DM tube failure. Updated with photo.

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[ARCHIVED THREAD] - DM tube failure. Updated with photo. (Page 1 of 2)

Posted: 12/19/2018 2:03:16 PM EDT

My DM Ti rimfire tube has failed. My son discovered a crack running almost the length of the can while out hunting tree rats this morning. Looks like another tax stamp waiting game ahead.

Laser Engraving done by AR manufacturing facility here in West TN. (I omitted their name because they treat me really well.)

Attached File

Posted: 12/19/2018 4:14:12 PM EDT

[#1]

Bummer. Pics? How old was it? Gun(s) it had been shot on?

Posted: 12/19/2018 5:36:26 PM EDT

[#2]

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Quoted:
Bummer. Pics? How old was it? Gun(s) it had been shot on?

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I’ll get pics latter, it’s about 3 yrs old, only used on Rimfires with most of its time on a Savage bolt action with CCI Standard velocity LR.

Posted: 12/19/2018 6:10:19 PM EDT

[#3]

Find a good TIG guy and have him lay a bead on the crack

Posted: 12/19/2018 6:13:52 PM EDT

[#4]

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Quoted:
Find a good TIG guy and have him lay a bead on the crack

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This is what I was thinking. As long as it's not through the SN, a repair should be doable.

Posted: 12/19/2018 6:31:34 PM EDT

[#5]

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Quoted:
This is what I was thinking. As long as it's not through the SN, a repair should be doable.

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Quoted:

Quoted:
Find a good TIG guy and have him lay a bead on the crack

This is what I was thinking. As long as it's not through the SN, a repair should be doable.

Unfortunately the crack is at the bottom of the last line of laser engraving which includes the S/N.

Posted: 12/19/2018 6:40:24 PM EDT

[#6]

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Unfortunately the crack is at the bottom of the last line of laser engraving which includes the S/N.

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Id send it

The right TIG guy can make tiny welds

.060 sheet metal cut into inch squares

Posted: 12/19/2018 6:55:40 PM EDT

[#7]

I almost jokenly told him to put a hose clamp on it but I was afraid he’d take me seriously.

Posted: 12/19/2018 7:37:23 PM EDT

[#8]

With those low pressure rounds, I'd tape it up and call it good. If anyone ever needs to see the numbers, time for new tape.

Posted: 12/19/2018 11:14:52 PM EDT

[#9]

I have a customer sending me a can with a crack thru a dm 1.625 tube. It was built this year, has about 300 rounds total of which 40 or so were supers. The rest subsonic. I'll know more after i can put my hsnds on it.

Posted: 12/19/2018 11:15:18 PM EDT

[#10]

I have a customer sending me a can with a crack thru a dm 1.625 tube. It was built this year, has about 300 rounds total of which 40 or so were supers. The rest subsonic. I'll know more after i can put my hsnds on it.

Posted: 12/19/2018 11:15:49 PM EDT

[#11]

What were the specs on the tube, and what was the depth and method of engraving?

Posted: 12/19/2018 11:22:43 PM EDT

[#12]

I think that the laser engraving is the culprit.

I saw one that was cracked right along the wide, blocks engraving. I don't think it was depth. I think that the heat made it brittle. This was a CF rifle suppressor, though.

Posted: 12/20/2018 10:32:42 AM EDT

[#13]

What's the tube OD? Might be able to do a sleeve repair, cut out a window for the engraving.

I'd be curious what caused the failure. Maybe they got a bad batch of tube, or the wrong grade? Even annealed gr. 9 is pretty tough, and I've run full auto .308 from a 13" barrel through my Phoenix, which uses a .035" wall gr. 9 CWSR tube. It was already well over 1,000°F when I cut loose, still held together, even at the thread undercut where it's only .017" thick. I knocked out the melted remnants of the aluminum baffles, recored it and am still punishing that one.

It's an unlisted video because it came out like shit, and the wife bumped the zoom when moving camera for me, but a demonstration of what even a very thin walled Ti tube can handle

https://www.youtube.com/watch?v=wRBzyPvX4P0

Posted: 12/20/2018 5:44:40 PM EDT

[#14]

I had a 1.625" OD DM tube w/ Tar Heel State engraving crack right along the bottom of the engraving. Also dropped an ammo box on it, figured that was the cause.

Posted: 12/20/2018 6:52:32 PM EDT

[#15]

Quote History

Quoted:
What's the tube OD? Might be able to do a sleeve repair, cut out a window for the engraving.

I'd be curious what caused the failure. Maybe they got a bad batch of tube, or the wrong grade? Even annealed gr. 9 is pretty tough, and I've run full auto .308 from a 13" barrel through my Phoenix, which uses a .035" wall gr. 9 CWSR tube. It was already well over 1,000°F when I cut loose, still held together, even at the thread undercut where it's only .017" thick. I knocked out the melted remnants of the aluminum baffles, recored it and am still punishing that one.

