Recoating polyurethane tent flys

[Elliott Wolin]

I have to recoat a couple of tent flys, and some are for large family camping tents.  All are PU coated.

What is the latest on recoating?  Can you make your own PU recoating solution?  I see those little McNett bottles for sale, sort of expensive given the square yards of fabric I need to recoat.  Where might I get PU solution in bulk?

How about switching from polyurethane to silicone, since it’s cheap/easy to make a silicone recoating solution (just paint thinner and pure silicone caulk)?  With silicone I could coat both sides of the flys.

I wonder if I could just recoat with silicone over the PU and not worry about getting all the PU off, particularly if I recoat both sides.  Might the silicone seal the PU?  Or would it eventually flake off anyway?

[Nick Gatel]

A recent discussion here . . .

https://backpackinglight.com/forums/topic/restoring-a-shelter-with-a-degraded-pu-coating/

 

[Elliott Wolin]

True senior moment here, I discovered I asked almost the same question a few years ago.  And lazy, as I didn’t do anything about the rain flys since then.

In a partial effort at self-redemption, I note that some of the earlier posts were speculative.  Perhaps since then folks have more experience, and maybe new products have appeared.

And maybe someone has come up with a DIY PU solution.  Although I now see in the 2017 thread that Roger mentioned TPU, the latest version, as not a DIY product.  And given the experience of Mark Reis, perhaps I should just give up on PU recoating and go for silicone instead of using the bottles of the milky-white stuff I have.

[Elliott Wolin]

Alas I discovered my (six!) bottles of milky-white stuff are no good, just a lump of white stuff surrounded by some water.

So it’s silicone dissolved in paint thinner for me.  I’ll report back on how well it went on a large 6p dome tent fly and vestibule where I removed all the PU by multiple washings in strong detergent.

[Roger Caffin]

just a lump of white stuff surrounded by some water.
OK, I can see that happening, but it is a new one on me!

I would NOT try coating silicone over the top of aging PU: that will not go well.

Cheers

[Chris FormyDuval]

My older unopened bottles of tentsure turned lumpy and useless. I had better luck with new ones. It was a lot of work doing one section at time as it would soak right thru the fly so I had to have it suspended to dry. I learned that the hard way as a section still has the pattern of my patio table on it. If I didn’t really like the tent I wouldn’t have tried but not looking to do it again. Suggest trying whatever you do on the small one first to work out the production kinks.

[Elliott Wolin]

Intermediate progress report on recoating 6P tent fly with silicone/paint thinner:

I started with a pretty dilute mixture, perhaps 10:1 (measured by eye, very unreliable).  One coat on the outside, then one on the inside, then another on the outside (or maybe two, I lost track).  Recall I laundered away the original PU coating that had become sticky and smelly.

A spray hose pressure test showed recoat wasn’t that good.  Although sheets of water rolled off nicely, water sprayed through where the hose was aimed directly at the fabric.  My guess is this pressure would only happen with very heavy rain, but that happens.

Tried another recoat with a stronger mix, perhaps 6:1.  This seemed to work, no spray came through the fabric.  I think the early dilute coats saturated and bonded to the fabric well, and perhaps the later, thicker coats then bonded well to the earlier coats.  At least I don’t see any evidence for peeling yet.

One caveat:  during the second outside coat the wind picked up and blew a mass of yellow pollen from someplace onto the wet fabric.  Now my tent fly is sort of a different color in spots, and in some places the pollen balled up and I have little yellow lumps embedded in the coating.  I hope those don’t cause problems with peeling later!

Since the fabric is no longer soaking up the mixture, it doesn’t take that long to coat the outside, so I probably will do it one more time.  As I’m not entirely confident that the fly will perform well in heavy rain, we plan to take a blue plastic tarp with us to throw over the tent fly, just in case.  This is no problem since this tent will be used exclusively for car camping (it weighs a ton).

But it sure is nice to be able to stand up in a big, roomy tent and sleep on a six-inch thick air mattress!.

[Brad W]

Let it go man, let it go.. ;)

[Elliott Wolin]

Can’t!  As I noted someplace else, I think I need to enroll in a 12-step program…

[Elliott Wolin]

Also, the current version of this tent, Cabela’s West Wind 6P, costs around $250, more than I’m willing to spend, especially given that mine is in decent shape other than the PU coatings.

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