Permanently & Properly remediating surface rust?

[Inner Love]

I’m going to be gutting next week and prepping for insulation. I’m looking to convert / remove as much rust as I can before spray foam buries it.

After gutting walls and ceiling, I’m planning to power wash the 40 years of crud, wire brush the surface rust, then immediately coat with sprayable rust reformer before flash rust forms, turning the metal into a paintable surface. Then wipe with acetone the day before the pros spray the insulation.

I have two small roof leaks that I want to properly fill. Can someone please link a guide with great method / product? Prefer to fill them from the inside.

With that, what sprayable rust reformer did you use? And how did you like the result? Do you think your result will hold up over a decade?

[musigenesis]

I don't think sealing leaks from the inside is a good idea. If, for example, you have a small gap between roof seams, sealing it on the inside will prevent water from getting inside, but the gap outside will still be there. It will tend to accumulate dirt and shmoo which will retain water and start to cause corrosion inside that gap. Maybe whatever you use on the inside will ooze through the gap and prevent external corrosion, but maybe not.

[ISAF2009]

I used rustoleum rust reformer because i have seen it hold up on 15+ year old car restorations

[Inner Love]

Originally Posted by ISAF2009

I used rustoleum rust reformer because i have seen it hold up on 15+ year old car restorations

Which one, specifically?

Originally Posted by musigenesis

I don't think sealing leaks from the inside is a good idea. If, for example, you have a small gap between roof seams, sealing it on the inside will prevent water from getting inside, but the gap outside will still be there. It will tend to accumulate dirt and shmoo which will retain water and start to cause corrosion inside that gap. Maybe whatever you use on the inside will ooze through the gap and prevent external corrosion, but maybe not.

I've thought about that. When I power wash, I'll blast the leak holes from the inside to remove crud. Then I'll fill from the inside and outside. What is the longest-lasting product to fill the seam leaks with?

When I power wash, I don't want to create lots of surface rust, is there an affordable rust-inhibiting additive I can put in my power washers tank? And is there an affordable spot-free rinse, assuming it's a good idea to leave on bare metal?

[ISAF2009]

https://www.homedepot.com/p/Rust-Ole...E&gclsrc=aw.ds

A pressure washer isn't something I would use. Harbor freight sells a media blaster.

[Inner Love]

Originally Posted by ISAF2009

https://www.homedepot.com/p/Rust-Ole...E&gclsrc=aw.ds

A pressure washer isn't something I would use. Harbor freight sells a media blaster.

It’s not for stripping interior paint, it’s for blasting away all the caked on dirt and crud after gutting.

I’m using tap water for the rinse, which will leave spots after drying, I won’t be able to get to all of the spots. If the metal doesn’t dry within an hour, the existing surface rust will be exasperated. Chorine degrades to its natural state, sodium chloride, which will be in the water spots behind lapped up and inaccessible metal, contributing to metal cancer. So in my bid to clean the metal for permanent insulation, I will have introduced permanent corrosives, which will speed the corrosion rate and won’t be noticed until structural failure because it’s hidden by spray foam insulation.

I’m afraid to pressure wash all the bare metal because of this. Is there an water additive that converts the chlorides, other impurities in tap water into something inert and stable that can live on bare steel forever? A rust inhibiting / converting water additive? Is this something I can afford?

For general power washing, what I do is:
1) use foam cannon with undiluted Zep All-Purpose detergent
2) Agitate with gong brush
3) Rinse with spiraling, cone spray tip.

Maybe power wash then immediately spray a mix that mixes with the water to inhibit / convert rust, and leaves a forever fluid film after the water evaporates?


There has to be something made for this purpose.

How have you removed crud in your walls before insulation? Did you pay any mind to corrosion?

What can I do. I don’t want to over complicate this. I want to prevent problems before they can happen.

[ISAF2009]

I used a harbor freight media blaster, several caliper brushes, compressed air, an angle grinder with a cup wheel, and time. I would never consider removing rust with a pressure washer for your above stated reasons. I don’t know how you would make the tap water safe.

[ISAF2009]

I have only insulated my roof as of yet.

[Inner Love]

To be clear, power washing would not be to remediate the rust, but to clean the metal structure in preparation for rust remediation.

I want to decrease the corrosion rate, not increase it. I don’t want to pressure wash if I’m introducing new corrosive elements that would stay with Inner Love forever.

I am going to start removing panels Sunday or Monday. When all panels (and fiberglass batting) are removed, it’s time to make a decision on how to clean 40 years of crud.

[LargeMargeInBaja]

Good grief!
But, 'hey', I realize everybody is different...
.
2003, I scrapped the entire complicated disaster-prone door contraption on the rear of our rig.
Large hammers were involved, oxy-acetylene and angry saws.
Explosives were considered, but set aside, reserved for other fun projects.
.
In its place, I fabricated a steel wall with a steel door.
The steel door has matching dual dead-bolts, a third of the way up and a third of the way down.
.
After nearly two decades full-time live-aboard -- often on isolated Baja beaches -- I may someday get around to grinding away that lovely aged krusty patina.
But apply paint?
Probably not.

