What's in your "Fix" kit?

[DougPaul]

I carry 50' of military 550 cord (550 pound strength), which gets a lot of use, from lowering packs down cliffs to making a clothes line, and in a pinch it'll easily support my weight, yet weighs only 3.7 ounces.

By the time you tie a knot in that cord, the strength will be down to ~385 lbs--only about 2 to 3 times your body weight. It will also tend to weaken with age, UV exposure, and abrasion. Commercial safety factor requirements are on the order of 5 (or so I have read). Climbers use safety factors on the order of 2.5-3 for a maximum force fall (~2000 lbs on a 5000+ lb breaking strenth rope, which is specifically designed for shock absorbtion and protection of human life).

I suggest that you avoid supporting your body weight on the 550 cord--a shock load might easily break it. Or at least double or triple it.

Doug

 

[Lawn Sale]

I'm not going ice climbing with the cord, I'm just using it in an emergency.

But, thanks for the info.

 

[DougPaul]

I'm not going ice climbing with the cord, I'm just using it in an emergency.

I understood that. However, physics still applies.

My point was that even though the rated strength of the cord is greater than your body weight, it is still rather dangerous.

Just stepping up on a cord or catching even a short slip introduces significant shock loads...

If you want cord suitable for supporting a human, I suggest you use climbing accessory cord (static--designed for minimum stretch under load, not good for shock loads) or climbing rope (dynamic--designed to stretch under load to reduce shock loads). For example:

Bluewater cord ........ strength
5mm acc cord ........ 1280 lbs
6mm acc cord ........ 1730 lbs
7mm acc cord ........ 2470 lbs

Data from REI website listings, will vary with other similar cords:
5mm cord: http://www.rei.com/online/store/Pro...ategory_rn=4500700&vcat=REI_SSHP_CLIMBING_TOC
and table of cords:
http://www.rei.com/online/store/Sea...&group=4&text=1&vcat=REI_SSHP_CLIMBING_TOC:P3)
(Note 1 kilonewton = 225 lbs)

Knots reduce the strength of a rope by a factor of .7 to .5, abrasion, sunlight, and age further reduce the strength.

Doug

 

[Charly]

 

[mafogle]

A lot of good ideas - I never though to bring zip-ties or hose clamps.

Here are a few things in my kit that I don't think any one mentioned yet:

Superglue,
thermarest patch kit,
repair kit for my stove,
and an eye glass repair kit.

 

[skiguy]

I understood that. However, physics still applies.

My point was that even though the rated strength of the cord is greater than your body weight, it is still rather dangerous.

Just stepping up on a cord or catching even a short slip introduces significant shock loads...

If you want cord suitable for supporting a human, I suggest you use climbing accessory cord (static--designed for minimum stretch under load, not good for shock loads) or climbing rope (dynamic--designed to stretch under load to reduce shock loads). For example:

Bluewater cord ........ strength
5mm acc cord ........ 1280 lbs
6mm acc cord ........ 1730 lbs
7mm acc cord ........ 2470 lbs

Data from REI website listings, will vary with other similar cords:
5mm cord: http://www.rei.com/online/store/Pro...ategory_rn=4500700&vcat=REI_SSHP_CLIMBING_TOC
and table of cords:
http://www.rei.com/online/store/Sea...&group=4&text=1&vcat=REI_SSHP_CLIMBING_TOC:P3)
(Note 1 kilonewton = 225 lbs)

Knots reduce the strength of a rope by a factor of .7 to .5, abrasion, sunlight, and age further reduce the strength.

Doug

I would fully agree with DougPaul here. Understand the PHYSICS of what you are doing with your cord and get the right piece of cord that applies to your situation. I would not overlook this concept.

 

[Lawn Sale]

Amazing, absolutely amazing...



...I never thought of something as simple as superglue before! I've heard it works well to seal cuts, can anyone confirm? Hmm, multiple uses, lightweight, and cheap, does it get any better than that?

 

[skiguy]

Amazing, absolutely amazing...



...I never thought of something as simple as superglue before! I've heard it works well to seal cuts, can anyone confirm? Hmm, multiple uses, lightweight, and cheap, does it get any better than that?

I fell waterskiing a few years ago and got run over by the ski in the forehead after falling. Made a nice little slice. The Emergency Room Doctor took one look at the cut and said "Oh perfect cut for the glue"! Yes they used some fancy glue in a tube to seal me up, but I could have probably gone to the Hardware store and bought Super Glue and taken care of it myself. Super Glue will work but it only works on the right kind of cut. The cut needs to be a narrow slice,one that does not need to be pulled together;that's what stiches are for. Even better if the cut has a flap, much like the kind of cut or split you get on a cuticle this time of year. Simply and absolutely amazing stuff in the right situation!

