Tube erosion?

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cdhknives
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Tube erosion?

Post by cdhknives » Thu Jul 13, 2017 2:22 pm

I know blast baffles are usually made of tougher material (will be 17-4 in my design) to handle the erosion from direct impingement of the hottest, fastest, and most loaded with particulate jets. Do the tube sidewalls also get significant erosion from similar effects? I've never seen this addressed...everyone seems to just comment on the blast face erosion and bore peening.

In other words should I build the tube thicker (or add a liner) in the blast baffle area to compensate for increased erosion?

Primary concern (for me, today) is a 6061-T6 tube for 22lr but also applicable in general.
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partsguy22
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Re: Tube erosion?

Post by partsguy22 » Thu Jul 13, 2017 3:05 pm

I don't think this is such a big deal.

In all of my stuff it ends up caked in carbon fairly thick ...its funny my cans that use brakes have carbon marks in them that show exactly where the ports in the brake vent... anyway if the gas were causing erosion, I don't think it would build up like it does.
Unlike the blast baffle on say my 5.56 SBR can where it is bare metal with the thinnest coating of carbon

I think by the time the gases hit the tube wall they have both cooled and slowed enough that they won't do much damage but I believe a blast chamber should be thicker just to handle the muzzle pressure (a non issue on a .22 can).

ETA : None of my cans are AL tubes so this maybe completely wrong its just my observation
Also a liner or nesting baffles in a .22LR can will also help keep the tube "clean" so it will disassemble easer

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Capt. Link.
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Re: Tube erosion?

Post by Capt. Link. » Thu Jul 13, 2017 3:34 pm

You need to protect aluminum in centerfire rifle calibers the erosive effect could easily cause a breach.
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yondering
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Re: Tube erosion?

Post by yondering » Thu Jul 13, 2017 7:32 pm

Just anodize the tube, it'll be fine. BTDT. It's just a .22 LR after all. You sure don't need 17-4 for the baffles either.

I've noticed lately here people worry way too much about erosion and longevity of low pressure cans like .22 LR and 9mm.

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T-Rex
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Re: Tube erosion?

Post by T-Rex » Fri Jul 14, 2017 8:39 am

Everything said thus far is on point.

Most end users want SS internals so they'll have the ability to clean via ultrasonic, the dip, and other methods which would otherwise be detrimental to Al parts.
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cdhknives
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Re: Tube erosion?

Post by cdhknives » Fri Jul 14, 2017 2:15 pm

I will only run one 17-4 baffle...the blast baffle...to keep weight down. However I could visualize the deflection from the blast face directly impinging on the aluminum tube and wondered if anyone here had seen significant erosion on high round count cans from this. It would be reduced, but still seems like a possibility especially on pistols (which I expect to be my primary host).

I also plan to build the blast chamber thicker for several reasons. Threads. Higher pressure/durability. A step to seat the blast baffle against. I didn't want erosion to force an even thicker blast chamber...

Thanks for the info!
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Re: Tube erosion?

Post by Fulmen » Fri Jul 14, 2017 4:59 pm

Short answer: I doubt it. The velocity will be greatest at the bore, at the periphery the gas will flow slower and any erosion will be distributed over a much larger area. So except for the blast chamber (especially with an internal brake) I wouldn't worry too much about it. I put a grade 2 Ti spacer in my aluminum 222-can, not so much for the erosion but to add hoop strength where the pressure is highest. The baffles do erode a bit around the bore, but that's it.

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yondering
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Re: Tube erosion?

Post by yondering » Fri Jul 14, 2017 9:39 pm

cdhknives wrote:I will only run one 17-4 baffle...the blast baffle...to keep weight down. However I could visualize the deflection from the blast face directly impinging on the aluminum tube and wondered if anyone here had seen significant erosion on high round count cans from this. It would be reduced, but still seems like a possibility especially on pistols (which I expect to be my primary host).

I also plan to build the blast chamber thicker for several reasons. Threads. Higher pressure/durability. A step to seat the blast baffle against. I didn't want erosion to force an even thicker blast chamber...

Thanks for the info!
Again, it's just a .22; it sounds like you're going way overboard on trying to make it strong enough.

On the baffles - if a guy wants all SS baffles for cleaning, I get it. But if you're going to use some aluminum baffles, they might as well all be aluminum in a .22 can. You might as well use 7075 instead of 6061 for strength with no weight penalty and only minor cost difference, but you don't need a 17-4 blast baffle for erosion.

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Capt. Link.
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Re: Tube erosion?

Post by Capt. Link. » Sat Jul 15, 2017 11:07 am

cdhknives wrote:I could visualize the deflection from the blast face directly impinging on the aluminum tube and wondered if anyone here had seen significant erosion on high round count cans from this.
Several years back a member posted pictures of a [Red Jacket] aluminum tubed 7.62x39 suppressor.The internal damage in the blast chamber was extensive.The pressure tube would have ruptured in the near future if not caught.They used stainless flat baffles that were undamaged.
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partsguy22
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Re: Tube erosion?

Post by partsguy22 » Sat Jul 15, 2017 2:31 pm

I thought that was due to the fact AL weakens/softens so much when exposed to heat like that found in a centerfire can which worsens the erosion issue

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Re: Tube erosion?

Post by Fulmen » Sat Jul 15, 2017 5:42 pm

CL: Was it erosion or deformation from the heat&pressure?

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Capt. Link.
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Re: Tube erosion?

Post by Capt. Link. » Sun Jul 16, 2017 5:04 pm

Fulmen wrote:CL: Was it erosion or deformation from the heat&pressure?
I'm going to call it pitting as deep craters were all along the baffle tube wall interface.I don't believe that this was exposed to full auto fire.It would have benefited from some type of shielding.
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yondering
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Re: Tube erosion?

Post by yondering » Sun Jul 16, 2017 10:17 pm

Pitting sounds more like corrosion, but I didn't see it.

Still, that's a rifle round. This thread is about a 22 LR suppressor.

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Re: Tube erosion?

Post by Fulmen » Mon Jul 17, 2017 2:39 am

I agree, aluminum cans can corrode quite fast if not properly cared for. But without having seen it it's just speculation on my side.

That being said, aluminum centerfire cans are more common than roadkill around here, have yet to see a can with erosion at the outer walls.

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Capt. Link.
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Re: Tube erosion?

Post by Capt. Link. » Mon Jul 17, 2017 7:34 pm

Fulmen wrote:I agree, aluminum cans can corrode quite fast if not properly cared for. But without having seen it it's just speculation on my side.
The damage was pronounced on the baffle leading edge.If it was corrosive it would have been more uniform in distribution.It looked like the metal was soft and grains of powder impacted with the wall baffle interface giving it a moon like surface. This may be a worse case possible but you must take into account the prestigious builder. :lol:
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The only reason after 243 years the government now wants to disarm you is they intend to do something you would shoot them for!

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