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Old 02-14-2021, 02:35 PM   #1
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Lightbulb Permanently & Properly remediating surface rust?

I have a lot of surface rust on my rig with a few areas of pitting, and want to remediate all of it by way of chemicals. I know the difference between surface treatment and actual remediation, and a wire wheel won’t cut it. I know that rust remover and reformer are different products.

I’ve researched several different products, watched product comparison videos and thought of advanced rust removal methods (more on that later).

Dr. X looks very promising as it’s “reusable” which I’m taking to mean you can strain it, pour it in a jar, and use the liquid again and again until the active ingredients are reacted, even if that’s just two or three times.

I’m open to aerospace grade products if it means far less work, or it has qualities that enable it to reform rust down to the metal crystals as it’s exposed to open air. I know of ACF-50, however from what I know it’s designed for rust prevention and would be wasted trying to use it as rust remover. I also know that aerospace isn’t cheap.

I don’t have to necessarily get in between metal crystals, I just want to kill the metal cancer past the point where it will never spread again. This is where “good enough” lay for me.

I have some ideas to fully remediate surface rust & pitting on accessible but non removable parts:
-build watertight reusable encasements with fill and drain valves to submerge cross members and other parts, in rust reformer. Clean the surface, seal with tape / silicone (cheap silicone as it only needs to hold back distillates and solvents for 2 days), seal the top to minimize evaporation, and section by section reform cross members with a ready-to-coat surface.
-Magnet mount encasements with fill and drain valves for sheet metal that stay in place with a pint of liquid, sealed with silicone.
-dilute solution with carrier distillates, for slow but sure “vapor deposition” and use tape and garbage bags to create an environment where the solution can evaporate and condense until rust has been treated.
-inject between lap welds areas and other inaccessible surfaces that can’t be accessed, much less touched.
-Buy or build a cheap handheld steam cleaner, and use a non-flammable, high heat tolerant, plastic & rubber safe rust remediation solution, and blast product into pitted areas, laps and other untouchable surfaces.
-use a rust reforming emulsion to smear onto surfaces, let it do it’s thing, and then chip it away and immediately prime the surface if needed.
-mix that product that is a brushable rust reforming goop with a compatible liquid rust reformer, brush on and then wrap in cling film.

I’m concerned about using rust converter / reformer as I’m thinking the already reformed surfaces will stop the solution from getting to surfaces behind / underneath the reformed surfaces, resulting in “uncured” areas much like uncured spray foam in an enclosed area. Also know about flash rust, I would like to avoid flash rust if possible.

It goes without saying that without painting, all this work is futile. As I never want to paint it again, I want to use multiple coats of the best base primer I can get, then the best different color base coat I can get. Then I want to add at least 10 coats of the best tractor paint I can afford as I never want to treat rust again.

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Old 02-14-2021, 07:08 PM   #2
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Sounds like a lot of work.
If you plan on keeping the bus for another 10 or so years, that process you describe above might help? Trouble with rust/rot it must be removed completely in order to halt its progression to the "good" metal left on the bus.

Chemical treatments are okay for a few years, but the rust will eventually make a comeback if not fully/completely removed beforehand.

Good luck, and hopefully you find a course of action that works for you and your bus...
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Old 02-15-2021, 12:04 PM   #3
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Originally Posted by peteg59 View Post
Sounds like a lot of work.
If you plan on keeping the bus for another 10 or so years, that process you describe above might help? Trouble with rust/rot it must be removed completely in order to halt its progression to the "good" metal left on the bus.

Chemical treatments are okay for a few years, but the rust will eventually make a comeback if not fully/completely removed beforehand.

Good luck, and hopefully you find a course of action that works for you and your bus...
I’m keeping my bus for life.

I’m looking for chemicals that completely remove or convert oxidation. I want to cure the problem permanently, not just treat it. There is no structural rust on the frame, there is surface rust that could become structural rust existing in two places on the frame, one being a fender. I have only found one thru hole in the metal floor, that can be covered by a quarter (though I haven’t stripped the rotten subfloor yet). Being a PNW bus, the rust happened slowly and smoothly.

Why are chemical treatments only good for a few years? Is this without sealing the metal from the elements or with? Do the chemicals leave behind residues that become corrosive over time? If so, can I rinse with evaporating solvents, before priming and painting?

Dry electrolysis is an idea, I saw a cool documentary on the Pacific Coast Highway, one of the segments detailed how bridge engineers used electrolysis and anodes to extend the life of rebar inside of bridge concrete.

Keep in mind that things generally don’t decay linearly, they decay exponentially. I think I am still in the early stages of that exponential oxidation curve.

Other than chemicals and wire brushing (and perhaps dry electrolysis), what else is there? I want to know all the options and methods before committing to a course of action.
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Old 02-15-2021, 12:06 PM   #4
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Get a fiberglass bus..
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Old 02-15-2021, 02:27 PM   #5
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Come on now, my case is minor relative to what some members have dealt with.

Can a mod please replace the question mark with a period in the thread title?

