doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Invisible sleeve joints and damascus

Hi, just wondered what your opinions are and whether there's been any research done on the subject ?
If sleeving is the only option to save a beautiful old gun, the Tig work is done properly and they're struck up well , the job would certainly be pleasing to the eye , but I've often wondered what ( if any ? ) effect there is to the area immediately next to the welds on the old damascus or laminated breech end of the joint ?
I realise there's a nice sleeve of new steel running through and into the chamber, but after seeing instances where different metals have cracked or broken off next to the weld through either the wrong filler rod being used, the black magic of chemistry or lack of necessary heat treatment it got me thinking. I'm not an expert welder but have worked as a fabricator in the past.
Could the heat, even though it's localised, compromise the structure or integrity of the original blacksmith welded tube ?
Any input or ideas Gentlemen ?

Thanks for the inquiry, and I'm also interested in some learned opinions...from a gentleman...who has actually worked with pattern welded metal.

This is a c. 1867 MacNaughton of Edinburgh 12b sleeved from damascus to steel...back to damascus; with silver between all 4 joints; by John Foster and Graham Bull. Courtesy of David Trevallion.





I wonder if the silver 'spacer' was for more than just cosmetics?

Here's a crolle to ? laminated steel by Keith Kearcher that also appears to have a spacer

This may sound like a daft question but are they spacers or silver solder joints which have been wiped down or filed to suit ?
I only ask because I've not seen it before.

With the pattern matching problems that are sure to arise, are invisible joints an important goal?

What is the objection to the joint being visible? Either in sleeving or monobloc?

The business reminds me of the comedy duo Morecamb and Wise of the 60s, Morecamb was constantly teasing Wise about the joint of his toupee, especially when a show guest had a hair style hinting at a toupee. The line was "you can't see the joint on his".

I suppose thhe ring (as suggested) could perhaps be the "root gap" of the soldered joint?

TIG 'Invisible Sleeving'; c. 1890 William Cashmore, Birmingham 12b sleeved to 16b courtesy of Heritage Guns



Not so invisible; Lindner Daly



Bit more of a "gap"

Lefever G grade by Buck Hamlin, courtesy of Tom Archer

Drew, any idea what caused the blowout on the Parker?

Joe: it was a 1891 GHE Parker 10g sleeved to 12g and "restored". I have no information as to the wall thickness of the tube that blew, or who did the "restoration". The case colors to do not appear to be ol' Ed's work.

Two things catch my eye on the Parker blow-out.

1.The original chamber/monobloc is still intact & the rupture starts at the sleeved tube parting line.

2.The end of the shell is well past the normal chamber length. I just measured one of my Parkers and the shell shown appears to be about 3 1/4" to 3 1/2" in length. Could someone have stuffed a 3 1/2" magnum 12ga shell in this one? Did the shell case separate from the base & get lodged causing a higher pressure?

re: the silver spacers - since Trevallion and Kearcher are both still around (AFAIK), why not just ask them why their sleeve work shows the silver spacers? Rather than speculate.

Keith is retired, but his nephew Kody might know.

SRH

Thanks for your replies and input so far, some scary pics there !
It's the Tig weld method that's raised the question really but I can see the sense in a spacer when trying to match or disguise the patterns at the joint when using donor damascus tubes.
It's whether there's a problem with the weld heat "unravelling" or weakening the old welds between the iron and steel that got me thinking ?

The MacNaughton that Drew pictures on the previous page has the most attractive sleeving I've ever seen. Why try to hide what it is! Proudly display its heritage. And I believe the silver rings are used to highlight the difference. Beautifully done! And I love the extra touch of reverse "sleeving" the muzzles, ala Peiper of Belgium.

+1
I really like the three sections with damascus on the ends.
Gorgeous.

John Foster looks to be in some transition, but possibly one of our British correspondents could alert him to this thread
http://www.johnfostergunmaker.co.uk/

I'll venture an opinion. I don't believe the heat from a properly done weld will have any detrimental effect on sound damascus. The issues with welding generally have to do with higher carbon steels and alloys; some are real fussy about rod, temperature, previous heat treat, etc.

