I rolled my pagoda last night...

[doitwright]

John,

Can you post a photo of some cadmium plated parts and zinc plated parts next to each other?

[johnk]

John,

Can you post a photo of some cadmium plated parts and zinc plated parts next to each other?

Good idea Frank. I will be at the car this weekend and can grab some of both for the pics.

[johnk]

John,

Can you post a photo of some cadmium plated parts and zinc plated parts next to each other?

Not sure how good of a picture this is but while both the cad and zinc parts have many variations in color between themselves the zinc is a little more gold.

[wwheeler]

Just out of curiosity, why did you do some CAD and some zinc. Cad is at least twice the cost, but its durability is far greater than zinc. Plus, CAD doesn't have the dimensional build up that zinc can have. The color variation for either process can be attributed to many factors. One being the texture of the surface before plating and another being the chromate itself. Depending on how long it is in the chromate bath will determine the intensity of color and the "rainbow" effect.

I just plated a few small parts in zinc yesterday and left one of the parts in the plating bath a bit too long. Turns out that part had a very intense yellow chromate color when compared to the others despite being dipped in chromate for the same amount of time. I guess the heavier plate absorbed the chromate color faster than the others? Who knows, but there is an example of color variation on the finished product. I am sure the pros have similar issues and for the most part, don't worry about it. 

[johnk]

Wallace

I had every piece I thought I had cadmium plated for $400. However there is always parts you find later that you missed or new ones that you had to buy, short on bolts etc. I just set up a zinc plating process in my basement for those miscellaneous pieces needed as I go.

There definately is a difference in color depending on how long it’s in the chromate, how shiny the zinc is and the different metals, but cadmium has similar variations.  My problem is sometimes I get small spots that just won’t absorb the chromate. Haven’t figured that one out yet.

[wwheeler]

My guess is that those spots did not plate. Maybe there was some dirt, grease or paint left? If it has zinc on it, the chromate should stick. Does the part have these spots before you chromate?

Alternatively, I do know with the yellow chromate there can be an issue with it "sloughing" off. Meaning that the yellow was on the part in the soak, but didn't stick and slid off in the rinse. Are you using the Caswell materials? I had that for a while when I started, but haven't seen it again. I would have to rethink what I did to eliminate that. 

[johnk]

You hit the nail on the  head. The chromium sticks in the dip but washes off in the rinse on spots sometime. I am using Caswell’s products. Any advice you have is greatly appreciated.

[stickandrudderman]

I notice someone plated their BC. You must take steps to stabilise it from internal corrosion AS SOON AS IT COMES OUT OF THE PLATING SOLUTION! The same applies for all parts that have any hollowness to them. (Fuel pipes and injectors for example. The plating process does not plate the inside so those insides, which have been acid stripped of all protection, will corrode VERY quickly.

[johnk]

Good point. Thanks stick

[wwheeler]

I think what Shvegal did on his BC was to plate it upside down with all of the openings above water line. So in other words, only the can part and not the threads. I think that is OK. I agree, can’t have any plating fluid getting into spaces where it cannot come out.

Caswell has/had a great on line forum at one time and I read through the posts about the chromate not sticking. If I recall, it is important to be gentle with the part as it comes out of the chromate and then dip it in hot tap water. I think the hot water starts the “curing” process of the chromate. Then I spray distilled water on the part to rinse off the tap water. We have extremely hard water here and our tap water will leave bad spots if allowed to dry. Then blow dry with low psi air and bake with a heat gun. You can handle it after that but NOT before.

The other issue may be that you are not dipping the plated part in 10% acid (10 parts distilled water and 1 part Muratic acid) prior to chromating. That also helps clean the surface and prep it for chromate. BTW, from what I read, Black chromate requires Sulphuric acid, not Muratic. Muratic messes with the chemistry of the black chromate.

I have been doing this so long, it has become muscle memory and it takes a bit to remember exactly what I did. This seems only to be a problem with the yellow for some reason. But I still use the same technique for clear (slight blue) and black.

 

[johnk]

Very helpful Wallace. I was not following that rinsing process. I did leave the end of the threads on the BC out of the solution.

caswell support told me to dip the part prior to chromate into
Straight sulfuric acid for two seconds rather than the 10% solution. I tried and stopped that as it removes too much of the zinc. The 10% sounds like a better idea.

[Shvegel]

Stick,
As John mentioned my BC threads were kept above the level of the solution.  One of the reasons I got into plating was to do the things I would never send out.  What I refer to as the unplatables.  This was my favorite rig.  Air injection with wires down. 

