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JTH

How often do you need to replace your double wrapped rubber bands?

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Hi guys. I was using bungee style elastics for a while on my wings S.S. D-Bag with HMA700. The durability of the elastics were great but I had 2 hard openings since. The 2nd one was too much. Needing to put chances on my side and eliminate possible causes I switched out the bungee elastics and started using rubber bands, double wrapped. I don’t get many jumps out of them before they snap or start to show signs of failure. Like 4 or 5 jumps. Sometimes only one. How about you guys? How often are you replacing your double wrapped rubber bands? I’m using the 2 inch X 3/8 inch X .070 spec.
Thanks

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Rinse the rubber bands in soapy water, leaving the soap on them as they dry. This removes the powder they ship in, which reduces their life span and makes them a little slippery, extending their life a bit.

Hard openings are mostly caused by either not slowing down before deploying or the slider not being against the slider stops. Even a small decrease in speed can make a big difference. Putting your knees on the slider grommets is hard on your knees, hard on the slider material, and can move the grommets away from the slider stops.

If the canopy is staying in the bag until line stretch, the rubber bands breaking are not the cause of your hard openings.

Derek V

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Warm weather will cause most rubber bands to break quicker. I use one size, single wrap and cinch it down from the attachment to fit the lines being stowed. One size fits all! Rubber bands are probably not the cause of your hard openings.

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Thanks for the replys Guys. I was mainly wondering if sometimes lasting only one jump was normal or I'm just not good at double wrapping.

In my original first post I wassn't suspecting the rubber bands as the issue, but mentioned the bungee style elastics that I had been using and had since had hard openings, and then switched to rubber bands double wrapped. I have had no hard openeings since using the rubber bands double wrapped but replace them evey jump day, sometimes a couple times a day :)

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JTH

Hi guys. I was using bungee style elastics for a while on my wings S.S. D-Bag with HMA700. The durability of the elastics were great but I had 2 hard openings since. The 2nd one was too much. Needing to put chances on my side and eliminate possible causes I switched out the bungee elastics and started using rubber bands, double wrapped. ........ I’m using the 2 inch X 3/8 inch X .070 spec.
Thanks


———————————————————————————————

Completing your profile would help reduce confusion.
Brits use “bungee” to describe bare rubber bands.

OTOH the rest of us say “bungee” to describe rubber strands wrapped in a braided sheath (cotton or nylon).
We call bare rubber bands “rubber bands” or “elastics.”
Military specification rubber bands often fail after one use - especially with tight d-bags.

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To assist the thread in understanding the bungee stuff, see the attached photo for an example of how recent Wings bags have been built to use bungees.

(Their thinking is clearly different than that of the many manufacturers that say to use, or imply the use of, double stowed elastics.)

Wings bag w bungees (cap).jpg

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Thanks. That's exactly how mine were installed. They came stock with the new wings SSdbag when I got it last year and figured I'd give them a try. They retain the lines with considerably less traction then even single stow on a large rubber band. With my HMA700 lines anyway.

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JTH

was refering to these beauties that I was using first and hard 2 hard openings, prior to switching over to double wrapped rubber bands which I am currently using. (please see attachement)

Thanks for all your comments.



I've had bands break after just one jump. After some more research I determined that I accidentally wrapped it wrong which caused it to be much harder to release. As far as replacing them after 4-5 jumps, that's similar to my experience as well. Occasionally I'll get them to last longer, but I normally replace them after 5 jumps or so. However, I do NOT wait until they fail outright. If they are broken more than 30% of the way through, I trash them. You should be replacing the bands when they are worn, not when they are broke.

I'm not a fan of the bungee cords myself. They are a lot stronger than rubber bands which is not necessarily a good thing. Sure, it's good for durability but if the lines wrap around a stow and wont release, the locking stow is going to need to fail otherwise you'll have a bag lock. A rubber band will fail under the drag of a PC at terminal if the lines get hung up on the stows, but I am less sure about a bungee. I havent seen any testing so I cant say, but they are stronger and so in theory they would be far less likely to fail when you need them to.

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LeeroyJenkins

***Oh, they'll work just fine. Until they don't. Like when they wear out and you don't replace them. Or, as Westerly pointed out, you need one to break for some reason.



That doesn't differ from rubber bands.


