Removing anodized color with Multi-Etch
Removing color with Multi-Etch works much faster when the Multi-Etch is heated 150–160°F.
If you simply went past the target color you can dip the piece in heated Multi-Etch and it will work backward through the colors. Be sure to rinse as soon as you see the color you want.
If the color is uneven and you want to start over, etch time will be longer than when you etched the raw metal. Just keep etching until the color disappears.
Etch times for erasing high voltage colors will be longer than erasing low voltage colors.
For regular strength heated Multi-Etch, removing high voltage colors will take from 30 seconds to 2 minutes.
For double strength room temperature Multi-Etch (that has previously been heated 120–150°F one time), erasing high voltage colors will take 6–40 minutes depending on the titanium grade (see the titanium etch rates page for specific times). The time can be reduced in unused double-strength solution that is at least several months old.
Room temperature Multi-Etch, even if it has been heated one time, will take days to remove color from niobium.