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AndyfromTucson's avatar
AndyfromTucson
Explorer
Oct 19, 2016

Advice needed on delamination repair

One sidewall of the cabover of my Class-C had a lot of delamination. The previous owner had apparently replaced the Filon and luan in this area before, so I just took off the edge molding and pried off the Filon and rotten luan, which exposed the styrofoam and 1" aluminum square tubing framing underneath. After doing research online, here is what I have come up with for how to proceed; If you have any experience with something like this please let me know what you think:

- I want to use Azdel instead of luan for the fix because Azdel is synthetic and won't rot, but I have not been able to find a vendor who sells single sheets of it in the thickness I think I need (1/8 inch or 3mm). Any ideas on how to buy Azdel or similar?

- First step would be gluing the old Filon (still in one piece) to new luan (or Azdel if I can find it) using 3M Hi-Strength 90 Spray Adhesive to make a new Filon-luan panel.

- Second step would be screwing the top edge of my new Filon-luan panel to the top aluminum tube of the framing to get the positioning correct.

- Third step would be swinging the new panel out a bit, then getting under it and applying 3M 30NF Contact Adhesive (supposed to work on styrofoam) to the framing and styrofoam and the underside of the new panel, letting them dry per instructions, then pressing them together and using some sort of roller.

- Final, replacing molding with new butyl, etc.

Any thoughts, corrections or advice?
  • TriumphGuy's avatar
    TriumphGuy
    Explorer
    Oct 19, 2016
    I had to do a similar repair to the front and rear edges of the sidewalls of a previous 5th wheel. Forest River-claimed "aluminum construction" actually had plenty of wood studs inside.

    I used products from Rot Doctor to harden up what wood studs and plywood were left that I couldn't tear out and replace (CPES product) and the built back up the holes / gouges with their epoxy.

    Then I used Gorilla glue and new luan to re-attach the outer fiberglass. It held for years and sold it without any leaks coming back.

    I think your approach looks good as I understand you don't have any wood (left) but all aluminum and styrofoam, so you don't have a wood problem (other than the luan) but need an adhesive that will work with the foam.

    My only other thought is to try and figure out where your leak was coming from in the first place. I double covered the corners and edges of that 5th wheel with Eternabond as I didn't trust sealant anymore.
  • DrewE's avatar
    DrewE
    Explorer II
    Oct 19, 2016
    I would not attach the Filon to the new luan or whatever before attaching the latter to the frame, but rather the opposite way around. Probably either could be made to work, but I think it would be easier to install and trim the inflexible panel to the framework first and then attach the outer sheathing.

    I would probably use construction adhesive and/or epoxy to attach the panel to the foam and framework. Rolling a luan or similar panel firmly enough to get contact adhesive to attach it to styrofoam sounds tricky at best, and impossible for a metal framework if the metal isn't perfectly smooth. Good construction adhesive, like PL-Pro, bonds very strongly.

    From the picture in your other thread, the framework isn't aluminum but some sort of steel. Aluminum does not rust and typically is not painted. I don't think that matters much for your repair, except for some differences in driving screws or other fasteners into the framework.
  • fourthclassC's avatar
    fourthclassC
    Explorer
    Oct 19, 2016
    Looks like steel framing to me. Regarding delamination, I suggest you use lexan of the same thickness with holes drill randomly. Then use gorrilla glue. I know this seems like out of the box thinking but I have repaired a great deal of delamination like that. With the gorrilla glue it must be clamped completely and I have used pieces of 2x4 as wedges and a cargo bar, against my barn wall. I have sealed corners (after removing aluminum molding) with Proflex then covered with eternabond (had to be cut to width) then re-screwed on the aluminium molding with new stainless screws (Know as shutter screws in some places and they come with white painted heads)
  • fourthclassC's avatar
    fourthclassC
    Explorer
    Oct 19, 2016
    Looks like steel framing to me. Regarding delamination, I suggest you use lexan of the same thickness as luan, with holes drilled randomly to enhance the grip. Then use gorrilla glue. I know this seems like out of the box thinking but I have repaired a great deal of delamination like that. With the gorrilla glue it must be clamped completely and I have used pieces of 2x4 as wedges and a cargo bar, against my barn wall. I have sealed corners (after removing aluminum molding) with Proflex then covered with eternabond (had to be cut to width) then re-screwed on the aluminium molding back on over the eternabond, with new stainless screws (Know as shutter screws in some places and they come with white painted heads)
  • AndyfromTucson's avatar
    AndyfromTucson
    Explorer
    Oct 19, 2016
    fourthclassC wrote:
    Regarding delamination, I suggest you use lexan of the same thickness as luan, with holes drilled randomly to enhance the grip...


    Lexan sounds like a very interesting idea! I was really not looking forward to putting rot prone luan back into the wall.
  • Bumpyroad's avatar
    Bumpyroad
    Explorer
    Oct 19, 2016
    if the gorilla glue you are referencing is the type that swells when damp/applied I would certainly use something else. the stuff I used to glue a dowel into a cane handle sucked, a little pressure to the side started getting worse and there was no "stickum" involved, just expansion to hold it.
    use something else.
    bumpy
  • Joe417's avatar
    Joe417
    Explorer
    Oct 20, 2016
    I've used the gorilla glue (polyurethane). It works great for attaching panels where the material prevents drying. As Bumpyroad said, it does not work well for mechanical connection of levers. And as DrewE said, you may want to attach the substrate first and then the filon. Attaching the Filon to the substrate first only works well if there are no curves as in it is a flat surface..

    I built two clamping bands out of 10 ft. 2x4s to go around the camper. When I put the material in place, I put a sheet of plywood over it to cover the area being glued, then a couple of 2x4 on top of the plywood to distribute pressure and clamped it to the camper with Erwin hand clamps between the clamping bands and the 2xs on the plywood.
  • DrewE's avatar
    DrewE
    Explorer II
    Oct 20, 2016
    Joe417 wrote:

    I built two clamping bands out of 10 ft. 2x4s to go around the camper. When I put the material in place, I put a sheet of plywood over it to cover the area being glued, then a couple of 2x4 on top of the plywood to distribute pressure and clamped it to the camper with Erwin hand clamps between the clamping bands and the 2xs on the plywood.


    That's a neat idea. It occurs to me that one could probably rig up something similar with a few ratchet straps (and plywood and whatnot). Either one sounds a lot easier to manage than the profusion of props against the ground or a wall or something that I likely would have come up with on my own for this sort of repair.
  • fourthclassC's avatar
    fourthclassC
    Explorer
    Oct 20, 2016
    Gorrilla glue is difficult to work with because of the swelling and the stickieness- but if fill voids to completely support panels. It will make a mess if not clamped/restrained properly (also so the clamps do not stick) But it is waterproof when dried and the correct adheasive for this application in my opinion and from my actual experience. Before I used it I contacted Gorrilla Glue company and they said the glue will last longer then the substrates I was using.

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