I differs a lot from rubber bands. Bungee cord loses it's stretch and grip long before the nylon sheath will break. And the breaking strength of that sheath is more than enough to resist the pulling power of a P/C. Rubber bands just break.

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gowlerk

******Oh, they'll work just fine. Until they don't. Like when they wear out and you don't replace them. Or, as Westerly pointed out, you need one to break for some reason.



That doesn't differ from rubber bands.


I differs a lot from rubber bands. Bungee cord loses it's stretch and grip long before the nylon sheath will break. And the breaking strength of that sheath is more than enough to resist the pulling power of a P/C. Rubber bands just break.

Edit: confused threads.

"They will work just fine until they don't" - that can be said about rubber bands too.

While I don't feel like purposefully causing a bag lock just to prove you wrong, rubber bands are not guaranteed to break. Will they break before a bungee? probably. Is human error/poor gear maintenance the fault of the equipment? No.

So yeah, rubber bands will work until they don't.

More on topic, as long as your bungees were in good shape they wont cause a hard opening. As i said before I only use two.

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JTH

Hi guys. I was using bungee style elastics for a while on my wings S.S. D-Bag with HMA700. The durability of the elastics were great but I had 2 hard openings since. The 2nd one was too much. Needing to put chances on my side and eliminate possible causes I switched out the bungee elastics and started using rubber bands, double wrapped. I don’t get many jumps out of them before they snap or start to show signs of failure. Like 4 or 5 jumps. Sometimes only one. How about you guys? How often are you replacing your double wrapped rubber bands? I’m using the 2 inch X 3/8 inch X .070 spec.
Thanks


FWIW, I have a standard wings d-bag which has 4 closing bands (which go through the 4 grommets on the bag flap). I probably replace one of those 4 bands about every 6th jump or so (which means each individual band is lasting ~25 jumps).

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Good point. People double wraping 700 spectra or 400 hma lines have very different tension with the same sized rubber. An important aspect that is left out from any "do double stows" debate/instructional video.

If we are talking about safety there should be more than one size fits all large and small rubber bands.

A small rubber with tiny lines will be prone to line dump more than a 700 line group just because of the sheer volume of those lines and the tension that ruber creates on them.

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Quote

there should be more than one size fits all large and small rubber bands.


Technically that's TWO sizes fit all ;)

Parasport came out with silicone stow rings, creatively named "Silirings," that come in five different sizes. They come in packs of 12, one size per package. I haven't personally used them (my Sun Path semi-stowless bag came with Tube Stows, which are working fine for my particular needs), but if you're looking for more size flexibility, these might be just the thing you're looking for. You can get them at ParaGear (where I work), and probably a bunch of other shops too.

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Or we can cycle back around to trying heavy duty solid rubber stow bands (i.e. 'O' rings or castration bands)...

They have been proven before to out last rubber bands... including and especially when the lines are caught up on the bag. Trust them to keep the lines stowed all the way to the ground with little or now wear.

Bands are supposed to break.

With that, and use, they will wear out. They're a consumable item.
And we've proven that trying to overcome that is at our own peril.

With that in mind, several things to make life easier:
- good quality natural rubber seems to work best and last
- uniform bands (thickness, width) will last better
- new bands last better (dry-rot/cracked should be avoided)
- gear storage in hot conditions (trunk) will cause the bands to age
- replace cracked/torn bands to avoid an out-of-sequence release
- pre-stretched bands (before installation) will last better on the first few deployments
- washing them (as someone else suggested... dunno... haven't tried it yet)
- PD has MANY more packjobs/deployments than I have on a very wide range of lines/bags/band-types. They seem to feel double wrapped works best...

I'm not against innovation, but a review of what has been tried and lessons learned should not be overlooked.

Just my personal thoughts from a couple years in the sport.

JW

PS - used spectra and dacron (prefer dacron) and always double wrap my non-locking stowes... After PD's video, I'm considering double wrapping my locking stowes as well.
FWIW - I also split-stow and keep the container slack to less than 1 bag width. Haven't historically had any issue with bag-spin during deployment.
Always remember that some clouds are harder than others...

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fcajump


PS - used spectra and dacron (prefer dacron) and always double wrap my non-locking stowes... After PD's video, I'm considering double wrapping my locking stowes as well.



John LeBlanc specifically addresses this in the video below. It forgot where he talks about it, but he brings up a few points specific to that type of line stowing:

https://www.youtube.com/watch?v=f-mUyy1fhjE

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