heat shrink on lines

[justme12001 0]

Weekend before last, I saw a canopy that had heat shrink on the line just above the slinks covering the finger traps. This was on a canopy with 300lb lines.

When I asked the owner (a rigger) what it was for, he said it was to help against abrasion from the slider (esp with a full RDS). This is what I assumed it was for, or at least something along those lines.

My question is, do many people do this, are there any downsides? And a another question is could this have prevented the recent incident in Cali?

[peek 21]

justme12001

Weekend before last, I saw a canopy that had heat shrink on the line just above the slinks covering the finger traps. This was on a canopy with 300lb lines.

When I asked the owner (a rigger) what it was for, he said it was to help against abrasion from the slider (esp with a full RDS). This is what I assumed it was for, or at least something along those lines.

My question is, do many people do this, are there any downsides? And a another question is could this have prevented the recent incident in Cali?

The downside I would think of is that something must heat that heatshrink enough to make it shrink. (If anyone knows how this is done to keep the heat away from the lines, please tell us.)

I use a couple layers of Spandex sewn into a cylinder to do the same job, and this allows the lines to spread out to their natural spacing. Not quite as durable though.

[riggerrob 643]

Simply sliding on plastic tubing would be fine, however heating heat shrink tubing would do far more harm than good.

Another option is short, sacrificial extra suspension lines. I have only seen them on the outboard A lines of a handful of PD-360'canopies. They were installed on the highest wear lines on the corners of the canopy. The sacrificial line is a straight copy of the regularc(finger-trapped and bar-tacked) loop found on the bottom end of most suspension lines. The sacrificial line is finger-trapped into the outboard A line just above the regular joint. Basically, the sacrificial
Line "partners" the bottom few inches of the outboard A lines, so that you have 6 lines per connector link instead of the usual 5.

[yoink 321]

riggerrob

Simply sliding on plastic tubing would be fine, however heating heat shrink tubing would do far more harm than good.

Really?

I've used some heatshrink tubing in electrical work which constricts at pretty low temperatures. A 4-5 seconds from a hairdryer on medium usually does it.

[masterrigger1 2]

Quote

Weekend before last, I saw a canopy that had heat shrink on the line just above the slinks covering the finger traps. This was on a canopy with 300lb lines.

Danny,
They are actually 340lb lines, not 300lb......

When speaking line tensile strengths, it is important not to group the line strength; especially when the difference is about 1/5th stronger over the other.

Matt has been putting heat shrink on his lines here at the shop for about 3 years now with no known ill effects.

MEL

Skyworks Parachute Service, LLC
www.Skyworksparachuteservice.com

[gowlerk 2,193]

Quote

Really?

I've used some heatshrink tubing in electrical work which constricts at pretty low temperatures. A 4-5 seconds from a hairdryer on medium usually does it.

The heat of the slider friction in a fraction of a second is enough to shrink lines. Heat shrinking will occur when using heat shrink. Imagine that.

Always remember the brave children who died defending your right to bear arms. Freedom is not free.

[masterrigger1 2]

Quote

The downside I would think of is that something must heat that heatshrink enough to make it shrink. (If anyone knows how this is done to keep the heat away from the lines, please tell us.)

Gary,
Vectran and Technora both are not heat sensitive like Spectra and the lines in question are made of Technora. If fact it would take a lot of heat to damage either Vectran or Technora.

MEL

Skyworks Parachute Service, LLC
www.Skyworksparachuteservice.com

[masterrigger1 2]

Quote

Simply sliding on plastic tubing would be fine, however heating heat shrink tubing would do far more harm than good.

Careful with installing plastic tubing!
They can develop sharp edges and actually cut these thin lines and/or develop a condition known as fretting. fretting is where one component wears the other through movement between the two.

MEL

Skyworks Parachute Service, LLC
www.Skyworksparachuteservice.com

[PBandJ 0]

gowlerk

The heat of the slider friction in a fraction of a second is enough to shrink lines. Heat shrinking will occur when using heat shrink. Imagine that.

The slider heats the entire length of the lines as it descends at high speed during opening, and does it repeatedly jump after jump. Heat shrink tubing, on the other hand, is only applied to a few inches of the line at the bottom, and the heat is applied just one time. So there are differences in both time of exposure and the amount of line affected.

[justme12001 0]

I actually like the idea, seeing his was just the first time I had ever seen it done.

I am about to put a new line set on my velo, and was thinking about doing it as well. So I just wanted to see what other people opinions on it are.

I wasn't trying in anyway to say it was a bad idea or that I saw anything wrong with it. I just wanted to know if it was common or if anyone that has done it have had any adverse effects or if there were any they could think of.

I had already thought about the heat on the lines, and a few others. I am just seeing what people think. And I usually try not to mention people names on the forums, since I know how people get on here

[justme12001 0]

Quote

They can develop sharp edges and actually cut these thin lines and/or develop a condition known as fretting. fretting is where one component wears the other through movement between the two.

This was actually one of the other adverse effects that I thought off. I have had heat shrink "get hard" after shrinking, and was worried it might cut the lines.

Is there a specific type of heat shrink that should be used, or avoided?

[yoink 321]

masterrigger1

Gary,
Vectran and Technora both are not heat sensitive like Spectra and the lines in question are made of Technora. If fact it would take a lot of heat to damage either Vectran or Technora.

MEL

thanks Mel.