It's an unlisted video because it came out like shit, and the wife bumped the zoom when moving camera for me, but a demonstration of what even a very thin walled Ti tube can handle

https://www.youtube.com/watch?v=wRBzyPvX4P0

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All sorts of issues with that filming, but fun nonetheless to watch.

I'm gonna vote engraving issue as well was the cause of the OPs issue.

Posted: 12/21/2018 9:16:05 AM EDT

[#16]

You are required to have the serial number on the can. Are you NOT allowed to have the serial number in more than one location? For instance I've seen the info engraved on end caps.

Posted: 12/21/2018 3:10:36 PM EDT

[#17]

Regardless of the legality of re-serializing it, which I think is arguable either way, I'd be more worried about the repair.
Could you seam weld it? Sure. However, now you have a welded tube, one which failed as seamless. I wouldn't feel good about it. It sounds like something might have been off in the alloy or process.
I like 662's opinion on a sleeve, if you're unable to do it yourself.
If you have the skills, simply file another stamp; make a new tube w/ new serial; serialize the end cap w/ the old #; use old baffles, etc.

Posted: 12/21/2018 6:08:36 PM EDT

[#18]

OST

Posted: 12/24/2018 1:18:28 PM EDT

[#19]

Its too bad building another can using the same stamp/serial and destroying the old tube is illegal. Too bad.

I'd weld, use hose clamps, or even use some JB weld on it. 22LR should be ok.

Posted: 12/24/2018 1:30:45 PM EDT

[#20]

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Its too bad building another can using the same stamp/serial and destroying the old tube is illegal. Too bad.

I'd weld, use hose clamps, or even use some JB weld on it. 22LR should be ok.

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This.

Posted: 12/24/2018 3:27:22 PM EDT

[#21]

I have a DM .22 kit on order. Should I be concerned? Seems several people are having these issues from this thread.

I sent an email with some basic questions when I ordered back on 12/6 and never received a response. They also charged immediately and it remains in "processing", not "backordered". I don't mind waiting if the product was OOS, but it still says in stock on the site (where other variants of the product explicitly state they are OOS). I know they aren't fly by night and they are possibly overworked, but a response to someone who just sent you a couple hundred bucks for a presumably in stock item would be nice.

Posted: 12/24/2018 6:23:43 PM EDT

[#22]

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Quoted:
I have a DM .22 kit on order. Should I be concerned? Seems several people are having these issues from this thread.

I sent an email with some basic questions when I ordered back on 12/6 and never received a response. They also charged immediately and it remains in "processing", not "backordered". I don't mind waiting if the product was OOS, but it still says in stock on the site (where other variants of the product explicitly state they are OOS). I know they aren't fly by night and they are possibly overworked, but a response to someone who just sent you a couple hundred bucks for a presumably in stock item would be nice.

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Without pictures sounds like it is an engraving issue not a tube issue.

Deep engraving, sharp corners, weak link

Posted: 12/24/2018 7:18:40 PM EDT

[#23]

Its interesting and would love to see the pictures. Anyone know what the wall thickness of the DM tubes are. I know the SD is .070

I would imagine for 22 it should not crack, I just cant see that much pressure.

Posted: 12/25/2018 1:02:22 PM EDT

[#24]

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Its interesting and would love to see the pictures. Anyone know what the wall thickness of the DM tubes are. I know the SD is .070

I would imagine for 22 it should not crack, I just cant see that much pressure.

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The cracked tube that I saw was a 1.625/1.480 (ti)... so over 0.07 wall.

Posted: 12/25/2018 5:38:05 PM EDT

[#25]

Easiest way to find out, go to DM's website and look his tube selections. He gives the O.D. and I.D. measurements. O.D. - I.D. and then divide by two.

Still waiting on those pics, OP.

Posted: 12/26/2018 1:58:41 PM EDT

[#26]

Is there any way you can post pics of the failure area (blur out any identifying info or zoom in on crack).?

DM's 1.125 X 0.995" tube shouldn't be any thinner than 0.060" at any spot and reasonable depth engraving should leave plenty of material in a low stress area. Hoop stress on small diameter tubes is also less than larger tubes.

The tube may have had a defect from the mill, or the laser may have lingered too long in one spot.

For rimfire as long as it isn't leaking plumes of gas I'd adhesive bond a 1.125" ID aluminum sleeve on each end of the marking and just shoot the crap out if it.

Posted: 12/26/2018 6:21:54 PM EDT

[#27]

Quote History

Quoted:
any spot and reasonable depth engraving should leave plenty of material in a low stress area, or the laser may have lingered too long in one spot.

