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Dirtyrhoades · 05-12-2021, 11:56 AM

Hello all,

Since I recently installed a mini split air conditioner on my 97 class A winnebago, linked here, I will be removing the rooftop air conditioner and sealing up the hole, and I would like feedback from you fine folks.

The plan is to use a piece of FRP, such as found on the walls in gas station and restaurant bathrooms. I'll be sealing it with 6" Quick Roof Extreme, which I'm told is similar to Eternabond. First I'll prepare the area with eternaclean and eternaprime. Last, I'll use newflex 311 to seal down the edges of the tape. Does that sound like good way to go?

Second, the filon sheet on the roof is intact, but it's dry and has completely lost it's gloss. Should I go about restoring the filon before sealing up the hole, or would it be better to stick the tape to the dry filon?

If it is recommended to stick the tape to a restored surface, what should I use to restore the filon? One shop suggested any sort of marine wax. Suggestions welcome.

Thank you in advance, everyone.

amosnandy · 05-12-2021, 12:36 PM

Quote:

Originally Posted by Dirtyrhoades

Hello all,

Since I recently installed a mini split air conditioner on my 97 class A winnebago, linked here, I will be removing the rooftop air conditioner and sealing up the hole, and I would like feedback from you fine folks.

The plan is to use a piece of FRP, such as found on the walls in gas station and restaurant bathrooms. I'll be sealing it with 6" Quick Roof Extreme, which I'm told is similar to Eternabond. First I'll prepare the area with eternaclean and eternaprime. Last, I'll use newflex 311 to seal down the edges of the tape. Does that sound like good way to go?

Second, the filon sheet on the roof is intact, but it's dry and has completely lost it's gloss. Should I go about restoring the filon before sealing up the hole, or would it be better to stick the tape to the dry filon?

If it is recommended to stick the tape to a restored surface, what should I use to restore the filon? One shop suggested any sort of marine wax. Suggestions welcome.

Thank you in advance, everyone.

I don't know about the newflex 311, but the eternabond has some pretty specific directions for proper sealing. I would follow them closely, and think on Fibron you are suppose to remove any coatings or sealers before applying. In the past to repair Filon we have used a mechanical polisher to remove any oxidation, then use the cleaners but put no sealer or wax. Eternabond needs to be applied to a completely clean surface, free of wax sealers and oxidation. I think they even make a primer for it, though I don't think that is necessary.

What are your plans to reinforce the roof where the original AC units came out? Because they are rigid, the do have some structural support. If I were doing it I would cut a piece of Luan an inch or two larger than the hole, glue with waterproof wood glue and some very small brass or stainless wood screws. FRP is a fiber glass reinforced wall board. Filon would be a better choice. You might check with some local shops that do roof repairs and they may have some small pieces. I once got a patch piece that was leftover from replacing a complete roof. I think he gave it to me, saying it was waste. The one thing you want to avoid is using 2 different materials which may expand and contract at different rated, effectively breaking the seal to the roof.

I assume you have a plan to cover the ceiling inside where the intake came through.