TheSamba.com :: View topic - What's the best way to short term seal bare metal?

Thu May 05, 2016 7:12 pm

I've spent the last few days stripping my oval down to metal (mostly interior). I just found out I've got to leave town for work for a few weeks for work. Unfortunately the car has to be stored outside during the rainy season here while I'm gone. What would you guys do? I'm just looking for a temporary seal from rust so I can get back to stripping when I come home. Thanks!

Fri May 06, 2016 7:24 am

Brush it with Ospho or Metal ready.

Fri May 06, 2016 9:53 am

kman wrote: Brush it with Ospho or Metal ready.

Yes...thats the best I can think of as well....but bear in mind....these products don't do much unless they are actually on rust. They convert the rust to iron phosphate.

The polymer they leave on bare metal is pretty weak in the sun.

I definitely would not use primer. It could be ok for a season...but it has a high volume, porous surface because its a primer.

Water when it rains just hangs on primer and will work its way through.

I have seen other people have really good luck with just shooting a thin layer of any chap gloss enamel. In that way it reflects away a high portion of UV and some heat and has better waterproofing than a primer.

Make it something simple that just need mineral spirits to clean off. Ray

Sat May 07, 2016 4:37 pm

Gibbs oil, then cover it with a tarp. Mines been in bare metal outside for nearly a year. Stuff works awesome and one can is enough to do the whole car

Sun May 08, 2016 6:00 pm

http://picklex20.com/
I used this on a bug project that took years to finish, great product

Mon May 09, 2016 6:38 am

Picklex, Ospho, any product that has Phosphoric Acid in it will seal the metal surface from oxygen and eventual rust.

Wed May 11, 2016 5:33 pm

After phospo, should he wrap it with a good tarp, or would that hold too much moisture?

Wed May 11, 2016 5:58 pm

planenut wrote: After phospo, should he wrap it with a good tarp, or would that hold too much moisture?

The Phosphoric Acid or Ospho will dry, and basically add an electron to the metal substrate, thereby converting iron oxide (chemically unstable - rust) into iron phosphate (chemically stable). It's like primer at the atomic level. I'm pretty sure it's not UV resistant, so a cover or tarp that can breath would probably work the best.

Sat Nov 16, 2019 7:02 am

I'm looking for Gibbs Oil to spray or use a rag/bottle to wipe down some tools, metal parts and other metal I have in my garage and if it works give it a try on my classroom shop metal table tops and tools to prevent oxidation. The link below of the all metal hot rod impressed me to want to give it a try. Is this the correct product?

https://www.amazon.com/Gibbs-Brand-Lubricant-2-12o...s9dHJ1ZQ==

https://www.jalopyjournal.com/forum/threads/about-gibbs-brand-penetrating-oil.137392/

ExtremeBean wrote: Gibbs oil, then cover it with a tarp. Mines been in bare metal outside for nearly a year. Stuff works awesome and one can is enough to do the whole car

Tue Dec 17, 2019 3:35 pm

I used the kleanstrip phosporic concrete prep & etch wash you can buy at Home Depot in gallons. My whole bug has been bare metal in my dry-ass Arizona garage for a year now and still no surface rust.

https://www.homedepot.com/p/Klean-Strip-1-gal-Conc.../100406369

Fri Dec 20, 2019 2:49 am

gereonb, do I understand correctly that you washed your bare metal bug with phosphoric acid hosed it off and it is still bare metal rust free? It might also be because you are in a desert as I can't imagine doing that here on the New Jersey shore and get similar results. Can you post a resent picture I might have to move :wink:

gereonb wrote: I used the kleanstrip phosporic concrete prep & etch wash you can buy at Home Depot in gallons. My whole bug has been bare metal in my dry-ass Arizona garage for a year now and still no surface rust.

https://www.homedepot.com/p/Klean-Strip-1-gal-Conc.../100406369

Fri Dec 20, 2019 7:33 am

LAGrunthaner wrote: gereonb, do I understand correctly that you washed your bare metal bug with phosphoric acid hosed it off and it is still bare metal rust free? It might also be because you are in a desert as I can't imagine doing that here on the New Jersey shore and get similar results. Can you post a resent picture I might have to move :wink: I did the same thing and I live in HUMID Florida about ten miles in from the east cost. I used Eastwood After Blast which is basically the same product listed above. My car has been in treated bare metal for over 18 months with no surface rust to be seen (except in the spots I missed when treating the metal.)

