Author Topic: Welded seam barrel liners  (Read 18868 times)

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Offline Double D

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Welded seam barrel liners
« on: September 01, 2004, 01:34:59 PM »
You may have noted from time to time I warn against the use of welded seam barrel liners.  
 
The issue isn'’t the strength welded tubing. Welded seamed tubing can be very strong.  Your brand new cannon isn'’t going to burst on first firing because it has a welded seam liner.

It's the very nature of welds themselves that create the problem.  Welding often leaves inclusions and micro-pores in the metal.  These inclusions and micro pores can collect moisture and fouling.
 
When fired, particles of blackpowder fouling can be blasted into the micro-pores. The expansion of the metal from pressure and heat can allow these microscopic particles to be driven deep into the metal. When a wet swab is passed down the bore the steam can further imbed this fouling as well as cause condensation with in the incclusions.   Over a period of time this fouling starts the corrosion process.  The corrosion process takes place in the metal. The corrosion slowly grows until it is too weak to retain the pressures applied to it.  It can result in anything from pin hole leak to a catastrophic rupture.

Under normal use it's a problem that might not manifest itself for years.

That’s what happened with many Damascus Shotgun barrels.  These guns were used for years before any problems occurred. I have seen several of these burst damascus barrels and there did not appear to be any visible corrosion on the inside or outside of the barrel. One characteristic I did note, on a couple of the barrels was a darkening of the pattern of the seam in the area where an inclusion was corroding.

I can recall the first black powder cannon I built. It was made from Schedule 80 welded tubing.  When the rust started to bubble the paint over the seam we tossed that tube out and built another.  We never had an accident. I don’t know why. We were darn lucky.

Twenty years ago when I started serious shooting and building of model muzzleloading artillery one of the first warnings I received was about the use of welded seam tubing.  Don’t Use it, I was told!

Back then the magazine “The Muzzleloading Artilleryman” often had articles on cannon firing accidents.  Poor casting techniques, lack of liners in cast guns and welded seam tubing failures were prominent.  Even back then organizations like the North South Skirmish Association knew about the weakness in welded seam liners and had rules against their use.

So, you didn’t know about the problem with using welded seam tubing for making a cannon barrel and to save money you bought a cannon with a welded steel liner. Should you get the cutting torch out and make scarp metal or maybe stand it on end and use it as an umbrella holder.

NO!

First you are going to have to deal with the ridge of weld going down the seam.  

Inspect it.  Make one of those inspection mirrors described in the More Complete Cannoneer.  Look the seam over.  Do you see any defects?  Mark the muzzle of your gun right over the seam so you know where the seam is in your tube.  

Ream the barrel.  After reaming inspect the tube for defects.  That’s why you made the mark so you know where the seam is.

Next hone or polish the bore. Inspect the bore again looking for defects.

What do you do if you do find a defect?  If it’s a brand new unfired gun, I would contact the manufacturer.

You could also remove the liner and install a new liner.

If you don’t find a defect, shoot your gun!  Watch for signs of gas leakage between the liner and outer casting.  

When you clean the gun, watch for water seepage from between the liner and casting.  Make sure you use plenty of hot water to clean you bore.  

After every shooting inspect the bore with your inspection mirror.  Make sure your bore is clean and dry before you oil it and store the gun.  

Several days after firing inspect you bore again, look for signs of discoloration and seepage along the seam. Wipe the discoloration with a dry white cloth and check the color.  If you suspect a problem check it very thoroughly and if there is any doubt take the gun out of service until it is repaired.

If you are buying a gun with a lined bore ask if the liner is seamed or seamless.  If it is seamed and the gun is used have it inspected by someone knowledgeable in the construction of cannons before buying.  Better yet have it X-rayed for defects.

If you are buying a new cannon insist on a seamless liner.  Do not let anyone talk you out of it.

Offline Cat Whisperer

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Welded seam barrel liners
« Reply #1 on: September 01, 2004, 04:48:33 PM »
DD -


AMEN.


The cannon I saw explode some 12-15 feet away was only firing blanks.

You need to KNOW that when you light the fuse whether it's a cannon or a bomb.  Use only the strongest materials available - and certainly not ANY tubing that has a seam.

"You've got to be tough if you're stupid."
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Offline NitroSteel

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Welded seam barrel liners
« Reply #2 on: November 12, 2004, 01:56:43 AM »
Is it safe to use an oxygen tank to make a bowling ball mortar?  Do these rules apply to cannons only or cannons and mortars?

Offline Double D

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Welded seam barrel liners
« Reply #3 on: November 13, 2004, 03:54:03 AM »
Yes, using the O2 tank is fine.  Don't use welded seam for shooting anything black powder. Those big gas cylinders are seamless.

