subbase. Both require the same glue types. Filon is used on outer walls of newer RV's. Filon is lighter. You can get filon is a few colors also.

Filon or FRP doesn't matter. They both have the same issues. If the plywood subbase gets wet. The panel is going to bulge and do other stuff. So think hard about how you are going to seal the side to roof connection.

 

[saywhatthat]

if your plaining to use filon. best if it's floated. it expands quite a bit . Has a lot of resin and maybe a layer or two of mat you can make your own skin much stronger cuz you can add Wovening and all you need is a piece of $11 hardboard to use as a mold. What in the **** is wood?

 

[MickinOz]

FRP can be used for skinning. Caseydog did it.
viewtopic.php?f=50&t=29535&start=214
I believe he used stuff available from Home Depot or somewhere.
I believe it was screwed directly to the frame, no plywood underlay.
This is the build that inspired me to take the journey.
The simplicity is stunning and I even now, as I get about halfway through number 2, re-read the thread just to remind myself that we can overthink and overcomplicate these things.

I couldn't get a suitable affordable product to emulate this build here in Oz. Stuff made for caravans is available but it's $100's per metre.
In any case he told me via PM that the bathroom and kitchen stuff is brittle and hard to work with.

 

[Dan P-TNT]

FRP can be used for skinning. Caseydog did it.
viewtopic.php?f=50&t=29535&start=214
I believe he used stuff available from Home Depot or somewhere.
I believe it was screwed directly to the frame, no plywood underlay.
This is the build that inspired me to take the journey.
The simplicity is stunning and I even now, as I get about halfway through number 2, re-read the thread just to remind myself that we can overthink and overcomplicate these things.

I couldn't get a suitable affordable product to emulate this build here in Oz. Stuff made for caravans is available but it's $100's per metre.
In any case he told me via PM that the bathroom and kitchen stuff is brittle and hard to work with.

Good to know. I am forging ahead on my build and should be skinning soon. Galley is almost done and will be doing the inside skin soon, then on to electrical. I'll post a few pics soon.

 

[Dan P-TNT]

From what I've read in the forum, people seem to like pictures.
Here's a few on my build. So far so good for a complete rookie woodworker.

 

[MickinOz]

I would suggest that you wouldn't put sheet FRP on that.
I'm assuming you are in the US where everything is more readily available and usually cheaper than it is here in Australia.
You should skin it with thin plywood, then consider one of the many extra durable top layers available to you.
e,g, PMF, Aluminium sheet, epoxy resim with woven cloth, etc.

 

[PCO6]

FRP panels are fairly common on commercial built trailers. I have a Coachmen Clipper with FRP exterior walls on a stick built frame and have had no problems with over the 3 years that I've owned it.

Here's a thread on a home built ... viewtopic.php?f=65&t=72427

 

[Dan P-TNT]

FRP panels are fairly common on commercial built trailers. I have a Coachmen Clipper with FRP exterior walls on a stick built frame and have had no problems with over the 3 years that I've owned it.

Here's a thread on a home built ... viewtopic.php?f=65&t=72427

Thanks for the info. I've read through that post previously. From what I understood, he had plywood underneath all of his FRP and not a stick frame with insulation like mine. Good to know your Clipper was built that way. Finding thin plywood as an outside skin underlayment seems to be my biggest hurdle (Aside from learning what all of those lines on a tape measure mean ). His TD still looks good after 20 years though. Thanks for your reply.

 

[Shadow Catcher]

Our Filon which is FRP, is 15 years old.

 

[Hooch-TNT]

Hello Dan. I realize I'm about a month after your question, but here is what i have determined.I'm getting ready to plunge into a truck camper build and maybe a TD. I too thought FRP panels,also painted was my way to go.Now,I'm not saying they aren't,but with all my little pre-test panel projects, I believe FRP panels are WAY to flexible when glued to only framing.I think they definitely need to be glued to a plywood.But what i did find, is 4'x8'x1/8" sheets of ply,luan? It's available at the big orange hardware/lumber/everything in between store. It's called utility panel and is actually a little thinner than .125".It's also less than $16 a sheet. Another plus with these panels is it's half the weight of 1/4"(5mm)4x8 luan. It bends real nice and shows good strength when glued to 1x framing. I'll be covering my project with PMF, using cotton duck canvas that is found at the big Hobby store just past the Lobby. ($9.99 yard but often on sale for 50% off. I'm real happy with my test panels using this compared to the very rough painter drop cloths.

 

[Wrecit]

Did not see it mentioned but with FRP heat is your friend. Have put a 6 inch curve right angle in a sheet at my real job in the past. If you try to bend to tight a curve without a heat gun or torch you will shatter it

 

[Dan P-TNT]

Hello Dan. I realize I'm about a month after your question, but here is what i have determined.I'm getting ready to plunge into a truck camper build and maybe a TD. I too thought FRP panels,also painted was my way to go.Now,I'm not saying they aren't,but with all my little pre-test panel projects, I believe FRP panels are WAY to flexible when glued to only framing.I think they definitely need to be glued to a plywood.But what i did find, is 4'x8'x1/8" sheets of ply,luan? It's available at the big orange hardware/lumber/everything in between store. It's called utility panel and is actually a little thinner than .125".It's also less than $16 a sheet. Another plus with these panels is it's half the weight of 1/4"(5mm)4x8 luan. It bends real nice and shows good strength when glued to 1x framing. I'll be covering my project with PMF, using cotton duck canvas that is found at the big Hobby store just past the Lobby. ($9.99 yard but often on sale for 50% off. I'm real happy with my test panels using this compared to the very rough painter drop cloths.

Hey Hooch, You must have read my mind. I actually abandoned the FRP on stick frame idea and skinned it in the utility panel you mentioned. It did bend nicely and was easy to work with. I have the entire TD skinned now and will be doing the PMF this weekend. There is a nice lady on youtube that has a great tutorial on PMF. I'll be using her technique.

 

[MonteQuest]

I am using 1/16" FRP for the first skin instead of plywood. 4 x 8 sheets are available at Lowe's, Dome Depot, and Menards. Same as used for bathroom walls. About $38.00. 19 lbs/sheet. It easily follows the tight curves. My top skin will be Filon using contact cement. See my teardrop in the build journal. Monte's Ramblin' Rose.

 

[MonteQuest]

FRP used for interior ceiling.