How did you rustproof your bottom?

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cruiser

cruiser

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Hi Guys/Gals: I know this topic has been addressed before, but please offer your opinion. My very stock 1974 Duster has some surface rust on the bottom. I plan on keeping it forever, and I don't want the rust to become a problem to where I need to replace the trunk floor, interior floor, quarter panel extensions, etc. I'm thinking that there must be some simple one application treatment that I can use to coat the underside of my car so that I don't have to worry about rusting it out when I drive in the rain. Perhaps something like a POR-15 product that you just brush on, and it converts whatever rust that is there into a rust free impenetrable surface. I don't want to wire wheel down the bottom of the car and make it look new. There's gotta be some easy to apply one coat product that you can use by simply giving the bottom a good wash, then brushing it on. My metal is solid - for now. I want to keep it that way. Any and all ideas are welcome, but hopefully someone can recommend a simple one step process. Thanks!
 
Cruiser, I did do the wire wheel, down to bare metal, in 3 sections. PITA, it took me forever on a creeper. Last time I ever do that at 60+. Then I used POR-15, not optimal being on your back! Then I roughed that up a little and I sprayed Eastwood undercoating (cans) over that. We will see how it holds up as I plan on keeping my car a long time also.
 
I have been doing epoxy primer then raptor bedliner thinned 10%. It lays out very fine texture when thinned. Of course if your into OE restoration this route is not for you. Grey is epoxy, black is bedliner and thrid pic is close up showing the texture.
Pics are my friends 67 b'cuda im working on.

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POR15 is good for under the car, as it's out of direct contact with UV light, which breaks it down, unless it's top coated. I've used POR15 before with both good and bad results. But both ways, it's MESSY AS HECK. Rustoleum industrial rust paint is IMO a much better product, because it does the same thing, is not affected by UV light, needs no top coat and is FAR less messy. Much more affordable, too. I got mine for about 27 dollars a gallon at Lowes.
 
Rustoleum rusty metal primer is some good paint, especially if your on a tight budget. Hell, it looks like the same primer mopar used on the replacement panels bitd.
 
Woody'sScamp said:
Cruiser, I did do the wire wheel, down to bare metal, in 3 sections. PITA, it took me forever on a creeper. Last time I ever do that at 60+. Then I used POR-15, not optimal being on your back! Then I roughed that up a little and I sprayed Eastwood undercoating (cans) over that. We will see how it holds up as I plan on keeping my car a long time also.
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You dont need to sand the por15 if you catch it while its still tacky. About 4 hours depending on the humidity and it has isocyanates in it so be careful. It gets a bad rap now and then cause people dont use it correctly. Its tough stuff. I've tested it a lot.
 
By Garaging and not driving with inclement weather when I know it is coming!
 
In my opinion NOTHING beats POR 15. Not a one step process to do it right ( cleaner, neutralizer, two coats POR 15, top coat when tacky so no need to rough up like previous poster mentioned) but you will NEVER have to worry about it again. I also use it on boat trailers that have sat outside year round for 8 years, besides going in and out of water, and they look like they were done yesterday.
 
Had a lot of trouble with my bottom, but haven’t seen any rust. Too much iron in your diet?
 
MoparMike1974 said:
I have been doing epoxy primer then raptor bedliner thinned 10%. It lays out very fine texture when thinned. Of course if your into OE restoration this route is not for you. Grey is epoxy, black is bedliner and thrid pic is close up showing the texture.
Pics are my friends 67 b'cuda im working on.

View attachment 1715741897

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That looks fantastic and is exactly what I'd like mine to look like. Unfortunately, I'd have to disassemble the car and put the shell on a rotisserie, which is a show stopper for me. But yeah, in a perfect world, I'd like my underside to look just like that. Very nice work - my compliments!
 
RustyRatRod said:
POR15 is good for under the car, as it's out of direct contact with UV light, which breaks it down, unless it's top coated. I've used POR15 before with both good and bad results. But both ways, it's MESSY AS HECK. Rustoleum industrial rust paint is IMO a much better product, because it does the same thing, is not affected by UV light, needs no top coat and is FAR less messy. Much more affordable, too. I got mine for about 27 dollars a gallon at Lowes.
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Do you have a photo of the container of the Rustoleum industrial rust paint? Did you brush it on? How did you prep the surface? Thanks.
 
My dad swore by a massive oil leak and driving down a dusty back road. Bottom of the car looked like new when you scraped the 1/2 of crud off it 5 years later. He was a simple man.....
 
cruiser said:
Do you have a photo of the container of the Rustoleum industrial rust paint? Did you brush it on? How did you prep the surface? Thanks.
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Sure this is it. Same color I used too. lol I actually did brush it on. Personally, I prefer brushing it on because IMO you get better coverage. I didn't even thin it. I probably could have. It took it about a week to dry but that stuff ain't goin anywhere. Look at the label. If it does not say "all that" including "FOR INDUSTRIAL APPLICATIONS" and everything else, that ain't it. Be careful, because there are several different kinda and they all look similar.

https://www.lowes.com/pd/Rust-Oleum...r-Paint-Actual-Net-Contents-128-fl-oz/3223759

Here is the build thread for Vixen. Scan through it and you'll see where I applied it. I think it turned out very nice.

1964 Valiant "Get Runnin & Drivin"
 
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Surprisingly the factory under coating was in pretty good shape. I cleaned it well and put a thick coat of new undercoating on. It is a dry high desert car from Nevada and never had any rust
 
I opted to clean all the crap off the bottom of my car, what a chore that was. Once clean, I used the Rustoleum primer in the can, like RRR did. I also brushed it on, I think I got better coverage that way. I coated that with Rustoleum rattle can undercoat. It looks nice now, and I'm pretty confident it will protect the car. Here's the before shot:

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After cleaning and priming:

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And after undercoasting:

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My bottom is fine, thank you. LOL. That reminds me of a customer who came into the shop I worked in as an assistant manager many years ago. She evidently had her son's car. She looked me right in the face and said, "Can you grease my son's rear end?" I could not help myself. I burst out laughing, and she did too. It was hilarious. She eventually said, "You know what I mean." So we put some 90 weight lube in the differential of her son's car. She became a regular customer, and every time she came in, we had a good laugh.
 
Even if you do a good job with what ever product/method you choose, I think the key is to thoroughly inspect every few years and do the touch up before rust gets away from you. The best $1500 I ever spent on this hobby was a lift!!!
 
halfafish said:
I opted to clean all the crap off the bottom of my car, what a chore that was. Once clean, I used the Rustoleum primer in the can, like RRR did. I also brushed it on, I think I got better coverage that way. I coated that with Rustoleum rattle can undercoat. It looks nice now, and I'm pretty confident it will protect the car. Here's the before shot:

View attachment 1715742297

After cleaning and priming:

View attachment 1715742298

And after undercoasting:

View attachment 1715742299
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That looks real nice!
 
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