Offline Double D

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Re: Welded seam barrel liners
« Reply #4 on: August 06, 2006, 06:30:20 PM »
BBT for reminder

Offline Double D

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Re: Welded seam barrel liners
« Reply #5 on: August 06, 2006, 07:23:11 PM »
Is it safe to use an oxygen tank to make a bowling ball mortar?  Do these rules apply to cannons only or cannons and mortars?

Something to keep in mind in building a bowling ball mortar is that the pressure bottle is not the cannon.  The powder chamber is the cannon and should be built to meet safety guidlines.

Mortar cannon no difference...If your gun has a liner it should be seamless

Offline Double D

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Re: Welded seam barrel liners
« Reply #6 on: May 18, 2008, 02:23:38 AM »
BTT, the topic is current

Offline Victor3

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Re: Welded seam barrel liners
« Reply #7 on: May 18, 2008, 11:57:22 PM »
 Some related items I'm having a hard time understanding...

 Welded seam steel tubing is bad due to potential porosity at the weld, but no mention ever seems to be made of the fact that some seamless steel tubing can also have some porosity. I suppose the danger of corrosion along a weld (which can split) is of more concern than localized porosity at discontinuous points, but even seamless tubing has the potential for corrosion due to porosity of the material.

 Cannon liners often have externally welded plugs at the breech. Has the fact that there will be (unless pressed in with an interference fit) some clearance between the plug and tube (which will accumulate BP crud and corrosion faster than tiny pin holes in welded seams) ever been discussed?

 It's often said that a sleeved bbl should have a threaded vent liner to prevent gas from getting between the liner and outer bbl. For this to be truely effective, the vent liner must have an interference fit at the sleeve to seal the vent liner at the bore. Isn't this a concern?
"It is a capital mistake to theorize before one has data. Insensibly, one begins to twist facts to suit theories, instead of theories to suit facts."

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Offline Cat Whisperer

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Re: Welded seam barrel liners
« Reply #8 on: May 19, 2008, 01:02:10 AM »
In brief:

Localized porosity is to be avoided, obviously.  In ANY metal used for cannons.

We have discussed at length welding - well worth either another discussion or review, as we're talking safety. 

Interference fit is 'easily' achieved by press or shrink fit of the plug - again worth review or more discussion.

Threading - one looses 50% of strenght by cutting threads - ok if designed into the equation and can be combined with welding or compression or crush fit.

OF COURSE ALL of these are of concern - we're talking design of a SYSTEM, not just one segment of one part.

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Offline Double D

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Re: Welded seam barrel liners
« Reply #9 on: May 19, 2008, 03:12:08 AM »
Look to the N-SSA rules for guidance on breech plugs and vent liners. 

N-SSA lbreech plugs are first sweat fitted then welded in place.

Vent liners are threaded in place and provide a continious path from the interior of the barrel to the exterior. They are removeable for periodic inspection and replacement.

Porosity can occur anywhere. The potential for porosity is inherent in welded seam pipe and is a recognized feature of that material.

Offline GGaskill

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Re: Welded seam barrel liners
« Reply #10 on: May 19, 2008, 03:18:39 PM »
Having neither seen nor heard the term "sweat fitted" in the trade (although I am no authority on the trade), I am interpreting "sweat fitted" to be the same as shrink fitted, a situation where the hole is slightly smaller than the plug and the piece containing the hole is expanded by heat while the plug is contracted with cold so the pieces will go together.
GG
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Offline Double D

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Re: Welded seam barrel liners
« Reply #11 on: May 19, 2008, 04:35:39 PM »
George, I know we have discussed this before and I agreed with you.  I am beginning to believe it means just what is says sweat fitted or soldered!  Solder would seal the joint and keep the corrosive material out of the joint/

Offline GGaskill

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Re: Welded seam barrel liners
« Reply #12 on: May 19, 2008, 05:56:44 PM »
I am going straight to the horse's mouth on this one and asking for a clarification from the N-SSA.  Hopefully it will be cleared up shortly.
GG
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Offline Terry C.

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Re: Welded seam barrel liners
« Reply #13 on: May 20, 2008, 12:44:42 AM »
I've seen the term "sweat fitted" applied to shrink fitting before. It's fairly common but I don't consider it correct.

Items having an interference fit and assembled using expansion/contraction with heat and cold are shrink fitted in my lexicon.


To me, sweating implies the capillary application of solder or braze.


Of course I could be totally wrong, so YMMV...

Offline Victor3

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Re: Welded seam barrel liners
« Reply #14 on: May 21, 2008, 07:21:36 PM »
In brief:

Localized porosity is to be avoided, obviously.  In ANY metal used for cannons.

We have discussed at length welding - well worth either another discussion or review, as we're talking safety. 

