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Do it Yourself Zinc Plating Process

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Replied by mdscott on topic Do it Yourself Zinc Plating Process

Tom S. wrote:

Gplracer wrote: Great thread! It brought me to this forum. I have a 1978 DT125. I feel like my plating process is working but I get a think deposit of zinc like crust that has to be washed off. How do I keep this from happening?...


I'm glad to see another person try this. That formation of scale (crust) just seems to be an unavoidable part of the process. It's easily removed with a light touch on your bench grinder's wire wheel. But don't rub too hard. Zinc is a soft metal and the plated coating is thin. For about $3 at Harbor Freight, I purchased a set of miniature wire brushes to use with my air-powered die grinder. They work great to get into tight areas, holes, and corners. The brushes might also fit onto a Dremel tool.

@Scootern29 I have continued to research doing a chromate dip.

I have seen more than one source say that the bare zinc finish is susceptible to corrosion., but I have found no appearance of corrosion on the parts that I plated months ago. I have also read that the chromate conversion process leaves a harder surface than the bare soft zinc, making the finish more durable and resistant to scratching. Chromate solution is available in a variety of colors, with corrosion protection and hardness increasing with each darker shade. Clear chromate provides the least protection, yellow is next on the list, and so on. Corrosion resistance is measured through a standardized salt water spray technique. Yellow provides a pleasing iridescent finish and it seems to be the most popular color.

I still have great concern about the safety of chromate. One commercial site that I visited speaks of the hexavalent version of the product having been replaced by a safer, trivalent compound. I did not excel in my college chemistry classes, so although the words ring somewhat familiar, the fine points of this are lost on me.

Caswell Inc.- the firm that sells the great fuel tank sealer -also provides plating products. Caswell's yellow chromate product is described as containing the following ingredients:

- Chromium Trioxide
- Sodium Dichromate, Dihydrate
- Nitric Acid
- Sulfuric acid
- Water

Except for the water, I don't want any of those things in my garage. Caswell's SDS is very, very scary to read. But the You Tube vids that I've watched show guys splashing chromate all over the place and on themselves, not wearing protective gear, and not saying much about safety, or proper disposal of the chromate dip solution and the rinse water. There is a big disconnect here that I just don't understand. I will continue to research this and let you know what I find. I would sure appreciate hearing from anyone who can shed light on this.

Here is a link to Caswell's site:

Caswell Yellow Chromate


Tom good to here from you, not sure I missed any of your recent post.
Looking forward the your racing pics!
Thanks Mark
Roseville, Ca.

'06 GL1800
'98 KDX220
'75 Norton
'73 CB500K
'01 Honda CT110
'87 PW50
'64 McClane Edger
'02 Honda XR80R
19 Dec 2020 08:52 #121

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Replied by mike8162 on topic Do it Yourself Zinc Plating Process

I did some home research on the dichromate coatings for a quadrajet restore on my 442. Harold Demes has some great videos on Youtube for the quadrajets and a formula for the dichromate solution. I used it for all the brackets on the carb and it works well. It is just distilled water, a small amount of battery acid and sodium dichromate which I bought on ebay. I keep battery acid around but I think I was in it for less than $10. Not sure if I can put a link up so I won't but if you search the name it will come up.
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20 Dec 2020 03:39 #122

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Replied by Tom S. on topic Do it Yourself Zinc Plating Process

mike8162 wrote: ...I used it for all the brackets on the carb and it works well. It is just distilled water, a small amount of battery acid and sodium dichromate which I bought on ebay....


Thanks for this. Mixed in what quantity and proportions, please? Got a pic of a finished of the finished Q-jet?

I brought this topic up on another forum, oldminibikes.com, where a fellow chimed in with detailed info. He claimed to be recently retired from nearly four decades in the metal finishing industry. He had this to say about the chromate dip:

"Hello,
The trivalent chromate's are todays RoHS compliant technology. From a health and safety perspective it is safer than the old hex chrome versions. Any zinc plated part should be dipped in the chromate to increase corrosion protection. We required all of our zinc plated parts to be chromated in trivalent chemistries then a clear sealer on top of the chromate. The trivalent chemistries are not as protective as the hex versions. The sealers increase protection more. In either case tri or hex wear rubber gloves. Like the dish washing type. Not the latex shop type.
Disposal..... I've done home plating as well after retirement. I disposed of my extra chemicals at a local plater I know.
Sealers and chromates apply better when heated. Caswell should be able to tell you the ranges they suggest.
Regards,
Joe51"

Additional study led me to find that RoHS is a product level compliance based on the European Union's Directive 2002/95/EC, the Restriction of the Use of certain Hazardous Substances in Electrical and Electronic Equipment (RoHS). The substances banned under RoHS are lead (Pb), mercury (Hg), cadmium (Cd), hexavalent chromium (CrVI), polybrominated biphenyls (PBB), polybrominated diphenyl ethers (PBDE), and four different phthalates (DEHP, BBP, BBP, DIBP).
Last edit: 21 Dec 2020 07:43 by Tom S..
21 Dec 2020 07:41 #123

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Replied by mike8162 on topic Do it Yourself Zinc Plating Process

Not sure if you went to YouTube but if you go to Harold's page you have to hit the videos tab to get them all. His plating video is 22 minutes, the dichromate part comes in around the 8 minute mark. His formula is 1 gal. distilled water, 10oz. sodium dichromate powder and a half oz. of battery acid. It will only work if the part is zinc plated. I am very happy with the results, the longer you dip it the darker it will get.
Cheers
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21 Dec 2020 18:11 #124

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Replied by Grussell on topic Do it Yourself Zinc Plating Process

I performed my first zinc plating project last night. Zinc plates, vinegar, distilled water, salt and muriatic acid. I bought an adjustable power supply on line for $50. I plated all of my DT250 engine mount bolts, washers and nuts and for grins a tire bead lock. I used a soft brass wire wheel to polish the zinc. It was easier than I expected.
1978 DT400
1975 DT250
1976 YZ125C (in progress)
1976 YZ125X (in progress)
2018 YZ250FX (my race bike)
2010 Triumph America (my cruiser)
The following user(s) Liked this Post: Tom S.
Last edit: 27 Dec 2020 07:44 by Grussell.
26 Dec 2020 18:02 #125

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