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mtnGhost

mtnGhost

Member
Dec 15, 2018
3,564
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Defected from the PNW, United States
Thad a terrible mishap today that could have turned lethal. I was target shooting today deep in the mountains, had my new MKII on my shooting table as I was cleaning the barrel. My velocity dropped, so I decided to perk at the C3 bumper.

Longer version short - I swapped bipods while I was working on it, and then on my FC-G2. I didn't take much notice that it was seated 1 step closer to the muzzle. When I put the bottle back on, I heard the bottle valve open and the sound of my rifle starting to pressurize - but the bottle started bottoming our early. Just as I let up on turning it, I look down and instantly figure out what went wrong - the sharp corner of the bipod rail mount started digging into the the outer epoxy layer of the 480cc carbon fiber bottle!

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Man that could have been worse 👀 
 
I nicked mine putting on a bipod too. They are pretty tough-- since that is just the surface epoxy resin, can be touched up with a black permanent marker (or more elegant fixes). There is also an aluminum layer under the carbon, so pretty stout construction on these. Although all materials are notch sensitive, I doubt that you've compromised the bottle any with that scratch, just annoying though isn't it?
 
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I nicked mine putting on a bipod too. They are pretty tough-- since that is just the surface epoxy resin, can be touched up with a black permanent marker (or more elegant fixes). There is also an aluminum layer under the carbon, so pretty stout construction on these. Although all materials are notch sensitive, I doubt that you've compromised the bottle any with that scratch, just annoying though isn't it?
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Yeah, they're built to withstand little incidents like this! Definitely had a minor heart attack when I put 2 and 2 together. I knew the corner of that Accu-Tac mount was sharp and pointy, but in retrospect- it would probably have taken some Hulk strength to pop the bottle that way lol

I have three new floating spares for this MKII and my Crown(s), but this one is still fine. I'll probably just wrap some camo form around it and call it good 👍
 
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I thought you was screwing the air tank in and it pressurized and shot a pellet inches from your face. That was what I got from it as I was reading. A scratch on the bottle isnt such a big deal other than its looks. I've seen these bottle being drop, bang around, even shot at with a .45 cal 500 plus ft lb Texan and it doesnt even flitch. They are built like a tank.
 
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You could always sell it to a Crown VP owner (metal bottle) and use this as an excuse to pick up a 580cc bottle!

😉

For the truly picky out there you can cosmetically touch-up this sort of thing by carefully filling the scratch with satin polyurethane mixed with carbon black powder, then _lightly_ finish with 1500 or finer grit sandpaper. I had a neighbor with a business building carbon fiber parts for cars and learned a few tricks from him. 

But in general with a stressed vessel, best to leave it alone and not introduce other adhesives/chemicals onto the surface material. Heck, the scuba guys get all kinds of scratches (yeah, yeah-- lower pressure, but still...).

While it *appears* that the scratch is superficial, I can't judge the depth without seeing it in person, so if there is depth to the scratch, safest to have it examined by a professional inspector.
 
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get some super glue, squirt a dab on a bottle cap, then dab a bit on the tip of a tooth pic and start layering it into the scratch. Just take your time and do ONE layer, let it dry naturally, then repeat. Might take 3 or 4 layers to fill the scratch. Then finish off with a black sharpie. The tooth pic is your paint brush in the case, just make sure you go slow and don't let any super glue go over the edges of the scratch. Probably a good idea to use a new tooth pic every time you apply the glue. Medium size T-pins work well to. Super glue and carbon fiber love each other. When it dries, it bonds hard, it will never come off. Don't use super glue gel, just get regular liquid super glue. Lowes sells the Gorilla super glue, it will work well. You could also find something silly laying around the house, put a similar scratch on it, then practice your technique before going directly to the carbon bottle.




 
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Everyone using CF bottles should be aware of certain basic information just like you need to know some basic stuff when maintaining your vehicle.

