Rust Blueing Barrel plugging Truth

C

CedarGrove357

New member
I have read on intarwebs forums, university google, encyclopedia YouTube, etc. that opinions differ regarding plugging the barrel when rust blueing. So what is the truth? The training manuals I've read say the barrel should be plugged. From what I understand in synopsis, if done professionally, heated caustic acid is used to clean the barrel, then rinsed in hot water, then the salts are administered and the plugs are used to transport the barrel from tank to tank.

Considering the caustic nature of some cleaning solutions it would seem logical to me that the bore needs to be protected from the possibility of etching, pitting, etc. I also understand the potential for pressure to build inside the bore increasing the chance of a plug coming loose with catastrophic results. but if the bore is clean and dry before plugged, what would cause the pressure to build to such a degree as to blow a tightly fitted plug?

I have looked around for barrel plugs commercially made, but haven't found much at all. If I have to "roll my own", thats fine, but what material to use for the plug? Wood or cork has been suggested but then again, its stated to be porous and cork and nitric acid dont mix. Rubber is okay, but can swell if not resistant to caustic chemicals and heat. I would like to build the plugs where there's a screw through the plug, a fixed nut and washer on the inside and a washer and nut on the outside that I can use to compress the material to seal the bore.

One idea I had was using a diameter of threaded rod and creating a plug out of hi-temp silicone sealant with the nut and washer molded in the sealant, using cut shell casings for my mold.

What is the opinion of some of the long time smiths out there? Am I over thinking the problem? Yes, I am newbie smith myself. Thanks.
 
I never plugged a bore to rust blue. Sounds like you are talking about HOT BLUING. The water I used would eventually leave a slight white deposit (Lime) in the bore, but it cleaned right out. I never saw anything else caused by not plugging. I used well water (Not supposed to) and never had a problem with that either. For all I know the lime may have helped neutralize the acid.
 
Well, having rust blued a Superposed without plugging the bores, I can tell you it's a real thing. Had to hone the bores after rust bluing it to get rid of hte rust in the bores. I mean, think about it! Hot distilled water you boil the barrels in to convert the rust, degreased steel locked in a cabinet overnight with perchlorate on it? Of course it's going to rust! So unless your shotgun has chromed bores, plug the bores.
 
There are several processes involved and that can cause confusion.

First, there is the old shotgun, with barrels soft soldered together and lugs, rib, etc., soldered on. Caustic blue dissolves solder and that double becomes two single barrels. Stick to rust bluing at low temperature, and plug the bore since there is no practical way to card the inside of the bore or get rid of any rust that gets in there. Rust bluing is tedious but produces a good result.

Modern shotguns and rifles don't use soft solder, so should be OK to blue using caustic salts, but many folks don't want to see bluing in the bore, so those should also be plugged.

In addition, the use of barrel plugs gives an easy way to hang the barrel in the tank and handle the barrel without anything touching the metal and getting marks on it.

Jim
 
Thanks for the replies.

I am going to stick with plugging bores always if I am dipping a barrel.

The question now is what is used for the plug?

I'm not afraid to make my own, but since my experience is minimal, I am looking for guidance from more experienced craftsmen than myself. :o

Lol, and yes, I will be experimenting on my own "parts guns" first. :D
 
Recommendation from Brownelss or Dunlap, if you are going to plug the barrel, plug it TIGHT. One method was to run a rod down the barrel and hold neoprene plugs in with washers and nuts. That done for Parkerizing which will roughen the bore.
You do NOT want a plug blowing out and showering you with 280 deg. lye solution.
 
Traditionally, tapered plugs were turned from wood. (Some people say hardwood, some say it doesn't matter; others say it doesn't matter with big bores, but you'll screw yourself by using a softwood in a small bore.)

The plugs were then hammered in tight.
 
[HTMLI used well water (Not supposed to) and never had a problem with that either. For all I know the lime may have helped neutralize the acid. ][/HTML]

I have been using distilled water for years but have been thinking of trying my well water. It has a little iron in it so I'm little hesitant.
I don't plug the barrels but I do scrub them good with brush and CLP before I assemble the gun.
 
Do a search on the internet for"shotgun barrel plugs" and you'll find several sources for acid resistent barrel plugs in different guages.
 
