Black rust

kai · 21st April 2010, 11:00 PM

Hello Heinz,

Truth is, there will always be a bit of corrosion when placing iron/steel into acids - not that much of an issue with keris though if you're working with well diluted acids. Still, it's advisable to keep the exposure as short as possible by regularly checking the progress and frequently brushing the blade. The degreasing step should be done very carefully so that the acid can work evenly across the whole blade; also scraping thick deposits of rust/gunk off the blade with something safe like a piece of hardwood will help.

Pinapple juice works nicely and is supposed to be the gentlest of the fruit acids. If you have to work indoors with prolonged soaking times, the odors of the aged fluid may be a bit of a challenge though.

The advantage of acetic acid (vinegar) is that it is also acting as a vapor which seems to help reaching into crevices and loosening up tougher deposits. The active ingredient of several traditional cleaning solutions (like coconut "water") is acetic acid, too. Household acetic acid usually has about 10% strength while kitchen vinegar is around 4%. Check with the label and dilute to 0.5-1% for a start and go from there.

Regards,
Kai

21st April 2010, 11:00 PM	#14
kai Member Join Date: Apr 2005 Posts: 3,255	Hello Heinz, Truth is, there will always be a bit of corrosion when placing iron/steel into acids - not that much of an issue with keris though if you're working with well diluted acids. Still, it's advisable to keep the exposure as short as possible by regularly checking the progress and frequently brushing the blade. The degreasing step should be done very carefully so that the acid can work evenly across the whole blade; also scraping thick deposits of rust/gunk off the blade with something safe like a piece of hardwood will help. Pinapple juice works nicely and is supposed to be the gentlest of the fruit acids. If you have to work indoors with prolonged soaking times, the odors of the aged fluid may be a bit of a challenge though. The advantage of acetic acid (vinegar) is that it is also acting as a vapor which seems to help reaching into crevices and loosening up tougher deposits. The active ingredient of several traditional cleaning solutions (like coconut "water") is acetic acid, too. Household acetic acid usually has about 10% strength while kitchen vinegar is around 4%. Check with the label and dilute to 0.5-1% for a start and go from there. Regards, Kai