Hot Bluing at home

Barrels and barreled actions

So far, I have never done hot caustic bluing on barrels or barreled actions. However, from what I've read you should blue the barrel as any other part.

Do not plug the barrel when hot blueing/blacking. As the air you've trapped in the barrel heats up the match the 290 degree caustic solution it will expand a lot and it will blow out a plug.

That can make a mess with the caustic solution...

Below a video of a gentleman bluing a barreled action.

[ame]https://www.youtube.com/watch?v=YWqH7YsXHuY[/ame]

Note: the gentleman should be wearing PPE...:rolleyes:

more to come...
 
When hot bluing bbl'd actions or even revolver frames with their bbl attached, there's always the chance that any lube placed on the threads of either part during assembly will liquify and weep out of the joint betw the two.
That'll spoil the bluing right at the joint and if excessive, can run down the parts and cause even further spread of bluing damage.
No bluing at all, streaks, discoloration, ect.
You can have this same problem in Rust Bluing as well.

The other problem with hot salt bluing the bbl'd assemblys as one piece is that they are not a water tight fit in many instances.
During the bluing process, the hot salt soln makes it way into the threaded joint. Most times that salt soln can be washed & rinsed away in the post bluing rinse.
Sometimes not. Sometimes you think you have it all out and there's still some in there. There's no way of seeing it, it looks clear from the outside.

What trips you up is what appears later on. It may be a few days to a few weeks later.
A white bloom growth starts to appear around the joint. That's the dried bluing salts still trapped in the joint (or any parts you have blued).
The bluing salts attract water from the air and start to 'grow'. That's the white growth you see.
It'll keep growing and crawling onto the outside surfaces of the parts. Since it's wet and alkali,,it rusts and pits the steel it's on. The bluing is gone underneath.

If you've been around to shops and gunshows looking at enough reblued guns, especially bolt rifles,,you've probably noticed the problem on more than a few. Usually the white stuff is brushed off and oiled for a better appearance just before sale time. But the spoiled blue and the rust and perhaps pitting around the joint is hard to cover.
M98 Mausers are very prone to it as the shoulder of the bbl does not fit tightly to the front of the action. That allows the soln to get in there very easily. Tough to rinse completely out.

Oiling the stuff won't 'kill' it. It'll just grow back.
Plain boiling water will disolve it and can be rinsed away. That was supposed to happen in the original rinse after bluing, but didn't.

Sometimes a re-rinse can remove it for you, sometimes not.
Usually the finish is damaged and metal pitted already once it's growing on the outside of the parts.
Then it's remove the bbl time. Flush the stuff off.
Repolish and re-blue as separate pieces and reassemble.

The last part is the safest way to avoid the problem in the first place.

>
>added
You're right,,no plugs in the bbl when Hot Salt Bluing.
Totally un-needed and dangerous if done.

Also don't hot salt blue any bbl's or parts with soft soldered (lead) sights, ribs, sling swivel bases, ect attached.
The soln will degrade the lead component of any Lead alloy soft solder. The soldered joint will fail. It may take a few weeks or a few months, but it will break down and fail.
(Ithaca hot-blued the very last run of NID SxS shotgun bbl's in 20 & 16ga's that they made.
Another post war idea of doing things faster.
Then they started to see the soft soldered rib joints fail.
The entire lot of bbl assemblies were scrapped. The guns never re-bbl'd)

Since the soln attacks the lead in soft solders,,the newer (No Lead) Tin/Silver alloy soft solders are supposed to be safe to go through Hot salt Blueing.
I still don't trust them too, but I guess science is not on my side!

Another 'trick' to be able to hot blue soft soldered (lead alloy) joined parts was to add a small amt of potassium cyanide to the bluing soln.
The cyanide salts retards the action of the bluing soln on the lead in the solder.
I've seen that done. I did work for a 'smith that used to do that. He mixed his own salts too. Very proud of himself as a self taught chemist.
I stayed clear of the Bluing Room when picking up and delivering work after that.

I Rust Blue anyway.
 
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2152hq said:
When hot bluing bbl'd actions or even revolver frames with their bbl attached, there's always the chance that any lube placed on the threads of either part during assembly will liquify and weep out of the joint betw the two.
That'll spoil the bluing right at the joint and if excessive, can run down the parts and cause even further spread of bluing damage.
No bluing at all, streaks, discoloration, ect.
You can have this same problem in Rust Bluing as well.

