Belly band question for rear of Trillium 4500

[Dino C]

Hello,

I took out all the steal plates around my belly band and am ready to fill with bondo glass.

The only issue is that at the rear of the Trillium 4500, the belly band didn't have steel plates, but there is a rotted section of wood in the area of the belly band.
I removed the rear window and am able to remove the bottom window frame piece, and with a long screw driver, I was able to ascertain that the wood below, which I believe the dinette is screwed into, is still hard. It's just the wood around the belly band that disintegrated. I cleaned that area out, and am wondering how I can secure the fiberglass in the belly band area, as there is a void now where there was a 2-3" of section of wood.
Thanks

[Deborah S]

I did this a few years ago now and ended up scrapping back the ensolite in the interior and fibreglassed the inside too. I reglued it with contact cement. Fussy work but it worked out ok.

Deb

[David Tilston]

I also ran into this. The link below is the posing where I discover this design flaw.
https://www.fiberglassrv.com/forums/...tml#post403159

[Dino C]

Hey David,
Thank you. I read the thread. If I understood, you essentially put a piece of plywood into the space and glued it to the inside, and outside walls of the trailer? Is it glued to the top and bottom halves together? Elsewhere on the trailer, the inside wall is a lining of fiberglass, whereas at the back, they aren't connected at the belly band, so I am assuming this new piece that I should add will provide that join???
Thanks

[David Tilston]

I glued a 1/2" thick strip of plywood. just like the original, but I was not able to get all of the original plywood out. Below the belly band the original plywood was still firmly glued to the shell of the trailer, and the back splash of the table. What I glued in was just to match the height of what was still glued in below, and to stabilize the bottom of the window frame. After that I just filled the gap with fibreglass and resin, from the outside. The seam is visually identical to the rest of the belly band.

When I do it again, instead of 1/2" thick plywood, I will use pultruded 1/4" x2" angle:

https://www.grainger.ca/en/product/A...-FT/p/WWG4ATH9

I will cut it into two 1/4" x 2" strips, then glue them together and make a 1/2" x 2" strip. I'm trying to not use any wood in my final trailer.

[John in Michigan]

Dino, as you discovered, on the Trillium 4500 there is no fiberglass cloth backer strip behind the center seam on the rear side of the trailer. Furthermore there is no ensolite below the rear window, just an interior finished fiberglass panel. In mine apparently there was a wood backer but it was completely rotted out. See post #34 in my thread below (with photo):

https://www.fiberglassrv.com/forums/...tml#post699064

When doing this repair, fortunately I already had the rear window out. I was able to remove all of the rotten wood debris, clean the raw fiberglass surface and insert the aluminum c channels, glue and clamp...

[David Tilston]

John, I just looked at your link. Am I correct that you used ½" wide aluminum C channel to tie the exterior fibreglass, below the window, to the rear dinette back splash?

I used ½" thick plywood here, but I would choose a different material for my next one.

[John in Michigan]

Sounds strange but that's what I had and what I did. I wanted to use material that would not rot.

I used two opposing pieces of 1/2" channel wrapped around and held together by a small rectangular piece of pine. (Doesn't matter if the pine rots in the future. The c channels will stay in place.) I settled on the c channels because they stuck very well to the construction adhesive that I used to glue the exterior shell to the dinette backsplash.

Before settling on the aluminum c channels, I experimented with a piece of cellular pvc trim, but the construction adhesive didn't stick to it.

EDIT: In conclusion, use a 1/2" spacer that won't rot...

[John in Michigan]

Probably a more suitable 1/2" spacer would be a pre-fabricated piece of resin soaked fiberglass.

[Steve Hague]

I'm thinking of getting a sheet of Coosa Bluewater 26 for my next Trillium project. I'll probably get a 1/4 inch sheet and laminate to get the desired thickness of 1/2 or 3/4 inch. Likely not the most economical choice, but should be very strong and never rot. I'm curious if anyone has tried Coosa for fiberglass rv renovation/repair.

[drdoyle]

Don't worry about the inside you can fix that later. Use a spay can of foam in the gap. Sand it to be flush with the outside belly band and use 2 or 3 inch fiberglass cloth tape to tie the top and bottom shells together - several layers. Finish with feathering putty (international water tight epoxy) , sand and paint with the Finish of your choice - paint a nice blue stripe around the camper to match the 4500 stencils. I prefer west epoxy resin over polyester as I find it easier to work with and no smells.