Can't get rust blue right

[oldred]

I have for the last few days been trying to rust blue my custom built Highwall receiver but it has been little more than exercise an  in frustration! Fortunately most of my attempts were on scrap pieces of the same material the receiver was machined from but I just spent (wasted actually) all day making a mess that will have to be sanded off tomorrow. I am using Mark Lee Express Blue and the receiver is 4140HT steel, every attempt has resulted in a brownish/Copper colored surface that undergoes almost no change in color when boiled. It does have the soft coating after boiling that must be carded off but this coating is more brown than black, I followed the directions to the letter and then after failure I decided to experiment on the scrap pieces. I tried various surface temperatures and both light and heavy applications but the results were mostly the same regardless, the hotter the surface the darker the brown coating but it looked more like stain than rust- regardless it would not turn black when boiled in distilled water. Any ideas here before I just give up?


BTW, I honestly don't believe it's the fault of the Mark Lee solution because a search on the net brings up many satisfied users and nothing but success stories with not a single failure that I could find. 

[jhm]

     Before I went any further I would contact the manufacturer and msee what they say, I have no experience with those types of blueing but I have a friend who is always playing around with various types of blueing and he demostrates mvarious stages of anger also.  Jim

[quickdtoo]

I've done a couple barrels in Belgian Blue which sounds similar to Express Blue, the first cycle of boiling and carding sounds very similar,  it takes about a dozen repeat cycles to achieve a nice finish, each cycle getting a little darker, I use the boiling water tank to heat the barrel and card with degreased #0000 steelwool. They finished looking outstanding! 

Tim

[gunnut69]

All rust blues, that I'm familiar with, require multiple coats to achieve the final finish...

[oldred]

Since I posted this I have determined the problem to be the 4140 HT steel, I coated a piece of this material just as I would a gun part and placed it in a sweat box for over 18 hours with almost no rust appearing except for what looked more like a brown stain. The repeated rust/boil/carding sessions did produce a darker color but nothing I could do would produce anything except for a mottled mess, this morning I contacted a professional refinisher at a large gunshop and I will have this thing done there.