There has been no change in condition since the pictures below were taken. The blackish/dark spots are converted rust. The car is kept in a non-climate controlled garage.

Taken August 2018

Taken December 2018

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Emil

Fri Dec 20, 2019 9:23 am

So yes, I took a small hand pump with wand the kind you use to spray Weedkiller from ACE Hardware, watered down the Prep&Etch and then sprayed all the surfaces of the car. Then wiped them down with Tar and Wax Panel cleaner, which is petroleum based. February 13th 2018, so well over a year ago. I need to get done with the work on this things, haha.

Straight from the Acid bath and Blaster.

How it looks now in Dec 2019, still all good.

Fri Dec 20, 2019 10:48 am

Your approach sounds more efficient than mine. I used a hand triggered spray bottle to wet down the metal then used an old microfiber towel to wipe it off. I did three application cycles but did not follow up with any rinse or cleaning. I just let the damp metal air dry. I guess that is why I have crusty whitish buildup in some areas. BTW, I wish my floors looked that good.

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Emil

Fri Dec 20, 2019 10:57 am

The floors were so good and original thick metal I didn't want to completely replace them with thinner re-pop metal, so against my usual OCD I only replaced the rear sections you can see in the last pic. I did as good as a job as possible and tried to make it almost stock looking.

Sat Dec 21, 2019 10:35 am

I am in shock that this method works at all. :shock:

Sat Dec 21, 2019 7:48 pm

LAGrunthaner wrote: I am in shock that this method works at all. :shock:

Why? Its good chemistry.

And...no...you DO NOT wash the phosphoric acid off with water. There is NO RINSING REQUIRED.......UNLESS....you use very strong, non-diluted phosphoric acid or oxalic acid products.

For example....a product that is sadly discontinued....is Jasco metal prep and prime. It dilutes 2.5:1 with water to make a solution that is very similar to the other commercially available product ....Ospho.

If you do not dilute it....its solution strength will literally dissolve all rust down to bare metal very similar to muriatic acid. And ...without some very thin rust to convert, the only protection is the whitish polymer solution that hardens on the surface.

The reason why you MIGHT use it undiluted...is to actually dissolve deep crusty rust. It does this without causing hydrogen embrittlement to the surface metal like muriatic or sulfuric acid would.

If you dilute it properly....you let it dry completely for 24 hours. That amount of time...all of the phosphoric acid will have reacted and converted the rust to iron phosphate. If you do not want that thin polymer coating on it....then wipe it down with a solvent. This also depletes moisture if you use something like acetone. This further helps it not to rust.

Treating with phosphoric acid is not some "home brew" method. Its first class chemistry used widely in the metal plating and preparation industry.

However to use it properly and get the best results you need to know how it works. it is not designed to be an outdoor protectant.

It CAN do fairly well outdoor....if you have stripped the panel or part completely...then reacted the surface with an oxidizing acid like muriatic acid....to create hydrogen embrittlement...which causes flash rusting. Then with a nearly perfect thin coating of flash rust....treat it with phosphoric acid to convert it and do not wash off the sealer polymer.

The reason why this work better...is because in areas where there was no rust to convert...its just bare metal covered with a thin polymer coating. It does not last long outdoor.

But if you strip the surface clean....then pre-rust it with flash rusting in a uniform manner that covers the whole surface....the entire surface gets converted and sealed.

The main usage for converted surfaces in the metal industry....is as a rust-free primer for other paints. Converted steel/iron....iron phosphate...makes one of the best metal primers in the world. Ray

Sun Dec 22, 2019 12:37 pm

^^^ DAMN :shock:
Nice write-up, thanks. I learned something new.

Please allow me to take full advantage of your knowledge.
1) Does treating non-rusted, freshly stripped metal with a diluted phosphoric acid solution provide a good enough base for epoxy or MasterSeries primer? Would it be better/advisable to remove the current coating, allow the metal to flash rust, and then treat with diluted phosphoric acid?

2) I am considering flooding my heater and rocker channels/cavities with diluted phosphoric acid for 24 hours then draining them and letting them dry completely. Would this provide a reasonable surface over which to apply MasterSerries silver or am I wasting time and resources? The channels have internal surface rust, and pitting in areas, but I cannot accurately determine the depth of the corrosion layer.

Thanks,
Emil

Mon Dec 23, 2019 8:28 am

Evil_Fiz wrote: ^^^ DAMN :shock:
Nice write-up, thanks. I learned something new.

