# Alternative to hot Gun Blue Bath?



## seaweaver (Nov 19, 2009)

The danger of handling irons around a tub of 290 degree solution is not something I would want to do.
But I read(briefly..on Wiki) of large industrial operations using furnaces.
I left a blow dryer on an action last night to drive out any remaining moisture from cold blue cycles and to allow the oil to permeate. That action was very hot and in reading of the furnace operation was wondering why this cannot be achieved in a home shop?
Either w/ radiant heat or heat gun. Temp would have to be monitored closely but that is easy w/ IR temp guns.
Anyone thought of this? 
I am not familiar w/ the hot blue solutions and have yet to comptemplate their application during this process.
Any thoughts?
cw


----------



## Patchpusher (Nov 19, 2009)

290 degrees is the temperature that the salt solution must be to blue steel. The parts are hung on wires or put in baskets and lowered into the bluing solution. They are left in the solution for around 20 minutes. If you get the bluing salts on you you will get two kinds of burns, one from the heat and a caustic chemical burn. The furnace bluing is called Carbona blue. There are only a couple of guys doing this. This is not the same as color case hardening.


----------



## jglenn (Nov 19, 2009)

the biggest problem or issue with hot bluing is not so much the temps involved as much as the salts used to blue the action. They are Caustic. (most contain lye as a main part of the formula)


this  verses parkerizing which uses fairly hot temps but the mixture is much less caustic.

not sure you could ever get uniform temps across an action or barrel with  anything other than a liquid surrounding the entire item.


Brownells  has a bluing techinique similar to rust bluing using their Dicropan IM. Not nearly as caustic as your normal bluing solution.

for cold bluing Dicropan works very well as does their Oxpho blue.


----------



## Jranger (Nov 19, 2009)

My grandfather use to do hot bluing in a home shop. I have an 03 he did that looks like porcelain the blue is so shiny. He said it was a very dangerous process though.


----------



## NOYDB (Nov 19, 2009)

I use this for touch up any place I've fitted or modified material. I haven't done a whole barrel or action yet but based on my results so far I'm planning on re-doing a 336 that has had the blue rubbed off by a holster or case. 

http://www.shootersolutions.com/index.html


----------



## seaweaver (Nov 19, 2009)

This steel I was working one was giving me fits as the blue solution I was using seemed to work then stopped( hopps)....then rusted like crazy over night...so I polished the whole thing down again and started over finally w. the blow dryer heat thing I referenced to above.

I would be interested to try something different than cold processes(BC Casy has always given me good results but is not carried by wallys anymore), but I have to think this process of the bath immersions can be circumvented. The specific heat  of the steel would certainly aid a shop furnace process. I do not know what the temp of the metal was this am but it was very hot. Action and then barrel in front of a gas radiant heater like a propane "eye" should easily reach 290.
I'm thinking that at this stage a small pot of heated salt solution could be dipped into and brush applied to the steel. I'm thinking the action/ barrel could be suspended by wire and revolved in front of the heat source by a rotisserie turner.Perhaps a shield of  of sheet metal to help keep and regulate the heat
I mean whats required ? heat and solution right?
I see the benefits of this to be safer, simpler, and quite obtainable to make the set up by digging around the shop.
From what I have read (briefly) the heat is a necessary element for the reaction to occur and my thinking is any area not receiving the adequate temp would stand out and could be addressed.

Failures? limitations?





I found this on the carbonia
http://www.ronsgunshop.com/carbonia.html

and I found this Dept of Defense publication on treatments. (this is kinda neat.)
http://assist.daps.dla.mil/docimages/A/0000/0005/3933/000000039716_000000139526_QZYPSFIUNS.PDF

cw


----------



## Patchpusher (Nov 19, 2009)

My thoughts are that if it could be done it would have already been done. The salts turn into a semihard solution when cooled. You have to heat the salts to get them into a liquid form. They would be very hard to apply and you couldn't reuse them. A 40lb bucket of bluing salts from Brownells will cost you around $200.00 by the time you pay shipping and hazmat fees. You really don't want to be wastefull. I built my own tanks and burners and stands. I bought the mixing valves from Brownells.


