j a you must have been down this road before....charlie

The color of Nitre Blue is completely dependent on the temp that the salts are at.

Most think of Nitre blue as being the royal blue colors that are found in some applications where it is used.
However, near Black colors can be had at much higher temps. 830 degrees is the target temp for jet Black color. I have had a pretty hard time getting my salts anywhere near that temp, but I get very good results at 725-750 degrees. See the photos below of a VH that I Nitre blued the triggers and trigger guard on.

Brownells will tell you that you cannot heat the salts that high as it will ruin them. This is fake news as they say. I have been using the same pot of Brownells salts for years and evrytime they get heated up, they go up to those high temps.

Attachment 61589

Attachment 61590

I get the dark blue at less temperature by constantly watching the part. No matter what the temperature of the nitre salts, the part will not reach that temperature instantly, so as it changes colors I quit when it is what I desired. Yes I have had Barney purple colored trigger guards and had to start over because I pulled them too soon. But I admit to being an amateur.

Thanks J.A.; sounds like you have been there , done that. Is it reasonable to assume that standard commercially available salt will produce the appropriate color on a Parker trigger guard ? Can you start at say 570 and increase the temp to get the right color or should you start at a specific temperature ? How much material does it take to do one trigger guard and a set of screws ? Do you have specific recommendations as what to use at what temperature for how long ? Unfortunately, I don't have the where with all to attempt this myself, but would like to be able to discuss it somewhat intelligently with some one who can. Thanks again; I am just trying to educate myself.

Thanks J. A. looks like you have been there , done that. Do you have recommendations for what to use , at what temperature , for how long to get the appropriate color on a Parker trigger guard and screw set ? Are all commercially available products the same? can you start at a lower temp and increase until you get the color or should you start at a specific temp. ? How much material does it take to do one guard and screw set? Unfortunately, I do not have the where with all to attempt this , but want to be able to discuss it intelligently with some one who can. Just trying to educate myself. Thanks again, Bill.

My apologies! I got lost trying to post . Dah!! Ok so what color is the trigger guard supposed to be? If it should be black, can you not get the correct color using slow rust bluing process ? I guess that gives me away as some one who has never actually seen an original in pristine condition. Some pictures appear to be a deep royal almost black/ blue, and of a much higher polish; yes? no?.

Black with a tinge of blue to it in the light is correct. Nitre is how Parker originally finished them.

Rust blue will of course give you a black, but rust bluing small parts like guards, triggers and screws is a pain in the butt. It is much easier to hang them in the salts for a while and pull them out.

I quench in water immediately then dry and put into motor oil for 24 hours.

Brian who is in the business of restoring these guns would be your best bet. He is the professional, I am not as I wrote. If you send the parts to him when he gets around to doing a batch you will not be disappointed. Unless you are going to do a lot of them the time and effort to get set up (Brownells salts, stainless tub, propane burner, tongs, etc.) would not be financially worth it. It is also not a safe operation as you are dealing with hot chemicals where a mistake will put you in the intensive care/burn department.

As Brian wrote about using a higher temperature, you need to start higher than what the chart calls for. Even though it shows to be in the high 500s, like Brian I have to be over 600 degrees to get the correct colors.

One more question. Should the cross bolt be blued or hardened, for wear ?

Cross bolt?