Applying Rust Killer to under carriage /frame any reason not to ?

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rustytoolss

rustytoolss

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Is there a reason not to paint the under carriage of car with Rust Killer (after you wire brush any loose material). My plan is the wire brush the underside then brush paint on the Rust Killer, and leave it like that (maybe 2 coats).
Will leaving the Rust killer exposed cause any problems, if nothing else is done to the surface ???
 
I have YET to see anything that claims to "kill" or "convert" rust work. They all just turn it black and it keeps right on the hell rustin. The only successful thing I've seen is to scrape the loose rust off, wire brush it down to bare metal where you can and coat it with something like POR15 or industrial oil based Rustoleum to seal it. Once rust is sealed from air, it cannot continue further.
 
The last thing that you want to do is trap the moisture under some kind of paint. Undercoating/Ziebart works because it's petroleum based, but makes a HELL of a mess. If the surface rust is bad, use an air needle scaler.
 
ironbuilt said:
The last thing that you want to do is trap the moisture under some kind of paint. Undercoating/Ziebart works because it's petroleum based, but makes a HELL of a mess. If the surface rust is bad, use an air needle scaler.
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Really? Using that thinking then no cars would ever be painted, would they?
 
RustyRatRod said:
Really? Using that thinking then no cars would ever be painted, would they?
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I meant him spraying over present rust and rot. Without removing the moisture, it would just continue to rot under the paint.
BTW, a grinder, some sheet metal and a tig welder will "kill" or "convert" rust work. Just saying.
 
Rather than the rust converter, maybe a rust encapsulant to seal it away from moisture. Anything put under the car is subject to rocks & dirt while driving so it may be a moot point.
 
I have used a couple rust converter products that worked really well. Rustoleum makes a rust converter that works really well. It does kill the rust. Some products are not as effective
 
Rustoleum Rust reformer- But get it in the bottle not the spray can. It works
 
I got some industrial paint at work while doing my drum to disc swap.

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I have used a product called "Ospho" to amazing success on my vintage Ford projects. Heavy duty gloves, stainless steel brush pads, eye protect and elbow grease.

Knocked all heavy stuff off and used Ospho to get a '32 frame to beautiful bare metal. The say you can paint directly over it but I'm not sure. The Rustoleum I applied over it is sticking quite well.

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Sorry, can't find any pictures of the process but it works great!


I've also had luck with a product called "Evapo-Rust" though the way it works it's better as a 'dip' and not a treatment.

Good luck!!
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1) Remove rust and scale. I used a scraper followed by a wire wheel.
2) Rustoleum Rust Reformer after a wipe down with isopropyl
3) Brush on Rustoleum of the color of your choice. Sets up hard as epoxy in a few days. I recommend several coats.
 
I used the spray and it worked fine, as long as the metal is as clean as you can get it with a wire wheel, etc.
 
RabidScott said:
I have used a product called "Ospho" to amazing success on my vintage Ford projects. Heavy duty gloves, stainless steel brush pads, eye protect and elbow grease.

Knocked all heavy stuff off and used Ospho to get a '32 frame to beautiful bare metal. The say you can paint directly over it but I'm not sure. The Rustoleum I applied over it is sticking quite well.

View attachment 1715658862
Sorry, can't find any pictures of the process but it works great!


I've also had luck with a product called "Evapo-Rust" though the way it works it's better as a 'dip' and not a treatment.

Good luck!! View attachment 1715658866
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I have used Ospho for years. Be careful as IF you do not neutralize it with water you can get a delayed reaction with use of epoxy primers, or even stuff like Rustoleum enamel. I like it mail for pitted metal.
Get ride of all the rust you can with an abrasive. First. Don't go the rust convertor idea and changing a lump of rust into some inert whatever. If you use Ospho, apply a good wet coat. Let it dry at least a day, then use a Scotth brite, sandpaper, and get rid of the white phosphorous coating. If you want to neutralize it, wet again and let it sit for 10 minutes but not to dry. Then wash with water Dry with compressed air to keep down flash rust which really is not a problem if going back over with epoxy primer. Just my way. Your results may vary!
I like using a good epoxy primer. Seal that with any good single stage acrylic urethane. Or just Rustoleum.
NO need for expensive stuff like POR15. Rustoleum is just as good.
 
rustytoolss said:
Where can you buy rustoleum rust reformer liquid like in QT cans ?? to brush on ? how much does the bottle cover ? cost ?
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You can get it at Lowe's for about $10 a quart. I got a bunch of the junk brushes from HF to paint it on and I did one solid coat with touchup in the areas where it was a little light. It took a little over a quart to do the entire underside of my 69 Dart from the back bumper to the t-bar crossmember. I'm certain the rest of the second quart will do the front part of the car when I get it taken apart for a full front end rebuild.
 
