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TomAiello

Slider Bumpers/Link Covers (Silicon tube size?)

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Can anyone point me at the correct size silicon tube to use for (reserve size) slider bumpers?

I'm replacing the bumpers on about 40 BASE rigs, and I just want to buy a length of hose and cut it up.

Does anyone have an internal/external diameter hose (or better yet a link to a supplier) that works?

Thanks for any help.
-- Tom Aiello

[email protected]
SnakeRiverBASE.com

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Do you specifically want silicon or will vinyl do? What size links?

I buy vinyl for number 5 links at the local home depot/lowes/menards. OMG a brick an mortar store? :)

I can probably find the size but just take a link.

Silicon you will probably have to order.
http://www.usplastic.com/catalog/default.aspx?catid=799

But don't have the sizes off the top of my head.

I actually like the white webbing ones that Precision supplied for a while better. Can't think of an advantage to silicon for base but maybe there it one.

I'm old for my age.
Terry Urban
D-8631
FAA DPRE

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Looking at the chart, they are number 5 links.

I can buy tubing from McMaster, but I'm trying to narrow down the correct interior diameter so I'm not stuck ordering a range and then trying different ones until I find the right size to order more of.


How hard is it to slide the white webbing ones on and off the links? Do you happen to have a photo? I'm not really familiar with them.

I could probably just sew up some webbing covers. Maybe I'll give that a shot.
-- Tom Aiello

[email protected]
SnakeRiverBASE.com

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Not home at the moment. The ones I have are white but this is a pick from one if the FAA handbooks. The webbing ones are sized to slide on easily and be tacked down.

The links should be Mallione rapide(sp) French links of course. Real ones will have stamped the size' 3.5, 4, 5, 6 mm, the diameter of the stock.

I'm old for my age.
Terry Urban
D-8631
FAA DPRE

fig5-24.jpg

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You tack them such that you can slide them up off the link but no farther. Plastic or silicon bumpers have to be tacked down thse same way. No matter how tight they are they can come off the links , go up the lines and cause a malfunction. A friend had that happen on his wedding day jump.

On the cloth one put a tack of super tack at the bottom of the webbing through the link but not around the link. Then you can slide it up mostly off the link but no farther. ALL bumpers need to be tacked or threaded on the link like PDs witch hats. But all bumpers can be tacked to allow the bumper to go up just of the link but no further. For plastics ones ther're actually tied rather than "tacked" with a needle.
I'm old for my age.
Terry Urban
D-8631
FAA DPRE

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I use No.5 links on all of my canopies and use the silicon bumpers from APEX Base. They are just the right size for a No.5 link and while not difficult to pull up if needed, I have never had to tack them down. While most people probably should tack them down, as Terry suggested, I make a point of checking each one when setting my brakes and have never had one move up or down. And that is on my rig for video and my CRW canopies.

You might see if APEX will sell you a length of the tubing, since I would imagine they buy it by the roll, or maybe give you the supplier. If nothing else, you can order a few and measure them. You would probably have a better idea of what to order from the links that Terry gave you, if you liked the silicon ones from APEX.

Best of luck finding what you need.

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texascrw

I use No.5 links on all of my canopies and use the silicon bumpers from APEX Base. They are just the right size for a No.5 link and while not difficult to pull up if needed, I have never had to tack them down. While most people probably should tack them down, as Terry suggested, I make a point of checking each one when setting my brakes and have never had one move up or down. And that is on my rig for video and my CRW canopies.



Sure, you check it, until the one jump you don't.:S And does your packer check them? You may have never had a bridle knot up either, or a line hitch around a flap, but you are not going to be happy if one of those bumpers does get knocked up the lines. 6 inches of super tack per bumper, no needle needed, is cheap and easy insurance.:P My friend didn't like having to land his Hobbit reserve for the first time in dress shoes and a tux.
I'm old for my age.
Terry Urban
D-8631
FAA DPRE

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Councilman, (and other commentators) is absolutely correct that the tube type bumper, what ever it is made of MUST not be allowed the possibility to slide up the suspension lines. They have to be tacked down in some manner.

Using rubber surgical tubing, vinyl, or plastic are short cut solutions and are not the way to go. They are reminiscent of the 70's. I wouldn't use them; unless they are so tight they are like shrink tube, and even then should be tacked down.

In my opinion, the best bumpers, (if you are going to use Rapides) are the folded piece of webbing sewn up both sides and the lines go thru, and the Rapide link is "threaded" thru the folded part. Like the "pilgrims hats" supplied with soft links. But...I don't understand why anyone in the sport world, on ram air canopies with sliders still use Rapides? Soft links (more than one manufacturer) are faster and easier to put on and take off, and no bumper is necessary for a few jumps. Besides, soft links are stronger. Yes for many many jumps, as in a skydiver sport main canopy, even soft links need a bumper, and as all know, are supplied with the soft link = Pilgrim's hats. But for the few jumps put on a base rig, not necessary. Just be observant and replace at the sign of the slightest wear. Doubled 1500 Spectra has a huge margin of strength/safety. Rapides require bumper inventions. Why go there in the first place?

(In pilot emergency rigs with round canopies Rapides are just fine, as there is no slider. Just have to make sure they are tight. And.. a couple of turns around the suspension line loops are nice to keep the lines from migrating around the link.)

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TomAiello

There is a lot of discussion here that doesn't really apply to my (slider down BASE rig) case, but it's interesting to read it.

Does anyone happen to have the actual dimensions handy (ID and OD, or even just ID)?

Thanks!



Dontcha just love it when you ask a specific, detailed, direct question and all the folks answering it answer everything but what you were asking for?

The stuff I have in my box is 1" OD, 1/8" wall and 3/4" ID.

A piece I just pulled off an old rig down in my basement has a slightly thinner wall (0.10" vs 0.125") and slightly smaller OD. But still approx 3/4" ID. It seems to be different (softer).

I think the stuff in my box was vinyl from the hardware store. The stuff off the old rig may be silicone.

Hope this helps you.
:)
"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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