Steel v brass plating question - manufacturer puzzle?

[bradsan]

I'm currently working on a 30's car that offered an upgraded trim level that mostly involved adding chrome plated light buckets .

The parts manual shows a different part number for the the painted vs plated buckets.

I have on my bench an example of each type of bucket. They appear to be identical in shape and construction.

Both have a heavy mounting bracket riveted to the bucket ( no separate part number listed ) . This bracket is painted in one case and plated in the other. The rivets are painted in one case and plated in the other

 

So here's the interesting part ( to me anyway!)

While trying to repair the painted bucket to get it ready for chroming and comparing it to the plated bucket, (I currently have the bracket on the painted bucket removed), I came to realise that the painted bucket is steel and the plated bucket is brass.

Both of the mounting brackets are steel.

The rivets are steel in both cases.

 

The questions for all of the experts are as follows:

1) Why did the manufacturer use two different bucket materials? My initial thought was that the manufacture was trying to avoid the copper plating process but given the brackets are steel, this wouldn't  make sense as the brackets themselves would still need copper plating. I can't see them plating the brackets separately as you would still need to plate the rivets afterwards and risk damage during the assembly process.

 

2) Is there any reason not to have the steel buckets plated? There is rust and pitting behind the bracket of course and I'm not sure how the plater deals with that.

 

3) Should the brackets be removed for plating or left on ?  I'm about to rivet the bracket back on but don't want to create. more work for the plater. Do platers (good ones that is !) typically disassemble the light or do they just plate the entire unit and expect the service use will not create a problem in the near future..

 

Thanks

Brad

Edited March 28, 2021 by bradsan (see edit history)

[Akstraw]

Perhaps your best course would be to ask your plater directly.  I think they will give you straight answers for several reasons:  1). The good ones stand behind their work and won’t give you a recommendation that will fail down the road, and 2). Any question you may have, they have likely been asked and answered before.  I have had success with both R&D Finishing in Elizabethton, TN, and with Librandi’s in Harrisburg, PA.

[Bloo]

Do you not have both brass buckets? Missing or just dented? Steel is a more common thing for headlight buckets in general (you didn't mention what make and model this is). Steel will rust out. On one of my cars there were pinholes everywhere, and you cannot keep the water out. Spares I have seen for sale have all been worse than mine. If there were a brass bucket option for my car. I would be all over it. I'll second the recommendation for Librandi's

[bradsan]

Thanks for the replies.

Both cars are 31 Auburns. Both are in need of full restorations so its not nearly as exciting as it might sound!

I know the plated brass set are original to one car;  the painted set belongs to the car that came in boxes so I can't discount that they might be off a later 32 or 33  car which had the same headlights and therefore  steel might be a running change.

 

I'll follow up with  a plater or two and see what their preference is.

 

Thx

Brad

[Soupiov]

Did you check both with a magnet?  Steel housing might have been brass plated first as part of the chrome process so that is what you are seeing under the old chrome.

[bryankazmer]

It's possible to electroplate a layer of an alloy like brass, but much trickier than plating a single metal.  You are basically doing two electrodepositions at the same time at the same voltage.

[MHuppguy]

Sounds like you have headlamps from an early '28 Hupmobile A series car.  If so the explanation is simple.  According to the Hupp Parts manual, early A series cars came standard with steel, black head and taillamp buckets.  Chrome lamps were available as an option, then became standard at car # A115,001.These can be identified because the parking lights were mounted in the headlamp reflector, there were no cowl lights  While this was Hupp's practice, it may also been that of other manufacturers as well..

Sorry, I didn't know you are doing an Auburn.  But you should remove the mounts from the buckets so any plating solutions can be flushed away and not caught between the mount and bucket to cause problems later.  The mounting base can then be restored and reassembled  easily.  I use 1/4-20, stainless steel carriage bolts.  I turn the heads down on the lathe to the shape of the rivet head, polish them and they look "factory", even against the chrome finish.

