Metals Preservation

[Johnny O]

Throwing this under Fabrication as we don't have a dedicated section for prep and preservation (maybe we should?) since the Liberty and other Jeeps are fast entering the "classic" car category.

Anyway, decades of restoration of VW Bugs has made me pretty handy at turning steel, aluminum, and magnesium from eyesore to eye candy. But, alloys have changed over the years, so I have questions.

I'm a POR-15 products guy through and through. Which can't be beat for restoration and preservation, but may not be best for new fabs.

I have both purchased and fabricated various parts for Kahn made of aluminum. I'm getting ready for prep and coating.

Old school acid prep for aluminum has changed, trading H2SO4 and H2CrO4 (sulfuric and chromic) acids for H3PO4 (phosphoric acid).

After much research it appears that once again POR-15 is the winner, specifically the Brake Caliper kit which is suitable for any ferrous and aluminum alloys, not just calipers.

Curious if anyone has experience with this specific product on aluminum alloys.

 

[Luke]

Por-15 is my choice… judicious prep is mandatory however, otherwise it’s not much better than regular paint, the rust will return.

My best results on aluminum stared with Duplicolor self etching primer.

 

[Boueux]

Por-15 is my choice… judicious prep is mandatory however, otherwise it’s not much better than regular paint, the rust will return.

My best results on aluminum stared with Duplicolor self etching primer.

Thirding the POR -15 it’s the lowest VOC option I’ve found. I used it on a couple of now so-called vintage 4x4s that are still showroom fresh and clean a decade later.

I did seriously mask and glove up to use their cleaners as well as their zinc coating spray, but that’s another whole oyster. I’d certainly also avoid anything with silicone in it.. particularly seam sealer which is a serious water and hence rust magnet.

 

[Johnny O]

Por-15 is my choice… judicious prep is mandatory however, otherwise it’s not much better than regular paint, the rust will return.

My best results on aluminum stared with Duplicolor self etching primer.

I'll have to look into the Duplicolor. Thanks!

 

[Johnny O]

Thirding the POR -15 it’s the lowest VOC option I’ve found. I used it on a couple of now so-called vintage 4x4s that are still showroom fresh and clean a decade later.

I did seriously mask and glove up to use their cleaners as well as their zinc coating spray, but that’s another whole oyster. I’d certainly also avoid anything with silicone in it.. particularly seam sealer which is a serious water and hence rust magnet.

Yep. I'm a lab rat by trade so PPE is mandatory. I'm good up to Class 3 for chemicals and Class 4 for biologicals.

In this case I've got raw aluminum that needs to be black. Eventually I will have steel fenders and bumpers that need to have coatings match.

Sure I could have everything powder coated, but would raise costs and leaves no way to do touch ups from desert damage.

I could go bed liner, but then there is weight concerns and gray-out from UV exposure.

POR-15 made my bug pans look and last better than OE.

 

[Boueux]

Wait- wow. You PORed raw aluminum? and it took? How did you prep it, if you don’t mind me asking? And, have you ever anodized anything?
and yes, that Duplicolor self etching primer sounds interesting, too.

 

[Luke]

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If it went with my colour scheme I would have left it just primed it looked so good.

edit: I fixed the flaw near the left most “dimple”

 

[Luke]

Another of my favourite products… this is after 5 minutes.

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[Boueux]

Huh. And I thought Marine Qwik was fast. I’d hate to actually spray that stuff though.. eek.

 

[Luke]

Yes full face protection and thick rubber gloves are mandatory! Got a little on my skin once… felt like it was planning on burning right through to the bone!

 

[Boueux]

Airborn would be my fear. because it looks dangerously effective.

Great work though, nice share! Have you ever anodized anything?

 

[Luke]

You got it … outside only.

I have not…

 

[KJowner]

I've bought a wet blasting kit for my pressure washer, my alloys need refinishing badly, I have a couple of spares so I can do them 2 at a time, job for spring.
I'm trying to decide between gun metal gray with blue metal flake, straight gunmetal or black. The jeep is Atlantic blue, choices choices.

