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4GSR
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Here's what I use.
http://www.brownells.com/gunsmith-t...-chemicals/oxpho-blue--prod1072.aspx?psize=96
This is also sold by Birchwood Technologies under the name "Presto- Black". Used to be called "Tool Black" and may still be called that when bought at certain tool houses that would carry the stuff.
https://www.birchwoodtechnologies.com/store/Room-Temperature-Blackening-for-Iron-and-Steel.html
A couple of things to remember, degrease the parts. I go borrow a little Dawn dish washing soap from the kitchen. Use hot water to wash and rinse the parts off with. Do this wearing HF disposable gloves so you don't get finger prints on the parts from your oily hands. While the part is still fairly warm, head for the garage and start to applying the blackening solution using shotgun bore wipes or cotton balls. It should turn black instantly. After about 20 minutes, wipe off parts with paper towels and oil. DO USE WD-40! Steels with a high Chrome content may not coat evenly or coat at all. I've had this to happen, too. High hardness with high Chrome content like in some of the 4140-4145, 4340 materials may not coat very good. Heat in the parts does help, say 180-220 degrees F. Just a few pointers I've experienced in the past using this stuff.
Until about six months ago, I had a local source that did manganese phosphate coating which we use extensively for down oilfield equipment. What little stuff I needed done, they would do it for me. In exchange, I usually ground up special cutting tools for them in trade.
Ken
http://www.brownells.com/gunsmith-t...-chemicals/oxpho-blue--prod1072.aspx?psize=96
This is also sold by Birchwood Technologies under the name "Presto- Black". Used to be called "Tool Black" and may still be called that when bought at certain tool houses that would carry the stuff.
https://www.birchwoodtechnologies.com/store/Room-Temperature-Blackening-for-Iron-and-Steel.html
A couple of things to remember, degrease the parts. I go borrow a little Dawn dish washing soap from the kitchen. Use hot water to wash and rinse the parts off with. Do this wearing HF disposable gloves so you don't get finger prints on the parts from your oily hands. While the part is still fairly warm, head for the garage and start to applying the blackening solution using shotgun bore wipes or cotton balls. It should turn black instantly. After about 20 minutes, wipe off parts with paper towels and oil. DO USE WD-40! Steels with a high Chrome content may not coat evenly or coat at all. I've had this to happen, too. High hardness with high Chrome content like in some of the 4140-4145, 4340 materials may not coat very good. Heat in the parts does help, say 180-220 degrees F. Just a few pointers I've experienced in the past using this stuff.
Until about six months ago, I had a local source that did manganese phosphate coating which we use extensively for down oilfield equipment. What little stuff I needed done, they would do it for me. In exchange, I usually ground up special cutting tools for them in trade.
Ken
