Parker Process: "The dry process consists of heating the steel parts at about 600F, in contact with the fumes of acid metaphosphates of tungsten, strontium and molybdenum. The wet process consists of immersion of the parts in a 1, 1/2% solution (of the same)".Source; the same tome as above. Next week, my recipe for strained weasels in nitric acid followed by compote of wombat.
Restoring the last of the series "A" Comets.
- Thread starter greg brillus
- Start date
He missed the wombat: http://www.potw.org/archive/potw283.html
Greg, just Google "chemical blacking" for your local friendly firm. Or you can diy which wont lay on such a good coat. Like plating, the finish on the steel will be the finish after blacking.
I think black steel looks superb.
I think black steel looks superb.
Thanks for that Tom, will do........Only thing I can't work out is the rest of the bolts and nuts, as they were mostly all Aircraft bolts of UNF threads, so hardly any original bolts on it to see what their finish was. I would say the larger through studs were the black finish and the other hardware was cad plated or similar.
Greg,
Two things. Firstly, lest there be any doubt, almost ALL the threads were 26tpi CEI threads. But obviously, BSW in alloy. One exception that comes to mind is the rear springbox thin-nuts which were usually 0.710" hex and 7/16 " x 20tpi Whit Form of which I made a batch in SS (sorry!) a couple of weeks ago.
Secondly, we had some email-exchanges over the last week or so in the UK between several Series A addicts on the subject of the original fastener finish. There were some anecdotal views about parkerising and cad but no-one could be absolutely certain. Why not ask the Series A guru, Andrew Walker, and be sure to let us know the answer...
Peter B
Thanks for that Peter. There are several parts I have looked at on this bike, which include but perhaps not limited to.....The main large through studs that hold the engine plates to the gearbox and the front small engine plates.......these, plus the original Iron spool type wheel hub, and possibly the spoke flanges. All of these parts still showed signs of a black finish, definitely not black paint. I don't know if this applied to any of the actual studs on the engine itself, and I have no idea what finish all the other bolts should have been. Was Cadmium plating used before WW 2 I couldn't imagine all the remaining bolts having a black finish as well.
Just done some research on Parkerising, which indicate that the finish is a matt black and almost a porous finish suitable to coat in oil for extra protection. But I note that the finish on these original parts seems more shiny indicating to me it is more of a "Blued" finish closer looking to a rifle barrel. This seems logical, and I am leaning toward that type of process to refinish these parts.
There are mentions of Coslettising in Whittakerpedia, might be worth pursuing, especially as it seemed to be used widely in England pre World War Two. I have recipes for blueing, but usually use them on Saturday nights after I get shickered.
What on earth is SHICKERED, I like to understand what I'm reading, please educate me Charlie.
bananaman.
bananaman.