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HPC

Packing Old but Airworthy Reserves

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Yes, after an Act of Congress I'm finally starting to get the ever-elusive "yes" or "no".
Thanks for your reply.
Now, maybe you could use some of your rigger influences and get some of the others to come on board??;)
What's right isn't always popular and what's popular isn't always right.

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rmarshall234

>Nylon does not degrade from age alone.

Are you sure about this? Because I've heard otherwise. Not arguing the point, just curious.



It ages very slowly, but the material does age.

I can't claim any values with confidence, but here's something quotable from a 2014 post of mine in a similar thread:
(Although just based on a single Australian military study in 1984 that used elevated heat to then extrapolate strength loss over many years in more normal conditions.)

Quote

The explanation for strength loss due to time alone (such as in storage) is that nylon oxidizes over time, and as with many chemical reactions, it happens faster as the temperature increases.
...
The extrapolated strength loss of the canopy fabric -- i.e. calculated not measured -- would be about 1.75% when stored at 25 C over 20 years. Or about 1.5% if stored at 20 C for the same time.



http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=4604089#4604089

UV and mechanical wear from packing are another matter.

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Do you have a reserve age limit after which you won't repack the reserve, even if it's in excellent condition and inspected and re-certified by the manufacturer?



No. My reasoning is simple.

I treat every canopy the same no matter how old it is by inspecting it thoroughly myself.

Now add that to the fact that I have never known a reserve parachute to fail from normal use and/or old age. At least not any that did not have known issues like acid mesh. That is again never to my knowledge..ever.

MEL
Skyworks Parachute Service, LLC
www.Skyworksparachuteservice.com

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Thanks for your reply and explanation. I agree with you in that every reserve is different with regards to age and wear, and each reserve needs to be treated individually. Your judgment is based on condition, which has been what I've been talking about all along.:)
What's right isn't always popular and what's popular isn't always right.

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HPC

Why have you jumped into your time machine, gone back millions of years and returned with some dinosaurs? My OP had NOTHING to do with rounds. I clarified my question with a comparison between two reserves that are IDENTICAL except for age, and asked a simple close-ended question (that means a simple yes or no answer, followed by an explanation which my OP also asked to provide) to which very few responders have provided (thank you, Mr. Baumchen!).
Am I speaking Swahili here??



If you'll go back to read my original response to you, pagalwallah, I agreed -- in English -- that I would repack that recertified reserve back from PD, because it is still good enough to be produced.

Also, thank you for supporting my point that appropriateness for intended use should be a consideration in whether you should pack a particular reserve (regardless of age) for a particular customer. I note that Mr. Baumchen and I disagree about this.

-Mark

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HPC

This post is for riggers only.
Do you have a reserve age limit after which you won't repack the reserve, even if it's in excellent condition and inspected and re-certified by the manufacturer? If so, what's your reasoning?
Thanks.



No, age is not a factor for me. Design and my personal qualifications and familiarity are.
Always remember the brave children who died defending your right to bear arms. Freedom is not free.

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pchapman

quoted from a source: The extrapolated strength loss of the canopy fabric -- i.e. calculated not measured -- would be about 1.75% when stored at 25 C over 20 years. Or about 1.5% if stored at 20 C for the same time.



Peter, that is similar to what a colleague of mine found from (I think) some military study, perhaps the same one you refer to.

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masterrigger1

Quote


Do you have a reserve age limit after which you won't repack the reserve, even if it's in excellent condition and inspected and re-certified by the manufacturer?



No. My reasoning is simple.

I treat every canopy the same no matter how old it is by inspecting it thoroughly myself.

Now add that to the fact that I have never known a reserve parachute to fail from normal use and/or old age. At least not any that did not have known issues like acid mesh. That is again never to my knowledge..ever.

MEL



Does the Laser that failed a tensile test as soon as I started added pressure (no more than 3 lbs) twice not count because it didn't happen in the air? It would have been a catastrophic failure. This is a reserve I maintained for most of it's life so know its history. There was no reason for the failure other than transfer of the urethane coating from a Javelin reserve bag to the canopy. The feel of this transfer, which I've had on many other canopies, was the reason for the test. No acid mesh in site.

Should have shown it to you when you were here. I still have it, the owner didn't want it anymore.:o
I'm old for my age.
Terry Urban
D-8631
FAA DPRE

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Wouldn't that be the fault of the Javelin reserve bag's coating and not the reserve itself? IOW, had that reserve been say a PDR, could it be assumed that the PDR would have failed the test due to the urethane transfer?
Just wondering.
What's right isn't always popular and what's popular isn't always right.

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councilman24

No, I have found that transfer on lots of reserves as have others I've talked to. No others failed.



That can only mean that APS/FTS used an inferior material, or that the canopy was subjected to some form of degradation. Which do you suspect?
Always remember the brave children who died defending your right to bear arms. Freedom is not free.

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I can never keep the two companies straight but I've been told one would buy fabric whereever he could. Someone on here is related to other owner. I don't believe it was degeaded in any special way. Bad area was localized and I knew histkry of canopy. One owner and pretty much one rigger.