----------



## Patchpusher (Nov 19, 2009)

If you can find out where to get the carbonia and the temps, I would be interested. I tried to find out years ago with no luck. Maybe, I should just call Ron and ask him.


----------



## Patchpusher (Nov 19, 2009)

If you rust blued the parts all you need is the rust bluing solution, a damp cabinet, boiling water tank, some bore plugs and a few carding brushes.


----------



## seaweaver (Nov 19, 2009)

If the salts can be heated to a liquid state are they not brush-able?
If you have to fill a tray...that's going to get costly and I'm sure that's why a supply of guns to be coated is built up to make it worth while.
I keep thinking about how much really is need to react w/ the steel.
If it is in a liquid state I would think you could brush it from a small pot directly under the gun to catch residuals...

I have not studied rust blue...but I have no problem creating rust!

cw


----------



## Patchpusher (Nov 19, 2009)

I am pretty sure the bluing salts need to be in circulation around the parts. Otherwise, their bluing properties will be quickly depleted. This would result in an uneven finish. Even in a tank, only so many parts can be blued before the salts are depleted. Besides, if the part is 290 degrees and the salts are 290 degrees the stuff is going to run off the part faster than you can brush it on.


----------



## seaweaver (Nov 19, 2009)

THIS is the info I'm looking for!

Now....the action on the bench saturated in ...(yea) WD40 after the last "cold" blue...is now saturated in rust.

Is it the metal?
moon?
me?
This is nuts... I'm starting to think Rhino Liner...
But I'm going to research more on the Rust blue as it seem I have 1/2 of it down.
cw


----------



## Cknerr (Nov 19, 2009)

because of the of the hazards of  chemicals and not getting a satisfactory job of bluing when I did use chemicals, I now slow rust. Takes some time and a little elbow grease. But the most hazardous stuff is boiling water....if I want a black result. Otherwise it turns out a slightly reddish deep dark brown. The black version results is an incredible tough black with a hint of blue in the depths. It is difficult to get to rust and if it does, steel wool won't hurt the bluing. Actually the process is so old, it harkens back to the old British term of "Blackening"

Have you thought about trying that?

Chris

Edited: Patchpuller, I do not use any bluing solutions beyond water in a mostly gaseous state - high humidity


----------



## seaweaver (Nov 20, 2009)

That is what I'm leaning towards. I just need to read up on the process.
cw


----------



## Patchpusher (Nov 20, 2009)

One thing I forgot to ask you is what kind of polish are you using? I was told by L.C. Jackson not to use grease based polishes when rust bluing or color case hardening. Since, you already have red rust. Take one of the parts, degrease it carefull not to get body oils on it (wear gloves) and boil it in a pan of water on the stove. See if it will kick over to black rust. Not sure if it will since you put oil on it.


----------



## Patchpusher (Nov 20, 2009)

seaweaver said:


> THIS is the info I'm looking for!
> 
> Now....the action on the bench saturated in ...(yea) WD40 after the last "cold" blue...is now saturated in rust.
> 
> ...



Seaweaver, Welcome to the world of metal finishing!


----------



## dhepler (Nov 20, 2009)

Bicchwood casey has a product that is equal to hot bluing that is mixed with water and used at room temp with an immersion time of less than 1 minute.  I use it for small parts and is quite acceptable.  It is made for commercial applications.


----------



## Cknerr (Nov 20, 2009)

Seaweaver,
Slow rust is a pretty simple process. I'll explain how. 

First let me digress a little. The idea is to allow rust to build/accumulate on the surface. The trick here is the type of rust you re building. To illustrate my point let me use the grass out in your yard. Wish I knew where I read this - not my story and would like to recognize the author. Now back to the grass. There are 2 types to consider. One is the gorgeous and smooth stuff found on a golf club green.  The other is crab grass. The golf club grass is tough/durable and silky smooth. If you pulled up a chunk of it, not much earth would come with it. You would have a handful of stalks and roots with only a little soil. The crab grass is lumpy and when pulled up takes a lot of earth with it. With this slow rust process, we want to grow the putting green style of grass. The crab grass is a fairly close example of the nasty stuff we try to avoid.

