Finish on head bolts ?

[Ivor]

Hi again folks,
The existing head bolts and washers on my 1940 four look like they have never been plated or parkerized and I just looked at JG's site and those are cad plated. Does anyone know what finish they had originally ? Or do most people just paint the ?
Thanks in advance,
Ivor.

[Chris Haynes]

Cadmium plating will disappear with time and weather.

[T. Cotten]

Cadmium plating will disappear with time and weather.

Does it evaporate, Chris?

It can get pretty dark, that's for sure.

....Cotten

[PRG]

Howdy Ivor,

I have not been impressed with cad plating done in the aircraft arena, navy grade as done by Billmark in Dallas is vastly superior and more durable. Admittedly, when used in fasteners in high heat apps like your head bolts you must be fastidious in keeping it clean as darkened oil residue will stain them. There has been lengthy debate on this forum about modern cad finishes varying from that applied over half a century ago and at the end of the day an AMCA judge - generally acknowledged as the authority around here on rendering decisions regarding originality - will view cad with far more effection than any glass beaded stainless or similar attempt even if the color is off.

Billmark did my 441 at my link below.

http://www.patwilliamsracing.com/1941indianfour/

[Ivor]

Thanks Peter,
I should of said, that I'm in England and my four has a 40 motor in a 37 bike, so it's never going to be 100 point's job. More than anything, I was curious to know what the original finish on these bolts and washers was, as I can see no signs of plating what-so-ever on these bits. BTW, although most folk over here call it cad plating, all the platers that I've used in the past, actually use zinc plate.
Cherio,
Ivor.

[BoschZEV]

I have not been impressed with cad plating done in the aircraft arena, navy grade as done by Billmark in Dallas is vastly superior and more durable. Admittedly, when used in fasteners in high heat apps like your head bolts you must be fastidious in keeping it clean as darkened oil residue will stain them.

There is no "navy" or "aircraft" grade cadmium plating. Rather, the same Mil-Spec applies to all agencies allowing a choice of three thicknesses (2, 3 or 5 mil) and two possible post-plating treatments (or no treatment) depending on application. Both of the post-plating treatments leave the Cd colored so neither is appropriate for most of us. Any of the few places that still do Cd plating should be able to provide any of the three thicknesses.

As for oil "staining" the Cd, it's worse than that. Oil plus moisture causes actual corrosion of the Cd

[Chris Haynes]

Does it evaporate, Chris?

It can get pretty dark, that's for sure.

....Cotten

I have many paices that were Cad plated that are now bare metal and rusty.

[Ivor]

Yes, I cleaned some other nuts and bolts up with Jizer and the plating is still good, but these have got no signs of any sort of finish on them, and that's what lead my to think that they were not finished from new ? But then again, we don't know what folk have done with them, over the years.

[exeric]

Ivor, do you see any traces of nickel plating on those '40 motor fasteners? Indian was using a mix of nickel, and cadmium plated parts through the 1930s.

[Ivor]

No Eric, there is no trace of any finish on those head bolts and thick washers. I painted the cylinders in the end, because of the risks and expense of plating them. Some of the nickle was still OK, so I sprayed them silver, but now I'm thinking that I should of gone for Black. I can't decide whether to get the bolts zinc coated or just paint them. It will never be a 100 points bike, but with no evidence of any coating, it left me wondering what finish they had when it left the factory ? But who knows what has gone on by other owners ?
Thanks for your help,
Ivor.

[T. Cotten]

I have many paices that were Cad plated that are now bare metal and rusty.

Gosh Chris!

I've some Caterpillar cad that's close to a half-century old, and its still immaculate.

I "plated" a brass oil fitting with mercury once.

It evaporated. But coulda passed judging.

....Cotten

[Ivor]

OK, Thanks for all of your replies folk,
There was a black finish to all the non exposed parts of the head bolts and washers, so I heated the bolt heads and the washers until they were blue and quenched them in oil, to leave an almost parkerized look.
Thanks again, Ivor.