Any metal finishing folks on here? Zinc table...

Any metal finishing folks on here? Zinc table...

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Original Poster:

3,674 posts

197 months

Saturday 22nd September 2018
quotequote all
I have a zinc top table. The table frame is wonderful, as was the top when I got it. However, over time it has proven to be a very delicate finish.

It was treated with chemical (copper sulphate I think) to patina quickly, so it’s a slate-type finish. The problem is that the patina is easily scratched, and white rust type spots have appeared.

I’m tempted to get a rotating buffer and some fine wet & dry to sand the patina away back to shiny zinc, and do it again myself - and this time spray a clear lacquer on it and apply wax coats to protect it.

Anyone know where to start? Would I be better off sanding by hand/would the electric buffer be too aggressive?

For the solution, does anyone have any idea of the amount of copper sulphate crystals to use in a certain measure of water?

Any hints from those in the know would be well received.

The other option is to replace the top with a reclaimed wooden one which matches the bench we have for it. Again, not sure how plausible that is.

guindilias

5,245 posts

119 months

Saturday 22nd September 2018
quotequote all
An electric orbital sander could give you a great "machined" look, but if you want patina - sand it, put on lemon juice (for the "old" look) or copper sulphate (there are a good few videos on youtube describing it), then wax it, don't lacquer it. Wax can be touched up/repaired if it scratches, lacquer or clear coat will just scratch and need redone.
I assume it isn't a solid zinc top, but zinc-wrapped?
Might be worth checking for solder joints at the corners/underneath - it might be a nice wooden tabletop underneath which you can do what you want with.

guindilias

5,245 posts

119 months

Saturday 22nd September 2018
quotequote all
Also, internet says - "If you are sure that your floor is made of zinc than you can use next formula: 2 heaping teaspoons copper sulphate, 1 heaping teaspoon kitchen salt, 1 cup of water. Dark gray to black finish. Hope it helps and good luck!"

guindilias

5,245 posts

119 months

Saturday 22nd September 2018
quotequote all
And apparently clean the bare zinc with acetone to get an even patina.
I'm getting interested in this myself now!

guindilias

5,245 posts

119 months

Saturday 22nd September 2018
quotequote all
This fella needs an air powered caulk gun - and a cheap source of Sikaflex! https://www.youtube.com/watch?v=4ELO7yIOTbw

guindilias

5,245 posts

119 months

Saturday 22nd September 2018
quotequote all
I really like the look of the sprayed on/speckled patina in this video - https://www.youtube.com/watch?v=nrWukMAIdvw

Has me thinking that rather than replace my old cheapo laminate kitchen worktop, I might just clad it instead...

Testaburger

Original Poster:

3,674 posts

197 months

Saturday 22nd September 2018
quotequote all
guindilias said:
An electric orbital sander could give you a great "machined" look, but if you want patina - sand it, put on lemon juice (for the "old" look) or copper sulphate (there are a good few videos on youtube describing it), then wax it, don't lacquer it. Wax can be touched up/repaired if it scratches, lacquer or clear coat will just scratch and need redone.
I assume it isn't a solid zinc top, but zinc-wrapped?
Might be worth checking for solder joints at the corners/underneath - it might be a nice wooden tabletop underneath which you can do what you want with.
Thanks for that, very helpful. Yes, it’s zinc wrapped around a thick plywood slab.

It’s currently a medium-dark grey. Similar to the wiped/buffed on finish in that video. That’s how I’d like it to come up again ideally. I suspect I’ll try a very dilute solution and reapply if it’s too pale.

Regarding the sander - I’m not going to be using it to finish, but to take the zinc back to shiny from where it is now, before I start again. I’ll keep you posted if you’re interested.

Thanks for the tip regarding wax. The problem is acidic food will probably go through wax quickly, and get to the table so it’ll need doing again.. hence my thinking to do lacquer and a few layers of wax. Still open to persuasion on that.

I think (and I’m usually wrong with this stuff) that I need to sand it (by hand or machine) to shiny, clean with acetone, apply solution, cold water rinse, allow to dry, then protect.

So I need to figure out the best way to sand it (hand or machine with fine wet & dry), work out a decent mild solution and decide on the protection.

That video is pretty good. There’s a few out there. I suppose the benefit of this is that if I’m not happy, I can always start again.

guindilias

5,245 posts

119 months

Saturday 22nd September 2018
quotequote all
Acidic food won't harm wax - it's probably one of the most durable finishes there are in terms of staining, being eroded, etc. And it doesn't long to apply a fresh coat. No, it won't give a lot of protection against dents - but nor will lacquer or pretty much any other finish you can put on zinc and still see the patina.

dickymint

24,089 posts

257 months

Saturday 22nd September 2018
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Zinc or Galv?

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Original Poster:

3,674 posts

197 months

Sunday 23rd September 2018
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guindilias said:
Acidic food won't harm wax - it's probably one of the most durable finishes there are in terms of staining, being eroded, etc. And it doesn't long to apply a fresh coat. No, it won't give a lot of protection against dents - but nor will lacquer or pretty much any other finish you can put on zinc and still see the patina.
Right you are, thanks! I’m making assumptions based on my zero knowledge!

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Original Poster:

3,674 posts

197 months

Sunday 23rd September 2018
quotequote all
dickymint said:
Zinc or Galv?
I assume galvanised, but not entirely sure.