I have found that most of the hardware on my 27 Roadster appears to have been produced in natural unfinished steel and while some hardware came in nickel, bright zinc or the black raven finish, I get the feeling the plain steel hardware was probably just covered after a completed assembly was painted over.
As I refinish the nuts and bolts which are going to hold my car together it would be really helpful to know what finish to apply. Is there a listing of the finish types used on all the hardware by area?
Natural, black, brass or nickel. What came in zinc besides the wheel rims and hardware? I can't think of any. And nothing would have been bright zinc back then.
The vendors have diluted much of the original hardware with replacement hardware and parts from Chinese farm store shelves. It's junk. The generator post nuts I just got from Lang's came in bright zinc. Zinc! Really? What idiot would supply those in place of brass? I feel like I got ripped-off because they were priced as brass.
Are they blind at Lang's or just don't know the difference?
I remember reading (this is no guarantee, mind you) that most mounting hardware on the T was raven finish, but when I clean up bolts and such on the wire wheel there is nothing that looks like it was ever anything other than plain steel. Maybe the raven finish wears away?
I did read on the Forum that the radiator mounting thimbles are supposed to be raven finish - the ones I bought years ago appear to be zinc plated.
Ken, speaking of zinc, I just had my rims zinc plated. They came out with a lot of gold colored "stains" on them as if something were leaching out of the metal.
Well anyway, if there is a listing of where to use each finish type that would be a great help getting this car finished and back out on the road.
One of the clubs was putting together a list of hardware but it's a "work in progress". It's in PDF format. The list has comments that sometimes states the finish but it's not that reliable. I tried to find the site to see if it's been updated recently but I keep getting a 404 error on the address.
I'll try to attach the copy I have.
Bolts_nuts_threaded_items.pdf (75.7 k)
Forgot to mention:
The raven finish was similar to a black tooling finish. It can be achieved by various processes including chemical and/or heat-oil but it's a surface conversion finish that will easily buff away or be consumed by rust.
As a side note- You can blacken zinc plated hardware using a tool blackener but the results is similar to different bare metals. It will appear brown on some and work great on others. I've never tried a cold gun-bluing.
See the encyclopedia for paint on 1927 engines & attachments. For chassis hardware I use black satin Rustoleum. I don't know if it's available in Europe. Whatever paint you use, it wont stick to plated hardware. If I have to use new nuts & bolts I strip off the cad plating with muriatic acid then apply DuPont 5717S metal prep before painting.
I've used gun bluing on spark plugs. I think it looks nice.
Ken, thanks for the info. That's some piece of work the club is putting together!
Interesting about the raven finish being superficial and that it could be buffed away - this explains a lot of things.
I cannot have the Caswell chemicals for the cold blueing process shipped here due to restrictions, but I can get Black Iron Oxide Powder. Anyone know if it's possible to get a "raven" finish using this chemical?
Ferric oxide (black iron oxide) is what is left on parts after using the electrolysis method of removing rust. It washes off because there's no bond to the metal. It's already in a conversion state. You need a surface conversion process for the metal itself.
As I mentioned, there are heated chemical processes that use molten salts that will blacken steels. It's used all the time in the tool and gun industries. I don't know why you couldn't obtain the necessary salts in Spain. They produce a lot of guns in Spain. Don't they have gun shops or a place to buy the cold-bluing?
YouTube is full of examples of molten salts examples for blackening gun parts at home. For small parts, all you would need is a cooking pot and a way to heat the salts until they melt. (That and some safety gear.)
Ken, I may be able to get material for the heated process, it just sounded more complicated so I was looking for a cold process. I'll check out YouTube and see what I can come up with.
Steve, for now I am using a black satin chassis spray paint which gives a nice finish. Is the gun blueing you used on the spark plugs a cold or hot process?
I have used gun "bluing" on nuts and bolts for show but it seems to offer very little protection against rust. The term "bluing" is misleading since it seems to turn unplated steel "black". The look is nice but doesn't stay nice for very long so I would hesitate to recommend it for long term rust protection since it doesn't seem to offer that. The hardest and best look for most items that I like is the satin look of using a hard epoxy black primer. While it is really a primer it gets very hard if you don't overcoat it and it seems to really stick. I have used it as a finish coating on tools and things that I can paint after assembly. It is satin and has a slightly grey shade of black that is similar to the gun bluing look but it is much harder and does seem to prevent rust. I am open to anything new that you guys come up with since I am not totally satisfied with the look but I sure don't want to have to redo things again and again.
Just my .02
I've had pretty good luck with the black oxide finish from Eastwood. You now have to spray the items with a clear satin finish after oxiding them. I had to do a lot of bolts for my '25 when I restored it, and was somewhat pleased with the results. I even lucked out better at swap meets finding NOS nuts and bolts.