To seal or not to seal, that is the question...

[LarryJ]

I posted this in the construction section but this is probably a good question for this thread also.

I'm at the point of sanding and filling (and sanding some more...), next step is applying canvas.



My question is if I should coat the whole thing with a poly mix before applying the canvas?

I'd like the extra waterproofing penetration the mix would give, but don't want to decrease the hold of the glue holding down the canvas.

Thx

LarryJ

[mikeschn]

Hey Larry,

After reading the subject line, I said to myself, "Seal or course!"

After reading the details in your post, I suspect that the poly resin isn't necessary, because the glue/canvas/paint is probably all the sealant you need. But of course, I hope Glenn chips in.

Mike...

[GPW]

JMHO, the canvas/glue (painted later of course) is all you really need for protection ... And you “could" add a waterproofing poly mix later to anything that didn’t get canvassed over...

With poly first on the wood , the canvas wouldn’t adhere as well as on the bare wood , where it will stick like CRAZY ... All tests of canvas on plywood (TB2) ... the wood always failed first .. Try a small tests yourself with scraps ... Amazing the extra strength that canvas over plywood gives... but foremost it keeps BENT plywood from splitting and de-laminating... If I’d canvassed just the roof on my first wooden TD, I’d probably still have it ...

[GPW]

Just thinking about this a little more .... It may be best in the long haul to completely seal all inner framing/floor/hatches just as a matter of course. In a wooden trailer , a canvas skin outside wouldn’t be there to purposely add strength as with a foamie’ trailer structure... although it will . So actually the plywood walls /roof/etc. could be thoroughly sealed/waterproofed, and then the canvas applied over it with a primer , such as Glidden Gripper ... which would undoubtedly stick over the waterproofing component ( Poly +MinSpts in our case)

So Sad we’ve seen so many trailers damaged by a tiny amount of water intrusion ...  Damage that could have been prevented by a little waterproofing protection beforehand ...