Were higher carbon steels ever used with lower carbon/iron in making damascus? I think this could have been a problem for the welders/blacksmiths of old. I'd guess any heat treatable steel would have been in annealed state after welding into damascus.

DDA

Don: from the 'staining' thread

Steve said "1002 steel may be close to what was used in barrels."

and I agree

The chemical composition of only TWO samples of pre-1900 2 Iron Crolle was similar to AISI 1005 low carbon, low alloy steel based on Optical Emission Spectroscopy (OES).

Wrought Iron may have .05% - .25% carbon, so the steel component had to be very low carbon steel.

Also, your xrays of the damascus barrels didn't seem to show a network of weld joints, but rather the two components became a mono steel. I would suppose if the TIG welder thought they formed some embrittlement or other worry, they could stress relieve the barrels.

That appearance of the longitudinal barrel failure on the Parker sleeve gun might be a reason why the damascus smiths turned the long grain of the barrel's parent materials to right angles with the bore. I know it's not related, but that's how I would guess wrought iron, or questionable roll mill steel, might fail if the long grain followed the length of a barrel, a different intent from construction fasteners, axles, etc.

Craig: I'm only impersonating a metallurgist on DoubleGun but the gen-u-wine Metallurgical Engineer said this

"The Energy Dispersive X-ray Spectroscopy (EDX) study suggests that element migration between the metals occurred during the manufacturing process; the pressure rolling, twisting, and hammer welding of iron and steel laminates produced essentially a mono-metal."

Drew,
The statement by the metallurgical Engineer is a good indication that all would be well.
I'm guessing that it would usually be the better guns that get sleeved rather than a "clunker" with questionable barrel quality .
Saying that, it's often a bad idea to take things for granted.

I believe, generically, it takes time and temperature for carbon to flow from higher to lower concentration areas. Could be there wasn't enough heat or time for that to happen between the steel and wrought, but chances are at and near welds, the carbon has 'evened out'. Maybe, when some barrels color welds bright, and others color dark, the cause of the coloring is some element or elements that are not able to, or slow to migrate, rather than just the difference of being an iron or steel. Maybe.

I have to believe that the gen-u-ine Metallurgical Engineer would retract or reconsider that statement if he took a moment to think about his choice of words. If the process of rolling, twisting, hammering, and welding of iron and steel resulted in "essentially a mono-metal", then we would expect to see a mono-coloration after blueing and etching, i.e., no difference. There is still a significant enough difference between the layers that we can see, and sometimes even feel, the difference between the iron and steel. It is the contrast which we so frequently discuss and admire. Certainly, there is amalgamation and fusion within the weld joints.

In response to the OP's original question It is my belief that no detrimental change will occur on the damascus monobloc side of the weld BUT I can assure you you will have problems in the HAZ (Heat affected zone) immediately at the root of the weld pool on the tube side
unless treated.Typical modern sleeving tubes are SAE4140/UM8 material Chrome Molybdenum alloys which will crack/fracture unless heat relieved above there upper critical limit and lowered through lower critical limit slowly and evenly.
Regarding the failed Parker it looks to me as if someone followed the std monobloc cut point of 3&1/4" . This works great for 2&1/2" Chambers but it should more accurately be expressed as 3/4" ahead of the chamber/forcing cone intersection point. Thus for a 3" chamber a cut and finished length of 3&3/4" should be used.
I would hope John Foster or Gunman would review and comment.

What Hugh Lomas says about post-annealing of the TIG welded HAZ of the sleeving joint is very interesting and raises several new questions. Foremost would be my assumption that heat relieving or post annealing above the upper critical limit would be at a temperature that might also melt the brazing used to join the barrel breech sections and underlugs of the monobloc. In that event, any post annealing would have to be very localized to prevent melting the braze joints.

