Green Patina = "Var Degree" = poison ??????

[Oxbo Rene]

I was watching this young man's video on making a copper plate and he states that the green patina that forms on copper (verdigris) is poisonous,
and thus the copper needs to be coated with tin before consuming anything that has been in contact with it.
http://www.youtube.com/watch?v=VGqv47-Q ... 3JY0OM3f5w" onclick="window.open(this.href);return false;" rel="nofollow
I was just wondering about it and perhaps someone here would care to comment about this subject, especially as it pertains to copper still inards etc, etc ...
He starts talking about it at Min # 1:12 .................
The video sometimes starts out past this minute mark so ya might have to grab the slider and drag it back to before min # 1:12
Tx's

[Butterman]

Copper pipes have been used to supply water for many many decades and possibly even up to and past 100 years in some cities, let alone the thousands of years its been used for drinking vessels. Ive demolished lots of building and torn out alot of the copper in old building and most if not all the copper Ive torn out all had a green patina on the inside. So just form my empirical evidence I would consider it safe, tried and true.
On a side note my still does not build up any green patina on the inside.

Butterman

PS its kinda of interesting video, I sure do like his shear :>

[MDH]

The patina is copper hydroxide. Just react it with citric acid solution. Don't discard the blue liquid resulting from it, it's useful.

[Oxbo Rene]

This is a little more I came up with --->
http://en.wikipedia.org/wiki/Verdigris" onclick="window.open(this.href);return false;" rel="nofollow
"As verdigris consists of various poisonous copper compounds, one should always wash one's hands after handling"
And the dictionary definition -->
http://www.merriam-webster.com/dictionary/verdigris" onclick="window.open(this.href);return false;" rel="nofollow

MDH = It would be kinda nice if you'd elaberate a bit more on the usefullness of the blue liquid .......

[heartcut]

Copper carbonate (the regular fresh water verdigris) is insoluble in water and ethanol.
Copper chloride (the salt water variety) is a little bit soluble in water and/or ethanol but will precipitate as a solid when the liquid evaporates.
Both are toxic to humans, so don't scrape some off and eat it.

[aknewb1s]

The patina is copper hydroxide. Just react it with citric acid solution. Don't discard the blue liquid resulting from it, it's useful.

Useful for what?

[Oxbo Rene]

Yeah, really ! ! ! ! ????

[Gaztops]

I do a lot of metal detecting as a side hobby, and quite few coins of copper and bronze value have verdigris on them. According to the metal detecting fraternity the last thing you should do after handling such an item is to put your fingers near your mouth.

Some call it patina others poison, is it worth the risk. I value the insides of my stomach and don't even eat Indian food let alone green decomposition. I check my pipework from the pot to the liebig for verdigris and do a vinegar still clean out as required.