The other problem with hot salt bluing the bbl'd assemblys as one piece is that they are not a water tight fit in many instances.
During the bluing process, the hot salt soln makes it way into the threaded joint. Most times that salt soln can be washed & rinsed away in the post bluing rinse.
Sometimes not. Sometimes you think you have it all out and there's still some in there. There's no way of seeing it, it looks clear from the outside.

What trips you up is what appears later on. It may be a few days to a few weeks later.
A white bloom growth starts to appear around the joint. That's the dried bluing salts still trapped in the joint (or any parts you have blued).
The bluing salts attract water from the air and start to 'grow'. That's the white growth you see.
It'll keep growing and crawling onto the outside surfaces of the parts. Since it's wet and alkali,,it rusts and pits the steel it's on. The bluing is gone underneath.

If you've been around to shops and gunshows looking at enough reblued guns, especially bolt rifles,,you've probably noticed the problem on more than a few. Usually the white stuff is brushed off and oiled for a better appearance just before sale time. But the spoiled blue and the rust and perhaps pitting around the joint is hard to cover.
M98 Mausers are very prone to it as the shoulder of the bbl does not fit tightly to the front of the action. That allows the soln to get in there very easily. Tough to rinse completely out.

Oiling the stuff won't 'kill' it. It'll just grow back.
Plain boiling water will disolve it and can be rinsed away. That was supposed to happen in the original rinse after bluing, but didn't.

Sometimes a re-rinse can remove it for you, sometimes not.
Usually the finish is damaged and metal pitted already once it's growing on the outside of the parts.
Then it's remove the bbl time. Flush the stuff off.
Repolish and re-blue as separate pieces and reassemble.

The last part is the safest way to avoid the problem in the first place.
Click to expand...

S&W actually had this problem with front sights that we pinned, polished, and blued in place. I have seen it on model 27's.

What would be the benefit of bluing something that had crevices (threads) while assembled vs in pieces?
 
I have had the problem with slides around the barrel bushing area... the barrel bushing can not be removed and re-installed easily, so I have left it in place. If the water rinse isn't done properly, then the salts resurface and it is a bit of a nightmare...that space is tiny, but it happens...

I think the idea of boiling the part in water to get rid of all the salts is great...I will do it the next time to make sure all traces of the caustic solution are "boiled off".

I guess some people avoid disassembling parts to make the job easier...but cutting corners can be worse later...:(
 
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Bluing the parts as an assembly avoids having to reassemble finished blued parts and risk scratching or marring the new finish doing so.
Also risk damaging a frame or action by bending it in the removal process. Some are a real brute to remove.

...and not everyone that did/or does hot bluing has the bbl vise and all the necessary bbl clamp blocks of different forms and sizes and different frame and action blocks to take apart and reassemble everything that might come at them.

>
>
One of the laziest, incompetent hot blue operations I ever saw was a small shop that I did some out-work for in the 70's and 80's.
They were the repair shop/armorer I'd guess you'd call it for a local small PD. That PD was using Colt OP's and some P/PSpecials.
This shop did repairs when necessary *they did have an original Colt Armorers Chest stocked w/new parts.
What service they also provided was about once every yr or so was to refinish some % of the total # of revolvers.

The refinishing process was to remove the wooden grips,,remove the cylinders.
That was the disassembly process.

Any obvious scars or pitted areas got a quick swipe on a 180grit soft wheel buffer.

Then the frame with all it's parts still in it and the cylinder and crane with all the parts still assembled went into the hot blue cleaner tank, then rinse then right into the hot blue soln.

After being 'blued',, the assemblys were rinsed, oiled and cyl reassembled to frames. Grips reattached.
Here ya go boys..
 
2152hq said:
>
One of the laziest, incompetent hot blue operations I ever saw was a small shop that I did some out-work for in the 70's and 80's.
They were the repair shop/armorer I'd guess you'd call it for a local small PD. That PD was using Colt OP's and some P/PSpecials.
This shop did repairs when necessary *they did have an original Colt Armorers Chest stocked w/new parts.
What service they also provided was about once every yr or so was to refinish some % of the total # of revolvers.

The refinishing process was to remove the wooden grips,,remove the cylinders.
That was the disassembly process.

Any obvious scars or pitted areas got a quick swipe on a 180grit soft wheel buffer.

