The chromed ”spears” on my car were in perfect condition so they only needed a careful polish. But the cup, and accompanying parts, that hold the lamps were in worse shape.
Ponton-Mercedes Typ 220a, 1954-1956, © Daimler AG
The cups that holds the lamp holder are also not difficult; just drill-out the rivets, clean up, polish and plate it. The reflectors are easy as well. Remove them from the lamp holder and polish them carefully before having them chromed. Remember that any scratch/imperfection left after the polish will be visible also after the chrome procedure. Then is of course the question; how perfect does the blinker reflector have to be? In my opinion not 100%, the blinking will be seen anyway.
The actual lamp holder, however, involves some challenges if you want to make a complete restoration, the contacts need to be removed in order to:
- get free access for cleaning and polishing of the surface
- secure that the following plating process doesn’t destroy the plastic and/or bakelite items that insulates the contacts from the base plate
- avoid having the brass contacts being plated
Since this type of riveted contact exists in several items in the car (in several different measurements though), I really wanted to find a viable solution on how to remake them. If you have your own lathe you can probably make them yourself. Then it’s just a matter of finding the correct type of brass (there are several varieties with their pro’s and con’s). I suppose you need to be rather experienced and you will probably need to do a lot of experimenting to get the riveting to work out well.
Since I don’t have space for a lathe that alternative fell. Instead I tried to find them on the open market. Since this type of contact is not uncommon, it shouldn’t be a problem, right?! I don’t know how many companies I contacted, globally. Several dozen at least. I asked companies that make this type of contact as well as retailer/wholesaler. Either they didn’t respond at all, weren’t close to my specifications, said no due to the small quantities I was asking for or were faaaar to expensive for my restoration (including buying some extra in order to be able to sell to other restorers). From a motorcycle restorer in the US and a boat supply company in Stockholm I managed to buy some that looked similar. Upon closer inspection they however turned out to be unusable for this application. I now know more about rivets, their application and installation than I would like to. If you have a solution for these riveted contacts, let me know!
Most certainly you will damage the plastic items if you remove the contacts. I never came to look for a solution on how to remake these. My focus started with how I should remake the contacts. Since I didn’t find a solution for that I didn’t need to find a solution for the plastic items. If you have a solution for these plastic items, let me know!
Since the plating company couldn’t assure that the plastic details would withstand the plating process, I bought another set of cups/lamp holders. The lamp holders I got had bakelite instead of plastic to insulate the contacts from the base plate and that didn’t like the plating. Previously I’ve plated parts with bakelite on them without any problems, so it differs from time to time due to, to me as well as to the plating company, unknown reasons.
Again, the lamp cup you see in the gallery above is my old cup, but carefully restored. Looks like new. I doubt, but I don't know, you can buy these parts new from MB or elsewhere, at least for a decent amount of money. So, even if yours are in a bad, rusty condition, give this restoration a try. It's easy and doesn't cost a fortune.
As written above, disassemble them, clean them up and then sandblast them carefully so that the rust is 100% gone, otherwise it will start to rust again. Then grind/polish them to desired perfection and plate them. 1h work at the most.
If the cups have small holes and pitting after the sandblasting, it doesn't look good but it doesn't really matter (given what level you want your restoration to reach). If you have holes I would fill/cover them, even though you have the long rubber beneath the blinker spears. If you fill them with something before the plating, see to that the material stands the plating. If you fill the holes with something after the plating, see to that that process/product doesn't destroy the plating.
I suppose the easiest thing to do is to have the cups covered on the underside, after the plating, with 1-2 mm of e.g. automotive silicone (never use construction silicone etc for houses, contains acid which initiate rust), “liquid” rubber or likewise. Considering how a historic car is used, it will hold the rest of its life.
Final restoration and assembly not yet done so stay tuned!!