Refreshing old hardware, keeping it rust-free

[Shaun @ Tru6]

I've been soaking several sets of 69 - 73 suspension nuts, bolts and miscellaneous hardware for some time first in mineral spirits and then in PB Blaster. Next step will be to wirewheel everything down to clean metal.

Any ideas on what I can do with it after this stage to help protect it from rusting again, especially after mounted in the car? I've lightly coated some parts with a thinned down layer of POR15, but it's not factory and looks out of place.

In the absence of CAD plating, is there something I can soak this stuff in to help keep it fresh?

and anyone have a rear hub castle nut I can buy?

[Danny_Ocean]

Gibbs Brand is supposed to treat bare metal. I just bought some but haven't tested it yet.

[robmog]

shaun,
i don't know what your budget is but i've heard good things about the copy cad process. i plan on using it when i get to that point.
check this out.
http://www.caswellplating.com/index.html
bob

[Robert Buchanan]

Shaun,
Caswell has yellow chromate. Since your parts are alreay zinc plated you can simply "dip" your parts in yellow chromate to refresh them. It does not come out shiny like when new...but does have the correct color.

[gsmith660]

Might try Eastwood http://www.eastwoodco.com they have many different ways to blacken and anodize metal after you get it that clean may not be completely factory but will look good.

[Shaun @ Tru6]

THanks for all the great suggestions. I would send everything out to be Cad plated, but everything I've seen done is way too shiny. I want a factory look, but will be happy with an "industrial" one as well. The real end game of course is rust-free parts that stay that way.

What I wanted to do with the thinned POR15 was to just "stain" the hardware, but it was still too much. That said, this black oxide kit looks very attractive:

http://www.caswellplating.com/kits/black.htm

Simple, understated, effective all rolled into one.

[dtw]

Wire-wheeling individual bits of hardware is insane unless you are trying to restore smooth surface for concours work or extra-shiny bits. You're welcome to do that, and I do it to some stuff prior to plating. However before all that, just to get back to clean virigin metal, I whip up a strong batch of muriatic acid in a five gallon bucket. I soak all my pre-cleaned/degreased hardware in that. The crazed foaming tells you it is working, and it tickles when it splashes on your arm!

Try it, you will be absolutely amazed. Rinse thoroughly then dry quickly and they'll stay rust-free until you decide how to refinish them. Major time saver and cheap, too.

[Porsche-O-Phile]

Zinc plate?

[JFairman]

Phosphoric acid is the stuff for removing corrosion from bolts and hardware.
It foams too as it eats off the corrosion and old plating.
It's blueish colored and cheap. Home Depot has it in quart plastic bottles.
Think it's called Ospho...

Then have the stuff plated, plate it yourself, or spray paint it.

[AirCooledExcellence]

I cad plated my rear suspension components and fasteners. They came out like this:



Almost a year later they have dulled down quite a bit and look great!

[Tut]

If you're simply talking about hardware, as opposed to suspension pieces, wouldn't it be as cheap, and a whole lot easier, simply to buy new hardware? Paticularly when you start thinking about all of the time you would be saving to do other things to the car.

[911pcars]

CAD plating is best, but there may be limited availability in your area due to EPA regs for cadmium. Gold zinc plating services are more common.

Whichever method you choose, I would recommend checking with your vendor on heat treating after the plating process. Some do, some don't. Hydrogen embrittlement is a byproduct of the process. It weakens the base material unless treated afterwards; not too critical on small fasteners; more important on suspension fasteners and other high-strength, high stress applications.

MHO,
Sherwood

[KFC911]

I had mine cad plated, and although "blingy" initially like ACE's pictures show, they do return to a more natural state unless you keep your car locked up in a plastic bag . True cad plating is fairly hard to locate unless you can find someone who has been "grandfathered" in past the EPA regulations. Yellow zinc chromate is very close, and much easier to find a plater that will do that.

[Shaun @ Tru6]

I've got more than triple this with rear suspension and 5 cars worth of bits and pieces.

If the bling dissipates, I can go that route.

Any problem with shipping a box full of hardware somewhere in the country to have it all done once?

Any recommendations?

Approximate cost?