Polish the metal until it is a mirror. Any scratches, pits, etc will show up. The nice thing is if you miss a spot, they show up fairly early in the process. You can always go back and fix it. Then press on with the process. You don't have to remove everything. This is a good thing, guess what happens when you drop the &(*% thing on a concrete floor! The clean shiny patches will eventually catch up.

A critical step is removing any all oils, grease, wax, etc. this has to be done every time you return it to the humidity chest. Boiling it might help release some wax, but the oil and grease (and the wax) will float to the top and say there. When you lift the part out of the water - it will re-coat itself with what is floating on top. I don't bother doing it. Scrub the surface with a very soft brush and warm soapy water before going into the cabinet for the first time. Always wipe the metal down with an alcohol soaked rag or paper towel, then repeat the same thing with acetone each time before it goes into the humidity. After carding, only the alcohol and acetone wiping is needed. Even though you have latex or nitrile gloves on - only touch the metal with a clean paper towel wrapped around it. Found out the hard way some gloves have a release agent on them that appears to be oil based not always though. The box label doesn't say anything about it either. Because of that intermittent problem, had a full head of hair before I finally figured that one out.

Next is the rusting part. Stick the metal parts into a humidity chest/cabinet. I run mine at 100 to 120 degrees with about 85-90% humidity. Don't want higher then that  as that seems to cause the rust to go nuts and pit or nothing at all happens. Don't understand the later, but it does happen at high humidity.  You want an even layer of rust showing up. Here in Georgia, our summer nights work just as well. Just make sure there is no rain or a water droplet sit on the metal for long. That will be the cause of that crab grass rust and you get to start over up there in paragraph two (the one about polishing and pit removal)  Where it is thin is usually a contaminated surface, no problem, just try to do a better cleaning job next time. When it looks covered, about 6-8 hours the first time, card it. That means use steel wool, wire wheel, scotch brite, etc. to remove whatever isn't thoroughly attached. One note on oiless steel wool - it isn't! There is a small amount still there to prevent rust and aid in manufacturing. Place it in a jar full of acetone to remove the oil. You can also store it there if you can card your metal outside or where there is plenty of air movement. Might have to replace the acetone once to remove all the oil. Any oil will mess up your finish.

If you want a black finish, just after carding you place it in boiling water for 3 to 5 minutes. Don't add anything to the water. Just the stuff straight out of the faucet. It will turn black. Never notices much shading/tone difference between mineral content of different water.
You are turning Ferric oxide into Ferrous Ferric oxide. I am not a chemist, so I might have the -ous and -ic mixed up. It boils down to (pun intended) what is normally called hematite. The black stone is what you are building on your metal. Stone is some tough stuff! The first few rounds of this might only generate a slight graying. Don't worry, that is all that can be expected at first. It does build up over time. Eventually you will note it takes a minimum of 12 hours in that cabinet to get any rust. That means you are done! Congratulations. You have encased your metal with black stone. It is so well attached, you will find it impossible to chip (you can dent the metal, the finish will stay on) and almost rust proof. When rust does happen, steel wool in any form will take care of it. (very entertaining watching the horrified faces around you when you rub aggressively)Just remember to oil it occasionally .

The brown/reddish version is done the same way without boiling. It is only slightly less tough then the boiled black rock versions. Mineral contents of your water can make a marginal difference. Never had a client comment on it before. I notice because of lokking at so many.

When you are done (using an entire rifle for example), the darn thing up close will gleam and shine like a polished black mirror. 10' away it will have some gleam but not very bright - it will seem to pull in the light around it. 30' or more and it disappears. You can make easily out a black object, but that is because it is blocking something behind it. There is no flashing the country side even though up close you would expect it. A very neat side-effect.

People over the years have tried salt water, vinegar washes, even coating with salt cured bacon fat. All of those formulas are trying to accelerate the rusting formation. To date I have found none of them to be consistent enough to form a smooth coating of useful rust. Accelerators that work in a few hours do create a coating. It is a simple form of rust that has been dyed with other minerals or metals (like copper) and can not provide you with much of any protection. The salt water trick might work if you could stand over it all day and keep an eye on it. Since slave labor, ie.  apprentices, are not available these days, I default to something that is controllable and predictable. It takes anywhere from one week to two weeks to complete the procedure I outlined above. 
Hope this helps,
Chris


----------



## olchevy (Nov 20, 2009)

TO CKNERR

What about an accelaerated rust finish, I patina a lot of my carbon knives to keep them from rusting, can one patina a rifle. If so it would give a very unique non constant formation on it. I can do a light patina on metals so that the unique design is visible or i can leave it on and make it solid black.