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Though the HAZ should be inconsequential with a good laser, that is one reason I do mechanical engraving. Laser is great for doing detailed images with very shallow depth, but I prefer to run an .020" end mill for alphanumeric stuff that has to be deeper.

Posted: 12/26/2018 11:18:06 PM EDT

[#28]

Updated with photo at the top.

Posted: 12/26/2018 11:55:23 PM EDT

[#29]

It had to have been the engraving. Interesting to see how the crack moves through the letters.

Posted: 12/26/2018 11:55:55 PM EDT

[#30]

Quote History

Quoted:
I think that the laser engraving is the culprit.

I saw one that was cracked right along the wide, blocks engraving. I don't think it was depth. I think that the heat made it brittle. This was a CF rifle suppressor, though.

View Quote

I do believe you are right.

Posted: 12/27/2018 12:23:03 AM EDT

[#31]

Wow. Even with deep engraving it's hard to believe rimfire pressures, especially down stream of the blast chamber could have applied significant enough stress. Regardless, it looks like the fracture line followed the path of least resistance through the longitudinal engraved strokes.

Perhaps a clear lexan tube/sleeve would be an adequate repair 'tourniquet' for gas leakage? Or perhaps sleeve the interior with thin Ti and turn the baffles to fit if they have enough meat on them.

I wonder if a circumferential engraving orientation presents less of a path to propagate a crack?

Posted: 12/27/2018 1:26:58 PM EDT

[#32]

Quote History

Quoted:
Wow. Even with deep engraving it's hard to believe rimfire pressures, especially down stream of the blast chamber could have applied significant enough stress. Regardless, it looks like the fracture line followed the path of least resistance through the longitudinal engraved strokes.

Perhaps a clear lexan tube/sleeve would be an adequate repair 'tourniquet' for gas leakage? Or perhaps sleeve the interior with thin Ti and turn the baffles to fit if they have enough meat on them.

I wonder if a circumferential engraving orientation presents less of a path to propagate a crack?

I wonder if a circumferential engraving orientation presents less of a path to propagate a crack?

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Came to suggest this^, especially if at the "end" of the can.

Posted: 12/27/2018 2:44:48 PM EDT

[#33]

I know how I’d fix it...and it wouldn’t have included posting here.

Posted: 12/27/2018 2:53:22 PM EDT

[#34]

;), yep.

Posted: 12/27/2018 3:11:30 PM EDT

[#35]

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I know how I’d fix it...and it wouldn’t have included posting here.

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This

Posted: 12/27/2018 6:05:07 PM EDT

[#36]

Quote History

Quoted:

Came to suggest this^, especially if at the "end" of the can.

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The dilemma of engraving near the end of the tube, or the front cap, is potential of a baffle strike putting a bullet into or through the marked area. I think marking the thick metal of the rear mount is probably the safest place. It's not conspicuous when the can is mounted on a host, but actually makes sense from the standpoint of looking at the suppressor before mounting it. Might keep a 1/2-28 22 can from absent mindedly being put on a 1/2-28 9mm host. Probably a rare event, but I always look through a can for obstructions before threading on, as well as thread condition. So rear marking would be staring me in the face. Otherwise I only look at the marking position when using it as a clocking index.

Another benefit to marking the mount is if it is lost in the mail for marking it doesn't feel like the suppressor is lost. The thought of losing an NFA marked Form 1 item in shipping gives me pause.

Posted: 12/28/2018 7:38:05 AM EDT

[#37]

Ok so it seems most of the Outside to Inside dimensions are about .125 so .0625 wall thickness. This should be plenty thick. The design on mine uses a blast chamber spacer then 60 degree cones that are skirted, so this adds some strength but looses some volume in the tube.

I agree it looks the the engraving did it. May be another reason to start engraving the mount instead of the tube. Or the end cap. Thank you for posting pictures OP.

Posted: 12/28/2018 12:08:53 PM EDT

[#38]

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Quoted:
I know how I’d fix it...and it wouldn’t have included posting here.

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Me too, I wouldn't have posted here but my millennial son had already put a pic of it on the electronic smorgasbord for all the world and the NSA to see.

No, I'm not paranoid but I have worked for the Imperial Federal Govt (Active duty, contractor and now an Alphabet Agency) for 36 years and know how much they can "help you".

Posted: 12/29/2018 9:34:21 PM EDT

[#39]

Seems like laser engraving may not be the way to go for a titanium can. I had a titanium DM tube fail as well.. same story... right along the laser engraving.

Posted: 12/29/2018 11:40:02 PM EDT

[#40]

Quote History

Quoted:
Seems like laser engraving may not be the way to go for a titanium can. I had a titanium DM tube fail as well.. same story... right along the laser engraving.

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Any recommendations for an alternate engraving service? This has me a little paranoid.

