Teardrops n Tiny Travel Trailers

I just picked up some fiberglass panels (Kalwall) and pricing is cheap enough to play a bit with them. I never wanted to skin my camper body with plywood and then fiberglass so I went FG over XPS. Worked well, yet want something a tad stronger this time around. Build 2.0 about to happen.

I have choices of 2mm & 3mm sheets. Now I need to test them out and sample resined pieces to the xps. I'm not figuring much issue to this, but the seams.. That bothers me a bit!

The question comes to dealing with the seams. Asumming no matter how hard I try, there will be gaps to deal with. Micro-balloons to fill? Then fiberglass tape over? Should I purposely gap the sections and fill? Would that actually be stronger?

Thoughts folks?

Are the panels polyester based?

If they are you could use polyester structure repair putty to fill any gaps. It is a poly-based resin with fiberglass strands in it. You wouldn't need to use glass tape.

In the boating crowd its used to repair cracks in jell coats or fiberglass.

Sounds like an interesting material. Is there a retail source?

If you are applying this over foam with epoxy you really don't have to fill the joints. But mixing epoxy with microballoons to make a filler would work. You could also cut a strip of the material and epoxy that over the joint. You might be able to incorporate the strip(s) into the design.

Polyester might dissolve the foam underneath so I would avoid that.

Pmullen503 wrote:Sounds like an interesting material. Is there a retail source.

https://www.jamestowndistributors.com/p ... ail/336293

Thats what I have used. I am sure the different MFG's of boating supplies has the same thing.


For doing outside corners there will be a structure on corners. So it shouldn't come into contact with foam. That stuff stays where you put it. It doesn't run or drip.

Philip wrote:Are the panels polyester based?

If they are you could use polyester structure repair putty to fill any gaps. It is a poly-based resin with fiberglass strands in it. You wouldn't need to use glass tape.

In the boating crowd its used to repair cracks in jell coats or fiberglass.

No, it's not... Now, I need to re-check. You have me worried. I'll be using epoxy resin to bond it to XPS foam.

Pmullen503 wrote:Sounds like an interesting material. Is there a retail source?

If you are applying this over foam with epoxy you really don't have to fill the joints. But mixing epoxy with microballoons to make a filler would work. You could also cut a strip of the material and epoxy that over the joint. You might be able to incorporate the strip(s) into the design.

Polyester might dissolve the foam underneath so I would avoid that.

https://www.kalwall.com/
My source is from Facebook Marketplace. The dude has an agreement with the company for the end cuts and seconds. He has trailers of product. Let me get through some testing and if it shows real promise, we'll figure out how to get you some!

Ya, Polyester won't work with XPS..

Philip wrote:

Pmullen503 wrote:Sounds like an interesting material. Is there a retail source.

https://www.jamestowndistributors.com/p ... ail/336293

Thats what I have used. I am sure the different MFG's of boating supplies has the same thing.


For doing outside corners there will be a structure on corners. So it shouldn't come into contact with foam. That stuff stays where you put it. It doesn't run or drip.

Thank you for the info and the source! The site has many folks to reach out to! I saw MEK and immediately went to Red Flag.. I believe that will melt the XPS I hope to bond to.. Over plywood, awesome!

RJ Howell wrote:
https://www.kalwall.com/
My source is from Facebook Marketplace. The dude has an agreement with the company for the end cuts and seconds. He has trailers of product. Let me get through some testing and if it shows real promise, we'll figure out how to get you some!

Ya, Polyester won't work with XPS..

Great, always looking for new techniques and materials.

RJ Howell wrote:
Thank you for the info and the source! The site has many folks to reach out to! I saw MEK and immediately went to Red Flag.. I believe that will melt the XPS I hope to bond to.. Over plywood, awesome!

Yes anything poly will melt XPS foam if it comes into contact. Are you planing to build with no wooden structure in this build?

you could also use epoxy boat fairing compound on the corners. Its two parts. Mix one to one. This stuff sounds hard. You need smaller grit paper to remove it.

https://www.jamestowndistributors.com/p ... tail/97775

I used that on my first camper build.

Philip wrote:

RJ Howell wrote:
Thank you for the info and the source! The site has many folks to reach out to! I saw MEK and immediately went to Red Flag.. I believe that will melt the XPS I hope to bond to.. Over plywood, awesome!

Yes anything poly will melt XPS foam if it comes into contact. Are you planing to build with no wooden structure in this build?

you could also use epoxy boat fairing compound on the corners. Its two parts. Mix one to one. This stuff sounds hard. You need smaller grit paper to remove it.

https://www.jamestowndistributors.com/p ... tail/97775

I used that on my first camper build.

