Copper Care : Rust and Patina

[Nays_Shine]

I have come to realise that I missed a couple of important facts regarding patina and rust when researching and building my still. I never really understood the importance of forming a good patina to prevent ongoing rust ; how you maintain a patina; and why you should neutralise copper after soaking it in acid!

First Mistake:
After my build I got everything really clean and super polished by soaking in vinegar, sanding with 1000 grit sand paper and polishing with 0000 steel wool. It looked beautifully shiny and bright. My mistake was not (probably straight after the vinegar cleaning run) soaking everything in a baking soda / water mixture so as to neutralise the acid. I think this is why I always have to spend a lot time trying to clean red coloured oxide, which forms on the inside of my still. If I rub a damp white coloured cloth on the inside of the still, the cloth becomes quite red.

Second Mistake:
I thought the oxide issue could be resolved by soaking my copper in the back set after each run, as a method of cleaning. Again, I would not use anything to neutralise the acid after these soaks. Let’s just say that, after doing this four or five times, my copper mesh packing has now almost completely dissolved!

Third Mistake:
Not realising the importance of establishing a good patina on copper; and ensuring that once established, this patina is cared for and maintained.

Result:
I am currently spending a couple of hours before and after each run, trying to clean all traces of red oxide from my still. By the end of a long run, a fair bit of red oxide has reformed.

What I should have Done:
I think that after the initial cleaning or sacrificial run; I probably should have:
1) applied the baking soda treatment (what ratio of water to baking soda should I have used?)
2) cleaned everything in (distilled?) water (or heads?) using a soft brush (no soap or chemicals)
3) quickly dried it off using a clean cloth or hair dryer
4) put it in the oven on 150oC for 30 minutes (I heard that this aides the patina process)
5) put all of the copper in the cupboard and left it there for a month (seriously), to allow a patina to form
6) only ever used water and a soft brush for cleaning
7) avoid use of anything that will mechanically or chemically scratch or remove the patina

Question: How do I get rid of the rust and form a good patina?
I am thinking that the best thing to do now is to:
1) soak everything (except for my new Mac packing, which seems to be ok) in a mild vinegar / water solution for a day or two, so as to remove any traces of oxide
2) then follow steps 1-7 from above

Please let me know if you think that this information is factual or not; and if you have any better tips or advice on copper care.

Happy distilling over the Chrissy break!

[scythe]

Probably all you need to do is neutralize the still after the acid wash.
Then just rinse the stull after each use in water.

Also i would advise against using 0000 steel wool on copper for the same reason you dont use it on stainless, it will get impregnated into the copper and cause the red oxide issue you have.

[warramungas]

Dunno. Never, and I mean never cleaned mine since the first cleaning run some 15 years ago. Never seems to get any dirtier. Just always give it a good rinse in hot water everytime I've finished with it. It dries quicker that way. Never acid washed.
It'll never win any beauty contests but I don't display it.
If you're asking how to keep it nice and shiny permanently I'm not even sure that's possible without regular applications of elbow grease.
As for the copper oxide, unless it excessive or in the product stream causing off flavours just rub it off with a soft cloth. It'll settle down eventually. If its in your column its not soluble (in etoh) so shouldn't carry in the vapour.
Don't try an keep neutralizing. Remember that old adage your parents told you. If you keep picking at it it'll never get better.

[AndyCapp]

The patina you are seeking is in fact made up of the oxides and carbonates that you are so furiously removing all the time. You just need to ease up on the rubbing and acid washes and let it form. Rinse the still with water after use, let it drain well and dry and the surface will darken up as you desire.

An acid wash is only required if things get really manky. In 30 years I have only resorted to it a few times, usually when refurbishing a long unused kit.

[Nays_Shine]

Thanks a lot people.

Scythe: 0000 getting impregnated in the copper - that is something I would never have thought of! I had a bunch of it wrapped around some dowel. I plugged into my power drill and honed the shit out of my column. Its going to be good and impregnated now! Crap. How do I get it out?

Andycapp and warramungas: I'm currently running my still for the 42nd time this year; so probably time to give it a bit of a break anyway! Seems that if I just leave it for a while the patina might form eventually? Some of the copper has a nice patina,so yeah; I guess just let it do its thing and be patient. Assuming the steel wool thing isn't an issue of course (I just checked the package and it appears that i was in fact using grade 1)!

Its very reassuring to hear that the red oxide isn't alcohol soluble and probably wont be getting into my drink.

[Nays_Shine]

"If you keep picking at it it'll never get better."

It took me a couple of reads to get this. Ive got it now! Quite relevant! Haha. :)

[warramungas]

You can give the loose reddish rust a wipe off with a soft cloth. Don't try and buff it out though. That red stuffs not the patina. Just loose Cu oxide.

[Nays_Shine]

I have noticed after this latest run that the oils from the tails (I ran late into tails as an experiment to see what would happen) has put a nice coating over everything. It does not have an unpleasant smell (the last batch already had 1x strip and 1x reflux run prior to been put through for a 2nd reflux), so I am happy that this will provide a protective coating until I use it next; and may add to the patina. I figure if any off flavours were to come out from this next time I use it, they would all be out by the time heads has completed anyway, so wont affect my hearts cut.

What I am taking from your replies on this post is that I should be patient (rather than concerned) and sooner or later a good patina will form. Once that happens, I will no longer get the reddish copper oxide forming. Even if I do, its not soluble in alcohol anyway. In the meantime, it is ok to wipe the red stuff off, but not vigorously. I have been using a soft bottle brush attached to a power drill (no soap). Maybe this is too abrasive? I think Im done distilling for a month or two anyway, so Ill just wait and see what happens.

Thanks again for everyone's input.