For the home plating specialist

[brewsky]

It's funny that you say that. Besides my chemistry foot in the mouth comment recently, I was wondering if you could actually do this. The challenge would be to suspend a cathode inside the tank such that it would plate out on all the surfaces. My guess is you would be fiddling with it for hours to get it right. I think the perfect shape would be a long tent shaped piece, but you would never get that into the filler neck. Then there is the balancing act of getting is suspended off center and still not tip down and touch the tank. You would have to experiment with making the short end heavy outside of the tank, until you got it right. Not sure you'd ever be able to fish a long strip in there and be able to straigten it out to do the job.

Rob

I was thinking of a U shaped anode that could be bent and shaped a little after it was inserted in the tank.
Since the process seems to be "line of sight" as long as all the interior nooks and crannies could "see" the anode it should work. Maybe even do it in stages.
Maybe fit a few thin plastic discs over the anode to keep it insulated and suspended.

[Snakeoil]

Yup, I agree, stages would be the way to go. Do each side of the tunnel separately, then the sides, then the top of the tunnel. Toughest would be the top of the tank since you would have to invert it and maintain the cathode suspended above it, Probaby running a stiff copper wire thru a hole in a rubber stopper would be a good way.

Or, we could all stop acting like Mr. Wizard and just line the damn thing like everyone else does :-)

regards,
Rob

[Wilf]

Rob,

I am relieved to read your report! With respect to the sugar, I have read that it serves as a 'brightener', but was never sure whether that term refered to the brightness of the finish or was plating jargon with a different meaning. I tried making an electrolyte without the sugar and could not see a significant difference in brightness. The syrup you made may well have slowed the process down, but I have no way of confirming that.

When I start a new batch of electrolyte I put the zinc in the solution the night before so that the next morning the solution is loaded with zinc ions and the plating doesn't take so long. Keep in mind that the larger the surface areas of zinc and part, the more current needed to do the job in a given amount of time. Unless you have an adjustable power supply capable of handling the power requirement, larger pieces such as your spacer will just take longer. When I plate reeally small parts like #6 washers and nuts, I put a couple of power rectifier diodes in the supply line to drop the voltage (and thus the current) to prevent them from plating too fast which leaves a lumpy, crusty, black finish that doesn't always bond well to the steel.

Your set-up looks totally practicable, and you're getting good results.

And, yes, it is line-of-sight, so multiple parts will mask each other. I often interupt the process several times to rotate parts for a more even coating. (Turn off the power, or you risk a short!) Also, areas closest to the zinc will be more heavily plated than those farther away (law of inverse squares).

Wilf

[Snakeoil]

Wilf,

Today's experience bears out your comments. The bath was now loaded with zinc from the day before so things went much faster.

In my research, I found that the brightener causes the zinc to plate out with smaller a smaller crystal size than if you did not use a brightener. It's cheap enough so might as well use it.

First part I did today came out much brighter. Instead of an iridescent blue/gray color out of the bath, it was more of a chalky light gray, almost white. When I hit it with the brass brush it shined up much better than the parts done yesterday.

Today I made a second rig for doing IDs of bushings and such. I'm going the front axel nut right now, plus a bunch of other parts. I have to do down and move them around so they get evenly plated. The new righ uses a 9V charger with a 200 ma limit. So I have another adjustable pot in the circuit. I went to Harbor Freight to get another cheap DMM and they had their good DMM on sale for $19.99 and I had my wallet full of 20% off coupons, so I got that one. Hard to believe how cheap these have become. My old Fluke cost about $400 when it was new back in the 80's.

This process is working out great! I cannot tell you all how please I am with the results. The 9V system seemed to work fine as long as I kept the current below the charger's limit.

regards,
Rob

[zoom]

Snakeoil what do you mean: "The final surface was kind of an iridescent blue/gray color that when carded became a bright shiny silver." What is "carded"? I am a newbe to this.

So what was the final recipe of the elctro solution?

What is the difference (obviously cost and ease of getting the chemicals) in electrolight solutions (like yours and the one that was posted in the classic motorcycle link, that I provided earlier in this thread)?
Do you think one will produce a shinier surface?

[Wilf]

zoom,

The recipe in the link calls for zinc chloride and ammonium chloride, rubber gloves...I don't really like the idea of ammonium or chlorine compounds in an electrolyte. Something about the possiblilty of ammonia and chlorine gases scare me.

The recipe I use has easily obtainable ingredients and you can soak your bare hands in it if you like. The only gases given off would be hydrogen and oxygen, but with the small surface areas we're dealing with, there is very little danger of creating an explosive mix under normal room ventilation. It's simple, cheap, works very nicely for my needs, is completely non-toxic and pretty much harmless.

Rob,

That's a useful observation with respect the sugar and brightness--I might want to do some control tests on that.

With the two potentiometers in your 9 volt set-up, you are basically using a voltage divider. It would be interesting to know what the voltage at the anode is while plating with a 200 mA current.
That might make it easier for others to cobble together power sources for their needs.

Wilf

[Snakeoil]

Wilf,

Based on the results of plating with a small 2.9 volt charger and with a similar charger rated at 9V, I suspect that the voltage does not make a lot of difference. I think it is the current that is king here. Both these have a 200-250 ma limit and I control to something lower than that and check the charger to see if it is hot or warm to the touch. The 2.9V was hot until I put the pot in the circuit. If you use a more powerful x-fmr like from a train set, then my guess is the current could be higher and that could make a change in the plating quality. The plating kit I bought years ago to do gold could be done using dry cells. I tried a slot car x-fmr I had and it make the gold blotchy and dark. I need to dig out the instructions because I remember them saying something about either the voltage or the current causing this.

In case it has not been clear, the chargers I'm using are the small molded transformers that have wall outlet prongs coming out of them and plug directlty into a wall outlet. They are typical for charging cell phones, RC batteries, small hand tools with non-replaceable batteries, etc..

By the way, I tried to light the gasses coming off the bath. I held a butane BBQ lighter right over the bath with it bubbling and nothing. Not even a change in the flame. H2 dissapates in air very quickly and I don't think there is enough O2 to make a difference.

Zoom, go back and read the entire thread and the referenced thread in this thread and you will find all the info. I would also suggest you Google Zinc Plating because there is good background info to be found.

Another observation is pits do not like to plate. The center drill hole in my front axel did not plate all the way to the bottom. There were also some deep (a few thou) pits on one part of the axel nut that would not plate and remained dark. None of this can be seen and to protect those areas, I'll just put some silver paint on them and wipe it off to fill the pits. It could be that I did not get those pits clean enough or there was still some rust in them. Might bead blast those areas and replate to see if they will then plate.

All in all, I'm extremely pleased with the outcome of this science project. I plated stuff until after midnight while I watched Pearl Harbor and Saving Pvt. Ryan on the tube last night. Today I did some small fasteners in the tank. Castle nuts, speciality bolts, and such that are not easily obtained. I forgot about them as I was working and left them in for about 3 hours. They plated fine, but the surface was a little lumpy and there were little pieces of black grit all over them and the suspending wires. I think it might be the black gunk from the cathodes precipitating out of the bath. It rubs right off, so creates no problems. I think I'll scrub the cathodes today and filter the bath to see if it makes a difference.

I also learned that you can zinc plate stainless steel. Would have thought not, but the stainless wire I'm using is all plated.

Now that I know how good this works, I'm pissed that I just finished putting the swingarm back together and have it all greased. I'm going to pull it off again to plate the head of the pivot bolt, castle nut and the two end plates. Pivot bolt is full of grease. Might just tape off the holes and cross my fingers.
regards,
Rob