[KFC911]

When I sourced a metal plater locally, it was a "set fee" (I don't recall how much, maybe $125 or so), and I could have put as much stuff as possible in his cylinder shaped "cad tumbler" for the same price, so I'm sure it would vary greatly depending upon the plater. My 930 rotors wouldn't fit, so those he did in yellow zinc chromate on his rack system. Just a caveat...no matter how careful you and he are, I can almost guarantee that when the box returns, a few items will be missing . Fortunately, in my case is was just a few nuts & washers, etc. (I had pics, and counted everything before/after).

[dtw]

If the hardware is in a rough-textured state (as it will be after an acid etch or sandblasting), then you will not get a super-shiny result. No worries.

Cad plating is really hard to come by, and those who have found it aren't talking. Regrettably, my own plater won't even let me spread their information around. They are an industrial plater and don't want to deal with anyone but locals for hobbyist work.

Cad is nearly 10x more expensive than zinc - I was paying well over $1.50/lb for it, when zinc was to be had for $0.17/lb or less.

The warnings regarding hydrogen embrittlement are worth heeding, especially if you're getting suspension bits plated. It is not made-up and it is not a 'maybe' proposition. It WILL happen and your fasteners WILL break - the only 'maybe' is if it will happen at an inopportune time/place. Ensure that any quotes you get include the cost of baking. My plater provides me with a data sheet detailing the results of my work's bake process as documentation. I'd advise dealing with a plater who can do the same for you.

A google search will bear fruit for leads - BTDT.

[Shaun @ Tru6]

I've just ordered the Black Oxide kit.

When it come in, I'll go do some testing with muriatic acid, wire-brush, etc. and then the Black Oxide with some spare late rear shock mount bolts I have to see how it come out.

Will post results.

[Tim K]

Originally Posted by 911pcars

... I would recommend checking with your vendor on heat treating after the plating process. Some do, some don't. Hydrogen embrittlement is a byproduct of the process. It weakens the base material unless treated afterwards; not too critical on small fasteners; more important on suspension fasteners and other high-strength, high stress applications.

MHO,
Sherwood

Originally Posted by dtw

...The warnings regarding hydrogen embrittlement are worth heeding, especially if you're getting suspension bits plated. It is not made-up and it is not a 'maybe' proposition. It WILL happen and your fasteners WILL break - the only 'maybe' is if it will happen at an inopportune time/place. Ensure that any quotes you get include the cost of baking. My plater provides me with a data sheet detailing the results of my work's bake process as documentation. I'd advise dealing with a plater who can do the same for you.

A google search will bear fruit for leads - BTDT.

I was told that the occurrence Hydrogen Embrittlement was a function of the carbon content in the parts. However, there is no direct correlation between, for example, the grade of a fastener and the carbon content. I did not know any of this and my local CAD plater did not suggest baking when I dropped off a load of suspension parts and fasteners. It's not worth the expense of determining the metallurgy. The car is long gone now, and I found this out much later. There were never any issues but next time I'm not taking any chances.

Tim

[euro911sc]

When I was an engineer in MA we used these guys a ton:

http://www.globalspec.com/Supplier/profile/AotcoMetalFinishing

They may not do CAD, but I'm pretty sure they did zink... It's an easy drive, right up 93 and over on 128... there may be others nearer to you, but Cambridge is pretty tight and the industrial part is getting smaller every day You should not have to mail it all out.

Best regards,

Michael

[304065]

Sean,

Black oxide doesn't have ANY corrosion resistance. Sure, you get a uniform black finish, but the corrosion resistance comes from being coated with oil, which also makes things shiny for a while. I know this because I've got a fair amount of experience with the Caswell Black oxide kit: the Studs on an early SWB engine case are all black oxide. And they are all, invariably, rusty. You can re-black them, but make sure you rinse well with water, or you'll get brown rust from the acidity of the solution. And then it won't be period correct. If you want black, you can get black zinc.

I agree with the crowd here, have everything plated in Zinc with a Yellow Chromate Conversion coating. This is what the factory did. Like I said, if you want black, there's even black zinc, or olive drab, or clear (like silver cad). Zinc plating exhibits MUCH higher corrosion resistance than any older-technology treatment.

When you wire wheeled it the plating came off. Now it's a sitting duck for R U S T. Gibbs is an interesting idea, but how would you ever keep every nut and bolt treated while assembled?

If I were you I would get every nut bolt washer and other piece of loose metal you could lay your hands, INVENTORY it like you're OCD and then send it off to the plater. It's amazing what a difference it makes.