Undercoating

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RussellK
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Undercoating

Post by RussellK » Wed Aug 10, 2011 10:55 am

Anyone have an opinion to offer regarding undercoating? Our bug is rust free and I'd like it to stay that way. Does the spray on rubberized stuff actually help. Is there a danger of it trapping moisture? Does it help with noise?

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Amskeptic
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Re: Undercoating

Post by Amskeptic » Wed Aug 10, 2011 11:42 am

RussellK wrote:Anyone have an opinion to offer regarding undercoating? Our bug is rust free and I'd like it to stay that way. Does the spray on rubberized stuff actually help. Is there a danger of it trapping moisture? Does it help with noise?
I like the aerosol rubberized paintable undercoating. It is not half the water trap of heavier brush-on applications. It is able to find crevasses. You can use compressed air to help blast into the nooks and crannies and over and behind all the tubes and whatnot under the car. It needs a clean surface to bond with. If you have extant undercoating ready to peel off, it is just going to come off with it.

Over several years of annual applications, it becomes a useful sound damper dust preventative.
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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Hippie
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Re: Undercoating

Post by Hippie » Wed Aug 10, 2011 5:40 pm

+1.
My bus has old, old undercoating of that type, and I've not seen rust where it has flaked or been removed.
I think the water trap fear is over rated. Inside the drain holes and frame members though, I like to spray a thinner Waxoil-ish type product like 3M Rustfighter 1, or even a few light coats of Thomson's Water Seal. And, of course, not overdo it to the point that I create water trapping pockets of goo or plug the drain holes.
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RussellK
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Re: Undercoating

Post by RussellK » Thu Aug 11, 2011 6:33 am

That's a good point on those drain holes. I'll be keeping that in mind when we do the Beetle. I think a good undercoat on the underside and some Por15 down in the spare tire well and on the interior side of the pans under the back seat (where the battery is) will be the way to go.

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