While 100% stoppage of metal cancer isn’t physically possible (as the automotive rust remediation experts I watched on YouTube say, the only way to fully stop rust is to cut it out and weld in a new piece. Source: https://youtu.be/rQhG6dyX_AI ), we can get close to 99%. I’m looking to stem the growth rate to the point where it’s infinitesimal.

I want to get as close to the edge before exponentiation of diminishing returns as I can, as I want to drive my bus until I can’t drive anymore.
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Old 02-23-2021, 10:15 PM   #6
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Unhappy

I'm getting lots of mixed information watching YouTube, reading other forum posts and looking at product listings. Seems like most people just want to cover up the problem...

Can someone share a detailed guide to using rust reformer, or information about how deep it can go into pores and how long before it goes "flat"? Nothing turns up on Google.

Other than an air needler and air drill (to attach wire wheels) & sandblasting gun, what other air tools are there for surface rust removal?

Edit: I'm going to start looking at marine rust remediation videos, as people with steel boat parts deal with varying degrees of rust all the time.
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Old 02-23-2021, 11:34 PM   #7
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I have found the general consensus on rust removal and prevention is basically four steps.

1. Remove as much rust as practical. Sand or media blasting is best. Sanding, grinding or using a wire wheel will also work.

2. Acid etch / convert any remaining oxidation iron phosphate with phosphoric acid. Make sure this step is compatible with the coating system you are using.

3. Paint using the best coating system for your application and budget. Perform the manufacture recommended prepwork for steps 1 and 2 and follow the manufactur directions for the coating application.

4. Repeat. No coating will last forever while some will last longer than others. There will always be imperfections in the coating, physical damage and weathering that will eventually result in corrosion. Regular inspection and repair is the best way to prevent serious rust problems.

There is a good explanation of paints and corrosion on "SV seeker" channel on you tube. The guy is building a giant steel boat in his backyard. On one of his videos he has a buddy that is a corrosion inspector explain paints and corrosion very well.

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Old 02-23-2021, 11:55 PM   #8
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I like rustoleum rust reformer with enamel paint on top. There is stuff around that I have used that combo on ten years ago and is still solid. This truck came in last october, it got sprayed with that combo by me when I was in high school when the owner, our long time customer moved here from Minnesota. Still rock solid and looking good
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Old 03-03-2021, 11:40 PM   #9
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I like rustoleum rust reformer with enamel paint on top. There is stuff around that I have used that combo on ten years ago and is still solid. This truck came in last october, it got sprayed with that combo by me when I was in high school when the owner, our long time customer moved here from Minnesota. Still rock solid and looking good
I am wary of spray can enamels and paints because to be at a low viscosity to spray out of a disposable can, durability is sacrificed (in a lot of products). Still, thanks for your recommendation of Rustoleum rust reformer.

As I strip the floor, the good news is that the metal was painted white in 1980 before the plywood and rubber was screwed down. If they didn't do this, I wouldn't be stripping the floor as this bus would have been scrapped 10-20 years ago because the floor would not have passed D.O.T. inspection. Lots of paint bubbling, indicative of pitting. Still, No soft spots or rust-created holes larger than a nickel.

Assuming I prep properly to shiny metal, will Rustoleum rust reformer (or any product) go deep into the porous surface that is bare steel to treat microscopic pockets of oxidation? This is what I've been trying to say all along.

I had an idea just now, to powdercoat as the base coat. Use a conductive primer on the bare metal, attach leads on both ends (or four corners) and powdercoat the segment. Use a heat gun to cure and you have a evenly applied plastic coating that sticks to the metal like adhesive to add your protective coats to.
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Old 03-05-2021, 12:15 AM   #10
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I used to powder coat a bunch of small parts in my garage. That was 2011ish. Unless things have changed drastically, I don't think a heat gun is really going to do the job. I had to bake the parts in an oven for 25 mins to get a good part temperature, and that was after preheating the parts to 200f before spraying the powder.
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Old 03-15-2021, 02:48 PM   #11
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Assuming I prep properly to shiny metal, will Rustoleum rust reformer (or any product) go deep into the porous surface that is bare steel to treat microscopic pockets of oxidation?
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Old 03-15-2021, 03:40 PM   #12
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No idea on Rustoleum rust reformer, but their oil based primer for rusty metal is a great product.
Best results are to roll or brush on. Let cure 24 hours, then top coat with their oil based paint, choose your color.

No matter how much one might want, any type of paint over any rust will not last "forever"...
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Old 03-15-2021, 04:05 PM   #13
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I don't thing there is a product or process available that meets your criteria for a 'permanent and proper' surface rust remediation.

I'm not a metallurgist but I think rust is 'stable'; that is to say, if the source of oxidation is removed, you don't actually have to get rid of existing rust. I think sanding and grinding or etching is just a means to ensure a good surface for the paint to adhere to, to keep the moisture out.

Using this logic, as long as the flaky rust and scale are removed, the broad surfaces should be well protected, even with the cheapest of paints. Its the nooks and crannies and the moving parts that come in contact with things that need something 'extra'.

