Posted by Alex C on February 12, 2004 at 15:37:37:
In Reply to: Tarnish problem on Kalison DS CC posted by Mike on February 11, 2004 at 22:50:08:
I'm going to guess you have acid leak. When the instrument is soldered together, flux is used to make the solder flow. If the tuba, particularly at the joint, is not properly cleaned, acid remains and can ruin the finish.
It's most common at the joints but I've had residual acid on the tubing which affected the finish. It makes silver flake, almost feels like sandpaper.
It's a guess...