The heat shrink tubing I use for electronics typically works in the 170 - 195 F range, just for information.

[nigel99 475]

justme12001

Weekend before last, I saw a canopy that had heat shrink on the line just above the slinks covering the finger traps. This was on a canopy with 300lb lines.

When I asked the owner (a rigger) what it was for, he said it was to help against abrasion from the slider (esp with a full RDS). This is what I assumed it was for, or at least something along those lines.

My question is, do many people do this, are there any downsides? And a another question is could this have prevented the recent incident in Cali?

An immediate downside if it was black heatshrink is that it can hide structural issues with the lines. Clear heatshrink allows visual inspection.

Experienced jumper - someone who has made mistakes more often than I have and lived.

[masterrigger1 2]

Quote

Quote:
They can develop sharp edges and actually cut these thin lines and/or develop a condition known as fretting. fretting is where one component wears the other through movement between the two.

This was actually one of the other adverse effects that I thought off. I have had heat shrink "get hard" after shrinking, and was worried it might cut the lines.

Is there a specific type of heat shrink that should be used, or avoided?

I have not seen any signs of danger with the heat shrink getting hard enough to do any damage.In fact, this is something that I looked at about 3 months ago after Matt had replaced his lines in the shop.

Since I was not in the shop when he actually changed them out, I pulled his old lines out of the trash and looked them over to basically get an idea of what type of wear Matt was getting and where.

BTW,this is something that is always different between each user.Post analysis of the old lines should be done when the new line sets are installed. This will help identify problems such as dinged or damaged RDS rings, bad toggle guide rings, etc...

MEL

Skyworks Parachute Service, LLC
www.Skyworksparachuteservice.com

[chuckakers 425]

gowlerk

Quote

Really?

I've used some heatshrink tubing in electrical work which constricts at pretty low temperatures. A 4-5 seconds from a hairdryer on medium usually does it.

The heat of the slider friction in a fraction of a second is enough to shrink lines. Heat shrinking will occur when using heat shrink. Imagine that.

Line shrink from the slider happens over many occurrences and over a long section of the lines. Applying heat shrink occurs only once and it occurs on only a very small section of line.

Chuck Akers
D-10855
Houston, TX

[gowlerk 2,193]

Yes, I was thinking of Spectra in my comment. The more dimensionally stable line types are more stable precisely because they are more heat resistant. Even so, you would want to be pretty careful applying the heat. If this becomes popular it won't be long till some people start to overdo it.

Always remember the brave children who died defending your right to bear arms. Freedom is not free.

[Jon26 0]

I always wrap that part of the lines (and the soft links and the tips of each riser) with 3M athletic wrap.
Its great because it only sticks to itself so zero gunk.
It definitely helps prolong the life of the lines.

[hackish 8]

While technically the heatshrink will shrink at about 185F most heat guns produce considerably more. I normally use a lighter for this. When it comes to sensitive electronics a calibrated heat gun is used and these can set you back $500-$1000. I'm not a big fan of this.

-Michael

[sundevil777 102]

I would think that a layer of aluminum foil between the lines and heat shrink tubing would protect the lines well, then the foil might be easily slipped out.

People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am

[hackish 8]

I feel like the problem is being over-thought. Burns from grommet heat seem to be really rare. It may be solving a problem that doesn't really exist. Instead the energy could be put into care and inspection of the gear.

I might be inclined to pass the inner and outer lines through a short piece of gutted ty3 suspension line. You could probably do the same with some spectra if you need smaller than the ty3.

Or make something like a PD slider stop and remove the actual stoppers so the grommets can be pulled down past the links. I think there are many options better/safer than heat shrink tubing.

-Michael

[mxk 1]

I put about 25 jumps on my new V3. It has standard risers, PD reserve slinks, and Dacron lines. PD recommended that I jump without the slink riser covers (SRCs) initially to see if there are any problems. I'll take some photos when I get home today, but I think there are definite signs of heat damage on the slinks (also discussed here). I jumped this rig without gloves for the first time a week ago and made it a point to feel the slider grommets immediately after deployment. They were rather warm, almost hot, and I obviously wasn't feeling the temperature right at the line contact points.

I knew that Dacron lines would generate more friction and heat, so this is just a confirmation for me that some sort of protection is needed. I'm not really sure what to use. The ideal solution would keep the slinks and risers protected, but without constricting the lines or preventing the slider from coming down past the slinks. Some people put the SRCs upside down with standard risers, but that still leaves the slider in the contact with the lines and sitting higher than it would be otherwise.

[skydiverek 63]

mxk

I put about 25 jumps on my new V3. It has standard risers, PD reserve slinks, and Dacron lines.

What canopy was that? Full name and size?

[mxk 1]

skydiverek

***I put about 25 jumps on my new V3. It has standard risers, PD reserve slinks, and Dacron lines.

What canopy was that? Full name and size?

Spectre 230.

[skydiverek 63]

mxk

******I put about 25 jumps on my new V3. It has standard risers, PD reserve slinks, and Dacron lines.

What canopy was that? Full name and size?

Spectre 230.

Yeah, so long lines, give slider grommets time to heat up...

[mxk 1]

Photos are attached. The Louie loops on the front risers tend to keep the grommet in contact with the slink, so you can see two marks there. On the rears, the grommet slides past the slink, so you can see one mark near the bottom and another one on the webbing.