Zinc electroplating

[Gordy]

Comparison. Zinc plated and wire brushed vs the old state still to be done. The zinc layer is thick enough to take a good brush on.


003845C5-8024-4465-AB3E-DE2577E54906.jpeg

Looking good

Inquiring minds want to know By chance did you mic them before and after, just curious how thick the plating is


Gordy

[Eugen]

Haven't thought about. @Gordy , I will the next ones. Good idea, thanks!

[JSinMO]

@Eugen Well done!

I’ve never tried this before, I’m going to have to keep this in mind for future use!

[Harry]

I was wondering about the threads on the fittings. I remember back when I was working on Harleys I would send various parts to a plating shop. I would have to clean out the threaded holes with a tap. The bolts would not screw into a hole until I cleaned the plating off the threads. Harry

[RoamingGnome]

Interesting project for sure...

The part of me that always wants to know more - would be interested to see the difference between plated and unplated parts after some exposure to the elements...

also remember seeing a web post about using electrolysis for rust removal...

https://www.instructables.com/Electroly ... aka-Magic/

[Eugen]

@Harry , as far as I can tell, the plating doesn't seem to be thick enough to affect the threads on these fittings. They screw in very smoothly. When the plating is finished the surface is a little rough, which I smoothed on the soft wire wheel.

@RoamingGnome In fact I just tried (again) electrolysis for rust removal, and every time I try it, it takes for ever, so I give up after a few hours. These are the rust removal methods I tried and my impression of them.

Krud kutter: this is baed on phosphoric acid. My favourite for larger surfaces, or when I know I'll paint over. Really good, again, for not very deep rust. You're supposed to wipe it after a while, otherwise it leaves a white residue. If you wipe it after it ate the rust, the metal has a dark appearance, an oxide which is a good primer for painting. For USA, the Ospho product is like this but even better.

Evapo-rust: good for smaller parts, you leave the parts in the liquid for several hours. It does not affect the base metal, and the rust does go away. Very deep rust takes a lot longer or doesn't get affected. This liquid is water based, so it's not as evil smelling like muriartic acid.

Muriartic acid: this is really dangerous, but I have tried it (surprise). I don't really like it, and it does eat the base metal too. But it does de-rust, if left long enough.

Electrolysis: my experience with this is that it takes forever to get any rust off. Not my favourite, I don't have enough patience for it.

Wire wheel: I have many wire wheels that go on the drill or angle grinder. The rougher wheels are by far the fastest way to remove rust, but you know, it requires labour. Most of the time this is what I do, at least to get the thicker rust off, and then apply the Krud kutter for an hour or so, wipe that, and ready to paint when dry.

Regarding the exposure to elements, the unplated parts are steel. I think you know how steel reacts over time. The plated ones have a zinc layer. I know how zinc reacts to the elements, especially when it is on steel. To me it's the thickness of the plating that was in question. So last night I put a very rough wire wheel on the cordless drill and went at one of the parts. I had to put a real effort for several minutes to remove the plating on that area. So it's both thick and really well stuck to the metal, where the steel was clean. There's a another aspect of zinc on steel. You know they use on boats and inside boilers, zinc sacrificial anodes. Look at the series in this picture. The order is such that the metals above corrode before the metal below it, if they are both in contact with a corrosive agent (like dirty water). So, zinc on steel, in water, steel will corrode after the zinc is gone, if both are in contact with the same water at the same time. This is why even an imperfect plating with zinc will be much better for protection than no plating at all. Imagine, in a boiler, there is a large surface of steel on the inside, and one or two pieces of zinc, to protect it. Because the zinc attracts the corrosion to it. That's my understanding of it.

[Eugen]

Update on the bath solution. My wife bought me pickling salt and new vinegar, so I replaced the bath last night. I didn't like the old bath started to have some dark deposits after three batches of electroplating.

The new bath is just white pickling vinegar (5%) and water equal parts, and pickling salt. The quantity of salt is not important, you just need enough to make the bath electrically conductive. For me for the 3 quarts of water and 3 quarts of vinegar, a pound of salt was plenty. How do you know it works? When you apply voltage to the zinc and parts you will see the parts bubbling. On my battery charger, set on 2A, the dial indicator also shows significant current draw.

To minimize confusion for people reading this at a different time, I will update the first posting of this thread with this new simple bath solution, because I like it best. It's simple, it stays clear, and works.

[Eugen]

The part of me that always wants to know more - would be interested to see the difference between plated and unplated parts after some exposure to the elements...

also remember seeing a web post about using electrolysis for rust removal.

Thought about it some more. In theory, as I said, the zinc plating should protect the steel fittings, but if that holds true in practice we will see. I can't think of any reason why it wouldn't, but as they say, the proof is in the pudding.


Also, you made me think about rust removal electrolysis so I had to try it again, but differently than I've done it before. Most recipes out there use water and washing soda, or epsom salt, or baking soda, and I tried these. One thing I didn't like was the foaming at the top.

Today I gave it another try using about two gallons of water, half gallon of vinegar, and a fistful of pickling salt. Used the battery charger on 12V and it was drawing about 6-7A and let it run for about 3 hours. Cleaned up nice except for some deeper rust pitting. I'll open up another thread on this and show some pictures.

I've also made changes to the zinc plating. I noticed clumping by the third batch of parts. I have a vague recollection that this happens if the current is too high or if the chemistry isn't right. Both might be true in my case. I think my battery charger isn't really limiting the current to 2A as it should.

Had to dig out my old lab power supply and set it to 6V, 1A. The playing is much much slower, but I think it's better. Changed the bath to 4 parts water, one part vinegar, and for almost two gallons of bath a cup of salt.

[RoamingGnome]

@Eugen I'm following your electroplating thread with interest... In a typical production oriented shop there isn't time for this sort of work, If we needed to clean up hardware that was being reused it would be off to the sandblasting cabinet or the wire wheel on the bench grinder. If hardware had to be replaced that was ok, as the cost was marked up and passed on to the customer. Now that I'm doing stuff for myself I have more time to experiment. especially in the future when we are living in the countryside and I have a real garage for experiments...

[Jancoe]

I'd like to try out this zinc plating process. I've already set myself up to do electrolysis. Here's a gooseneck hitch from my truck that I did. I'm sold on it. Barely any work on my end other than clean up.

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