Nitre Blueing

[JDHasty]

Sometimes I get a feeling that when a certain friend is encouraging me to try something new, they are either seeing if they can get me to volunteer to be a Guinea pig or are living vicariously through my experience.

Has anyone successfully used a contraption like this:

https://www.amazon.com/Titanium-Soldering-Stainless-0%C2%B0C-600%C2%B0C-Multi-directional/dp/B0B5GG136Z/ref=sr_1_42?crid=1FOO5138OLLS3&keywords=soldering+furnace&qid=1708205957&sprefix=Soldering+furnace%2Caps%2C351&sr=8-42

And stump remover from Home Depot? Exactly what stump remover granules.

I’m willing to give most anything a try, but not before I solicit input from someone with experience.

I’m not about to use one of my RCBS casting furnaces for any purpose other than casting bullets. Perhaps Harbor Feakshow has a similar small solder pot. They are just a couple blocks away.

[Nobade]

It works for screws and other small parts. Polish the parts out really well first and they come out a brilliant bright blue. You can do the same thing with a propane stove. Be careful and do it outside, any carbon source that hits molten KNO3 will ignite instantly.

[Patrick L]

I'm not sure I understand what you're asking, or what your intentions are.

Are you saying you want to hot blue small parts in a gizmo like this instead of traditional bluing tanks?

I'm just not clear.

[JDHasty]

Not hot salt blue. Nitre blue. I have seen multiple reference to using Lee casting furnace in Gunsmithing books and in magazines over the years, so it sounds reasonable to me to use this small solder furnace. According to my friend who suggested I do this on my own stump removing granules are the same as Nitre bluing salts.

[waksupi]

Nitre is just an element that will carry the heat. Nitre blue is simply heat bluing. I've even done it with a torch.
For small parts, just use lead. Wire your piece to a chunk of wire to get it down in the pot, set the lead temperature, and put the part in. You will have the exact same result.

I did the heat bluing on this one with a torch, came out well, and has worn better than expected after 14 years of use.

https://castboolits.gunloads.com/showthread.php?77646-Transitional-Flintlock

[Shawlerbrook]

I have blued many screws and small parts by heating and then an oil quench.

[john.k]

Yes,nitre blueing uses melted salts..........there is no water ,and any water introduced may well be disasterous.............the mix of nitrates melts at around the same temp as pure lead ,320C,and is useful for similar things such as spring tempering hardened steel.

[deltaenterprizes]

Stump remover from Lowe’s is what I used, it is potassium nitrate, be sure to read the label!
I don’t know what Home Depot has in it!

[Patrick L]

Oh, I see. Never tried that. But I'm with Shawlerbrook, have used the torch/oil quench on screw heads, pins, etc with good results. I've heard that referred to as "fire bluing."