This PDF by Luxfer has a LOT of information that can be gleaned on what damage is acceptable. The smaller gun mounted bottles are mostly the same.

https://www.luxfercylinders.com/img/rm_img/blog_img/454/attachments/1/luxcompinspectmanual.pdf

And you should go follow the links in my thread on CF lifetimes

https://www.gatewaytoairguns.org/GTA/index.php?topic=158055.0

Actually, don't use superglue, when I worked at a hydro shop doing lots of CF bottles for airplanes and fire departments (Federal Aviation Administration licensed/approved) we used two part epoxy {just that high strength hardware store stuff that says 'for plastics' in the double tube syringe} to fill/seal scratches that were cosmetic and also to affix the test decal
 
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You guys are freaking NUTS..!

First, that's an "aluminum"...bottle.! Seems some need new glasses.

Second, While I don't know what that gun is pressurized to, a gouge like that CANNOT...be "fixed" with some epoxy..!

Mr, mtnGhost -

While it is your face and eyes, and it may take a few more pressurization's, it WILL explode at some point in time, a much shorter time down the road than you'd wish..! I'd be buying a new bottle before I did ANY more shooting. I like my old eyes just where they are.

Mike

P.s. Working in the Aerospace industry for over 35 years and have SEEN bottles explode and why they did...please think long and hard before shooting that gun too many more times without a new bottle being installed.
 
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You guys are freaking NUTS..!

First, that's an "aluminum"...bottle.! Seems some need new glasses.

Second, While I don't know what that gun is pressurized to, a gouge like that CANNOT...be "fixed" with some epoxy..!

Mr, mtnGhost -

While it is your face and eyes, and it may take a few more pressurization's, it WILL explode at some point in time, a much shorter time down the road than you'd wish..! I'd be buying a new bottle before I did ANY more shooting. I like my old eyes just where they are.

Mike

P.s. Working in the Aerospace industry for over 35 years and have SEEN bottles explode and why they did...please think long and hard before shooting that gun too many more times without a new bottle being installed.
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Unfortunately you happen to be mistaken, it's not an aluminum bottle, both the picture clearly shows the fiber wrap and the OP says it is a CF bottle in his description. Let's not scare monger please. HPA is can be VERY dangerous if misused but if rational standards are followed it is safer than some other sports.

And I have years of experience evaluating CF damage and if it is LESS than a certain amount EPOXY IS THE DOT/FAA/Manufacturer APPROVED METHOD TO REPAIR. Generally if it's less deep than the thickness of your thumbnail it would be salvageable/repairable. There are other factors like the width and length of damage and some other things like bottom profile of the damage that cause stress risers (if there is any crack it's scrap) but on the picture it looks like a scrape, not even a gouge. On the job I measure with something more precise and evaluate with the repair manual before me. But based on the picture it has not gone through the protective layer into the strength layer which would have red tagged the bottle for sure. I describe this so the OP can look closer to make sure it's not V shaped gouge and is a flat bottomed scrape. I took out one of my bottles and compared the width and length of the scrape on his to where it would be on mine. It's also on the neck end where the wrap is thicker/stronger and more damage is allowable - if it were on the cylindrical body 'hoop stress' is more likely from similar damage that long and it might downcheck it.

You say you work in aerospace but so do I at a licensed Repair Station under the Code of Federal Regulations ( 14 CFR ) Part 145 ; When I repair a bottle I have to sign off on it using my FAA A&P license and if an incident EVER occurs I face huge fines or years of prison if I was wrong in my judgement or violated the rules and anyone's hurt or an aircraft is damaged.. not many people know that.

The picture does not appear to show the damage depth to be that much BUT if the OP wanted to be absolutely safe those bottles can be replaced for $100 to $200 unless he sources from the guns OEM who might charge too much... TalonTunes sells a certified bottle if he felt uncomfortable using one of the uncertified Chinese bottles (which NONE of them are DOT certified no matter what lies they say, just CE which is not 'legal' in the US [Note I have several Chinese bottles that I unofficially hydrotested myself and they passed so I use them on my Texans, any bottle I did not test is questionable for me to use. NO certified hydro shop can test and make legal a Chinese bottle, they have to be MANUFACTURED at a DOT certified facility and no Chinese company has tried to get the certification anyway]).