Acid mesh on rounds was never just the mesh. I had one canopy with two panels of one gore in contact with one piece of mesh. Both panels white. Since the day it was sewn together the two panels saw the same mesh and the same environmental conditions. Heat, light, moisture. One panel was fully degraded to no strength. The other panel was full strength. Fabric samples were supplied to Invista, spin off of Dupont, who made the nylon 66. But they never reported back to PIA any findings, perhaps to not admit any responsibility. It was NEVER just acid mesh. There where lots of acid mesh canopies and few with degraded fabric. And nobody ever publically reported issues with the fabric.

I'm an analytical.chemist but not a polymer chemist. At the time I examined good and bad fabric by x-ray fluoresence and FTIR spectroscopy. Couldn't find a difference.
I'm old for my age.
Terry Urban
D-8631
FAA DPRE

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pchapman

***>Nylon does not degrade from age alone.

Are you sure about this? Because I've heard otherwise. Not arguing the point, just curious.



It ages very slowly, but the material does age.

I can't claim any values with confidence, but here's something quotable from a 2014 post of mine in a similar thread:
(Although just based on a single Australian military study in 1984 that used elevated heat to then extrapolate strength loss over many years in more normal conditions.)

Quote

The explanation for strength loss due to time alone (such as in storage) is that nylon oxidizes over time, and as with many chemical reactions, it happens faster as the temperature increases.
...
The extrapolated strength loss of the canopy fabric -- i.e. calculated not measured -- would be about 1.75% when stored at 25 C over 20 years. Or about 1.5% if stored at 20 C for the same time.



http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=4604089#4604089

UV and mechanical wear from packing are another matter.


Excellent. Thank you for your reply! That is the science-based response I was looking for and very helpful.

(The OP's response that he heard it from PD carries weight as well, but I don't care for his tone and don't like that his profile is empty so I'm moving on from this thread.)

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That is why I no longer repack round reserves built during the acid-mesh era (1980s).

This is more about refusing to repack older GENERATIONS of equipment.
Heck!
I don't even have the tools (to test for acid mesh) any more.
Similarly, I don't pack rounds without diapers.
I do not pack any pre-Swift square reserves and the numbers of Swift (both 5-cell and 7-cell) are dwindling in my area. I rarely see square reserves built during the 1980s.
Micro-Ravens fell out fashion(around here) after a young, stupid, fat white man loaded one at 1.6 and broke several bones!

Sometimes manufacturers publish life-limits (e.g. 20 years on pilot emergency parachutes) as a quiet way of saying that their older gear had a few flaws (e.g. no riser covers on early Softies) and that they now build better gear (e. g. modern Softies have riser covers). If the older gear has been in service for 20 years, sunlight has probably faded the risers to the point that we worry about strength. Few PEPs (from any manufacturer) are still airworthy after 20 years in the California desert.

Maybe we should change our standard to "generations."
For example, the last major revolution - in parachute materials - occurred around 1990: kill-line pilot chutes, ZP fabric, zero-stretch suspension lines, collapse able sliders, mini risers, electronic AADs, hip rings, etc. So that moves the bar to 27 years ago for closet-queens, but any gear that has been jumped on a regular basis has worn out long before it reaches 27 years old.

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Ok, so we now agree that age and age alone has NO-effect concerning the deterioration of the fabric? (just asking because I have quite a few vintage things I would love to jump at least once)
Don't worry, I'm saving up to buy a big accuracy rig to fit all of that vintage fun in so at least I have an up-to-date cutaway system and reserve.
But that doesn't mean I want my vintage gems to rip apart when I try them :o)

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Just curious as to what vintage things you want to jump. I myself would like to jump some older (but well kept) mains, so long as the rig and reserve are relatively current.
What's right isn't always popular and what's popular isn't always right.

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HPC

Just curious as to what vintage things you want to jump. I myself would like to jump some older (but well kept) mains, so long as the rig and reserve are relatively current.

. I have a older talon that has a new old stock raven 3 249 sq ft with a few packs and no rides that I over stuffed with a f111 288 manta successfully. That has a 230 sq ft zp. that is "soft "fitting now
i have on occasion been accused of pulling low . My response. Naw I wasn't low I'm just such a big guy I look closer than I really am .


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HansVanBael

Ok, so we now agree that age and age alone has NO-effect concerning the deterioration of the fabric? (just asking because I have quite a few vintage things I would love to jump at least once)
Don't worry, I'm saving up to buy a big accuracy rig to fit all of that vintage fun in so at least I have an up-to-date cutaway system and reserve.
But that doesn't mean I want my vintage gems to rip apart when I try them :o)



There are a few guys on here who like to jump vintage stuff. You might start a new thread on it.

My understanding is that as long as you know what you are dealing with, understand the limitations of the gear and aren't jumping something dangerous (bad design, the Nova comes to mind), then go for it.
"There are NO situations which do not call for a French Maid outfit." Lucky McSwervy

"~ya don't GET old by being weak & stupid!" - Airtwardo

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HPC

Just curious as to what vintage things you want to jump. I myself would like to jump some older (but well kept) mains, so long as the rig and reserve are relatively current.



if you just want to jump a vintage main, then you can put it in a large modern(ish) container.

I have a few Javelin J7's and Dolphin D6's that I use for that. Reserves are SuperRavenIII's (249 sq ft)

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