Burst Test of the new Light Weight M-Rod air tube from JSA

[oldpro]

 Here is the first video. I think its important to know the tube would fail in the manner in this video long before the valve would fail in original post. The tube would swell at 9000psi and the oring would fail. Lloyd used a urethane 90d oring and a backer to keep it from extruding(failing like in this video) to force the tank to rupture. The tank actually never did rupture.

[subscriber]

I get mine today!!

Where did you order it from?

[oldpro]

I get mine today!!

Where did you order it from?

www.jsairrifles.com

[Kinetic45^]

So the 1 1/2 lb weight saving figure gets quoted...

But I would like to know real numbers because I am a precision type of guy, HaHA.  { Millwright, Gas turbine A&P n ex-machinist so live and breath exactness }

What is the weight of a GenII steel stock tube vs the weight of the Jefferson aluminum tube.

[subscriber]

double post...

[subscriber]

www.jsairrifles.com

Thanks.  Direct link for your product here:   
http://www.jsairrifles.com/Marauder-Aluminum-Air-Cylinder-Gen-2_p_25.html

[lloyd-ss]

So the 1 1/2 lb weight saving figure gets quoted...
But I would like to know real numbers because I am a precision type of guy, HaHA.  { Millwright, Gas turbine A&P n ex-machinist so live and breath exactness }
What is the weight of a GenII steel stock tube vs the weight of the Jefferson aluminum tube.

Well, I try to use the amount of precision that the job requires , and the one and a half pound figure in the video was a statement, not a quote  .

From a sample of one of each tube, rounded to the hundreth of a pound, actual weight measurements:

Marauder stock steel Gen2 tube  2.27 pounds
JSA Light Weight Gen2 tube 0.77 pounds

Weight savings = 1.50 pounds 

[FuzzyGrub]

The JSA statement on the website "This new air cylinder weighs 4.6 ounces," might have been just an estimate before the tubes were completed, or a typo.  I did use that number in some of my comments in other threads, though.  A Gen 1 air tube that I have sitting on the shelf weighs 35oz or 2.19lbs.  The Gen 2 air tube is slightly longer, so Lloyd's numbers look right on, as you would expect. 

[kkarmical]

You guys are making it impossible for me to ever just be done with my Mrod.  The good thing losing the weight... The bad thing having a stock tube just sitting around is only going to lead to some sort of project in the future... Which translates to I'll be ordering one soon.

Which leads to my asking maybe a dumb question, but if I use one without a gauge port, would that be best for going all in most power tune?  I can see the benefit of the gauge with regulation but if I go all in max fpe for 8 tune I'm thinking I can ditch the gauge just use gauge from my tank...

I'm probably going to end up with one of each...

[makoda]

well I ordered friday or saturday and it was already in the mail this morning.  I don't even know how thats possible.  Anyway I am a very patient person so I put it on the gun today already and shot it.  wow is all I can say, feels like a different gun completely.  Infact its lighter than my streamline(laminate) with the marauder synthetic stock and with the boyds jacardnia thumb hole stock.  As for the color some were wondering about, it is black so it doesn't match the purple hued shroud  , infact its a little more black than the marauder tube so the contrast is a little more.  oh well I don't' care anyway just letting others know. 

Now not sure if it was an overlooked detail or intentional but the hole for the transfer port adjustment screw is not there so unless you drill one you won't be using that anymore.  For me it doesn't matter anyway I always leave it fully open so I don't need to access it.

I would post a picture of my gun but honestly not sure how.  Had a relative put my avatar picture on for me and help me post some pics in nuah once but I can't figure it out.  Doesn't matter though, others were just wondering about the weight and yeah it feels much lighter.

[lloyd-ss]

I think I figured out how to attach a picture again.

This picture shows the front end of the light weight tube after the 10,000 psi test.  As stated previously, the tube grew about .050" in diameter and the volume increased about 20ccs. I think you can see the swelling in this picture.  The swelling stops in the vicinity of the o-ring. That's another good reason to keep the o-ring inboard of the threads.

[mobilemail]

10,000psi?? Most of us have a problem finding a dive shop that fills our tank to 4500.....

That said, I don't plan on exceeding 3000psi, have no reason to.

[lloyd-ss]

Ok, ok. So if you can't do 10k, how about 9k? 
Here are two pictures of the valve screw areas after the 9,000 psi test (o-ring failure).
Periodically check your airgun for this type of distortion, particularly if it is over-pressurized.

[oldpro]

 Thats some serious tension stress applied there. Im scared when I fill these high fill guns to 4500 not sure if I could keep my pants clean testing a tube to 10000PSI!!!

[Motorhead]

Ok, ok. So if you can't do 10k, how about 9k? 
Here are two pictures of the valve screw areas after the 9,000 psi test (o-ring failure).
Periodically check your airgun for this type of distortion, particularly if it is over-pressurized.

Knurling ... COOL 

[lloyd-ss]

Surprisingly, the 3 screws easily threaded out after the 9k test, even though the valve body had puckers about .008 tall at each screw counterbore.

I didn't try to take the screws out after the 10k test  ,  and this tube should be back in  the hands of JSA tomorrow.
Here is a pic after the 10k test. Click on the picture to expand it to see the detail. Scary. But it was more than 3 times the recommended fill pressure. 

[SilentMatt]

well I ordered friday or saturday and it was already in the mail this morning.  I don't even know how thats possible. 

I was in the shop Friday and shipped it right after you ordered...

[Motorhead]

Lloyd,
The valves retaining screws appear to be SS and not the OEM Black oxide.
Unless  it is just a lighting thing

Reason of inquire has a few issues that I make note of.
1st being the screws in use have the striated head that clearly indented into tube at retention holes in the 9K test & inspection.
Sharp corners made as such would become stress risers and create a point of fracture ... where as a SMOOTH head socket head screw would not.

Any thoughts on this ?

Scott

[lloyd-ss]

Hmm, Scott, I never gave it much thought. In fact, I have never really looked for socket head screws with a smooth head.  I would think that at normal loadings it wouldn't be an issue.
I looked thru my boxes of SS and blk ox standard and high strength socket heads, and have to say that I only found a couple of odd screws that had a smooth O.D.  Pretty much everything had the lightly straight knurled heads.  However, all of the low profile socket heads are smooth.

Also, during these tests, the tubes failed at the holes for the screw heads just about as calculated. And yes, they are SS screws.

[Motorhead]

Hmm, Scott, I never gave it much thought. In fact, I have never really looked for socket head screws with a smooth head.  I would think that at normal loadings it wouldn't be an issue.
I looked thru my boxes of SS and blk ox standard and high strength socket heads, and have to say that I only found a couple of odd screws that had a smooth O.D.  Pretty much everything had the lightly straight knurled heads.  However, all of the low profile socket heads are smooth.

Also, during these tests, the tubes failed at the holes for the screw heads just about as calculated. And yes, they are SS screws.

Thanks ... just had a thought seeing the sharp indents .. "AH' stress points for a fracture to start from

As we were