Interference fit is 'easily' achieved by press or shrink fit of the plug - again worth review or more discussion.

Threading - one looses 50% of strenght by cutting threads - ok if designed into the equation and can be combined with welding or compression or crush fit.

OF COURSE ALL of these are of concern - we're talking design of a SYSTEM, not just one segment of one part.




"Localized porosity is to be avoided, obviously.  In ANY metal used for cannons."

I agree, if we're just talking about a liner. I don't see how porosity could be avoided in cast iron or bronze though. They always have some.

Interference fit is 'easily' achieved by press or shrink fit of the plug - again worth review or more discussion.

 Easily acheived, yes. However, I wonder how many actually do it; I've seen at least a few posts here where folks simply weld in the plug with no mention of an interference fit. I got a quote from a well known cannon manufacturer for a liner who only welds and pins the plug in using a slip fit.
"It is a capital mistake to theorize before one has data. Insensibly, one begins to twist facts to suit theories, instead of theories to suit facts."

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Offline Victor3

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Re: Welded seam barrel liners
« Reply #15 on: May 21, 2008, 07:42:13 PM »
I've seen the term "sweat fitted" applied to shrink fitting before. It's fairly common but I don't consider it correct.

Items having an interference fit and assembled using expansion/contraction with heat and cold are shrink fitted in my lexicon.


To me, sweating implies the capillary application of solder or braze.


Of course I could be totally wrong, so YMMV...


 I've only heard "sweat fitting" used as an alternate term for soft soldering (as with lead-based or equivalent solder); not silver solder (aka braze), or shrink-fitting.

 I think it might be a misnomer on the part of the N-SSA. They probably mean "shrink fit."

 I can't see that soft or even silver soldering would be guaranteed to still be intact after the high heat required to make a solid weld of the plug to the liner after soldering it - The solder would most likely be dribbling out into the bore (or blasted out by boiling solder flux).

 However, language isn't an exact science. I would like to know what the N-SSA really means by the term though...
"It is a capital mistake to theorize before one has data. Insensibly, one begins to twist facts to suit theories, instead of theories to suit facts."

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Offline Victor3

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Re: Welded seam barrel liners
« Reply #16 on: May 21, 2008, 08:40:19 PM »
Double D Quote:

Vent liners are threaded in place and provide a continious path from the interior of the barrel to the exterior. They are removeable for periodic inspection and replacement.

 I understand. But unless there is some kind of a sealing element to the design (such as an NPT or hydraulic/pneumatic type configuration at the end of the vent liner where it meets the bbl sleeve), a vent liner will not prevent high-pressure gasses from passing between its OD threads/the sleeve's ID threads and into the void between the bbl sleeve and outer bbl.

 I'm not trying to be a pain with my questions in this thread; I just want to understand the logic behind some safety design points that look to be sound on the surface, but appear (to me) to be lacking key points if they are actually going to perform the functions they are designed to.
"It is a capital mistake to theorize before one has data. Insensibly, one begins to twist facts to suit theories, instead of theories to suit facts."

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Offline dan610324

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Re: Welded seam barrel liners
« Reply #17 on: May 21, 2008, 11:33:13 PM »
yeah it would be interesting to have those rules explained that they cant be misunderstood ,

if not even you native Americans can understand it and agree to one interpretation of those rules , how should we others do   ???

where to find the complete rules of how to build an barrel to NSSA standard ??
Ive so far only seen a few lines about the sleeve as an quote .
Dan Pettersson
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better safe than sorry

Offline dan610324

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Re: Welded seam barrel liners
« Reply #18 on: May 22, 2008, 01:58:04 AM »
what I understand the 1 caliber rule say it should be minimum 1 caliber walls in breach area , but how thick in muzzle area ??

how about the mortars , should the walls be equal to chamber diameter , or ?? of the bore I mean .
Dan Pettersson
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interested in early bronze guns

better safe than sorry

Offline Double D

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Re: Welded seam barrel liners
« Reply #19 on: May 22, 2008, 02:55:14 AM »
You need to look at the construction of a vent liner.  It's made of copper and has a seat in it to seal the bottom of the vent so powder gases don't pass around the vent. I think there is an element of explosive swaging going during the first couple of shots


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Re: Welded seam barrel liners
« Reply #20 on: May 22, 2008, 03:10:35 AM »
the treads and the bottom seat is understandable , but how can they have an larger diameter on top of that and then an smaller again ??

