[Cardo]

Thanks. I found the different descriptions confusing. I also found this guy's description of his process too. I was planning on trying it. I'll post results in the near future. http://www.southsandia.com/forum/web...ncplating.html

[dataway]

Yep, I exchanged a few emails with him years ago. He got good results with his formula and for the most part that's what I still use.

[Cardo]

So, Corona dictates that i do my own plating due to the places i was going to use are shut down. I followed this thread, and had excellent results. Thanks Dataway and PY for all of the help.

[dataway]

Cardo, excellent results! What formula did you end up using? Any details on what voltages/amps/time worked for you? Part prep?

Your results look more uniform than mine.

[Cardo]

I ended up using the formula that you said you use, the one that is in the link posted in post #81 above. I started out around .64 amp, and went up from there. Lower and slower is definitely better. Smaller thinner pieces seem to plate best around .60 amp, thicker heavier plates better around .80 - 1 amp. I plated several pieces, and toward the end of the day, I started getting some black sediment showing up on the edges, which comes off when brushing but i think i will mix a new solution (same formula) and start again. I tried higher amperages (up to 1.6 amp) and that is when the black started showing up. Some of it is starting to accumulate in the bottom of the bucket too. I think the higher amps may have "cooked" my solution somewhat. Prep - all pieces were glass beaded, dipped in the muratic acid solution, (200 ml acid to 4 liters water) till it stopped bubbling (5 - 10 minutes) rinsed in tap water, and straight into the plating. I plated all of those parts twice.

[dataway]

Excellent. I think sometimes I lack the patience and try to speed things up too much ... or try to use solution that has sat around for a couple of months.

I'm slowly learning ... gather and prepare everything I want to plate, mix up a new batch of solution, do all the plating in one or two days and throw out the used formula.

Your result were really nice. Only about 70% of my stuff comes out that nice and I end up stripping, mixing a new batch and doing it right the second time

Satisfying isn't it? I have some parts I plated several years ago that have by lying around waiting for installation and they still look great. Specially when you clear/gold chromate them.

[Cardo]

So i've finished up my plating for now anyway... a couple of more observations. For the best results that i was able to achieve, when i first mixed my solution, i used hot tap water to help dissolve the Karo, and i achieved my best results with the water hot. If i end up doing any more plating in the future, I will buy something like a fish tank heater to maintain the temperature. Lower and slower yet, .30 .40 amps is even better yet. It seems like the finish is easier to brush off and shines better if you go slow and have the water hot. And lastly, you will need more than one brass brush. They wear out pretty quick. Thanks again Dataway for the thread, couldn't have done it without your help.

[dataway]

You've actually inspired me to replate some of my stuff. I did a lot of mine in the winter when the shop was chilly. I knew the water should be warm but I kind of ignored it, tried an aquarium heater but didn't have the patience. I know the temps have a large effect on the speed and quality of the reactions. Most of my poor results were do to trying to rush things.
I was using distilled water (my water comes from a deep well and has some minerals in it), but I DO have a hot plate right in the shop that I could have used to warm it up ... if I wasn't in such a hurry.

Wish I had an area I could dedicate to the plating.

Are you going to try any of the Chromate coatings on top of the zinc? The Eastwood clear works nice. I also have tried it with my own batch of Sodium Di-Chromate, hit and miss, looks great when it works well though. But that stuff is a bit dangerous.

[Cardo]

No Chromate for now anyway. I use the Eastwood Clear a lot though. The well water may actually work better.... I was reading an article about No Rosion coolant additive this morning, and they actually discouraged the use of distilled water in cooling systems due to the lack of ions lost in the distilling process. They want you to use some kind of ionized water.... It makes me strongly consider just using premixed coolant. My tap water here is fairly hard, so the well water could possibly be better? I don't know, but you could try it on the next go around.

[dataway]

You know you might be right, the distilled water has got suck up a lot of the zinc right from the get go to "normalize" itself ... zinc that would no longer be available for the plating process. Also would suck up the salt and other chemicals .... I don't think the water will give this stuff up until it's reached a point where the water itself is "satisfied"

[dataway]

Have any of you fellow "Zincers" done any brush plating with zinc? I have a hood latch I want to try to selectively plate some parts on.

