Dyneema and heat-shrink

[B-Baysailer]

I made up a couple new haylards from endura braid after making the eye splices I lock stitched and whipped them I like to put some heat shrink on them has anyone had any problems with the dyneema .the critical temperature of dyneema is 150 deg F but the heat shrink shrinks at 203 deg.F so you have to get it pretty hot.

[gamayun]

What's the point of a heat shrink if there is a properly done whipping? My understanding is that heat shrink is used to prevent water ingress around something plastic. It has this bead of glue that also melts with the shrink. I would think the temperature needed would be really bad for Dyneema, which is sensitive to heat.

[atoll]

you would need to be very careful when heating the heat shrink at the ends where the dyneema is exposed as it melts the strands very quickly with an open flame

[mikereed100]

I have done this often using a heat gun. Just be careful, don't overdo it and you will be fine. I believe Colligo does this quite often as well.

[billknny]

Originally Posted by mikereed100

I have done this often using a heat gun. Just be careful, don't overdo it and you will be fine. I believe Colligo does this quite often as well.

I had Dyneema rigging made for my old boat by Colligo. The splices all had heat shrink on them.

Other riggers use silicone self-amalgamating tape. No heat, and available in a wide variety of cool colors

[B-Baysailer]

I was careful with the heat gun I know calligo and evens use it .I was just wounding if anyone has ever had a problem with it? I like how it finishes the splice and protects the wipping from uv thanks for the replys

[ggray]

If you are concerned about the heat, buy tubing size that doesn't need to shrink much.

I threaded some heat shrink over a cable so it would be there when I needed it, and before I got around to using it, heat from the sun (in Virginia) had shrunk it to where it would no longer fit over what I planned to cover.

So it will start shrinking at lower temps.

[thinwater]

Originally Posted by B-Baysailer

I was careful with the heat gun I know calligo and evens use it .I was just wounding if anyone has ever had a problem with it? I like how it finishes the splice and protects the wipping from uv thanks for the replys

Heat shrink tubing comes in a number of temperature ranges.

What function does a whipping serve with Dyneema? None, according to the manufacturers. Then this is only about appearance, which is probably part of why Colligo uses it (fancy justifies a higher price). If it is about wear, only a spliced-on Spectra cover makes much sense.

A better way to make it last longer is to buy the halyard ~ 2' too long and replace the splice in 5 years. 5 minutes work, tops.

[B-Baysailer]

This is for endura braid a core dependent rope so a class 2eye splice

[B-Baysailer]

I didn't know that they have lower temperature heat shrink thanks

[ggray]

I don't think it is lower temp shrink tube, just that it starts shrinking at lower temps. It hadn't shrunk all the way, just enough I couldn't slide it over what I wanted to cover.

This experience/situation was nearly 25 years ago, but I assume the shrink tubing hasn't changed.

[estarzinger]

Originally Posted by B-Baysailer

heat shrink on them has anyone had any problems with the dyneema .

Originally Posted by B-Baysailer

This is for endura braid a core dependent rope so a class 2eye splice

If you are doing dacron covered splices, and are 'normally careful' with the heat gun - you are pretty ok with the heat issue.

I was told some years ago by new england ropes to put the heat shrink in place and put in it near boiling water - at the time they though that was the perfect temp to shrink the tube but keep the dyneema safe. But most pros I know are just careful with a heat gun.

[B-Baysailer]

Yes it was a Dacron covered rope and i was careful . Did you ever test a rope after it had the heat shrink put on it (back when you were testing rope)thanks

[estarzinger]

Originally Posted by B-Baysailer

Did you ever test a rope after it had the heat shrink put on it (back when you were testing rope)thanks

yes, when I was working on best practices for dyneema life lines I did some testing with heat shrink and heat in general.

the basic conclusion was #1 certainly possible to put heat shrink on without measurable damage/strength loss, but #2 quite a number of 'pro made' samples I tested were obviously not so carefully done and did show damage/strength loss, and #3 braided dyneema chafe sleeve (especially the sleeves specifically made for the purpose) were better than heat shrink for the specific lifeline application (protection where it ran thru stanchions).

On general heat testing, there is a duration factor. So relatively low heat (like 70c) for a long duration will create damage, and high heat for a short duration will create the same damage. But these combinations of temps and durations dont really come into play much in 'yachting' applications - surging quite high loads (racing loads) around a winch drum is about the only place I have seen them.