I have hydroed close to 6000 bottles {about 2500 of those were CF} (you do 30 a day for years and it adds up) and NEVER had a CF fail the hydro after it passed the internal and external visual inspection and/or repair I did! Lots of steel, stainless steel hermetic fire extinguisher and aluminum bottles fail, it's actually scary how many. I've filled a dumpster with those!

I could more comfortably suggest he locate a hydro facility with a familiarity with CF bottles (just because they hydro doesn't mean they know CF) and ask them nicely to do a visual and OK it. But if he could not get it done for free then it might cost more than a new bottle if they charged.

P.S. / FYI - Note that it's a gun bottle and they don't get tested like the bigger bottles because they aren't usually taken to commercial fill stations (as long as you use a bottle privately the DOT does not apply! Transported, used or filled commercially DOT rules) BUT if it were to be judged but the same standards then the repair HAS TO BE TRANSPARENT and if you used a marker it would automatically fail the bottle the next time because the inspector could not see the previous damage because it was 'covered up'. Also for the tube guns or the section of tube on a bottle gun, anything under 2" is not DOT regulated so they don't have a lifetime or need to be tested or documented.



Now let the OP decide what he wants to do
 
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Great oportunity to get a brand new 580cc bottle! https://talontunes.com/shop/carbon-fiber-tank/ :D

you can use that valve!, and guys, it is an aluminum bottle for sure with a CF wrap.

For that price, I would not take a risk of using that scratched bottle. Looks like it touches the aluminum part?
Click to expand...

That's what I was thinking this morning - pull the valve out and dissect the bottle. I've always wanted to cut one in half anyway 👊
 
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Kenetic45 -

You are mistaken, as in absolutely wrong, incorrect and foolish with your comments.

ALL...it takes is to note the bright shiny scratch. Carbon fiber does NOT scratch with that look of a witness mark.

I do NOT see any carbon fiber ANYWHERE in that picture. I DO see, some light scratches at about a 45°, but that is NOT, carbon fiber..! It might be someones silly attempt to make it look like carbon fiber, not even close. If it were carbon fiber, you would see broken fiber ends along the full length the gouge, there are none, the whole length...anywhere...there are none..!

mtnGhost -

I applaud you mtGhost for your decision to buy new. Very intelligent move.

Mike
 
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Great oportunity to get a brand new 580cc bottle! https://talontunes.com/shop/carbon-fiber-tank/ :D

you can use that valve!, and guys, it is an aluminum bottle for sure with a CF wrap.

For that price, I would not take a risk of using that scratched bottle. Looks like it touches the aluminum part?
Click to expand...

That's what I was thinking this morning - pull the valve out and dissect the bottle. I've always wanted to cut one in half anyway 👊
Click to expand...

No need! take the valve out and you will see 99% aluminum and 1% donno... carbon fiber? jajaja torch the bastard! jajaja 

And give that scratch bottle away for repairing, you will probably make someone happy.
 
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FYI All CF bottles have a THIN aluminum bladder, repeat THIN that is mostly to hold the shape wanted for the bottle while it is on the wrapping machine and then going through the heat cure process.

The bladder also acts as an impervious barrier to the gas BUT 99% of the strength is in the CF composite matrix.

The Carbon Fiber strength layer is COVERED BY A THIN EXTERNAL GLASS/FIBERGLASS layer to protect the CF. It can be scratched and scraped and as long as the underlying CF is not damaged the bottle still retains FULL STRENGTH.

Go to the link I provided from Luxfor bottles and READ / SEE FOR YOURSELF.

Finally, the tightly wound composite usually does not fray fibers out if damaged. Seeing fray is a visual inspection danger sign that the type of damage is too severe to pass.

Additionally, when scratched, fiberglass frequently has a white appearance in the scratch and the photo is just showing white without much contrast so it 'looks' like aluminium reflecting. Having a racing bike I scratch it's fiberglass all the time so I kind of recognized that.
 
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