product testing

[sonnylawrence]

I do not have access to data on drop tests for nylon daisey chains. I can coordinate a test in about a month at a university mechanical engineering lab.

Anyone with anything they want tested, e.g., partially worn carabiners, daisey's, purcell, etc., please send to me in the next 2 weeks. Let me know if you want a drop test or slow pull test. Tell me the history of the item being tested. Please send it to:
Sonny Lawrence
306 Bellevue Avenue
Redlands, CA 92373

[rcwild]

Excellent, Sonny

Several things come to mind:

Various diameters and qualities of rapid links found in hardware store. Those with SWL stamped vs those without. Perhaps comparitive test of "certified" maillon rapides found in climbing store.

Aluminum rap rings. New and those that have worn through one wall of material.

Nylon daisy chains with fall factors 1, 1.5 and 2. End to end. Individual loops (clipped short).

Holding power of valdotain on various rope diameters. Single strand 8mm, double strand 8mm, single strand 9.2mm, double strand 9.2mm, etc.

I'm sure I'll think of some more.

FYI -- Southern Utah University expects to offer an outdoor recreation degree program beginning fall of '06. May include canyoneering specialty in cooperation with the ACA. They'll be looking for special projects, i.e. environmental studies in canyons, gear and system testing, etc.

[johnswelchvi]

Any results?

[sonnylawrence]

I liked the ideas Rich posted. I need people to send me items to break. It gets expensive for me to buy new gear and then break it.

[paulsailer]

can you test ropes

[sonnylawrence]

I can do a slow pull test on a short section of rope or sling which is accurate. I can do a drop test that is more approximate but still useful. For example, a friend had an old Spelegyca that he thought was bad. With drop testing and 20/20 hindsight, it was still very good.

[sonnylawrence]

I can do a slow pull test on a short section of rope or sling which is accurate. I can do a drop test that is more approximate but still useful. For example, a friend had an old Spelegyca that he thought was bad. With drop testing and 20/20 hindsight, it was still very good. I need about 5 feet of material to test.

[ratagonia]

Excellent, Sonny

Nylon daisy chains with fall factors 1, 1.5 and 2. End to end. Individual loops (clipped short).


Having done some testing myself, let me wave the banner for Fewer Tests and More Datapoints. Breaking ONE rapide tells you how strong that one was, but very little about how strong Rapides are, in general. Breaking 10 rapides (of the same size and make) tells you quite a bit about that rapide in general.

Breaking Daisy Chains by dropping steel weights is an especially futile endeavor. When a person falls on a daisy chain, the dynamic part of the equation is the person. If you replace the person with a steel block, then the test has very little relation to reality. Got access to corpses, by any chance? This is not a test people should volunteer for.

Give me an address, and I will send you 10 rapid links X 2 different sizes, and a few other things to test.

Tom

[paulsailer]

Give me an address to send stuff to and I'll send you a bunch of stuff.

[sonnylawrence]

Please send items to:
Sonny Lawrence
306 Bellevue Avenue
Redlands, CA 92373

My attitude about such tests is to give a person a rough idea of what occurs at different forces. It is not conclusive. At times it sure causes me to pause and reconsider gear!

[sonnylawrence]

Mark Fitzsimmons sent me nine screw links to break. They were all unmarked. There was no indication as to the safe working load, etc. Mark had put tape on them stating they were from “Mr. Stuff.� They ranged in cost from $0.75 to $1.25. The machine that broke them can only go to 50 kN. Hence only one of the large screw links was broken. In all cases, the threads stripped off. The link did not actually shatter. After the threads popped, it very slowly opened as force was increased.

Small size: three links which were 8 mm diameter stock, 8 cm long, 3 cm wide, broke at 25.97 kN, 32.8 kN and 22.71 kN.

Medium size: three links which were 10 mm diameter stock, 9 cm long, 4 cm wide, broke at 29.4 kN, 26.8 kN and 14.26 kN. (Yes, the third value was much lower.)

Large size: one link which was 12 mm diameter stock, 11 cm long, 5 cm wide broke at 49.5 kN.

[Zarka]

Very interesting, so the .75 and 1.00 pieces have the same break strength. The threads on one of the 1.00 parts were a little messy which ought to account for the lower strength.

[paulsailer]

A bunch of stuff is on the way

[sonnylawrence]

Paul Sailer sent me the following to destroy. He indicated most of the software was around 10 years old. The brackets indicate what knot was used to fasten the material to the machine or to make a loop.

Edelrid dynamic rope 10 mm (?), red with blue stripe, broken as a single strand at 14.4 kN [figure 8]

Edelrid dynamic rope 8 mm (?), red with green and white stripes, broken as a single strand at 10.9 kN [figure 8]

Metolius ¾ inch sewn sling, brown with black stripe, broken as a doubled strand at 18.9 kN. The stitching separated.

Sewn runner ½ inch, purple and white, marked with 23 kN broken as a doubled strand at 26.7 kN

Tubular 1 inch webbing, lime green, broken as a doubled strand at 21 kN [water knot]

Tubular 1 inch webbing, white, broken as a doubled strand at 21.2 kN [water knot]

Tubular 1 inch webbing, purple, broken as a doubled strand at 23 kN [water knot]

Tubular 1 inch webbing, blue, broken as a doubled strand at 22.8 kN [water knot]

Tubular 1 inch webbing, brown, broken as a doubled strand at 16 kN [water knot]

Tubular 1 inch webbing, red, broken as a doubled strand at 24 kN [water knot], 20 [square knot]

Webbing, ½ inch, rainbow, broken as a doubled strand at 18.7 kN [water knot]

Small diameter pull cord broken as a single strand 0.62 kN [figure 9]

[sonnylawrence]

Tom Jones sent me the following to destroy. The words in quotes were stamped on the hardware.

Imlay Clipster, 11 each: two were broken in a slow pull test, breaking at 22 kN and 21.4 kN. Both broke at the girth hitch. One also had the stitching near the girth hitch pulled out.

“Rapid link SWL 2650� 8.2X3.7 cm, 9 mm diameter: broke at 38.5 kN


Screw link “WLL 2640�9.7X4.1 cm, 10 mm diameter: broke at 33.5 kN


“Rapid Link SWL 1900� 7.6X3.4 cm, 8 mm diameter, 10 each: two were broken (before the machine broke): 33.4 kN and 37.6 kN

Screw link “China� 5.7X2.6 cm, 6 mm diameter, 10 each: broke at 19.8 kN, 21 kN, 16.1 kN, 13 kN, 16.6 kN, 16.4 kN, 16.8 kN, 11.1 kN, 21.4 kN, 9 kN

All of the screw links separated at the threaded gate except for two of the “China� links as pictured. The remaining screw links and Clipsters will be broken in a few weeks.