Restoring Nuts, bolts and fasteners

[David]

You'll need a lot more than electro plating on a Lancia Beta body

A sacrificial anode might be the way to go....they protected my 100 year old iron boat ....but not from ice abrasion.

[ace llani]

Are you sorted with this now?

25 years in the fastener trade..

You can re plate rusty bolts, nuts etc. as long as they don't look like they came up with the Mary Rose.

An electro plater will acid dip them to remove rust, old plating etc.

then they can be re plated.

an electro plater will charge you a minimum charge as they are usually barrel plated - meaning they chuck everything into a barrel which tumbles them while they plate, so they can put about 25 kilos into a barrel (minimum).
Also - the barrels have holes in them to allow the solution into the barrel, so be aware that very small parts can fall through these and into the plating vat. We worked on 2% loss which is deemed as acceptable.
Parts can also be wired up and plated on a jig, but this is more costly (chrome will always be done this way. leaves a witness where the wire was and the plate can't take.

Zinc plating is he norm - but many different specs are available, and cost little extra.

the spec has a ZN reference, which relates to the thickness of the zinc plate. Lowest is ZN2/3 but you can go up to about ZN12. It's not thick enough to affect the thread tolerance.

Next thought - zinc plated parts are then passivated - dipped in a solution to protect the zinc.

silver - zinc plate and clear passivate
yellowy colour - zinc plate and yellow passivate.

Difference?

clear pass - silver, pretty uniform colour, more cosmetic.

yellow pass - more resistant to corrosion.

Passivate is the same cost - just different colour. zinc and yellow parts will not come out all the same yellow.

Zinc plated parts are spec'd from a corrosion test either way - salt spray test - which attacks the plating aggressively so can be measured in hours.

the test has two figures -

hours to white rust - the white powdery residue you see on hot dip galvanised parts start to lose their sacrificial coating of zinc

hours to red rust - when to zinc is gone, and bare metal rusts.

Yellow passive takes about 3 times longer to get to red rust because its far more protective. then same time to red rust from there.

You noticed things like Rawlbolts and construction fasteners (that aren't hot dip galvanised - IE dipped in molten zinc) are usually yellow?

Not as pretty, but more rust proof.

you can also paint over zinc and yellow more easily.

And so, ends the day's lesson on zinc plating.

Many other finished are available - done them all, including chrome on plastic, and gold for bathroom fittings.

[dern]

25 years in the fastener trade..

That reminded me of the fast show…

25 years in the fastener trade. Man and boy. Hardest job in the world.

Good info though, thanks.

[ace llani]

25 years in the fastener trade..

That reminded me of the fast show…

25 years in the fastener trade. Man and boy. Hardest job in the world.

Good info though, thanks.

I used to walk there and were uphill both ways..

No problems - lots of fastener knowledge and always happy to help

[dern]

Ha ha