My builds are a it different from the norm over here.. I'm designing up truck camper 2.0 Steel is my sub-structure unless I can prove a SIP can work in the loft area..

OK, steel frame covered with fiberglass panels.

You plan to insulate later, right? So you could use polyester filler because there is not foam near it while it curing. I'd still use resin + glass cloth on all the corners to make sure it never leaks.

What were you thinking for the interior surfaces?

For people without the metal working tools and skills SIPs might be easier. I was thinking more along the lines of SIPS.

Pmullen503 wrote:OK, steel frame covered with fiberglass panels.

You plan to insulate later, right? So you could use polyester filler because there is not foam near it while it curing. I'd still use resin + glass cloth on all the corners to make sure it never leaks.

What were you thinking for the interior surfaces?

For people without the metal working tools and skills SIPs might be easier. I was thinking more along the lines of SIPS.

I'm still working through how much steel I need vs. SIP. That over-hang (my loft over the cab) is the reason for steel structure. If not for the 'loft', this would be a SIP build. Like my original build, the panels will be between the steel ribs. What I learned was the 1.5" foam was more than enough to go through mid 20F with evening/morning heat (my little Buddy heater). Most times, 30F or above, just making coffee did the trick.

Still awaiting warmer temps to start experimenting on joints. I do figure FG seams no matter what, but my do some rubber style gasket on corners to help. Again still working through this..

The biggest issue with 1.0 build was how the edges between the steel and the inserted foam reflected through. Not sure I'd require anything with these panels I hope to use, yet if I can reduce 'any deflection with filler, I would like to do so. The file would be between the steel & XPS foam.

I've done an edge test on a home-built SIP and was very impressed! My cousin and I did it with a 24" tall and 1.5" thick FG'ed XPS panel. When we cut it down to possible spanners.. it's deflection as became too great. Meaning as joists, not so good for hope for weight. If you know of anyone or other info accordingly, lease pass along. I'd love to removed all this steel for the build!

Temps are finally at a point I can start my testing of product and no worry about overnight freezing. I've been itching to get started!

First was to use some scrapes of XPS I have around and setup a routing jig to insert a band on the edge. Using my 1.5" XSP I have a jig to rout & insert a 1" strip of my fiberglass panel (Kalwal). I sanded the surface to rough it up a bit, as it's smooth & shinny and gave it a Mineral Spirit wipe down. Bonding with the resin worked yet not as well as I hoped. I didn't bond two sections together, just wanted to see how well the FG strip will bond. Also did a 6" x 6" piece to the face of the XSP. Again works, but not as I hoped. I wanted to see more or consistent XSP on the FG piece. Also thinking it may be the age of the resin (Raka) and having some new here now, I will redo this test.

Next was using the Gorilla Glue. I used this on my original build and the truck camper build and love how well it works. Again it worked vey well with the FG strip routed in. Issue here is the expansion of the GG. Know that I do not moisten the pieces, but allow only the humidity in the air to start the reaction. This system works well for me (and my area of the country). Using this on the face creates an issue of clamping or somehow adding pressure to not allow uneven expansion. Nevermind the costs involved..

For fun I tried some contact adhesive on two pieces of the FG strips and bonded them. That works very well! Issue there is the contact adhesive is solvent based and eats the XPS. I know this from previous testing. Have never tried water-based contact adhesive and had to order some as no one around me is carrying it. If nothing else, I'm very curious what the reaction of it will be to the XPS. Has anyone tested this before?

It seems my local Box Store must have just received a shipment of XPS, so I'm heading over today to grab 3 sheets. Since I want to rebuild the roof of the existing Truck camper (better support over the width and change clamp positions) anyway, this will be the sampling (in real life conditions) of my testing.

So far I figure to rip the XPS into 8" section, insert a FG strip into one edge and using the GG bond them. This process I'm confident in. By then I should have the WB contact adhesive to test for bonding the FG panels. FYI purposes, my roof is 10' long by 6'-4" wide. I created a curve N/S to allow water run-off, yet also add some stiffening to the roof. Because the XPS is scored, that created a weakness. Hence the rips and addition of routed in FG splines.

Safe travels!

My Owner;
Had a product similar over a green house / Sauna. I hated walking on it.
Thanks for sharing

I'm pretty happy with the chopped strand (mixed fine) for creating of filling gaps (~1/8"). Now for some finer fairing..

I tried some corn starch mix and works decent. Spreads smooth. Tomorrow I sand it and throw a coat of primer over to have a good look. I lost count of ratio as I was mixing, yet I do believe if it wasn't 1:1 it was pretty darn close.

Anyone else used corn starch? Curious of your thoughts of mix, cost & final outcome.