Posted: 12/29/2018 11:50:50 PM EDT

[#41]

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Quoted:

Any recommendations for an alternate engraving service? This has me a little paranoid.

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End cap, preferably the barrel end.

That’s where all of my F1 cans are marked.

Posted: 12/30/2018 12:27:04 AM EDT

[#42]

Quote History

Quoted:
End cap, preferably the barrel end.

That’s where all of my F1 cans are marked.

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View All Quotes

Quote History

Quoted:

Quoted:

Any recommendations for an alternate engraving service? This has me a little paranoid.

End cap, preferably the barrel end.

That’s where all of my F1 cans are marked.

I could have sworn a year or two ago the ATF said suppressor have to marked on the tube. Did they back off on that?

Posted: 12/30/2018 12:50:42 AM EDT

[#43]

ETa: Double tap

Posted: 12/30/2018 12:51:42 AM EDT

[#44]

Quote History

Quoted:
I could have sworn a year or two ago the ATF said suppressor have to marked on the tube. Did they back off on that?

View Quote View All Quotes

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Quote History

Quoted:

Quoted:

Any recommendations for an alternate engraving service? This has me a little paranoid.

End cap, preferably the barrel end.

That’s where all of my F1 cans are marked.

I could have sworn a year or two ago the ATF said suppressor have to marked on the tube. Did they back off on that?

Got a link?

I’d engrave the rear end mount if I ever form 1 a can. I know it’s been done in the past without issue unless that’s changed.

Posted: 12/30/2018 1:17:52 AM EDT

[#45]

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Got a link?

I’d engrave the rear end mount if I ever form 1 a can. I know it’s been done in the past without issue unless that’s changed.

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Quoted:

Quoted:

Any recommendations for an alternate engraving service? This has me a little paranoid.

End cap, preferably the barrel end.

That’s where all of my F1 cans are marked.

I could have sworn a year or two ago the ATF said suppressor have to marked on the tube. Did they back off on that?

Got a link?

I’d engrave the rear end mount if I ever form 1 a can. I know it’s been done in the past without issue unless that’s changed.

Here it is: https://www.federalregister.gov/documents/2016/05/04/2016-10382/identification-markings-placed-on-firearm-silencers-and-firearm-mufflers

Looks like it was just a proposed rule change, but I can't find any evidence that anything ever came of it.

Posted: 12/30/2018 10:57:07 AM EDT

[#46]

These recent incidents of failures at the engraving are a good example of why some paper shuffling, central planning bureaucrat shouldn't dictate design details on a pressure vessel that could rupture in front of your face.

Hopefully if the marking guidance ever comes up for revision again these examples will still be in fresh in memory of those able to object.

Government do gooders have ruined toilets, shower heads, hot water heaters, dish washing detergent, alkaline batteries, with no proof of benefit. I've spent hours and hundreds of dollars de-lawyering my Ruger rimfire pistols. Every time you look at a product manual and have to wade through pages of worthless common sense warnings to find a useful spec or feature described it's an example of the same mentality.

Posted: 12/31/2018 9:28:05 PM EDT

[#47]

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Any recommendations for an alternate engraving service? This has me a little paranoid.

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For all my NFA engraving needs, I use Orion. All their engraving is done with a rotary engraver, they don't do laser engraving at all.

Orion Arms

Posted: 1/1/2019 11:38:22 AM EDT

[#48]

Is the engraving on the bbl end (highest pressure / heat) or on the far end?

Posted: 1/5/2019 1:15:15 AM EDT

[#49]

Quote History

Quoted:
Me too, I wouldn't have posted here but my millennial son had already put a pic of it on the electronic smorgasbord for all the world and the NSA to see.

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Well it is only one side of the can, and does not show the identical engraving on the other side.

Posted: 1/10/2019 6:05:21 PM EDT

[#50]

This is technically from a medical journal, but deals with the effects of laser engraving on metal (and specifically titanium).

https://www.hindawi.com/journals/jme/2013/570354/

Interestingly (and unfortunately) an engraving depth of 75um (.003 in) resulted in a fatigue strength that was significantly lower that an un-engraved surface.

While this article does not address issues critical to us, such as the change in metallurgy due to applied heat and hoop strength, it does provide some valuable insight.

I wonder is refinishing an engraved surface by a technique such as vapor honing could blend any sharp edges and minimize stress concentrations. This wouldn't provide a crisp looking engraving like I prefer, but it may help.

Since I already have several in-process Form 1s with titanium tubes already engraved I am going to stick with M baffles or similar that inerterlock. At a minimum this should more evenly distribute the pressure. I may also weld the baffle stacks on my rifle caliber cans.

[ARCHIVED THREAD] - DM tube failure. Updated with photo. (Page 1 of 2)

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