UKC

Hi All,

I know there are lots of older threads on re-threading but none cover my specific query.
I am aware that the most popular method of re-threading is based on the info on this page:

http://www.needlesports.com/3334/cord--and--tape.aspx

and gives me two options (for rockcentrics):

1) 8mm cord - double fishermans (bulky)
2) 5.5mm Dyneema - tripple fishermans (expensive, long knot)

Regards cams I have considered:

1) 5.5mm Dyneema - tripple fishermans (long knot would be more of a problem on short sling)
2) Double over a sling as per Chris Tans "death tips" but have ruled this out due to risk of only clipping one end of the sling: http://www.kakibusok.plus.com/Equipment/ReslingCams/Resling.htm
3) Sling with larks foot - ruled out as considerably weakens sling

What I cannot find are any posts (most pre-date this product) from people using Elderid Tech Web. You can buy this stuff by the meter more cheaply than 5.5mm Dyneema cord and I think a tape knot is neater than tripple fishermans.

I took a look on the Elderid site which has more info on the specs for this stuff:

http://www.edelrid.de/en/tech-web-slings/

"Tech Web 12 mm has significantly greater knot stability than 8 mm Dyneema and 16 mm polyamide. This means that it provides additional safety, particularly when used as a belay sling. As a knotted sling Tech Web complies with the EN 565 standard (15 kN) and therefore may be sold by the meter."

According to the chart towards the bottom of that page Tech Web when knotted with a tape knot Tech Web retains +95% of its original strength (closer to 98% looking at the chart).

Unless I am mistaken this is saying that Tech Web tied with a tape knot is going to give me 15kN x 95% = 14.25kN before the sling breaks or the knot slips.

At this point I have two questions:

1) Am I reading this right, will it give me 14kN on a tape knot?
2) Has anyone else used Tech Web for reslinging cams / hexes and if so how did you get on with it?

Thanks









What I am really interested in at this point

In reply to jezz:
The chart is comparing the strength of the knotted sling to the strength of a sewn sling. Both of these are significantly stronger than a single strand.

As elderid sewn tech web slings are rated to 22kn I think the knotted sling would be rated 20.9 kn.

Which cams are you considering using this stuff for?

In reply to CurlyStevo:

Thanks very much for your reply, do you have any idea how much the sewing process reduces strength in a sling?
What I am getting at is what would the likely strength of 15kN Tech Web be if sewn?

The cams I have are old Wild Country Friends and a couple of other brands, all are similar in that they have drilled / machined holes vs wires or loops. Some will take a double loop, not sure the WC Friends will as the holes on those are smaller.

In reply to jezz:
"Thanks very much for your reply, do you have any idea how much the sewing process reduces strength in a sling?
What I am getting at is what would the likely strength of 15kN Tech Web be if sewn?"

It doesn't weaken it, loops are stronger than single strands both knotted and sewn. The sewn Tech Web slings are rated 22 kn and the single strand 15kn and the tape knot 20.9 kn. (see this chart for more info, 16mm beal tubular is 1350 dan, as knotted sling 1850 and the sewn 16mm tubular is 22 kn http://www.beal-planet.com/en/express-anneaux-sangles/78-anneaux.html )

The only issue I can see is if the tape is particularly cramped in the hole as this will weaken it somewhat, however I doubt 12mm would be an issue although its will be a little thicker than dyneema I would imagine, what is the original width of the tape in the tech friends? I'm guessing 12mm.

In reply to CurlyStevo:

I guess another way to look at this is to compare Tech Web to the products / methogs on this page:

http://www.needlesports.com/3334/cord--and--tape.aspx


So unless the tape knot in Tech Web (which is not as prone to slipping) is inherently weaker than the fishermans knots used in cord it should be viable alternative?

In reply to CurlyStevo:

"It doesn't weaken it, loops are stronger than single strands both knotted and sewn"

Thanks, I was missing the obvious there.

I think I can get a single length through the holes in the cams to form a loop. I can definitely do it on some of them.

I was more bothered about the rockcentrics really in terms of avoiding the bulk of 8mm and cost of Dyneema on longer slings.

In reply to jezz:

It should be fine on the rockcentrics IMO

In reply to CurlyStevo:

I asked Edelrid for more advice on this not thinking I would get an answer, but they kindly replied to say:

"Thank you for your question to Edelrid.

Tech web would be very suitable for your suggested usage, strong and thin enough to thread onto larger nuts. As the Tech web has the nylon outer it has great abrasion resistance and knotability, the same as a normal nylon sling, with the added benefit of the dyneema core.

The knot stability is good, similar to a nylon sling, however, it is important to ensure the tape ends are long enough and secured to stop the knot loosening.

Hopefully this answers your question, if you need any further info please let me know."

So I will be going with this stuff to rethread my Rockcentrics and from that will decide if its suitable for the cams.

In reply to jezz:
I would advise body weight tensioning the water knots. I would be surprised if the ends slip through the knot or it comes undone after doing this. But it is advisable to keep an eye on water knots in tape and leave fairly long tails

Some people stich the ends down although this doesn't stop the knot loosening and so may not increase safety. In the past I have half hitched the ends around the tape and then stiched the ends down to the half hitch although this is a bit bulky.

In reply to CurlyStevo:

If you are worried about the knots you can always use a sewn sling to rethread your cams with a bowline on a bight as shown here:

http://www.netknots.com/application/files/6514/5828/5610/bowline-on-a-bight...

Imagine the two ends on top of the illustration to be joined, and simply thread the bight shown at bottom through the appropriate hole on the cam stem when tying the knot. You can then push the knot all the way up to the cam, so that the double bight completely disappears.

CB

In reply to jezz:

No idea about techweb but if it's certified for sale off the reel it's strong enough knotted to form a useful sling.

I used sewn 6mm slings onto the stems of my old flexi-friends. Both loops clipped for short, 'larksfooted' onto the cam's stem end for long. Very neat though 6mm slings are hard to find, 8mm would fit.

I put a few old hexes on 20mm tape. Certainly in the bigger sizes the knot fits in the body of the hex.
jk

In reply to jkarran:

I considered larks foot but after reading this (see table below video) was not so keen on the idea:

http://dmmclimbing.com/knowledge/improvisation-larks-foot-or-basket-hitch-v...

Clipping both ends (like basket hitch) is better but I was worried about the risk of not clipping both ends. I know its easy to check both are clipped but would rather have avoided that. However, on a cam there isnt much room for knots so maybe Ill go back to that idea as per the second example here:

http://www.kakibusok.plus.com/Equipment/ReslingCams/Resling.htm

Or pay to send them to the US to be reslung properly.

I think I will go ahead and use Elderid Tech Web on my hexes.

In reply to jezz:


You didn't say your cams had wire stems!

With rigid stems or the usual wire with crimped on eyelet it's little different from slinging a krab. You do have to check for edges in areas the sling wouldn't have previously contacted and it does impose a small bending load on the end of the stem but nothing it can't handle.
jk

In reply to jkarran:

I have a few different types of cam and was worried about the way the load may fall on the stems, if I used that method I think I would stick to cliping both ends rather than larks foot.

Ive just ordered 100m of Edelrid tech web that was on sale, its a 'little bit' more than I need but it worked out at 80p per meter rather than £2.60 and it looks really versatile and I'm sure it will come in handy so once I'm done with my hexes I may try that on the cams with a tape knot.

In reply to jezz:


When will the '101 uses for Edelrid tech web' book be on our local climbing shop shelves?