OK, so a lot of people have asked me about the zinc plating and chromate conversion process, so I'm just going to leave this here.
For zinc plating at home, there is no substitue for Tom Gugliotta's write up with nice pictures
http://www.southsandia.com/forum/website/zincplating.htmlwant a CB750 part walkthrough? look at grepper's attempt here (although he still hasn't shared how he got the blue finish with me
)
http://forums.sohc4.net/index.php?topic=119931.0The only thing I did differently is the prep work before plating. I am not privy to a good sand blaster, so I spent a lot of time laboriously cleaning away gunk, followed by days of soaking in evaporust (for small parts) or slathering them in loctite's rust dissolver (larger parts), then wire wheel cleaning the larger parts and dremel wire wheel for small parts (yes, I'm very compulsive since I've cleaned and plated everything down to the smallest washers). After this cleaning regimen, I dipped all parts in the muriatic acid dip (see Tom's article) followed by a rinse in water, then a dip in denatured alcohol to get all the contaimnants and old zinc off.
Once all this is done, the next most critical step is getting the balance right with the power supply being used. This is a very long and boring process and will initially take some trial and error. After a few failed attempts, I eventually got it right and the general rule of thumb is that you need 0.1Amps per square inch your're plating. Use that as a guideline and decide how many parts you want in the electrolyte tank at a time.
The article demonstrates a fairly large size part, so the final step after plating, (which is to wire brush off the excess, then polish with steel wool) works really well. For smaller parts like bolts and nuts, I had to gently polish with a fresh steel wire wheel at the lowest RPM setting on my dremel. Do it too aggressively, all the zinc will brush right off, do it too gently, you won't get the shine, so again, boring and tedious but great once you get the hang of it.
Once you have all the parts nicely plated and shined up, you'll notice that Tom's article just mentions the chromate conversion process, but no amount of searching will yield you the article. Its because Tom never published it, and only provides a copy to those who personally request it. He does so with good reason, due to the toxicity of the reagents involved. Now before you go running scared $hitless, know that this is just a precaution to protect oneself from someone else's stupidity. Unless you are working with this stuff day and night and it is in constant contact with your skin, you'll probably be fine doing it at home. When I reached out to him, he responded and explained why he hasn't published it, then provided me with the basic safety routine (gloves all the time, goggles, don't drop stuff from a height etc. etc.) and sent me a copy.
That said, Tom's recipe for chromate conversion will yield the yellow iridicent finish, mostly found on center stand pivots, springs and other such items. Almost all the rest of the bike has parts that have the clear/blue chromate finish. Now this, was a real pain in the A$$. Proprietary garbage that no one will share and after months of googling, some random university experiment doc had the recipe for it. But, the reagents are too costly to mix this up on your own. That's why I didn't even bother with it and went with Caswell's pre mixed concentrate, which ended up being cheaper. The yellow chromate mix on the other hand, is cheaper to mix at home than buying Caswell's pre mixed concentrate. Not only that, Tom's chromate article has an excellent side by side comparison that shows that the DIY mix produces much better results than Caswell's.
Before you go asking me for Tom's chromate article, let me tell you I will not be able to share that per my agreement with Tom. You can reach out to him directly and he will gladly help you out, or there is always Caswell's mixes to fall back on. Chromate conversion is the final and easiest step, the real test of patience is the cleaning and plating process. I hope this helps out, good luck to who ever tries it.
