Pickle keeps turning blue!
(Key West, Florida)
Hello and help! I'm so frustrated... my pickle keeps turning blue, even when it's new. I keep re-making it, and have 2 pickle-pots: one with Sparex, and one with vinegar/salt, and I use bottled distilled water. They BOTH turn blue within a week, even the one dedicated to silver only! I live on a houseboat in key west, Florida and am beginning to think that it may be the atmosphere. if I try to pickle brass or bronze, they often become copper coated, or turn a yicky black-ish color that needs to be filed off. do you have any ideas about the cause/cure?
No worries Svetlana. Take a deep breath! The pickle turning blue is completely normal. The acid solutions absorb copper oxides from non-ferrous metals like copper or those containing copper, turning them blue. The more copper - the bluer the solution. For this reason, many folks use two pots - one for copper and it's alloys and the other for silver. As Sterling silver only has a small amount of copper, the rate of absorption is much slower. The blue color will not harm the non-ferrous metals you put in it unless you also introduce steel to the pot, then you'll start plating whatever's in there with copper.
The only time you need to change out your pickling solutions is when they are either not working quickly or if they become compromised with a ferrous metal which as I mentioned, will plate anything put in it with copper.
As to the pink copper "plating" you're seeing on your brass and bronze, yes, after heating and then pickling, they will get a layer of copper oxides on the surface, much like silver would do if you had steel in the pot at the same time. This is a very easy fix! Once you're all done with the heat, put the pieces in a super pickle. Here's how.
Mix 3 parts white vinegar with 2 part hydrogen peroxide in a glass or plastic dish. You do not need to heat this solution as it works just fine at room temperature. Place the copper oxide-plated non-ferrous metal (gold, brass, silver, etc) in the solution. Make sure there is enough of the solution so that the metal items are completely submerged. It takes about 10-15 minutes or so for the metal item to be restored back to it's original color, free of a copper coating. You may want to wipe the item during the soaking and then place it back in the mixture.
As the super pickle works, you'll see tiny bubbles rising from the metal and the solutions turns..........yep. Blue! Works like a charm with no buffing necessary! HOWEVER, never leave the metal for longer than say 30 minutes in the solution as the super pickle will damage the structural integrity of the metal if exposed for too long in it. Rinse with clean water and proceed with your finishing technique for the piece.
Another thing important for you to know is that the super pickle will not remove torch residue from the metal. You must first cleanse the dirty metal in the regular hot pickle and then use the super pickle only for removing the pick copper oxides.
While our humid, hot and salty Florida atmosphere is very hard on metals - especially those containing copper - I hope you are glad to know you won't have to be relocating your houseboat any time soon!