[o1marc]

Originally Posted by ISAF2009

https://www.homedepot.com/p/Rust-Ole...E&gclsrc=aw.ds

A pressure washer isn't something I would use. Harbor freight sells a media blaster.

I would, and have, used a pressure washer before I'd ever do sand blasting inside my bus. The water dries in minutes. Media will end up everywhere and hard to remove it all. Mix some prep and etch rust converter in the spray if worried about flash rust. Damaging rust takes time. I pressure washed the whole inside of the bus, sanes cockpit. Easily removed all the left over insualtion for the walls and ceiling.

[Inner Love]

Originally Posted by o1marc

I would, and have, used a pressure washer before I'd ever do sand blasting inside my bus. The water dries in minutes. Media will end up everywhere and hard to remove it all. Mix some prep and etch rust converter in the spray if worried about flash rust. Damaging rust takes time. I pressure washed the whole inside of the bus, sanes cockpit. Easily removed all the left over insualtion for the walls and ceiling.

Thank you.

Damaging rust takes time, do you mean damaging rust takes time in water?

Mix some prep and etch rust converter in the spray if worried about flash rust.

I’m not just worried about flash rust, but the impurities in the tap water staying behind and raising the corrosion rate, even if that raise is half a percent. Half a percentage over 50 years is a marked increase in total corrosion, then again, if I’m alive that long I will be able to afford the most advanced restoration. Basically, my minimum design life for Inner Love’s body, skeleton and insulation is 50 years.

Any product recommendation?

[o1marc]

Originally Posted by Inner Love

Thank you.

Damaging rust takes time, do you mean damaging rust takes time in water?



I’m not just worried about flash rust, but the impurities in the tap water staying behind and raising the corrosion rate, even if that raise is half a percent. Half a percentage over 50 years is a marked increase in total corrosion, then again, if I’m alive that long I will be able to afford the most advanced restoration. Basically, my minimum design life for Inner Love’s body, skeleton and insulation is 50 years.

Any product recommendation?

Wash it, let it dry, paint it with a Rustoleum rust preventive primer and paint.

[Inner Love]

Originally Posted by o1marc

Wash it, let it dry, paint it with a Rustoleum rust preventive primer and paint.

Rust preventive? Does rust preventive convert existing rust?

I need to know about the longevity of painting the metal, as I don't believe it would hold for 50 years. As the Rustoleum paint ages, the paint could become the weak link in the chain, and the spray foam could begin separating from the body (as it stuck to the paint), creating lots of stiff squeaks over time.

I'm reluctant to paint as it may open a can of live worms I don't have time to catch.

I have half a gallon left of Klean Strip Concrete and Metal Prep, which I used on the stripped exterior panels before priming. It converts rust black, and protects the surface from flash rust ahead of coverage. You can find it here: https://www.homedepot.com/p/Klean-St...0220/100406369

Money is running low, I can only afford to do what's critical to making my trip happen, do proper and long lasting prep for the insulation, and have the insulation sprayed.

I can't afford any delays or detours. From what I can tell (and experienced), this Metal Prep product looks like a good product to use for my prep. Can I please have a second and third opinion about this? IF using this product per the label to remediate my interior body and panel rust, and protect the surface before spraying isn't a good idea, please explain why.

[Rucker]

I re-read the thread and it reminds me of a conversation with my delightful but on-the-spectrum nephew. I love these conversations but at some point we need to pull back and get perspective. Here's my perspective:

18 years ago I welded up a box scraper to level my property to build our current house. I didn't sand, scrape, or even prep the metal and hardly cracked the flux off the welds. I found a half-empty can of black paint and sprayed it on.

I just walked out to the metaphorical back forty and kicked the weeds away from the implement to assess the oxidation. It looks approximately like it did when I unhitched it from the tractor and poured concrete.

We get an average of 17 inches of rainfall in this part of California (I think you're close, in San Jose?), so about the same precipitation, same level of corrosion, if just sitting in the back yard.

But okay, you'll take it on the road and it will be subjected to salt corrosion every once in a while. Still not a daily driver in the snow belt.

And, if you read my other posts you know how much I like to obsess over details and planning, so even with that in mind, I recommend you buy cheap Rustoleum at five bucks a can, spray that crap on, and run your bus into the ground; and I predict that one day far into the future and after many happy years of use it will end up in a junkyard where it will sit for yet many more years with no perceptible rust.

[Inner Love]

In response to Rucker, which specific Rust-Oleum paint product contains the most rust inhibiting elements per ounce, and sticks to both metal and cured spray foam for decades? I have a Campbell Hausfield air sprayer and half a gallon of acetone so it can be a paint can or spray cans.

