Triumphrat

Snakeoil

As I have always understood it, electro-plating is a line-of-sight process. So that means you get better plating on the side that faces the electrode.

Based on that, I make my zinc electrode circular so that it totally surrounded the piece being plated. I even put a strip across the bottom, which I've since abandoned when I replaced my first zinc electrodes after they were pretty much depleted.

So, I cannot tell you how having 4 equally spaced electrodes will work. But my guess is it will work better than a single plate.

Don't forget to charge your electrolyte with zinc by either putting pieces of zinc in the jug of electrolyte over night or just leaving the solution in you set-up overnight. This will give you better results right off the bat.

Since you are in the UK, I would think that mold is a pretty common problem on house roofing. The product I use is a zinc sheet metal product. Here is a link to one of the products available here in the US. This is not the same brand that I use, but they are all the same from a zinc content point of view. Nearly 100% pure.

http://www.z-stop.com/

Last night, I took all my handing wires/hook, which were heavily plated with zinc from doing two bikes, and put them in a container of vinegar and left them overnight. I just went down to check and they are all zinc free now. Plus that zinc charged that batch of vinegar for use when it comes time to make new electrolyte.

I cannot speak to your chemical question. What I use works for me and is dirt cheapm So, if it ain't broke, I don't fix it.

regards,
Rob

ed_h

Acebars--

The process I use is based on zinc chloride. It's the only one I've ever used, so I don't know that it works better any of the other formulas. The chloride may be a little trickier to get than the ingredients in Rob's bath.

One small advantage is that the zinc chloride bath by definition comes pre-charged with zinc.

I use two cast zinc marine galvanic protectors for anodes. They are about 3 x 4 x 1/2 inches, and come with an embedded copper wire. It can pay to try to use fairly pure zinc anodes, as the bath can get contaminated with impurities in the anodes, notably copper and iron.

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Acebars

I can get zinc chloride quite cheaply 500g for less than £5.

Have you been successful using only two anodes? If this is the case I'd prefer to go with the pure yacht rods as 1.5 kilo will probably last me a life time. But then again perhaps 700g plate will be enough.

Ed couple of questions if you don't mind are you using a straight zinc chloride solution? Likewise are you adding sugar and how many parts per litre are you doing it with?

I got an A in A-level chemistry but it was so long ago I can't remember anything, but according to my basic ionic equation it should work?

Yea you maybe right, I may stick to this method as I have all the ingredients and they seem fairly safe materials to work with.

Snakeoil

One of the reasons you use Epsom salts instead common table salt, which would work just as well, is because the electrolysis process would cause the solution with table salt to release chlorine gas, or so I've been told. Given that is is NaCl, I can see that happening. Epsom salts are MgSO4.

Chlorine gas + plating set-up in the basement = dead plater.

regards,
Rob

Acebars

Hi Rob,

Yea I did think about that, thats why I also mentioned Zinc Sulphate also at £5 for 500g

ZnSO4 might just be very nice to use.

I'll start with the MgSO4 and then do some testing and report back.

ed_h

Acebars--

Yes, an anode at each end of the bath seems to work well. I do sometimes rotate the part by 90 degrees during the run, but when I forget to do it, parts still seem to come out fine.

My bath is zinc chloride and ammonium chloride. It's called an acid chloride bath (even though there is no acid added), and Google will turn up a lot of info on it. I add a small amount of gelatin, which is supposed to give finer grain (don't know--never tried without it).

These baths don't give off chlorine. Chlorine much prefers to be ions in solution rather than a gas. There will be small amounts of hydrogen and oxygen, but I believe this is true no matter what the chemistry.

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Snakeoil

That's interesting Ed. I've read in more than one article that chlorine is a risk when using the wrong electrolyte. Glad to hear it is another urban legend.

regards,
Rob

Acebars

Ed I think what you are making by mixing those two is Zinc Ammonium Chloride which is common in electroplating, although I'm having difficulty getting my chemistry exactly right I believe it will look like something like this in solution.

NH4+ + Zn2+ + 3CL-

As you make chlorine gas during electrolysis this will also readily dissolve in a reversible reaction with the solution as chloride ions, making the solution more and more acidic effectively making Hydrochloric acid and I can only imagine with prolonged use you will be making it very acidic.

All electrolysis creates either alkali or acidic electrolyte eventually. But this one is very chloride heavy which is my concern for home use.

Snakeoil

Break out your sliderules, boys. We got ourselves a chemistry war!!

Who'd thunk a bunch of knuckle draggin' motorcicle riders would be posting chemistry equations on the internet someday?

Somebody write this date down. This is living history.

regards,
Rob

ed_h

Don't really want to turn this into a chemistry discussion as Snakeoil fears--we're probably the last three staying with this thread anyway.

There is plenty that still isn't understood in electrochemistry, but the acid chloride zinc process has been studied quite a bit. The main reason for the ammonium chloride is to buffer the solution to stabilize pH. I use the solutions for a long time--a year some times, and PH doesn't vary much. When I do discard a bath it's usually because of a buildup of some contaminant, like iron. There are ways to chemically get the iron and other impurities out, but starting over is sometimes easier.

Other than impurities and contaminants, the only thing entering the process is zinc metal from the anodes, and the only thing leaving is roughly the same amount of zinc metal on the plated article. Other than that, it is a little hydrogen and oxygen, and some evaporation, both of which are compensated for by adding water.

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