I would say it depends on the amount/severity of the rust. Also depending on the amount of miles the car will see.
Watching as I'm doing underside of our 69.
Good luck and post up what you decide on using.
 
RabidScott said:
I have used a product called "Ospho" to amazing success on my vintage Ford projects. Heavy duty gloves, stainless steel brush pads, eye protect and elbow grease.

Knocked all heavy stuff off and used Ospho to get a '32 frame to beautiful bare metal. The say you can paint directly over it but I'm not sure. The Rustoleum I applied over it is sticking quite well.

View attachment 1715658862
Sorry, can't find any pictures of the process but it works great!


I've also had luck with a product called "Evapo-Rust" though the way it works it's better as a 'dip' and not a treatment.

Good luck!! View attachment 1715658866
Click to expand...

Never heard that one at ALL. All I've ever read and heard regarding Ospho was that it MUST be neutralized first. Good luck.
 
4spdragtop said:
Same here I've heard Ospho being used quite a bit on here, BUT ALWAYS neutralized prior to coating/painting.
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The Ospho site doesn't actually "say" to neutralize it. It says let it dry and wipe down with mineral spirits before painting.

Ospho
 
What do folks mean by "neutralize it." Do you rinse with a base solution?

I've used Ospho to prep a lot small parts. All I've ever done to prep for paint is rinse the part with water afterwards, dry it, wipe it down with acetone, and on to paint. That process has worked great for me.
 
Neutralize refers to "returning" to a pH level of 7 or somewhere thereabouts.
pH scale runs from 0-14. The lower the number the more acidic. To counter act the "acid", usually its wiped/rinsed with something "basic". Basic is the higher end of pH scale(lye) up to 14.
Hope that helps?
mopowers said:
What do folks mean by "neutralize it." Do you rinse with a base solution?

I've used Ospho to prep a lot small parts. All I've ever done to prep for paint is rinse the part with water afterwards, dry it, wipe it down with acetone, and on to paint. That process has worked great for me.
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4spdragtop said:
Neutralize refers to "returning" to a pH level of 7 or somewhere thereabouts.
pH scale runs from 0-14. The lower the number the more acidic. To counter act the "acid", usually its wiped/rinsed with something "basic". Basic is the higher end of pH scale(lye) up to 14.
Hope that helps?
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I understand pH and how neutralize an acid. I was just wondering if people actually rinse their parts with a basic solution after soaking in phosphoric acid. To me, that'd be a total waste of time. A simple water rinse works fine.
 
I agree, I'm thinking it depends on how long the piece sits in the acidic solution for? An extended period may need more neutralizing?
mopowers said:
I understand pH and how neutralize an acid. I was just wondering if people actually rinse their parts with a basic solution after soaking in phosphoric acid. To me, that'd be a total waste of time. A simple water rinse works fine.
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RustyRatRod said:
The Ospho site doesn't actually "say" to neutralize it. It says let it dry and wipe down with mineral spirits before painting.

Ospho
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If you go to SouthernPolyurethanes site it gives lots of tech info on all their products, but some detailed recommendations for their epoxy primer and Ospho. It can all be read there. Lots of people there here us SPI products and me too, and love their stuff.
I have a 62 Dart (Yes B body) that I picked up. Had no paint on top side and lots of surface rust/pitting. I used the Ospho on the top side and I must have not neutralized the deck lid. I epoxy primed it , and to be honest I forget what I used, it old have been SPI, TCP Global, PP or Kirker. Then it got high build urethane and on the lid maybe polyester primer. Sealed with epoxy primer an topcoated with single stage acrylic .
6 months later, I have some "pimples" show up on the lid. I will sand it back down and start over on it. No bid deal, but things can go South and bit you in the butt!!!
I like the Ospho especially to kill rust in pitted metal. But it needs to be neutralized and cleaned. My opinion is it is a cleaner not a so called convertor.
I needs to go on metal very wt, and remain there long enough to work. I definitely needs to be removed from any metal that is not rusted.

I had a 63 Dart-6 years back and had lots of surface rust on just the hood. I DA'ed just the hood and put a good coat of Ospho on it and it sat 24 then I wiped it down and applied a heavy coat of Rustoleum with yes, a foam brush! I would not touch it for 6-7 month and it sat outside. I wanted to see how it how seal and hold up.
First thing I noticed was I had a wrinkling of the enamel in a few small places. After it had dried maybe a week, I tried to DA those wrinkled places down with the DA and 80 grit. I could hardly touch it! ha When I got back to this car7 months later, the Rustoleum had faded, but it was stuck n there very good! I epoxy primed over that and continued on. 2 years later all was good. It was an experiment.
 
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