I understand the general setup, I'm mainly wondering if I can use my usual zinc bath solution for the brush plating electrolyte along with a zinc strip covered in cloth or foam. Or even just use the solution with a charged bristle brush.

[MUSLCAH]

Nice thread...Iam watching

[dataway]

Latest edition to the "fun with zinc plating" show

So ... removed the filler neck from my original 68 GTO tank to use on the replacement. It had some surface rust that I wanted to remove, tank end was nice, but from the middle to the opening it needed to be sandblasted ... which removes the original zinc plating.

What I ended up doing was blasting the top 2/3thds of it ... I wanted to preserve the very nice solder tinning that was still on the tank end, and I didn't want to plate the whole thing, again because I don't know what it would do to the tinned tank end.

Thought about painting it, but the paint would be scrapped off by the cap the first couple of times it was used ... so the compromise is, plate the cap end, paint the middle, leave the original galvanizing and solder on the tank end.

This is the results before painting and I'm not going to polish the zinc as normal because the OEM filler necks weren't very shiny from the get go. Maybe try to buff it very slightly so it doesn't powder up.

[6d7gto]

I had been doing this on hundreds of parts over the years. Then alarms went off when I was told that hydrogen embrittlement can occur due to the electro plating process. Any comments from experts in this field would be helpful.

[Shiny]

Not an expert but you should not worry much about embrittling mild steel parts. Anything high strength, heat-treated, or high carbon would be risky. High-strength fasteners and springs would be good to avoid. Most brackets and small parts are low risk.

"Steel with an ultimate tensile strength of less than 1000 MPa (~145,000 psi) or hardness of less than HRC 32 on the Hardness Rockwell Scale is not generally considered susceptible to hydrogen embrittlement."

https://en.m.wikipedia.org/wiki/Hydrogen_embrittlement

You can mitigate by baking at ~400 F for several hours, but needs to be done immediately after plating. Embrittlement is caused by atomic hydrogen combining into H2, which takes a little time..... but not much.

Mike

[dmorg1]

I am not a plating expert by any means but I do manufacture parts that require various types of plating.

It is my understanding that the embrittlement is only a concern with materials that are 40 rockwell and above. (I may be wrong on this)

I have a few parts that I manufacture that require hard chrome plating and my plating vendor does bake them to relieve embrittlement. They are 45 RC but also plated to a mil spec.


Dave

[Shiny]

Originally Posted by dmorg1

I am not a plating expert by any means but I do manufacture parts that require various types of plating.

It is my understanding that the embrittlement is only a concern with materials that are 40 rockwell and above. (I may be wrong on this)

I have a few parts that I manufacture that require hard chrome plating and my plating vendor does bake them to relieve embrittlement. They are 45 RC but also plated to a mil spec.


Dave

We see it about the same and agree it's not just zinc... it's any electroplating. This is one benefit of electroless nickel...it's a good way to avoid risk for hydrogen embrittlement on hardened steel parts but it also needs a post-bake.

Being a dinosaur, I used to spec materials and finishes and we had a "standard" note about baking. We would apply it to anything with over about 30 points carbon, anything heat-treated, or anything with high stress and/or stress concentrators that were subjected to impact or really high loads.

And it's not just an issue in plating. Even exposure to seawater can introduce atomic hydrogen and embrittle parts... probably a result of corrosion chemical processes.

[Joe]

Spent my entire 35-year career in supply chain working with platers/ heat treaters/powder coaters etc. Prior to retiring in 2015. A guide to help you in your plating/post plate bake work...
Look online for ASTM B 633 (plating) and ASTM B 850 (post plate bake). Both are industry guides. Hydrogen embrittlement is a big issue when plating parts. Based on the hardness
of the part being plated will determine the minimum time it should be baked after plating. To reduce the risk of embrittlement. Hydrogen never is completely eliminated from any part.
Bake times just reduce the risk of failure. Any part that should be baked gets baked prior to the final chromate process. I am taking a bunch of my 66 parts to a plater I know in Buffalo in
a couple of weeks. I'll see if I can get copies of both spec's.