So in my imagination I am getting close to painting my car, and am wondering if I should do some sort of undercoating? What are your thoughts. What brand? How much product did it take? Was it hard to work with? Regrets? Thoughts?

Thanks

I'm going to do a tinted bed liner sort of material for the underside and I think the interior, tool. Like Raptor from UPOL. Apparently, you can tint it any color.

Wurth SKS Stone Guard is a nice coating, plus it's a German company. It's in aerosol cans but my only experience is with using their gun to apply it.

I'm not crazy about the worth. It's pretty expensive and every so often, it doesn't set up fully. Scrapes off easily. It's an issue that worth knows about but doesn't have a solution. I'll probably go with a bed liner as well. That stuff is tough. I'm not going to use it inside. Sir Andy said his is very hard to clean. Because of the texture, it doesn't wipe off.

OK so maybe epoxy primer, seam sealer and then bed liner...

I took the entire underside of my car to bare metal, then POR15'd the whole thing, then seam sealer, then Wurth undercoating product in rattle cans (used about 6). Did it on the rotisserie. It's held up well.

It took about 30 hours. In hindsight it wasn't necessary as I didn't discover any new rust and the primer was decent, but it was worth it to me to know for sure that I had good metal. I didn't have any problems with the Wurth stuff and thought it was a good product.

I did however document extensively with photos, as undercoating brings up...questions.

#41 as new at PMB

Bob BClick to view attachment

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When I cleaned off the factory undercoating it had this texture and was tan. #41 914-6

Bob B

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I was looking to do the Upol tintable Raptor as well. So far I really like Upol products.
I tried some of their Gravitex and it goes on very easily and turned out well. I also like their copper weldable primer.

I heard the Raptor is really durable and can deal with a bit of flexing.

I am thinking about Lizard skin for the firewall inside and out, then coating that and everything else under the car with Raptor.

Unfortunately, getting my project to the point of actual spraying undercoating seems like a far off dream at this point

-Andrew

Bob, you have two of the nicest 914s on rotisseries, hows the blue one coming?

Bob,
What did pmb spray on there? It looks great. Is it tinted yellow or did they paint over it?

Wurth was what was on it from the factory so we just put it back on, as it is a very high value 6 restorations. The Cannery Yellow overspray was from the big bucks paint job. This is the way the master @PMB said it should be done just like when it was built in 1969.

74- V8/930 trans Blue car on rotisserie got a little primer, as I am lazy and need to do some welding of the plate to hold the duel brake masters and the clutch master.

I have removed all of the paint from the bottom of that car and later will put on some 3M-body schutz from a gun when done. It looks clean and black and fresh and covers mistakes in body.

Bob B
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On my Ghia in the fender wells first was the epoxy then I put on the Raptor tinted bed liner and then color spray over that. I figured if the paint chipped the bed liner was still there. The tint tends to be much lighter than the actual color coat.
I can tell you it makes it much quieter and the stuff is hard.
If you want the black wheel wells you can also spray the Raptor liner in black.

Here's mine. After walnut blasting and body work was complete, the underside was painted with a commercial coating, Sherwin Williams Poline.

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Then it was coated with kevlar LineX bedliner

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Keep in mind, my car has been highly modified and it didn't matter to me that I was doing something different.

OK, those look great. Sounds like I will do 2k primer then seam sealer then Raptor in gray, then cover with base coat.

Thanks all for your comments,

Peter

Bumping this up to ask those who have, or plan to use Raptor why you chose Raptor instead of Upol's Gravitex. Is it just because Raptor is tintable? Staring at my shiny new floor pan has me thinking about undercoating a lot. On one hand, I can't think of a reason why 2K bed liner wouldn't make an excellent undercoat. On the other, I'm wondering why the manufacturers aren't promoting their products for this purpose. Gravitex seems to be Upol's undercoating product so I'm just wondering why Raptor instead?

Hay Brock,

I put on a couple of cans of gray and it did 2/3 of the underside not including the wheel wells and they I bought 3 more cans of the black as it seems that no one has gray anymore. The Black was less money at around $17. A can. What I see and feel is the stuff is easy to put on and seems to be on their very good. It has almost Teflon cooking pan feel.

The black stinks more than the gray and it dries in a few minuets but still stinks for a few days. If you could lake it out side to do this your wife will not hate you as much for doing this. I did my in the shop with the ventilation on full blast and it did smell. I used a vapor mask and did not smell anting while putting it on but when I took it off it was very strong for 6 hours.

