cold/dip burnishing?

[ST1100Y]

We could use a [metal-works/conservation] section here.

Up till around '96 Honda did an excellent job in corrosion protection on their bolts; after that Chromium VI (the dark olive-green finish) was out...

Whenever you clean a rusted bolt, also the last remaining protective oxide/galvanic layer get's removed...
Shiny ones can be electrode nickel plated... but what about the former green/now black ones?

Looked at some cold brush/dip black dye/tarnishing kits lately (gun owners might know), especially for tiny items like the screws holding the clutch/F-brake reservoir covers...
Seems pretty straightforward:
clean - de-grease - acid dip - dye (possible repeat) - put into fixing liquid - soak overnight in dehydration oil for fixation
works on steel and aluminum...
The kits come with all 4 liquids/solvents required (and I'd use distilled water for rinsing between the baths...)

Anyway, how good is the actual corrosion inhibition in the long run?

 

[Oldbikefixr]

We could use a [metal-works/conservation] section here.

Up till around '96 Honda did an excellent job in corrosion protection on their bolts; after that Chromium VI (the dark olive-green finish) was out...

Whenever you clean a rusted bolt, also the last remaining protective oxide/galvanic layer get's removed...
Shiny ones can be electrode nickel plated... but what about the former green/now black ones?

Looked at some cold brush/dip black dye/tarnishing kits lately (gun owners might know), especially for tiny items like the screws holding the clutch/F-brake reservoir covers...
Seems pretty straightforward:
clean - de-grease - acid dip - dye (possible repeat) - put into fixing liquid - soak overnight in dehydration oil for fixation
works on steel and aluminum...
The kits come with all 4 liquids/solvents required (and I'd use distilled water for rinsing between the baths...)

Anyway, how good is the actual corrosion inhibition in the long run?

What are the electroplating regulations like in Austria? That would be the best rust inhibiting tact, either home kits or professionally done.
For r/c model hardware, I use a cold bluing solution from a firearm shop. Some is now years old with no return of rust. But....they don't get the same humidity exposure that bike and car hardware does.

 

[Slydynbye]

I just dip them in Evaporust if required, then dry and spritz with WD40 .

 

[SMSW]

Blueing - on firearms - is a controlled rusting process and does not protect a gun from rust. Take your favorite Holland and Holland double, place it outdoors for a couple of nights and see what happens. Browning made a very sweet bold action .22 cal rifle called the T-bolt because you pulled straight back on the locking lever (not up and back). They also, for some unknown reason* salt cured the wood used for the stocks and blued the rifle. Many of these guns developed severe rust because of the residual salt in the stock.

Guns tend not to rust very much because most guys have been taught to oil them ad nauseum. Black powder and some primers are corrosive, which is why these guns must be thoroughly washed, dried, and oiled after use.

*Not unknown...it was a faster way of drying the lumber.

 

[ST1100Y]

Guns tend not to rust very much because most guys have been taught to oil them ad nauseum. Black powder and some primers are corrosive, which is why these guns must be thoroughly washed, dried, and oiled after use.

Yep, remember this well from the FN FAL/STG 85 (and all other arms trained on back in the day)... especially before action on a rainy day...
But also our bikes (at least mine) get protective solvents applied frequently, Spray Cleaner & Polish or Nanotec car wax, which should at least slow the corrosion by building a barrier...

Electroplating is a different animal I'm looking at, might be difficult on items too tiny held in a wire loom... and the, by now further and further restricted access to chemicals might raise problems...

 

[SMSW]

Electroplating is a different animal I'm looking at, might be difficult on items too tiny held in a wire loom... and the, by now further and further restricted access to chemicals might raise problems...

You are right that electroplaters (companies) are becoming an endangered species. Over here there are platers that charge a flat rate of something like $40 or $50 to plate a number of pounds of nuts, bolts, fasteners (small stuff). I ran across such a place when I was working on my Guzzi a couple of years ago - I think that was for cadmium plating - like the fasteners on early British bikes. You might find such a place by talking to guys restoring old bikes.

 

[Jerbear]

I would be concerned with the electroplating or any other plating for that matter, thickness. It can vary anywhere between .0001" to .020" (0.0025mm to 0.508mm). On fine pitch, small diameter fasteners the plating could potentially cause an interference with the mating tapped hole. Unless of course you plating process is very well controlled and repeatable. On noncritical fasteners I have personally elected to changing them over to stainless steel ones. In this case noncritical meaning not requiring high torque values. Only potential concern is the presence of galvanic corrosion which occurs when two dissimilar materials are fastened together ie. aluminum and stainless steel, when exposed to the elements. However, it can be easily remedied by application of small amount of dielectric lubricant between mating surfaces.

 

[SMSW]

Only potential concern is the presence of galvanic corrosion which occurs when two dissimilar materials are fastened together ie. aluminum and stainless steel, when exposed to the elements. However, it can be easily remedied by application of small amount of dielectric lubricant between mating surfaces.

Or aunt seize. I really doubt that any dielectric lube will stay on the threads. If the stuff were that tenacious, then smearing it on connectors before assembling them would prevent any electrical continuity or raise the resistance of the connection to the point where heat was produced...damaging the connectors. Enough d-lube will be scraped off the screw threads to allow sufficient conductivity to promote corrosion. I've never had a problem using electrogalvanized screws and nuts

Regarding the thickness, a quick look at Wikipedia said that chrome plating may be 2 mu-in, but decorative plating could be 20 to 40 mu-in. The latter translates to .04 thou, or 0.00004 inches. I do not know the standard manufacturing tolerances for machine screws and nuts, but I doubt .04 thou would cause a problem. Cadmium plating is spec'ed from 5 to 25 microns, or 0.0002 to 0.001 in. While this might pose a problem today, I never saw any unusually tight fasteners on my old Triumph. (In fact, didn't they say you could always find a Triumph by following the trail of nuts and bolts on the road?)

I'm no expert on plating, the numbers I quoted came from fast google searches. However, I did quote in post #6 that there are platers who serve the restoration market. Were the thickness of the plating sufficient to cause an interference fit w/ standard fasteners, I'm sure folks would not be having mating parts plated and I would have read about this problem from a couple of prolific Guzzi restorers.

 

[bdalameda]

My son Ben is restoring an old Husky dirt bike. He made his own electroplating setup and replated most of the fasteners, misc brackets, shift and brake lever as well as much of the brake hardware. He said it was pretty easy to do but he is a Chemist. He said there were many YouTube videos about doing this at home.
Here's a good video:

 

[ST1100Y]

Nickel-plating steel seems pretty straightforward...
Still in research about the black-zincking... (like some bolts, or the crimp/banjos on brake-lines...)

Chrome will/might require prepping by copper plating & polishing first...

And blackening aluminum so it'll last seems to require quite some efforts...

Also an issue if submerging or tampon-application is effective/applicable, shape and size of parts come in play there

Considering efforts (& value!) of the parts in need of plating, I'd rather go with a beefed laboratory power supply offering adjustable volt and current control, as agonizing with a flimsy plug-in transformer with a cheap/unstable VRR inside...

Already have a tumbler in delivery , essential to clean smaller parts like bolts, nuts or even carb-bowls... which media/granules are effective on what is gonna be another learning experience...
A polishing machine/stand will also be unavoidable...
https://smartreloader.com/en/product/smartreloader-sr737-tumbler-nano-220v/