Are there any active rust inhibiting paints I can afford?

My idea:
1: Brush at all oxidation I see with wire brushes, pick up and vacuum anything that won’t wash away.
2: Power wash 40 years of crud in 3 stages: pre-wash, foam cannon undiluted Zep All Purpose detergent, agitate throughly with gong brushes, then do extended final rinse with tap water (does spot free rinse leave any chemicals behind?).
3: while still wet & drying; spray Metal Prep throughout to prevent rust growth when it dries. Follow all other instructions on label. Wire brush and spray badly affected areas.
4: Wait one day, come back and wire brush bad oxidation while spraying more metal prep on missed spots.
5: Do final wipe down to remove residue. Inject new automatic transmission fluid between lapped up metal using syringes. Surface tension should leave a fluid film behind (does 10 year old ATF turn corrosive?)
6: anyplace I can’t brush off or blast an air nozzle, squirt a little loctite rust inhibitor. Wipe off and Vacuum up as much Metal Prep residue as I can.
7: final once over before spray painting said Rust-Oleum rust inhibiting product. As this will be forever buried by insulation this painting can happen fast and loose.
8: after first coat dries, spray some more on seams and anything I think is undersprayed.
9: give it a bare minimum of 3 days to cure before spraying. Feel good that I took the extra steps for Inner Love longevity.
…
936: Toke a blinker of resin-less, zero-THC broad spectrum terpene isolate while watching the sunset from the Bonneville Salt Flat, without metal cancer on my mind as I blocked, enclosed, coated, painted, oiled, treated, anodized, or sprayed nearly every square inch of steel and iron surface area with the most effective products and methods I could afford.

Feel free to create your own numbered list with your idea.

[Rucker]

I tend to sit back with a cup of tea, but each to his own. Funny!

The only thing I'd add is do the painting at the height of summer for driest, warmest days. Painting in the cold or wet will delay curing from days to weeks.

Regarding rust 'inhibitors', I don't get the sense that Rustoleum or any other 'rust-inhibiting' paint actually has an additive. They just inhibit rust through their protective coating, or maybe the way they flow and set.

Rust inhibitors are specialty chemicals applied before final paint application, but they just prevent rust from occurring during the time the metal is bare.

Once the paint is applied, no water or air can come in contact with the metal, so it is effectively prevented from rusting. The rust comes if the paint is chipped off or peels, or didn't get applied correctly in the first place.

So to your point, the best rust inhibitor is perfectly applied paint. If you apply closed-cell foam over that, all the better.

[musigenesis]

Rustoleum rusty metal primer supposedly contains fish oils (!) which help it incorporate the rust into the structure of the hardened paint. I dunno ...

[Inner Love]

I just power washed the gutted interior today, and now have a 18,000 BTU heater, a shop fan, and a pair of halogen lights (1000w) inside to dry it out as it’s nighttime when I finished.

I don’t think spraying a rust converter while it was still wet right after rinsing would have made much of a difference, as the corrosion rate began spiking the moment I began to pre-rinse.

What is the difference between Ospho and Kleen-Strip Concrete and Metal Prep.

I want to spray on my rust converter / reformer tomorrow and then start spraying primer. I have opted to only spray metal primer before spray foam as paint would the weakest link in the chain (source: Project Farm’s latest video testing roll on truck bed liners).

Curious: Why aren’t zinc based primers / coatings a common thing for ongoing rust protection? I know there’s a reason why it’s not a thing.

Is Ospho the best product I can use? For lapped up bare metal, surface rust inside welds, and galvanized steel?

[musigenesis]

Originally Posted by Inner Love

What is the difference between Ospho and Kleen-Strip Concrete and Metal Prep.

Essentially no difference. They're both just diluted phosphoric acid and surfactants. According to their Safety Data Sheets, Kleen-Strip is 30%-60% concentrated while Ospho is 45%.

Originally Posted by Inner Love

Curious: Why aren’t zinc based primers / coatings a common thing for ongoing rust protection? I know there’s a reason why it’s not a thing.

Zinc coatings are used all the time for ongoing rust protection. That's what galvanized steel is - steel with a zinc coating. It's just easier to apply it in an industrial setting than trying to DIY with something paint-like (which do exist). Zinc coatings are sacrificial, which means they're eventually used up by corrosion. Paint, if applied correctly and re-applied as necessary, will prevent water and oxygen from reaching the steel in the first place and thus prevent corrosion forever.

Originally Posted by Inner Love

Is Ospho the best product I can use? For lapped up bare metal, surface rust inside welds, and galvanized steel?

Ospho will just treat existing rust and its residue will briefly block the formation of new rust. It's not of any use on galvanized steel (which will have no rust unless the zinc coating has been used up) except to etch it and you're better off using a proper self-etching primer instead.

The best product you can use to prevent steel from rusting is paint.