Not really any over spray but put paper and blue masking tape all over any areas you do not want to get it. My car body is on a rotisserie so it was easy for me to use it. Good control from the can but better shot from 20 inches away

I give these stuff 5 stars at this point. I tried to scrape it off with my fingernail and it is stuck on well. I am going to cover the gray with the black so I will have a uniform look.

Good luck,

BobClick to view attachment Click to view attachmentClick to view attachment

Thanks Bob,

That's great info. I'm still 2+ months away from being ready to spray, so it will be an outside job. I did toy with the idea of spraying primer and then undercoat on just the underbelly in the garage, but have pretty much nixed that idea and your info about smell will help me stick to it.

I was leaning heavily toward 3M or Wurth schutz but am very intrigued by the bedliner. I've dug all over the interwebs for info and have yet to read any substantial negative complaint about bed liner as an undercoat. The main complaint I see about rubberized undercoat is that it dries out over time and then can chip or crack. That fits my experience with other cars. And yes, my wife has "odor Tourette syndrome." No matter how obviously smelly something is, she compulsively says, "that stinks."

For my project, I'm not going to get too picky about originality on the belly coating. I will undercoat in black to match how my car rolled away from the dealer but without that stuff globbed all over my suspension and cables. But I'm interested in whatever provides the latest and greatest long-term protection.

Unfortunately, I like actual data, but haven't found any objective tests comparing options. Spray-on bedliner seems like an ideal undercoat but, back to my question, why is it not being marketed for undercoating, and why do brands that sell bed liner have different products for undercoat?

Not sure what is in the bed liner. The rubberized Wurth stuff may be different than what was used at the factory back in 1970-76. The factory stuff is over 45 years old and still is somewhat soft. The idea is that small rocks bounce of or it and it deadens the sound.
The texture of the Wurth or 3M when shot from a gun is great for Valances and rocker panels on Porsche cars like my 86. Takes gloss paint and it sticks well. I have seen the bed liner look good in a semi flat like what was used in trunks in US cars from the 60s as
http://www.zolatone.com/technical-documents/


I did use a 3M schutz
With a gun not a can back in the 80s. Not easy for me but I was on jack stands
Let us know what you can find.

Bob B

I just got done spraying my car with Raptor liner tinted with PPG Shopline JAU SS paint in Mexico blue. I think it turned out pretty great. The underside was blasted, cleaned, primed with Master Series silver rust encapsulator, seam sealed and then bedlined.

Looks awesome!

That looks amazing and seeing it on your build thread is the reason I bumped this one. I"m curious what made you decide to go with Raptor?

nice life. what brand?

Thanks for the kind words. I decided on raptor for a few reasons...

I have good past experience shooting raptor on truck beds and I have zero experience with body schutz. So, I was familiar with the raptor product and comfortable using it. We used a similar product (not as good looking in my opinion) made by Herculiner in our '74 VW Thing for the wheel wells and inside the tub. It's held up excellent so far after 8+ years, I just am personally not a fan of the texture.

Here's some pictures of that different style liner and how we used it before:





I've never read anything negative online about others using bedliner for this reason. But, I have read complaints about body schutz if not applied properly, etc. Raptor is pretty straight forward to shoot and I even think it uses the same style spray gun as the Wurth product.

I'm not sure if you can tint or paint over body schutz? But I love the fact that my underside will color match the car and will also be protected from the road. I'm also not sure of the cost for the alternative, but raptor is one hell of a bargain at $100 (plus the paint to tint and schutz gun if you don't have one).

Just my $.02

Thanks! Exactly the kind of information I am looking for. Like you, I haven't found a single complaint about Raptor, whereas criticism of rubberized undercoat is easy to find. Most complaints about schutz seem stupid, but a few seem legit. There is even a thread on a restoration forum specifically asking people to share negative experiences with Raptor. Two pages of rave reviews and not a single negative experience. But reviews after long-term use are rare, so your experience with herculiner is very helpful. I think this stuff looks like "the bomb" for undercoating. I just don't understand why manufacturers aren't marketing the out of it for this purpose.

Wurth undercoating I believe. Same as was on the car from factory and a shit load of it. Have you seen the film where Porsche is putting this stuff on with a huge stick on 356?
Early 914-6 has it put on by hand not sprayed over the covers? I see if I can find a picture of the covers in the trunk

Bob B

Valance on my 86 Carrera from factory with paint on it. Same as on rockers. Chip resistant

Bob B
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