[broker-len]

you can not chrome directly over steel need a coat of copper or brass    so when the early car makers wanted to use chrome they would use brass, if it was painted would use steel     I have chrome head lights on my Plymouth,,,the plater I think used a coating of brass or copper on top of the steel then the chrome

[37_Roadmaster_C]

Typical high quality chrome plating on steel is a tri-plate process. First plate the steel with copper, brass works also, then plate nickle then plate chrome.  The copper can be plated thicker and multiple times if needed. This is the step where show quality finishing takes place. The copper is filed, sanded, buffed and polished until no scratches, pits or other defects can be found or seen. When a perfect copper finish is obtained then the final plating of nickle and chrome are done for a show quality finish. If this process is not followed the finish is not stable and will have a much shorter life.  Less expensive, yes. Lower quality, yes. Proper for the time, NO. Worth the cost, NO. In my opinion....

[chistech]

Many cars had both types of buckets. Many were “flash” chromed to save money, chrome right over the steel, no copper, no nickel. My 32’ Olds is a perfect example of depression era flash chroming. An old joke used to be , “ take a leak on the tire and the radiator shroud will rust”. Many Chinese auto parts are still flash chromed today and that’s why they rust quickly. Chrome is actually porous and allows moisture to penetrate to the surface underneath. Often times manufacturers had more than one supplier of spec’d parts. Those buckets might look identical but be made by two different companies. I have both Guide and Reflex brand tail light buckets that are identical in every way other than name and the internal design of the bulb contacts. With the lens in place, that difference is unnoticeable. Brass is easier to form and requires less tonnage in the die presses, plus it’s easier on the dies than steel so this is why most all buckets have brass rims. Even the steel buckets had chrome rims because those were made from brass. The riveted on ball mounts are always steel as the brass is just too soft to handle the torque of the bind bolt to keep the headlight in its position. Again, the use of brass or steel rivets could be just as simple as what was available at the time of manufacture.

[bradsan]

Thanks for all of the responses.

 

Chris,

I think you're probably right on what went on at the factory level.

It's pretty clear from looking at the chrome/brass assembly that there is no plating underneath the 'ball mounts' so they likely flash chromed the whole thing and hoped to sell the owner a new car before 90 years were up!

I followed your Olds adventure and noted your attention to originality. Did  you follow the consensus here and take the buckets apart for plating?

Rivetting finished parts back together strikes me as a bit nerve wracking. I've never tried forming stainless rivets and i can't see forming plated steel ones without damaging the finish

I've used the Restoration Supply rivet head screws but they are challenging to tighten! The last time I used them , I used Nylock nuts ( since you couldn't get at them after assembly so they wouldn't be seen) Had to cut a slot in the screw to stop the head from spinning and even that was challenging. Unfortunately , their closest size is 10-32 and I need 3/16

 

Brad

[chistech]

On 4/28/2021 at 9:31 PM, bradsan said:

Thanks for all of the responses.

 

Chris,

I think you're probably right on what went on at the factory level.

It's pretty clear from looking at the chrome/brass assembly that there is no plating underneath the 'ball mounts' so they likely flash chromed the whole thing and hoped to sell the owner a new car before 90 years were up!

I followed your Olds adventure and noted your attention to originality. Did  you follow the consensus here and take the buckets apart for plating?

Rivetting finished parts back together strikes me as a bit nerve wracking. I've never tried forming stainless rivets and i can't see forming plated steel ones without damaging the finish

I've used the Restoration Supply rivet head screws but they are challenging to tighten! The last time I used them , I used Nylock nuts ( since you couldn't get at them after assembly so they wouldn't be seen) Had to cut a slot in the screw to stop the head from spinning and even that was challenging. Unfortunately , their closest size is 10-32 and I need 3/16

 

Brad

I drilled out the rivets and used the SS rivet head screws but used nuts with the built in star washers. No problem tightening them. There is no real thread in the 3/16” size other than possibly 12-24 so 10-32 is what is used. Most buckets have at least 6 attachment points so they stay put without much issue. My ball socket flanges are painted black and not chromed so removing them was the only way to really get them right.