----------



## seaweaver (Nov 20, 2009)

Thanks CKNERR
I'm beginning to understand this better and better.
Now I need to find something to fit the action in for boiling.

I am concerned about those areas that I do not want this bluing...like the inside of the receiver especially where the bolt travels What to to about those spaces?
cw


----------



## Cknerr (Nov 20, 2009)

Yes, there are other methods. 
When restoring a Damascus barrel for example. Trying to get the contrast between the different layers is most important in this circumstance. That process is totally different. I am also sure the owner is never going to take it shooting or out in the field. Corrosion protection is no longer a big concern. 

Slow rust is probably not the best way to show off your kind of work. It is strictly utilitarian with a lucky break - it does happen to look good and prevents flashes of light. 'course, you never know until you try it. Won't be the first time I was all wet! Most bluing/rust removal solutions should work on it, so you can go back to step one if it doesn't work. 

The patina you are referring to usually involves phosphoric acid. It has a lot in common with Parkerizing. The black colored machine crews etc. use the same chemistry. It does work to a small extent with corrosion prevention. It can make a thin coating on the surface that holds oil - way better then bare metal any day! By getting it to react more in one area then another, you can make some pretty neat patterns. I buy a gallon of the stuff at a time from BirchWood Casey for touch ups. That size lasts a few years. Tried it on alunimum and brass yet? Turns them black too. Usually not the color wanted on brass, but it does work.

Please ignore this if you already know about it. Found out it is easy to contaminte the whole bottle and make it useless over time. If you pour a little into the cap and throw that out when done, your solution lasts a lot longer.  The stuff in the cap gets a tiny amount of contamination off of your swab. That is enough to effect the rest of the contents in the bottle. Hard to believe such a tiny amount will do it in.....but it will compromise the whole bottle.

If you repeatedly treat a rifle barrel, you can build up a very nice even black finish that looks pretty good. I have done that once myself. Had a show to take a rifle to and didn't have the time for the usual slow process, too cheap to get it properly blued, so used that stuff. Looked fntastic until the rust set in a few months later. 

Doing a metal finish with that solution is close to what is considered normal these days. The formula for factory bluing on lower priced fire arms has switched to acid based  formulas that can be scraped with a finger nail......guess what they use?!!!!

@Patchpusher have no idea how well the rust would turn black. I would guess, and it is a guess, the oil will have little effect in the end. The boiling water will remove the oil over time and the natural process of converting the ferric oxide would then go the usual way. Don't add any soap or other stuff to help remove oil! The rust will likely react with the slightly base Ph of the soap in ways that might not be predictable. Just let the boiling water do it's thing. 

Take care,
Chis


----------



## olchevy (Nov 20, 2009)

yeah my "acid" was pickle juice soaked paper towel and wrap it around the blade for tenmins to however long the longer the darker.....lol Im low tech,but it works on knives...


----------



## Cknerr (Nov 20, 2009)

To prevent rusting, paint it. Couple coats of molding release or other plastics that are heat tolerant can be used. Plain old paint works too and can be sprayed on. They can be removed with stripper. Just check between operations to make sure it hasn't been damaged. There are plastic plugs etc. that can be used. Wood is usually not a good idea as they absorb chemicals and water that will cause rust that is not good. The wood can be treated not to absorb water....and that usually works.

The hard part is not using anything that will spread/melt/ooze. It will ruin your edges. You can also just let the insides of the receiver get blued and remove it later....my usual way of doing it.

