Yellow Zinc vs CAD

The Ejector seats we made for the F18s were so rust proof and generally well made they had to be able to work after being left on a ships deck for 12 months. The spec on them was something else.

 

Mike - 100% glass beading dulls the finish. But, nothing will get into the tiny areas or remove the corrosion like the glass beads.

So, yes - that is why I tumble after - it re polishes the surface and brings the parts back to the finish that the glass bead dulls. You can see the perfect results in my photos.

 

Take Dave's advice.
If you can find a plating company there is nothing really that compares
The Eastwood method is amateur hour.

 

We used a lot of electroless nickel plating on parts for vintage race car restorations because it did not need to be concours correct but the added durability of the nickel was welcome. Also many old race cars just had bare steel parts and we didn't want them to rust. We glass beaded all the parts first so it produced a dull silver finish. It can be used that way to get where you want to be finish wise.

 

In my main business, we do (have done) a lot of electroless nickel - it's in a totally different league (not saying you don't know this) to zinc. Electroless nickel adds thickness and threaded holes need to be masked or oversized tapped unless you are doing a very thin layer.

It's one of the most corrosion resistant platings.

 

Picture, please!

 

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I have plated several hundred pieces in my home shop. First most automotive fasteners have not been plated in cadmium for sometime. Zinc is the replacement. Furthermore as a point of clarification, the yellow is not from the zinc plating process. It a post plating process using Yellow Chromate. The red/green color develops when the parts is hot air dried. There are also different colors other than yellow. There is black, olive drab, and blue chromate colors It seems to me Blue is used on metric hardware, yellow on grade 8 bolts.

Hydrogen Embrittlement is usually not a problem in most applications. Little brackets and low strength 125ksi bolts, drive pulleys, should never be taken to the high end of their strength their rating.

The job of zinc plating is the zinc protect the base metal and the chromate protects the zinc.

 

If that had been a glass bead finish it would come out a soft, slightly dull and slightly textured finish. Gun manufacturers, especially Smith & Wesson use it on action parts on stainless steel guns. The stainless they use does not machine smooth so instead of devoting a lot of labor the make the action work well they make the trigger, hammer and a few other parts from carbon steel then electroless nickel plate a textured finish to blend in. Look at a stainless S&W to see what I mean

 

That's just a picture I grabbed from the net. The stuff we have is not as bright but still has a sheen. More satin. Plating always follows the surface finish for the most part.

 

Very true, if I strip old material with acid the original surface hold true through the plating, if glass bead or sand blasting it is a dull finish after plating. I the surface is wire wheeled after glass beading the surface is again shinny zinc. There is also an additive used to the plating process called "Zinc Brightener" which makes it almost chrome like. If the brightener is not used it gives a cadmium look. A fresh brass piece plates very well and gives this bright finish. Plating is a science and an art in that there are many variables which seem to appear at the beginning of most every session. Part of the process is placing the anode (Zinc) in proximity of the part being plated. The inside surface of a right angle bracket is kinda a B**** to plate and the anode needs to follow the shape of the part being plated. Moving the parts around while plating helps with the final result. Varying the current, time, and arrangement need to be monitored during the plating process. Attached it an example of some work I did on a warmed over 22RE engine.
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Great idea. I'm currently doing some work on my MG TD and am installing my new blast cabinet this weekend. Will definitely need to plate some stuff after blasting. What media are you using in your tumbler for that part of the process?

 

Are you using Eastwood stuff or something different?

 

This has been the best thread I have read on Ferrari chat in some time.

This is really really good stuff

 

I did all the pieces on my Bora in 1989 with actual cadmium plating via a south SF Bay Area plater who was doing NASA stuff at the time. It's a deeper yellow gold almost mustard and uniform in color. It's still spotless today, all of it! I've done other pieces on subsequent cars with yellow zinc and it just doesn't hold up. I beleive cadmium is also most the toxic for the environment. Now doesn't that just figure ...

It's either illegal, immoral, fattening or cadmium.

 

We use a mix of various plastic and synthetic media. Different sizes and shapes as we found that the bigger pieces do the bulk of the work but the little get into tiny areas. Also media will get logged so you need to be careful removing it. We also use a solution with ant-corrosion properties. We have created a custom mix / dispense system for our tumbler as we run it quite a bit. Note from the photo I posted, it's a very large tub machine.

 

https://www.finishing.com/100/89.shtml

But good luck finding anyone who offers the real thing.

 

Luck is not needed

SFT Products

 

Thanks so much because what I used way back when is utterly amazing by comparison.

 

Couple of quick shots of parts from the last batch I had done. I prepped the pieces only by glass beading them. As you can see, they had a frosted appearance before plating but still came out pretty shiny. I think that batch of glass was pretty well worn so that probably helped.

I'll look around and see if I can find any plastic media that would be appropriate for tumbling the next batch after blasting.
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I'm using the Caswell products. They cater to single home users to huge plating shops.

https://www.caswellplating.com

 

I have had better results using a Caswell kit than a commercial platers. The reason being you can spend the time on prep.
Most platers will simply bead-blast the crap out of everything then plate, which gives the dull finish as already discussed here.

The Caswell kits though, you need to throw away the low-cost power supply they sell and use a proper bench-top current-controlled supply, which are not that expensive, and also buy a fish tank bubbler and heating element for good results.

328 Sanden compressor bracket:
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