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Underbody wood “reseal”
I am currently doing a series of repairs/improve on our 2000 Rear bath,

Entry steps have been removed to be cleaned up and repainted, the wood framing the steps are mounted requires some serious attention.

I don’t think any rot has taken place, wood still feels and looks good but the original sealant/coating is completely falling apart.

I am intending to remove the sealant/coating and apply a layer of penetrating expoxy resin to prolong/seal the wood for the future. That said, I am genuinely struggling to remove the original factory coating.

It appears lazy daze sealed the joints with the usual parlastic, but then some sort of black coating resembling tar is applied all over the wood.

Does anyone have any experience or knowledge of what kind of underbody sealant they applied to the exposed wood from the factory? And better yet, a decent way to remove it?
2000 RB

Re: Underbody wood “reseal”
Reply #1
"...but then some sort of black coating resembling tar is applied all over the wood."

What you have may be ordinary automotive undercoat, the kind of stuff that's used where roads are salted in the winter. Does it have a different texture than ordinary paint? If, in fact, that's what it is perhaps another coat of the same would be a good idea.  ::)
Steve S.
Lazy Bones & Cedar
2004 30'IB (Island Bed)
Yesterday is History, Tomorrow is a Mystery
Live for the day!

Re: Underbody wood “reseal”
Reply #2
Following!

1998 MB in Sunnyvale CA

Re: Underbody wood “reseal”
Reply #3
I spray automotive undercoating underneath every few years. It is a lot like Tar.  Especially under the back bumper, there is exposed wood. The undercoat is sandblasted with sand thrown up from the tires.  RonB
RonB (Bostick) living in San Diego
Original owner of "Bluebelle" a '99 TKB

Re: Underbody wood “reseal”
Reply #4
Older LDs used an asphalt emulsion undercoating, as Lazy Bones suggested.
Newer model have galvanized sheet metal covering the bottom. Our 1983 had undercoating, the 2003 has sheet metal.

Heat and a sharp putty knife may all it takes to remove the undercoating.

Larry
Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze

Re: Underbody wood “reseal”
Reply #5
Our rig has galvanized metal covering the underbody, but a few areas like the step have no galvanized covering.

I have noticed a black tint coating applied to exposed wood around the door frame (behind the striker plate) as well as on the wood inside the storage boxes and the wood inside the refrigerator compartment.  I imagine this is all some sort of asphalt based coating to protect the wood from moisture.

I guess the tricky part is figuring a way to remove it enough to either replace with the same stuff, penetrating sealant/ paint likely will not adhere all that well to the old dirty coating.

I’m very reluctant to use typical automotive undercoats, I find they usually facilitate rust by allowing water/moisture to propagate between the metal and coating.
2000 RB

Re: Underbody wood “reseal”
Reply #6

Hi Cor2man;  The spray on undercoating is reserved for coating wood. Especially the wood piece at the base of the back wall adjacent to the bumper.  The wood needs to be dry and I clean with a wire brush before applying more. It just builds on the old coating.  Pieces of the old coating come off if not attached well.
   The back of the step well on mine peeled off during a trip.  I was inspecting underneath and found lots!! of fresh looking staples and clean (mostly) bare wood exposed on the back side of the step well.  Took two cans of 'asphalt' spray. I think it is some polymerizing plastic now-a-days.  The application of staples holding the carpet on was amazing!
   For metal items, frame and such, I use a phosphoric acid based flat black spray paint. Amazon.com: SEM 39673 Black Self Etching Primer - 15.5 oz. : Automotive  RonB

As an Amazon Associate Lazy Daze Owners' Group earns from qualifying purchases.
RonB (Bostick) living in San Diego
Original owner of "Bluebelle" a '99 TKB

Re: Underbody wood “reseal”
Reply #7
Ron,

Do you have a link yo the undercoating you mentioned?
2000 RB

Re: Underbody wood “reseal”
Reply #8
My 88 looks like the wood under side is coated with automotive under coating. I do touch up with aerosol cans of under coating from Auto Zone. It is the only store that carries it near me.
It is time to do it again after 5 years.
Rodney
1988 Mid Bath

 
Re: Underbody wood “reseal”
Reply #9
If refinishing bare wood under the steps, I would use an oil base wood primer before spraying any undercoating. It is cheaper than epoxy and problem almost as effective.

Larry

Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze

Re: Underbody wood “reseal”
Reply #10
If refinishing bare wood under the steps, I would use an oil base wood primer before spraying any undercoating. It is cheaper than epoxy and problem almost as effective.

Larry


Larry,

My original plan was to remove the coating but since it is literally soaked into the wood removal seems impossible. Since the wood seems adequately intact I would like to just remove any loose coating and overcoat the original asphalt emulsion with a similar product.

Unfortunately I am struggling to find such a product that is actually geared towards waterproofing wood. Best I can find so far is an asphalt based fence post protectant but I am not sure if that will give the solid coverage like what the factory used.
2000 RB

Re: Underbody wood “reseal”
Reply #11
I have used the spray automotive undercoating for many years and it seems to work fine. Oil-bases paints and primer work well too, it’s like painting your house.

Larry
Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze

Re: Underbody wood “reseal”
Reply #12
I use this stuff, every few years. Particularly the under rear bumper area is eaten away by sand on the road.  Auto Coatings Rubberized Undercoating Product Page
RonB
RonB (Bostick) living in San Diego
Original owner of "Bluebelle" a '99 TKB

Re: Underbody wood “reseal”
Reply #13
Quote
I use this stuff, every few years.

I use the same stuff under the front fenders. Adheres well and looks clean.
jor
09 27' MB
10  Suby Forester

Re: Underbody wood “reseal”
Reply #14
I used the Rustoleum product as well as a couple other brands, the Rustoleum definitely goes on the best but latex gloves are in order.

Jon
1994 MB