Seamed liners

[jlimebrook]

Even though I've been surfin' for cannon information for several years, I only recently discovered this forum.  Man, how I wish I'd found it earlier.

Reading some posts from a couple of years ago, I noticed a positive distaste for welded seam liners in cast barrels.  This kind of bums me out because I just finished a pair of 1/3 scale 1841 six-pounders on No. 1 carriages (that's them in my pic, with the lovely Emily).  The tubes are from Grey-Star and have welded seam liners.  Also, one of the liners seems to be about 3/8" off center at the breach end, similar to, but not as bad as another tube referred to on this forum a while back.

This is going to take some of the fun out of my cannon addiction.  On the plus side,  I intend to never fire projectiles from these guns.  I am sticking with 1 oz. foil-wrapped loads with a little newspaper wadding  which, as far as I can determine, is well below maximum for this caliber.  I will  probably never fire  more than a dozen shots a year from them

My question is, am I or my friends and family in danger from these guns?  Would I be foolish to try and proof these tubes?  Is there any record of catastrophic failure of these Grey-Star tubes?

[Cat Whisperer]

jlimebrook -

WELCOME to the board!

You've made some good observations.

I have seen one cannon explode, back in the early 60's.  If I remember right it was a 'little' to much overloaded.

It can happen.  I would think (oppinion now, take it for what it's worth) that if you were rigorous about keeping to the 1oz loads and a SMALL amount of newspaper that you'd do ok.  (Pressures with bullets are much greater.)

Read through the comments that others toss in, and take the SAFEST approach.

Understand the principles - seam-type liners will corrode OVER TIME inside the seam where it's porous, weakening the tube.

[Double D]

First let me welcome you to the board. Glad to have you.

Sorry to hear you bought from Greystar before you were able to fully research then on our board.  If you had been able to research Greystar you would have learned that there have been some issues witht them about seamed liners and crooked liners.   You would have also learned that Graystar has made it right for everyone who has had problems with crooked liners.  The will not do anything about seamed liner if that is what you ordered.

Seamed liner are  no different than a damascus barrelled shotgun.  Here is my post from two years ago that is linked in the FAQ's at the top of the board explaining seamless liners.


 

You may have noted from time to time I warn against the use of welded seam barrel liners. 
 
The issue isn’t the strength of 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 occlusions and micro-pores in the metal.  These occlusions 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 occlusions.   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 occlusion 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.

[rusty barrels]

DD I respect your knowledge and expertise in black powder cannons but I have to totally disagree when you compare a seamed pipe to a damascus barrel, their construction are very different. Some Damascus barrels are still being used today, mostly Parkers with black powder. You just have to be careful be it seamless or not.

[jlimebrook]

Thanks for giving me the benefit of your experience, guys.  I will take your advice to heart.  It helps a lot knowing that the main disadvantage of the seamed liner is its tendency to corrode along the weld.  I've always been pretty anal about cleaning my shooting irons.  After a good wash with hot soapy water, I usually wipe the bore with TC Bore Butter or Ox Yoke Wonder Lube.  This regimen has always kept my BP rifles in good shape, but I  haven't been able to find a 1" bronze bore brush anywhere.

[Evil Dog]

A 20mm bore brush might work, should be able to find at your local Army Surplus store.  "Boiler" brushes also work well... that is what I use in my 2 1/4" bore.

[Double D]

DD I respect your knowledge and expertise in black powder cannons but I have to totally disagree when you compare a seamed pipe to a damascus barrel, their construction are very different. Some Damascus barrels are still being used today, mostly Parkers with black powder. You just have to be careful be it seamless or not.

Iell me how they are different.

I can recall the Hunter safty course I took back in the early 60's in Oregon and they talked about how a damascus twist barrel was made and how the were susceptible to bursting and why---tiny little  pockets  in the welds that developed rust let go. THe guidance given way back then was to not fire  damascus barrels even with black  powder.

Later when I went on to College and studied Precison Machine technology-gunsmithing the issue of Damascus steel barrels was discussed. There I learned in more technical terms how strands of different types of steels were twisted and hammer forged around a mandrel to form a barrel.  I learned that this manner of welding was less than perfect and often left occlusions in the seams--tiny little pockets--that were suspectible to corrosion and rusting which weakend the welding seam. 

Sample of barrels were examined that had burst.  Some had burst along the seam and the was no sign of internal corrosion.  Some had some very serious and visable pockets.  The college had a very lovely damascus twist barrelled shotgun that had been Xrayed and the occlusiions were very visable in the film. But the barrel was intact.   Also shown us was the  more expensive damascus twist barrel than had been formed around a seamless tube.  The inner shot gun barrel was seamless and the outer cover of the barrel was damascus. 

When I had my shop I had burst barrels ccome in. Two  come to mind.  One was a simple burst seam a few inches long.  Some time in its recent life the gun had been reblue and you couldn't see the damascus pattern, until I polished it.  The other was the classic starburst.  Both Guns were old and had been shot for years.

Just becasue you have shot your wonderful old Parker Damascus for years doesn't make it safe.  Damsacus barrels by there simple mean of manufacture are inherently weak design.  Kinda like the low number Springfields, not all are brtitle, just guess which one isn't.

To carry it over to the electrically welded seamed tube I would characterise that weld as far superior to a damascus weld, and the seamless tube carries the warning.   

[Cat Whisperer]

...
  I will take your advice to heart.  It helps a lot knowing that the main disadvantage of the seamed liner is its tendency to corrode along the weld. 
...

The problem is that it corrodes INSIDE the weld - because the weld is porous.  Not easy to detect without destructive testing (sectioning) or it failing (does so without warning).