How about selective use of undercoating, which has some elasticity to bridge those nooks and crannies and other microcracks?
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Old 03-15-2021, 04:42 PM   #14
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Question

Thank you Rucker for your response. So you don’t think there is a process or product for permanent and proper rust remediation?

What about just proper rust remediation?

Below is a cross-post from my build thread:
Quote:
Originally Posted by Fastlane View Post
...
I watched SV Seeker’s rust-related videos and learned a lot. It looks like Coal Tar coating is the gold standard if you want a super durable, flexible coating provided you can afford it.

If it doesn’t get done right the first time, are your chances ever going to be better the next time?
From what I gleaned about coal tar in this video, it sounds like one of those things that is worth saving up for. I haven’t looked at coal tar prices, much less coal tar epoxy prices, but I know it’s a consideration. I’m still in the rust remediation planning stage.
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Old 03-15-2021, 08:29 PM   #15
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Quote:
Originally Posted by Fastlane View Post
Thank you Rucker for your response. So you don’t think there is a process or product for permanent and proper rust remediation?

What about just proper rust remediation?

Below is a cross-post from my build thread:


From what I gleaned about coal tar in this video, it sounds like one of those things that is worth saving up for. I haven’t looked at coal tar prices, much less coal tar epoxy prices, but I know it’s a consideration. I’m still in the rust remediation planning stage.
Great video, I just subscribed to the dude. Some takeaways from what the corrosion professional is saying:
  1. You can wire-brush the loose scale (rust) by hand and then just paint and get adequate results (that's almost a quote at 6:05)
  2. You do not have to remove every last microscopic bit of corrosion before painting, since rust-preventative paint encapsulates rust before curing
  3. In atmospheric conditions (i.e. out in the open) rust advances pretty slowly through steel - about 0.004" per year

He does talk about various more elaborate techniques (including sandblasting), but they're really talking about corrosion conditions (like industrial applications and boats in salt water) that are much, much worse than the floor of your bus is ever going to face (assuming you've stopped all the leaks). That's why, although I went to town on my badly-rusted floor with many applications of Ospho, I would have felt comfortable with the pro's "adequate": just wire-brushing the loose stuff off and then painting with Rust-Oleum rusty metal primer.

The youtuber apparently did some long-term corrosion treatment tests by painting rust metal with various treatments and then leaving it in a churning saltwater bath for a year. I'm curious to see what his results were.
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Old 03-15-2021, 08:33 PM   #16
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Quote:
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From what I gleaned about coal tar in this video, it sounds like one of those things that is worth saving up for. I haven’t looked at coal tar prices, much less coal tar epoxy prices, but I know it’s a consideration. I’m still in the rust remediation planning stage.
I'm not sure if my bus had the same stuff, but on much of the underside there was some variant of tar-like undercoating, and wherever that stuff was still present, the metal underneath looked like it was fresh from the factory. The only spots where it had come off were where the floor had rusted completely through - there were a lot of those spots, unfortunately.

Whatever that stuff is, it's absolutely fantastic if you're concerned about rust on the underside.
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Old 03-15-2021, 10:11 PM   #17
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My biggest concern would be those spots you can't reach. When I was growing up in New Hampshire I remember cars with flappy fenders-you know, where the salt from the road accumulated on the inside of the fender, right where the bracing strut hold the fender.

There is no practical way to remediate and coat some parts of the vehicle, and that's where it's needed the most. That's what I meant by no proper and permanent method.
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Old 03-16-2021, 04:02 PM   #18
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Quote:
Originally Posted by Rucker View Post
..
There is no practical way to remediate and coat some parts of the vehicle, and that's where it's needed the most. That's what I meant by no proper and permanent method.
So this is what you meant?

For accessible, butted up sections of metal on the body, the only way I can see is is to spray then pack. First spray brake parts cleaner and wash as much contaminants away as you can. Spray a penetrating rust converter that leaves a fluid film, then spray with mineral spirits to strip it away, and then inject or pack in something thick, sticky and oil based, that you need to heat to 250 degrees to make runny (so no matter what the weather is, your coating never moves).

For the insides of tubing, box beams, and frames and other inaccessible metal surfaces; you want stuff that creeps so you eventually coat every surface. This is where my "vapor deposition" idea would shine. Wash out dirt buildup with tap water mixed with a product or recipe designed for this application, with copious amounts of corrosion inhibitors. If I had a box frame, I would drill 1mm holes for the .95mm spray straw to get to spots the spray couldn't reach.

Another channel I recommend is Sweet Project Cars, they have good and cheap tricks that actually last. They have a series going on where they're reconditioning a work truck, and treating lots of rust on it.

Remediating rust sucks, but it can suck less with great products and great methods.
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Old 03-16-2021, 07:16 PM   #19
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I like your thinking. Maybe I like your overthinking!

I realize I did the single most effective thing you can do to inhibit rust: move to the sunbelt. Ha!
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Old 03-17-2021, 11:21 AM   #20
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I like your thinking. Maybe I like your overthinking!
...
I would rather overthink than underthink things I’m in doubt of.

I just wish Project Farm would create a video on rust reformers / converters.
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