When I started the restoration of our 1937 Oldsmobile convertible, I wanted everything to be as authentic as possible, since it is very rare to still have the factory-installed cloth interior. The car was painted once in the late 1940s or early 1950s, with the original paint left on. The last time it was on the road was 1953, garaged until my wife and I bought it in 2010. I lightly sanded down the paint in one area until the original paint was visible, then buffed it out, and got it scanned to match new paint.
One of the details I wanted to get right was having the correct bolts with the proper markings on the heads and the correct finish (not like a lot of restored cars I see with new bolts and grade markings on the heads). My parts book shows about 98% of the bolts, washers and nuts have a cadmium finish, so that's what I was looking to achieve. Since I had another ’37 Olds that I made into a street rod, and had access to two other ’37 Olds in local junkyards, I was able to get every bolt I needed, with the correct markings, and rust-free.
I thought about sending all the bolts, nuts, washers, springs and brackets out to get them cadmium-plated, but I had heard horror stories about other people sending small amounts of bolts to large companies that end up losing them. Since I worked very hard and spent lots of hours gathering all the correct bolts and other items, I didn't want to chance losing them.
I've seen the Eastwood Tin-Zinc Electroplating System in their catalog for many years but didn't think it was the finish I was looking for. I asked some of my friends who restore cars if they had ever bought the kit and tried it but they hadn't. So the bolts laid around for a few years while I was getting the frame and body ready (I don't work real fast).
Finally I thought I would buy their electroplating system and give it a try. I wore the rubber gloves supplied in the kit so no oils from my fingers would get on the items. I also wore the eye protection supplied in the kit since I would be working with electrolyte, and I wanted to be able to actually see the car with both eyes when it was finished!
I glass-beaded a few bolts and cleaned them. The first bolts were a disaster. They were crusty and looked terrible. I found out it was just a matter of trial and error until I was able to get what I thought looked like the original cadmium finish. I ended up coating 1 or 2 small bolts at a time for about 4-5 minutes. Larger bolts or other items may take more time, depending on their size. Again, it's trail and error, outside temperature (works better in warm weather), keeping charged batteries (takes longer when the batteries get discharged), and making sure the items to be plated are cleaned properly.
One way I could tell when the batteries were getting discharged was when I placed the item in the electrolyte to be plated. If the electrolyte didn't start to bubble right away, I knew the batteries needed to be replaced. I kept lots of new batteries on hand because the plating goes a lot quicker with fully charged ones. I didn't count, but I probably coated between 100 to 150 items and only used about 8 "D" batteries.
This coating system isn't just for bolts; anything that is brass, copper or steel will coat well. I used it for bolts, nuts, washers, springs, brackets, grease fittings and front wheel dust covers. This kit is not recommended for stainless, chrome, aluminum or pot metal. This plating system isn't designed to fill rust pits. The smoother the finish is before it's plated, the nicer it is after it's done.
The Autosol polish in the kit works great. It takes very little polish and not much rubbing to get a nice finish. For some of the items I first took a fine brass wire wheel and very lightly removed the gray finish that was on the piece after plating. Then I used the polish supplied in the kit.
A friend of mine who restored his 1937 Oldsmobile used Eastwood's Metal Blackening Kit for all his bolts. When he saw how nice my bolts and other items turned out, he bought one of their electroplating kits and is in the process of redoing all his bolts.
I would recommend Eastwood's Tin-Zinc Electroplating System to anyone who wants to have a finish that looks, in my opinion, as close to cadmium as you can get...and you don't have to worry about sending all your items out and taking a chance on them getting lost. Final note: make sure you work in a well-ventilated area.