Then the frame with all it's parts still in it and the cylinder and crane with all the parts still assembled went into the hot blue cleaner tank, then rinse then right into the hot blue soln.

After being 'blued',, the assemblys were rinsed, oiled and cyl reassembled to frames. Grips reattached.
Here ya go boys..
Click to expand...

:eek: :eek: Wow!!!! How long before the blueing salts retained inside the frame corroded the lock work and turned the revolver into a paperweight?
 
Sources + final comments

Hi guys...

some things that are still missing from this thread.

Sources:

In case you want to learn more and or double check all the info I condensed.

http://guntechtips.com
(everything started here, fantastic description of the process, and how to)

Royal blue Bluing - Pistolsmith
(interesting discussion about formulas and "tones" of bluing)

https://www.brownells.com/userdocs/learn/076-200-135_Bluing_Booklet.pdf
(good explanation of how to use brownells formula, also serves as a reference of the process)

Hot Caustic Bluing - Show and Tell - Bladesmith's Forum Board
(good explanation of formula and process)

3 Ways to Blue a Gun Barrel - wikiHow
(good explanation of the process, good illustrations)

http://castboolits.gunloads.com/showthread.php?172959-Homemade-Blueing-Salts

http://castboolits.gunloads.com/showthread.php?36054-Hot-Blue


Thanks, and Acknowledgments

Thank you all for all the contributions and the likes.

Thanks to: skjos, BC38, Neversink n Klapperthal, PeteC, stansdds, JohnHL, Dieseltech56, 2152hq, chief38 & SAFireman for all your comments in this thread.

Final thoughts

Forum member skjos gave me the idea of creating this thread. I have to admit I was very hesitant given how dangerous the process is and I almost didn't write it. But then I had a different thought, I am more afraid of becoming someone that does not try anything.

I have been trying to teach my kids the value of learning things. Of being able to repair stuff. Go hunting, fishing, shooting. Use tools, tie knots, use a compass, read a map, ride a motorcycle, shoot a gun. I am terrified of the thought of the next generation becoming people that the only thing they can do is watch TV and play playstation.

I hope that this thread serves as an inspiration to others to start their own projects and teach us what they learn in other new threads.

And, if you decide to do hot caustic bluing at home, please for the love of God wear your PPE.

God Bless
 
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Very nice write up thanks for posting it. For all of you do it yourselfers be very careful with all of this stuff, guzzitaco is spot on about the dangers. Also somebody mentioned potassium cyanide, that stuff can be very dangerous I would hate to see somebody poison themselves or a loved one. Look forward to seeing a competed gun from Guzzitaco.
 
Troystat said:
Very nice write up thanks for posting it. For all of you do it yourselfers be very careful with all of this stuff, guzzitaco is spot on about the dangers. Also somebody mentioned potassium cyanide, that stuff can be very dangerous I would hate to see somebody poison themselves or a loved one. Look forward to seeing a competed gun from Guzzitaco.
Click to expand...

Thanks Troystat...

I have done a couple...(posted in the semi-auto forum)

SSV Frankengun Project

M910 Slide learning project

here a couple of pics:



 
Warren Sear said:
That is an example of what could be accurately termed an understatement. :)
Click to expand...
Got that right.
The PH of human tissue is slightly acid.
Sodium hydroxide is a caustic - at the opposite side of the PH scale.
Acids react very strongly with caustics, so caustics do WAY more tissue damage than acids.
 
I can see your wife letting you do the metal work , but how did you talk her in to letting you do this ? Seriously though , looks like the parts are coming out nicely , keep up the good work !
 
guzzitaco said:
Hi John,

I honestly don't know, maybe the reaction would be less "violent" if the water is hot but I am not sure.

I think the problem with the water is due to the caustic reaction itself, where the lye (sodium hydroxide) generates a reaction when it interacts with water. Maybe warm or hot water, would make the reactions less violent, but there will be a reaction...

As I read it in another forum: ("Add water . . ." Such a simple statment. Adding water to a working blueing bath is a bit like adding water to the working lead pot. Neither the bath nor the water like it!) (I guess it's like me at my in-laws Xmas dinner :D)

The only "safer" way to add more "liquid" that I have found (reading) is to add more bluing solution. So, you would have to mix extra bluing solution and use it to re-fill the one that is evaporating...however, my concern would be the higher saturation of salts...