[wwheeler]

caswell support told me to dip the part prior to chromate into
Straight sulfuric acid for two seconds rather than the 10% solution. I tried and stopped that as it removes too much of the zinc. Yeah, don't do that. The 10% sounds like a better idea.

Hmm. Maybe you misunderstood them? Straight acid (sulphuric or muratic) would completely burn off any zinc plate in a matter of seconds. No, the 10% works well and will start to fizzle the zinc plate in a couple of seconds. Once that happens, pull the part. When it the part comes out, you will notice that any staining or slight discoloration from plating is gone. But, there is still plenty of zinc plate left.

I use straight muratic acid to clean the steel parts just prior to plating. They are free of grease and paint, but may have some old plating remnants and the acid takes that right off. Caution: Dealing with straight acid is VERY dangerous and you have to be extremely careful. Skin burns and inhalation of acid fumes are bad things. Also never add water to straight acid. Always the reverse.   

[johnk]

This was back when I started with Eastwood solution and called I Caswell to ask why their chromate would not stick (I didn't know at the time that Eastwood solution wasn't made to accept chromate). He told me to use straight acid rather than the 10% that I had read about.  I think he was new as there were a few other things he told me that didn't make sense. I do use muriatic before plating. I will try the 10% sulfuric wash before applying the chromate next. Hopefully the 10% solution will resolve that.

Thanks for your advice wallace.

[wwheeler]

If you haven’t yet, you might also look at the Caswell forum and look that topic up. There may be some other info on that to help you be successful. Good luck! Yes, pretty surprising info from Caswell and I hope that guy isn’t still there!

[doitwright]

Mike’s Restorations has a few YouTube videos with plenty of suggestions on how to get it right.

https://youtu.be/hTupOgImpWo

[wwheeler]

Wow. I just saw both videos. He does way more preparation than I do and I though I was excessive. His parts are 100% perfect, but I think there has to be a point where the outcome doesn't justify the time involved. I do about half that work and mine are quite nice. I guess we all have our own levels that we want to achieve. There are a couple of items I saw that I wanted to comment on:

1) I stopped using a circulation pump in the plating bath and couldn't see any difference with or without. Caswell said it wasn't totally necessary. Anybody else not use a pump?
2) Not sure he is using full strength Muratic acid in cleaning the parts. I buy the stuff for pools at the big box store and when it is in a open cup, it fumes. And those fumes cannot be breathed in! I have to keep my acid bath covered at all times. I also could not leave a part in for 30 minutes or else it would be eaten alive. My parts stay in for about 10 seconds. And the way he was splashing the acid around makes me nervous. That is what makes me believe it is diluted.
3) I do not plate spring parts because they will develop issues from hydrogen embrittlement. I doesn't happen all of the time, but it has happened enough that I don't plate those anymore. That also includes split lock washers. I have broken many in the past that were re-plated. Since they are standard and inexpensive, really not much reason not to use new.

Anyway, just some thoughts.   

[Shvegel]

Plating is a lot like seasickness.  Everybody seems to find what works for them.  I do very little prep.  Clean the grease off,  Bead blast to remove any rust or remaining grease then 30 percent Sulphuric acid in water until all the original plating then Zinc and Chromate.  I do use a circ pump in my bath unless I am doing 1 or 2 parts then I don't bother. 

[wwheeler]

Do you find that the results with the circulation pump are better and how so? I may go back to that.

[Shvegel]

I don't see a difference.  I just stir the mix with a stainless rod if I need to do one or two parts and fire up the pump if I am going to be there for more than an hour or so. I also quit heating the solution a while ago.  Probably the biggest mistake I made was using solid zinc sheet for electrodes.  As it deteriorated it left chunks in the finished product.  I now use round electrodes bought on Amazon and have not had an issue.

[wwheeler]

Interesting about the electrodes. I still use the sheets and haven't seen any problems, but the round ones may give better uniformity. Do you have a link to those?

Yes, no heat for me as well. I just plate when it is 70* F or higher and have had no issues. 

[Shvegel]

I use these.  I drill and put a female thread on one end and thread them onto a stainless rod.  I was using very thin zinc flashing material before.  The problem arose when  the zinc sheet started to lose chunks as it broke down.  Most plating shops use a cage filled with balls which makes sense now.

[johnk]

Unfortunately I messed up my back while running and I wasn’t able to work on my car for almost a month but I’m better now. Just finished installing the exhaust and I’m back on the engine.

[johnk]

Today more progress on the engine hope to have it ready to turn the key on the next week or so.

[wwheeler]

I just noticed the oil cooler hoses with the original type screw on fittings. Did you remake the hose assemblies?