Is there actually any record of how "dull chrome" plating was carried out in the years 1930 to 1960, approximately ? I've yet to find a UK plater who seemed able to give a feasible explantion and it's clear that some hope to get away with plating over a bead-blasted surface and others try to flash over dull nickel.
I'm not convinced at all. Original 1930 Norton fasteners show all the milling and turning marks. They're barely fettled. They were definitely not bead-blasted prior to plating.
Then there is the puzzle of Raleigh Cycle Group dull chrome. I play around a lot with 1950s bicycles and it's characteristic that the reverse faces of components such as chain rings and brake calipers are often dull on that side and bright polished chrome on the front. How did they achieve this if the dull plating was the product of an alternative process? The bright chrome doesn't wear back to a dull surface, and the dull doesn't cut back to shiny...was it a directional thing in a final plating sequence that put a bright layer over a build-up of dull plate ?
Proper mid-Century dull chrome is "smooth", even though it's not reflective.
I'm not convinced at all. Original 1930 Norton fasteners show all the milling and turning marks. They're barely fettled. They were definitely not bead-blasted prior to plating.
Then there is the puzzle of Raleigh Cycle Group dull chrome. I play around a lot with 1950s bicycles and it's characteristic that the reverse faces of components such as chain rings and brake calipers are often dull on that side and bright polished chrome on the front. How did they achieve this if the dull plating was the product of an alternative process? The bright chrome doesn't wear back to a dull surface, and the dull doesn't cut back to shiny...was it a directional thing in a final plating sequence that put a bright layer over a build-up of dull plate ?
Proper mid-Century dull chrome is "smooth", even though it's not reflective.
I recently had a pair of solid levers dull plated by my local plater. He knows his stuff and has been in the game a long time taking over from his father. I talked with him and he wanted a good sample which i gave him. He told me that the process and materials to do this are lomg gone. He took my sample and a few scraps of mild steel from me to experiment . He took his time and what he achived was very near to the original sample i gave him. I could see that very little if any polishing had been done on the samples. It was defiantly plating and not just zinc plating.I gave him my solid levers and clamps to dull plate and i was happy with the finish. He's done more for me recently but i have noticed the finish varies. He says he needs a sample evey time. Price is eye watering though:grimacing:
Nothing I send for dull plate goes near the polishing shop (That can add £40-£50 an hour). They remove any existing plating by reverse electrolysis and then bead/light grit blast everything so that it's all matt to start with. After that I've no idea about the process, but it's never expensive!
Here are some RE standard Amal levers that have covered many miles since they were done years ago. Ron
email (option): ronpier@talk21.com
Interesting topic! I always had the feeling, that at least some parts were treated with some kind of abrasive action before being plated, not sure what exactly, but can sometimes be seen on NOS parts.
The way I go about with it, is to first completely clean the parts, beadblast, deburr, clean up threads, restore hex's with a file, then either lightly wire wheel, or polish, and after that I will very lightly beadblast the parts again, and only then bring it all to the platers, I use a firm in Rotterdam, Holland, as they do some matt chrome plating from time to time, but it has to wait till they have the special baths for it. I also did do some parts, without the beadblasting, and found it came out too shiny, so I will keep using this method, it's very, very labour intensive, but you can make it as nice as you want.
The costs are also high for the plating, about a euro, for a washer, more for bigger stuff, but there's really nothing that comes close to the superb finish, and it looks very nice, even after ten years, but needs to be kept a little oily, otherwise small rust spots may appear, but they can be removed with fine steel wool.
Will try to find some pictures, but people who have seen my Big 4 outfit, will know what it looks like, a nice dull surface, with a blueish sheen on the chrome.
Cheers,
Lex
NOS dull chrome bezel
My plating on special Norton 1/4" nuts and bolts.
Some more stuff
My plating on stainless steel made Norton headbolts (early type) this was a very succesfull experiment!
email (option): welbike@welbi**.net
yes, interesting! I did a test with my aqua blasting and this happened:
dry blasting does -as you know- not work as it eats at the chrome.
as you will notice only a tiny bit of 'lifting' happened near the groove, so care still needs to be taking, dont linger too long on one spot
this however looks useable :wink:
email (option): info@wetblast.nl
Unfortunately, the terminology has not been standardised. Norton, in the factory records refer to the finish as "dull chrome" and I believe that other period sources do too. Most modern chromers using trivalent chromium talk about "satin" or "sateen" and provide a brushed finish. Nobody seems to be able to replicate the 1930s - 1960s finish consistently and yet it was clearly a mass-production process..but seems to have left no trace of what was actually done.
I've looked in all the old engineering text books that I can find and they're vague at best.
Whatever "period" dull chrome was, it was clearly cost-effective and easily available...cheaper than polished chrome. It can't just be down to the nickel layer, or Raleigh couldn't have achieved different finishes on different faces. There is a simple trick here somewhere and it's been forgotten.
Here's an Amal spec card for the WD16H. "Usual bright parts dull chrome finish." If a modern chromer refers to this as "satin", then they're incorrect. It's "dull", or it's a different finish.
"Dull" Chrome is what Machless & BSA called it.
Rob
email (option): robmiller11(a)yahoo.co.uk
Exactly, here a 1940 page of the G3WO parts list, unfortunatly they didn't use the prefixes anymore on the G3L parts lists.
Cheers,
Lex
email (option): welbike@welbi**.net