View Full Version : Turning red rust into black oxide

05-23-2009, 10:26 PM
Someone once told me how to turn red rust into black oxide. Trouble is I do not remember who or how. Any one care to share their secrets? Gary P. Hansen

05-23-2009, 10:43 PM
Phosphoric acid. You can buy it at a greenhouse supply for the best price. Same stuff that is in Coca Cola but stronger.

05-24-2009, 12:07 AM
The esay way is to Walmart or your hardware store and buy the stuff called rust converter.Yes that is the name

05-24-2009, 05:31 AM
Boil. No i am not calling you names.
The old fashioned way of browning was done by controlled rusting and carding.
This brown layer can be converted to black by boiling.
Lots of work for a quality layer but everlasting and fun to do.

05-24-2009, 05:52 AM
The full black oxide process is available in the reference section of my web site.


05-24-2009, 03:09 PM
to convert a rusted surface to black you need to boil in water, then card off the loose stuff.

Gunsmiths call this rust bluing. several cycles are needed for good results, using a browning or rusting solution to cause the rusting.

05-24-2009, 04:26 PM
The process i described is called rust blueing.
The proces Evan described is called hot blueing and there is something to add.
The enamel will desolve in the lye when hot. Not sure what is better to use.
Store the mix airtight as the co2 will desolve in the mix after some time and render it useless.
There are a few other types of hotblueing as good for your health as this one

05-24-2009, 04:59 PM
The process on my web site describes hot bluing but that isn't what I referred to initially. A soak in phosphoric acid will turn all the red oxide to black. You can either heat it to fix it or just scrub it off to remove it.