While there are @ 200 degrees difference its still a risk. In the past I've used localized flame heat on the HAZ working in from the tube side then reduced T by reducing temp of flame and moving flame away and down tube from HAZ. This way high temp area is kept well away from any brazed joint which seldom get above 250f. I certainly would not want to subject whole monobloc to 1450-1500 F.

Hugh,

If I am aundestanding this right, there would be no HAZ problem with simple soldering of the tubes, ie no welding of the joint, and having the joint line visible. Is this correct?

Yes,absolutely,Lead/Tin soldering is achieved a temperatures significantly below lower critical limits.Additionally the whole monobloc is heated and cools gradually.

Hugh, thanks so much for the enlightenment. In case anyone failed to understand, good welders can work in small areas with the temperatures needed by the alloy steels. There is no need to heat the whole assembly to welding/heat treat temps - only the small HAZ.

I don't think the Met Eng meant that the steel and iron were homogenized, rather they have become more joined than "just stuck together."

DDA

I'm pretty sure that's what I was saying when I questioned the Met Engineer's use of the term "mono-metal". "Mono-metal" would certainly seem to imply homogenization. And I also said the following, which would indicate that they are more than "just stuck together."



I read several articles on Post Weld Heat Treatment which all suggest that there is more involved than simply playing a torch on the HAZ. It sounds as though doing some seat of the pants post annealing or heat treatment would be preferable to nothing at all. But some degree of control is necessary depending upon the alloys that have been welded, and the desired end result properties, ranging from full annealing to normalizing to stress relieving. Two of the factors are time and temperature which is why I questioned the possibility of affecting the brazing of the monobloc section. That could also be controlled with the use of heat sinks or heat control pastes. Here's a few articles to consider, but hardly all there is to know when the weld is subject to high pressures only inches from your face:

http://www.thefabricator.com/article/met...strengthened-st

http://www.superheatfgh.com/heat-treatment/heat-treatment-applications/post-weld-heat-treatment/

http://file.scirp.org/pdf/JMMCE20100600005_84007347.pdf

"the weld is subject to high pressures only inches from your face"

well said, and reason enough to accept the faintly visible line of a weld free solder joint.

I would like to see some images of the sleeving process especially the old barrel removal and metal preparation.

thanks j

jlb

My question is why you need to use an alloy steel for the tubes to begin with. Plain 1040 carbon steel is more than adequate for shotgun barrels and its strength is not degraded by brazing or welding.

Here you go jib

Pennsylvania Gunsmith School http://www.pagunsmith.com/photos3.php?g2_itemId=533

http://www.picturetrail.com/sfx/album/view/20580224 mostly courtesy of Toby Barclay www.heritageguns.co.uk

Because pretty much all gun barrel steel today is an alloy steel. We do not have the choices available today past gunmakers had.

Even if you had access to tubes made of earlier low alloy steel, the TIG weld joint would still have a Heat Affected Zone (HAZ) after welding that would have an altered metallurgy. I am absolutely NOT saying that TIG welded sleeving jobs are undesirable. But I've always been concerned whether the gunsmiths who do it fully understand the potential risks. I've told the story here of being totally blind for about a half-hour after a complete head separation on a .22-250 rifle. Anyone who experiences something like that has more respect for these kinds of things. Personally, I dislike seeing the joint of soldered jobs even on new manufacture monobloc guns. Some are very well done by real craftsmen, and some are butt-ugly. The jobs with the turkey-track engraving intended to hide the joint just scream cheap and dirty.

The idea of TIG welded sleeving joints is very appealing for obvious reasons. For proof that it could be done safely, one need only to examine the barrels of Thompson Center Contenders and Encores. The interchangeable barrels of these guns have the barrel lugs welded directly beneath the chambers of some pretty high pressure center fire cartridges. I would bet that there is some carefully controlled post weld heat treatment done to these barrels after welding and before chambering.

http://www.hellis.com/

whilst we're on the topic, thought this may be of interest. Towards the end of the page it tells of the first sleeved barrels to be submitted and pass proof. These were the work of Mr. Bill Roper who passed away last year.