"...heated caustic acid is used..." It's caustic soda not acid. Absolutely not nitric acid. Usually sodium hydroxide(aka lye.). Don't get it on you, especially in your eyes, but it doesn't bother steel in any way.
Read this. https://www.ccohs.ca/oshanswers/chemicals/chem_profiles/sodium_hydroxide.html
And this. http://www.oxy.com/ourbusinesses/chemicals/products/documents/causticsoda/caustic.pdf
"...Parkerizing which will..." Does nothing. Did my .243 years ago with Lube-rite(making a silk purse out of my sow's ear of a rifle. Worked too.). Didn't have a cast bullet and the barrel got phosphated. Made zero difference. Other than the inside is black now. That being the only reason to plug the barrel. Cast bullet tapped light into in the muzzle and an empty spent cartridge in the chamber.
I'd be thinking wood vs anything steel for a shotgun too. You don't want even the remotest of chances of damaging a choke or choke tube threads.
"...it's going to rust..." If it gets a chance. Rusts because all and any trace of any oil is gone. Nekkid steel. Professional metal finishing shops will put the thing right into the next tank without any time between tanks. Makes the rust issue go away.
 
I am inclined to use filtered rainwater, I have a couple of buildings with new metal roofs which just sheet the water right off. I live in a 110 year old farmhouse with an active cistern about 5' deep and 6' in diameter that still holds water. I'd be using a commercial water filter just to be sure no impurities get to the tank.

I have two carbon steel tanks and two stainless steel tanks, each 48 by 6 by 6, for blueing. As I am planning this out, my concern was protecting the bore.

The single rod all the way through the barrel and capped on both ends with neoprene just gave me a "V8 moment". That sounds like the best, simplest and most secure idea I've seen so far. I totally agree with the ultra tight fit and the catastrophe of boiling salts going everywhere [which I vehemently wish to avoid].

I will also look into the shotgun barrel plugs for the right material.

Your input is greatly appreciated. Now to make my own "silk purse from a sow's ear" [savage 887]
 
"Other than the inside is black now. That being the only reason to plug the barrel. Cast bullet tapped light into in the muzzle and an empty spent cartridge in the chamber. "

No difference? Well, when the inside of the barrel turns black and the customer's face turns red and purple, there can definitely be a difference in the gunsmith's life expectancy!!

The bullet/case business will work OK but 6"-8" pieces of dowel rod will do better and give you a way to hold/hang the barrel without touching the newly polished surface. I never worried about the kind of wood, just using whatever wood was handy, tapered on a sander if necessary.

Jim
 
I have never had the inside of a barrel turn black or rust up from rust bluing, but I do not use a sweat cabinet either. I would be leery of pounding wood plugs into a newer shotgun muzzle. Most are quite thin. If you want to try your well water, use an old stainless pot on the stove with a small part and see what it does.
 
The OP never said it was a shotgun, but he did say he may cut a "shell".

If indeed it is a shotgun ( or any other bore larger than a .22) the hardware store sells threaded rod, which is very cheap. 4 feet will be around 4 dollars. Then you can use a rubber washer, backed by a steel washer, and you can tighten it all down.
There are also rubber "core plugs" made by Doorman products, which are made to use a wrench to expand the plug. These are made to easily replace the metal plugs which are usually hammered into an automotive engine block. I have seen fairly small ones, but I don't know exactly the size of the bore you are working with.

Myself, I would employ the threaded rod to be certain the "plugs" would not come loose.

Good luck

Rich
 
There is a difference between rust bluing and hot caustic bluing.

Rust bluing uses an acid solution which promotes rust which is either left brown (browning) or boiled in distilled water (bluing). The acid inside of the bore can theoretically lead to pitting and other nastiness inside the barrel.

When we do our hot caustic bluing on rifle barrels at school, we just clean and strip the bore just as we do the outside of the barrel and blue the whole thing inside and out. Can't speak to shotguns though.
 
It's unneccesary. I've never plugged a bore when bluing or parkerizing- and I've done hundreds. My Ruger-77 got parkerized and it didn't effect the accuracy. I reblued my Ruger Mk-II .22 and didn't plug the bore- and it still shoots amazingly well.

How are those wooden plugs going to fare after being soaked in water for a couple of hours?
 
How are those wooden plugs going to fare after being soaked in water for a couple of hours?
Click to expand...
They swell and form an even better seal, with little compromise in strength.

But who is soaking barrels in water for hours at a time?
 
Still more great replies, and thanks for the second on using the threaded rod.


I apologize if I misled people on the "cut case" idea. Theory was to cut the back of a case for the chamber needed, and fill it with high temp silicone sealant and let that cure. Once cured, pop it out of the case and there you have a chamber plug. Not sure if that idea would still hold true, but its an idea.

I've read of wooden plugs possibly leaking after soaking in hot water.

As far as firearm type, I am talking all types possible from .177 through 12ga.

At any rate, protecting the bore, regardless of how inexpensive or expensive it is is my goal. I'd rather not take chances on that one time the salts attack that one particular area in that one particular barrel on that one particular firearm that happens to come across my bench. "An ounce of prevention . . "
 
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