I suppose this should be some sort of cross-section diagram .

or is it meant that the upper area between the smaller diameter of the vent liner and the cannon should be filled with lead after installing the liner ??
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Offline GGaskill

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Re: Welded seam barrel liners
« Reply #21 on: May 22, 2008, 08:37:47 AM »
I think the upper part is square so you can use a wrench to tighten the vent liner.  The drawing shows across the flats instead of the diagonal.
GG
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Offline dan610324

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Re: Welded seam barrel liners
« Reply #22 on: May 22, 2008, 07:30:23 PM »
but you still got the surrounding material directly in contact with the liner .
Dan Pettersson
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Offline GGaskill

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Re: Welded seam barrel liners
« Reply #23 on: May 22, 2008, 09:11:48 PM »
but you still got the surrounding material directly in contact with the liner.

I am not sure I understand your point.  I think the drawing is missing lines representing the hole in the barrel above the widest part of the liner.  See below for my interpretation.  And the interior of the barrel should be crosshatched or otherwise marked as a section.

GG
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Offline Victor3

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Re: Welded seam barrel liners
« Reply #24 on: May 23, 2008, 03:03:41 AM »
You need to look at the construction of a vent liner.  It's made of copper and has a seat in it to seal the bottom of the vent so powder gases don't pass around the vent. I think there is an element of explosive swaging going during the first couple of shots



 That design would suffice to prevent leakage. It's similar to the way I designed a vent liner for one of my cannons.

 However, the only N-SSA rule on vents I found is:

10.4.1    Vent

“The vent must provide a continuous smooth unbroken passage from the exterior to the chamber.”

 As I read it, the hole through the center of the vent liner would satisfy the above requirement by itself; no mention is made of any sealing element as shown in your depiction. Nor is the material that the vent liner is to be made of specified.

 I suppose there must be some accepted "tribal knowledge" among N-SSA officials as to what's acceptable and what isn't...
"It is a capital mistake to theorize before one has data. Insensibly, one begins to twist facts to suit theories, instead of theories to suit facts."

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Offline Double D

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Re: Welded seam barrel liners
« Reply #25 on: May 25, 2008, 06:41:11 AM »
  However, the only N-SSA rule on vents I found is:

10.4.1    Vent

“The vent must provide a continuous smooth unbroken passage from the exterior to the chamber.”

 As I read it, the hole through the center of the vent liner would satisfy the above requirement by itself; no mention is made of any sealing element as shown in your depiction. Nor is the material that the vent liner is to be made of specified.

 I suppose there must be some accepted "tribal knowledge" among N-SSA officials as to what's acceptable and what isn't...


It's not tribal knowledge, but historic design and construction. What you see is a depiction how original vent liners were constructed. (Thanks for the extra lines George) Orignal vent liners were installed to address the issue of vent erosion in original guns. They are removable and replaceable.  With a lined barrel with you get the extra advantage of reducing the migration of powder residue to the seam between liner and outer barrel.

Matt Switlik's The More Complete Cannoneer has a good description of vents and their use. But of course the book is out of print right now...but we have been promised, that the new edition is coming!

Offline Victor3

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Re: Welded seam barrel liners
« Reply #26 on: May 25, 2008, 10:17:57 PM »
 Okay, that makes sense - If you're building a gun for use within the N-SSA, make its features match historical ones. I'd think that their rules on some points might be more descriptively written though.

 It would be a bummer for someone to build a cannon that they thought met the requirements, only to have it 'shot down' due to some ambiguous point. Probably best to submit drawings to them for approval before building.

 I'm surprised that no N-SSA member has chimed in to clear up the "sweat-fitted" question here. One might assume (by their silence) that the definition is unclear to them also.

 Maybe they haven't read this thread ???
"It is a capital mistake to theorize before one has data. Insensibly, one begins to twist facts to suit theories, instead of theories to suit facts."

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Offline Cat Whisperer

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Re: Welded seam barrel liners
« Reply #27 on: May 26, 2008, 02:46:59 AM »
...
 I'm surprised that no N-SSA member has chimed in to clear up the "sweat-fitted" question here. One might assume (by their silence) that the definition is unclear to them also.
...

And I'm surprised that no one here has posted it there and reported it here!

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Offline Double D

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Re: Welded seam barrel liners
« Reply #28 on: May 26, 2008, 03:58:44 AM »
I had an email from one NSSA member who said he always thought it mean shrink fit.  I agree that their rules can be a bit vague, George did you get a response from the N-SSA board?

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Re: Welded seam barrel liners
« Reply #29 on: May 26, 2008, 06:06:43 AM »
George did you get a response from the N-SSA board?

I actually emailed cannon534@aol.com who is, by implication at least, Charlie Smithgall, N-SSA Commander and a source of information according to this line from the N-SSA information webpage:  "For more information about the N-SSA, contact N-SSA Commander, Charlie Smithgall at (717) 471-4000 or email to: cannon534@aol.com".  I have yet to receive a response.  I will make a post on their forum today and see what results that gets.
GG
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