 

[Ohio-white-kj]

Por-15 is my choice… judicious prep is mandatory however, otherwise it’s not much better than regular paint, the rust will return.

My best results on aluminum stared with Duplicolor self etching primer.

I stripped and repainted my aluminum wheels, maybe 10 years ago. Used the Duplicolor self-etch primer and Duplicolor wheel paint and clear cote. Still looks great.

Held up better than the factory clearcoat.

 

[Johnny O]

Wait- wow. You PORed raw aluminum? and it took? How did you prep it, if you don’t mind me asking? And, have you ever anodized anything?
and yes, that Duplicolor self etching primer sounds interesting, too.

POR-15 has an acid etch metal prep, which is then primed with their excellent zinc deposit primer. Follow with the color of POR-15 of choice and you get the usual virtually indestructible coating. Did my custom aluminum floor pan in the VW over a decade ago and it still looks better than stock.

Anodizing is easy if you have the equipment. Many "room temperature" ways to do it yourself if you dont care about color, most common is the scub and phosphoric acid wash followed by brush on gold colored ferric chloride. This process is best for small parts and is purely cosmetic, not a very durable finish.

Hard coat anodizing is more involved for specific colors: serious cleaning and prep with scotchbrite immediately followed by a hot acid bath, usually 6-8 molar aqueous sulfuric acid or 10 molar chromic acid for an hour. Then a deionized water rinse. Finally the parts are bonded and dyed with a range of chemicals dependent on color via DC voltage electrolysis.

 

[Johnny O]

I went ahead and ordered the POR-15 kit: 30$ free shipping direct from them with military discount. Will test on some scraps I have and report back. Also got the Duplicolor stuff, will test that too.

Main goal is to get my incredible American Adventure Labs spare tire delete coated. Will also do my self fabbed antenna and drip trays for hood vents too.

 

[Boueux]

Great information all the way round. Much appreciated. Please remember to eschew seam sealers and any use of silicone

 

[Johnny O]

Great information all the way round. Much appreciated. Please remember to eschew seam sealers and any use of silicone

I’ll install silicone gaskets where applicable and always use ABS and/or BUNA washers to prevent galvanic corrosion for dissimilar metals. (Nylon absorbs water and swells.)

Lots of folks forget that ferrous (including stainless alloys) and nonferrous metals will corrode when in direct contact and in the presence of mineral-laden water…even faster in presence of sodium and calcium chlorides (sea water or anti-icing road treatments). Know as “galvanic corrosion”.

I prefer to encapsulate exposed hardware heads with Lexel too. For torx and hex sockets a tiny drop of silicon oil or turbine oil in the recess ensures they clear if one ever needs to remove the encapsulation and remove said hardware. Is an old surface navy trick that has never done me wrong.

 

[Johnny O]

After a resounding success with some lab-brewed powder coat stripper, I now have clean aluminum parts in addition to all the other geegaws.

The experiment will go as follows:

1. POR-15 Caliper Kit
2. Duplicolor
3. Rustoleum Acid Etch

#1 is a complete kit. #2 and #3 are prep and primer to be followed with Rustoleum Industrial Gloss. All three will then be followed with Rustoleum Gloss Clear and a hand rubbed coat of "Ceramic" type car "wax".

whole process will only take a 48 hour period as I have a drying/curing oven at the labs.

I have a fresh tube of lexel, PTFE washers, and a fresh bottle of ZoomSpout turbine oil for the fasteners.

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[Johnny O]

The stripper I reverse engineered and modified is Benco B17 by Spectra Coatings. I decided to share that detail since the formula is on the readily available SDS/MSDS. It didn't say "Proprietary formula" so I have broken no laws.

I am going on record questioning the hydrofluoric acid in the actual formula. Dangerous and unnecessary, but potent stuff for coating removal.
My version used a similar amount of chromic acid which is equally nasty, but turns the formula into a combination stripper and room temperature anodizer for aluminum. And, I created an acid neutralizing rinse that converted the hexavalent chromium waste to a harmless oxide.

Next post, results of coatings and brine testing.