Please allow me to take full advantage of your knowledge.
1) Does treating non-rusted, freshly stripped metal with a diluted phosphoric acid solution provide a good enough base for epoxy or MasterSeries primer? Would it be better/advisable to remove the current coating, allow the metal to flash rust, and then treat with diluted phosphoric acid?

2) I am considering flooding my heater and rocker channels/cavities with diluted phosphoric acid for 24 hours then draining them and letting them dry completely. Would this provide a reasonable surface over which to apply MasterSerries silver or am I wasting time and resources? The channels have internal surface rust, and pitting in areas, but I cannot accurately determine the depth of the corrosion layer.

Thanks,
Emil

Sorry for the delay!

Ok....understand....while the mixed phosphoric acid products like Ospho and others....provide some "limited" protection because of a polymer precipitate that comes to the surface......on bare CLEAN metal.....they do not work well.

The real protection from rust with phosphoric acid products is that any rust that is on the surface.....as long as its thin.....maybe .003" maximum.....gets converted to iron phosphate. And if that converted iron phosphate is thin....so the layer goes all the way to metal....the oxygen sources that were in the original rust.....are gone.

BUT.....iron phosphate is porous enough ....just like the rust it was converted from.....that there are micro-fissures running from top to bottom. This is one reason its a superb primer for paint and industrial oxide and powder coatings.

So the iron phosphate layer is not really waterproof. Thats why a lot of the phosphoric acid mixtures have a polymer sealer in them.

This polymer layer can range from a thin satin sheen that is just fine as is.....to a crusty white layer that is not ideal under paint.

This is why the better directions on some products say to apply on surfaces that are going to be painted without much extra prep.....with either foam brushes that do not leave puddles of foam.....or to wipe off excess ....as long as the surface is saturated....and then let dry completely.....and then if necessary...wipe down with acetone to remove excess sealer before painting.

The Master series.....is superb.....but a different animal.....with some of the same issues as phosphoric acid.....but using different chemistry.

Ok.....so the problem with phosphoric acid as mentioned above.....is that if you apply it to thick crusty rust.....it cannot penetrate all the way through and convert the rust. So it leaves oxygen and moisture that can rust further over time. Think like....crevices or corners between two adjacent panels at a 90° angle....that might be 1/32" or 1/16" thick.

Rust that thick needs to be mechanically or chemically removed.

The master series.....also has problems on really thick rust wherever is cannot,penetrate far enough to encapsulate all the way to metal. This is why they note on their site that ideally....media or grit blasting to bare metal is best.

But.....on complex underbodies.....if you can strip to metal so you know there is no thick rust...and flash rust....then if its going to be a while until you het to applying the master series......hit it with ospho or similar. Let dry 24 hours.....and leave the sealer layer on. Keep it from direct water like rain.

When it comes time to apppy the silver rust sealer....wipe it down with acetone. Then appy master series.

If you cannot do that seauence to make sure that you are not messing up the adhesion of the master series....do not use the phosphoric acid.

Master series has killer chemistry.....af least as good as phosphoric acid. What it does is penetrate the rust. Chemicals in it....namely naptha.....FEED on the oxygen in the rust....consuming it. The paint then dries....sealing it. The high aluminum content and urethane paint formula makes a superb anti moisture and anti rust layer.

And....because its a paint....Master series also works just as well on clean metal....sucks the oxygen off it ....and keeps it rust free.

So.....inside of the heater channels.....I would do it one of two ways.

1. If its very crusty.....and you cannot reach in there to knock that crustiness back to a thin layer.....use an undiluted phosphoric acid product with good ventilation. Keep rewetting the phosphoric acid a couple of times over a few hours so it does not completely dry amd form the sealer layer.

Then rinse it out with water. This will dissolve the crusty stuff and get rid of the excess....so the sealer layer does not form. Rinse very well......then let dry completely for a day or two....and then hit it with Master Series silver rust sealer. Two coats.

2. If you can reach into the heater channel with something that allows you to get rid of the crusty stuff.....like an abrasive brush on a drill extension.....or sand blasting.....then pressure wash or high pressure water hose it out to get a dust free surface.....mainly just get rid of the big stuff.....then completely dry for a day or two.....then use two coats of master series.

I am about to do my entire front under body with Master series. I missed my time window for outdoor temperature and I am waiting for a 48 hour period whdrd its going to be 60+.... :roll: ....yeah...I know. I may have to wait until spring. Mine has been stripped of as much undercoating as necessary....some bare metal....and had been sealed with a thin layer of Ospho. Waiting ro put the silver on.
Ray