There's also an interesting patent taken out by Henry Monk of Chester where he assembled his barrels in a similar way to the monobloc barrels we see on many OU guns which is basically the same way that barrels are sleeved. I can't find a link to that but there's a mention of it in Diggory's first book.

Neither of the above really contribute to this thread but may be of interest to those who like to read about these lovely old guns.

I wonder if the weld is there just to make the joint invisible. If the weld at the breech holds the tubes in place , would the weld around the joint need to penetrate the sleeve or just "fuse" the outer surfaces so it can be stuck up and re blacked ?
If the molten pool from the arc isn't too deep, it may not affect the tube beneath it too much.
Does that make sense ?
I realise there's heat present but it can be controlled and is localised so if the job is done slowly, maybe a pool at a time at one barrel, then the other, to allow for cooling, I'm pretty sure they wouldn't get too hot.
Another thought which leads me to think the weld is more cosmetic than structural is that they can't go all the way around, there's no room between the barrels between the top and bottom rib to work with.
I may be wrong but can't see a way to weld all the way around both tubes.

Welds can be made all the way around. I have a set of barrels that had a tiny crack welded dead between the barrels, on the right tube, about 8" from the muzzle. Don't know how he did it, but he did it.

SRH

Hi Stan, could the barrels be flexed apart at the muzzle end if the ribs were removed ? Maybe that would create enough room to work.
I'm not picking on what you say , just wondered.
I know there are some very clever and ingenious welders out there.

A small diameter 2% thoriated tungsten TIG electrode sharpened to a needle point and extended out a bit further than normal from a very small diameter ceramic cup can fit into a very small place, along with the filler rod. The ribs would of course be removed during a sleeving job, but the welding is done so close to the breech that spreading the muzzles apart wouldn't help much at all. I have no familiarity with laser welding, but I wouldn't be surprised to hear that it could be done in even tighter spots than TIG.

Hi Keith, I have a pair of scrap barrels here that I'm practicing rib relaying on and there's a surprising amount of movement between the barrels at the muzzle end when the ribs are removed which got me thinking that the repair toward the muzzle that Stan had done could've been made possible that way.
I see your point (no pun intended) about a fine Tig electrode too though. I have read about and seen pics of the sleeving process but ideally it'd be good to see the job being done to understand the work involved, I don't do any work on barrels other than blacking/Browning and raising the odd dent here and there as I'm not qualified or experienced enough to do the technical work but I'm intrigued with the whole business .

Remember the replacement barrel is machined and inserted into the monoblock. The joint is a lap joint or a socket weld. The first barrel of a pair is easily welded all around. The second takes a little push, and a little pull, to bring the filler in between the barrel set. Not unlike a pipe fitting.

The ribs were of course off the barrels when the weld was done. Keith Kearcher did the work. I was removing a bulge when the top rib popped loose. I removed the bottom one and sent them to Keith to finish removing the bulge, then relay the ribs. When he finished removing the part of the bulge between the barrels he found a tiny crack where the bulge had been. I asked him what he thought and said let's try welding it up then testing it, as it was only about 8" from the muzzles. He ran a pretty good bead dead between the barrels, but I couldn't say whether or not he sprung them apart in order to do so.

SRH

Although probably not absolute one should be able to mike the barrel OD's at a given point then measure across both barrels at that same point. When this measurement across the barrels becomes greater than the sum of the two diameters then it can be reasonably safely assumed there is now a gap between the two. Barrels are normally "Jointed" in at the breeches for some distance until their taper causes them to no longer touch.
At the normal distance for a sleeved joint there would be little "If Any" between the barrels. I believe the purpose of either the weld or solder is to prevent the tubes from moving forward, not to per se add strength to the barrels. It would thus seem that on a weld job sufficient surface could be covered without having 100% of the circumference welded.

The bicycle industry uses TIG welding more than most. For reasons of srength the welds are proud of the frame tubes. If things need to be beautified they fillet the welds, adding a gentle curvature over the weld "waves". As far as I can tell flate faired welds require V chamfers on tubes and are regarded as less durable than full weld frames.

Maybe they know things we do not.