Copper / Brass Oxidation? - Page 2

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yooncs (original poster)

#11: Post by yooncs (original poster) »

Then is leaving it as is the best solution? I'm sure descaler and copper cleaner are safe as I rinse the parts throughly.

decaf_Ed

#12: Post by decaf_Ed »

timo888 wrote:Acid (e.g. from descaling solutions) causes copper to turn pink, as Jeepin' Geo described.
This could be somewhat disturbing. :? Does this mean that the scaling I've been scrubbing off my sinks and tubs all these years is actually the insides of my copper pipes? :cry:
-Ed

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HB
Admin

#13: Post by HB »

Are you using well water? In our area, well water has very high iron content. North Carolina is well known for hard clay, which contributes to turbidity and leads to pinkish / orangish deposits around water fixtures.
Dan Kehn

decaf_Ed

#14: Post by decaf_Ed »

I'm on city water plus a water softener (even the drinking water goes through the water softener). The film near my faucets doesn't build up very fast (not like when I was on well water years ago), and it takes quite a few months before I begin to notice it. But it's about the same color as yooncs' parts. I haven't yet opened up anything large inside my Expobar to see what color is inside.
-Ed

yooncs (original poster)

#15: Post by yooncs (original poster) »

I soaked parts in descaler and was able to remove those pink scales. Thanks for the help! The previous owner is in WA, and water there must have high iron content I assume.

One last problem I'm having is that I soaked copper / brass parts along with stainless steel parts, and stainless steel turned copper color. :shock: Is there a way to turn them back to what they were? Do you think it is just cosmetic or is there any safety issue?

frogsickle

#16: Post by frogsickle »

I'm in the same boat. I soaked my copper tubes, brass fittings and chrome (nickel? Stainless?) boiler in citric acid. The end effect was that all parts turned pinkish. It was as if the brass and Stainless were electroplated with copper, or something. (Yes, I'm the result of public education.) Anyway, my concern is that, besides it looking strange for everything to be pinkish, my health could be at risk? Any biochemists in the audience?

alain

#17: Post by alain »

Do you drink 7up or pepsi once a while? Most of it is citric acid! It is non toxic. One thing you could do to neutralize the acid, is simply to let all your parts bathes in a coffee cleaner such as Cafiza for a while. Citric acid has a strong tendancy to remove the plated Nickel, use a coffee cleaner with very hot water for those parts. Pink is a good sign, green or black are more problematic.

LordFoo

#18: Post by LordFoo »

I can't find the link, but there was a discussion within the last year about chrome flaking off when using a Cafiza "chaser" after descaling (with citric acid) chrome parts. This happened to my E61 mushroom -- not sure if it is due to the aggressive chemical reaction, or just the fact that the chrome wanted to stick to the scale more than the copper, but be careful/aware.

alain

#19: Post by alain »

I think that it is the scale attaching itself to the nickel (chrome is toxic) in your E61 'mushroom', and when trying to remove the scale, you also remove the nickel, but citric acid is aggressive enough to 'eat' the nickel, a coffee cleaner is much less aggressive, or go and try with 7up. If you want to avoid all these problems, just buy a good water filtering device.

Ben Z.

#20: Post by Ben Z. »

I'm not sure the exact chemical reactions, but when you have a few different metals in a bath, strange things can happen. I am almost certain you are seeing the deposition of pure copper (basically electroless plating) on your parts, especially the stainless. On the brass, it could also be that the acid solution preferentially disolves the zinc, leaving pure copper behind. Sometimes, the copper-containing corrosion products may be more soluable than the metal, so they go into solution off your tubing, disociate, and then the Cu redeposits on the brass and stainless. If the pH of the solution changes during the descale operation (of course, it would) then I could easily see some chemicals going from soluble to insoluble. In short, I kind of doubt this is oxidation.