Somewhere down this thread someone mentioned concerns about using wax based abrasives. The wax is hard to remove! It can takes solvents, sometimes heat, and other troublesome machinations to remove if you are not smart about using them. BTW, the usual chemicals used for degreasing before standard bluing will remove waxes.  I find it pretty much impossible to polish with out using wax or grease based buffing compound for the final polish. I usually use a buffing wheel for the last final polishing to get a mirror finish. By this point of prepping the metal,  it really helps that the surface is very smooth and there are no pits, scratches etc. for the wax to hide in/attach itself. Using hot water and soap with a soft brush seems to do a pretty good job of getting it off. A final rub down with acetone seems to be good insurance too.  

I'll try to post some pics of what I am talking about. The Marlin I am restocking and mentioned in other threads is getting all this done to it.  I'll make sure I take pics before cleaning things up.

Hope this helps,
Chris


----------



## boneboy96 (Nov 20, 2009)

It's just amazing to watch Chris work his magic in person!


----------



## seaweaver (Nov 21, 2009)

Thank you!.....oh....

I found a trove of info here
http://www.finishing.com/4400-4599/4469.shtml

After leaving the  stripped and super clean steel hanging in the shop all night w/ the doors open...and fog all night....

NO RUST. I should have started out by not wanting to blue my steel!
cw


----------



## Cknerr (Nov 22, 2009)

lol, yup - polished steel doesn't like to rust! If you envelope it in moderately high humidity and heat it will have a much better chance. Part of what I mentioned below was the problem of getting the darn thing to do anything when the humidity was above 85% -90%. Fog is 100%, so it is not surprising. It will eventually, but it can be like watching a rock grow! 

I built a small cabinet about 2' square x 5' tall. About a 12" above the floor is a holder for a stainless steel bowl and a light bulb under it. Took awhile to find the right height above the light bulb to keep the humidity correct...but I did eventually. There is another bulb half way up attached to an old thermostat. It was an old fashion one with a mercury switch  that could take the current to run the bulb. It turned the bulb off and on to maintain temp. There was also a small fan that kept the air circulating. The little fan made a BIG difference - kept the rust build up even. 

Over the years, the seams finally opened too much, started looking really shabby, and it was getting in the way so I gave it a neighbor to dry herbs and stuff in. As I build another one, I'll try to post pictures. However, it is really as simple as explained above.

On the link you sent: The acids they mentioned are oxidizers. Nitric + kerosene = some of the first liquid rocket propellant! Adding all the metal will use up a lot and reduce the chance of pitting. They are really speeding up the rusting process. My way is a lot slower I will have to admit. It also is a lot safer. A very dear friend lost the sight in one eye from a tiny drop of lye (similar end result for acid) that made it past a face shield and safety glasses. He was an up and coming competitive shooter too. That ended right then -and my desire to mess with those chemicals. 

On a side note, except for the humidity cabinet, there is no other extra equipment. No tank, chemical storage, burners, etc. I do admit to a small S/S tank I lay on the kitchen stove to boil water in when doing a barrel. The carding is by hand or the same buffing equipment I polish with.

Since this thread is getting kinda long, let me start a new thread on metal prep and bluing. I'll take some pics in the shop to start things off.

Chris


----------



## seaweaver (Nov 23, 2009)

I did my first boil yesterday in a cab pot half/half.

now...
_Adding all the metal will use up a lot and reduce the chance of pitting_

I don't understand. I understand the process to speed up the rusting... but using an oxidizer will decrease the chance of pitting?
This seems to make sense as all metal starts at an equal jumping off point.

cw


----------



## Cknerr (Nov 23, 2009)

sorry I wasn't too clear. It slows down the speed of the reaction and keeps the the process very consistant. At full strength, you will have patches of intense reaction and the area beside it that is getting used acid from won't react so fast.  

I have only played with some of the alternate "fluids" to speed up the rusting a very long time ago. Most of what I have read about or heard are a mystery to me. NOw just ofr for giggles (some people are serious though) - there are recipes that specify panther pee (maybe send the aprectice to collect it) and urine from a menstruating women (?!). The acids mentioned in that link are going to do much better then panther pee I'll admit. Beyond that observation can't say much. hmmm, keep rabbits out of the shop?

One thing to keep in mind - the faster something works, the faster more damage can occur before you can do something about it. This is why I like slow and steady and nothing more harmful then water.

Chris


----------