I am sorry I don't have a better answer at this point...:o
Click to expand...

I can assure you that adding caustic to hot water will instantly cause a very violent reaction. Always mix caustic with cold water. Always add caustic to water and not vise versa.
 
epj said:
I can assure you that adding caustic to hot water will instantly cause a very violent reaction. Always mix caustic with cold water. Always add caustic to water and not vise versa.
Click to expand...

Hi EPJ,
John's question refer to adding water to cool down the solution as it has "burned"part of the water in it. The bath works at 275 to 295 F and since water evaporates at around 212, it will tend to "disappear" from the bath, lowering the level in the container and increasing the temperature of the remaining solution.

Thus, water must be added to the bath to continue the reaction at the desired temp range and to keep the level in the container where parts are submerged.

You are right, when water is added to the caustic bath there is a violent reaction. John was wondering if by adding hot water, instead of cold, it would lower the violence of the reaction.

I haven't tried adding hot water, since the process is complex enough to add another "layer' to it...but in the video I posted, you can see the gunsmith adding water from the boiling tank to the bluing bath...

hope this clarifies John's question and my answer.
 
I have home blued knife blades and some gun part's and have some more to blue. I made up my first solution, but then bought a pail of salt from Brownells. I have worked with caustics and other dangerous chemicals, steam etc for a lot of my adult life

It won't help much to add boiling water to the mixture over room temperature water. The problem is the rapid expansion when the water right as it becomes steam. One sq inch of water forms 1600sq inches of steam at atmospheric temperature. The amount of expansion from 70f to 212 f is very very small, but in that instant that it goes over the edge it goes up factor of 1600. Actually the cooler water should be less violent because it slightly cools the solution it touches and therefore SLIGHTLY slows down the forming of the steam bubble

The only good solution is simply add the water slowly and if you will notice in the video the guy is actually putting the water on the side of the container right at the edge of the solution. The container is as hot as the solution so he is causing his water to mix and any steam to form right at that edge which probably releases less solution in to the air as the steam flashes off. It also prevents the water from being injected beneath the surface of his solution and forming a large steam bubble under the solution and blasting it upwards.

If you have all your stuff mixed right and have an decent sized container, you shouldn't need to add much water. Get your parts in asap and try to keep your boil at the lower end and stave off adding water as much as possible. If you want to run more parts you can always allow the solution to cool below 212 ad water and heat it back up when the second batch is ready.

I have a some guns that need a bath, but don't want to do it until I finish some projects and they are all ready so I can set up do them one after the other

I have used a pipe full of special salt mixture super heated to 1500f to harden knife blades. At that temp it is a thin red liquid and of course has zero H20 in it. Nice thing about this method is once in the solution there is no 02 to burn carbon out of the surface of the steel, Go from there right to the oil and the blade looks just like when you stuck it in the solution once you wash it off. As it is a liquid the blade gets heated evenly everywhere and warping is very rare. The only problem is it is kind of dangerous (DUH) Anything you place in it had best be well over 212f for a while so it is bone dry when you insert it or KerBOOM and hot fire everywhere. You also have to cool it with a tapered rod stuck in it so when you heat it back up you remove the rod and the hole it leaves gives it a place to expand so you don't blow a big super hot plug of salt out into your shop. Be careful out there boys and girls
 
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Brownells sells HotSalt bluing neutralizing kit.
It's a bag of Sulfamic Acid (dry powder) basicly along with some Ph test strips and eyedroppers.
You have to supply Hydrochloric acid in the form of muriatic acid along with Sodium Hydroxide (Lye).

With these chemicals you bring the highly caustic salts to a ph neutral and disposal down the drain is supposedly OK.

It isn't cheap,,at around $250 IIRC.
You can buy just the bag of Sulfamic Acid w/o the do-dads and it's about $10 cheaper!

EPA is tough on those that throw this stuff away w/o proper disposal.
A large shop I worked in in the early 90's got fined in the multi 100'sK $$ for improper disposal of bluing salts. They also received fines for improper set-up in the bluing room that wasn't catching any splash over, poor ventilation, ect.
It didn't help that the wash down drains in the bluing room simply went under the ground and spilled out on the bank and into a stream that ran along the property.
EPA & DEC were not impressed!

The neutralized salts can't go into a septic system, or at least that what the rule used to be. It had to go into a sanitary sewer system so it was directed further to a municipal water treatment facility.
 
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