 

[WildPeaks]

I understood that. However, physics still applies.

My point was that even though the rated strength of the cord is greater than your body weight, it is still rather dangerous.

Just stepping up on a cord or catching even a short slip introduces significant shock loads...

If you want cord suitable for supporting a human, I suggest you use climbing accessory cord (static--designed for minimum stretch under load, not good for shock loads) or climbing rope (dynamic--designed to stretch under load to reduce shock loads). For example:

Bluewater cord ........ strength
5mm acc cord ........ 1280 lbs
6mm acc cord ........ 1730 lbs
7mm acc cord ........ 2470 lbs

Data from REI website listings, will vary with other similar cords:
5mm cord: http://www.rei.com/online/store/Pro...ategory_rn=4500700&vcat=REI_SSHP_CLIMBING_TOC
and table of cords:
http://www.rei.com/online/store/Sea...&group=4&text=1&vcat=REI_SSHP_CLIMBING_TOC:P3)
(Note 1 kilonewton = 225 lbs)

Knots reduce the strength of a rope by a factor of .7 to .5, abrasion, sunlight, and age further reduce the strength.

Doug

You've got to be kidding!

Lawn Sale is an Ice Climber! He is well aware that he can't dangle from the cord.

I thought this post was about quick fixes???

 

[DougPaul]

(cord strength info deleted)

You've got to be kidding!

Lawn Sale is an Ice Climber! He is well aware that he can't dangle from the cord.

His posts suggested otherwise:

I carry 50' of military 550 cord (550 pound strength), which gets a lot of use, from lowering packs down cliffs to making a clothes line, and in a pinch it'll easily support my weight

I'm not going ice climbing with the cord, I'm just using it in an emergency.

There are also many readers of these posts--my post included enough information to allow a non-technical-climber to choose an adequate cord if he contemplates supporting body weight on it.

Doug

 

[mafogle]

Doug, I think you missed Lawn Sale's point - 550 paracord can support your weight in a pinch. Which is important to know if you find yourself up a creek without a climbing rope - to mix metaphors.

Besides, 550 is cheap and good for so many things that you'd never want to cut up a piece of even 5mm acc. cord for. For instance - emergency shoe laces, running a bear bag, zipper pulls, repairing a broken tent cord, lashing together almost anything, making a snare, or a bow drill to start a fire, and pull out the core and you have a piece of fishing line.

550 paracord deserves to be in any "fix-it" kit.

By the way, the old 1983 NFPA standard specified the working strength of a rope to be 1/15 of the tensile load. So, any novice who's contemplating supporting their life on a rope should get a real climbing rope and some expert advice before using it.

 

[skiguy]

Doug, I think you missed Lawn Sale's point - 550 paracord can support your weight in a pinch. Which is important to know if you find yourself up a creek without a climbing rope - to mix metaphors.

Besides, 550 is cheap and good for so many things that you'd never want to cut up a piece of even 5mm acc. cord for. For instance - emergency shoe laces, running a bear bag, zipper pulls, repairing a broken tent cord, lashing together almost anything, making a snare, or a bow drill to start a fire, and pull out the core and you have a piece of fishing line.

550 paracord deserves to be in any "fix-it" kit.

By the way, the old 1983 NFPA standard specified the working strength of a rope to be 1/15 of the tensile load. So, any novice who's contemplating supporting their life on a rope should get a real climbing rope and some expert advice before using it.

I don't think Doug is missing a single point here. Dangling or supporting your weight is one thing on a rope; but what Doug is talking about if you look at his original post is the potential forShock Loading An entirely different concept.
Let's take a loaf of bread,tie a piece of sewing thread around it and carefully lower the loaf of bread out of a secound story window to the ground.Probably the loaf of bread if lowered uniformally will make it to the ground. Now let's take the same scenario but this time as you are lowering the loaf of bread about half way down the thread slips through your hand and you catch the loaf of bread with the thread about a foot before it hits the ground. This time you would probably have a good chance of feeding the birds with the bread crumbs. A 200lb hiker/climber would only have to fall Three(3) ft. on a 550 paracord to exceed the the load strength of that cord. Agreed paracord 550 makes for great repairs, but I would bring something stronger to lower my own body weight.

 

[DougPaul]

I don't think Doug is missing a single point here. Dangling or supporting your weight is one thing on a rope; but what Doug is talking about if you look at his original post is the potential forSHOCK LOADING
I agree with skiguy.

A 200lb hiker/climber would only have to fall Three(3) ft. on a 550 paracord to exceed the the load strength of that cord. Agreed paracord 550 makes for great repairs, but I would bring something stronger to lower my own body weight.

Here is another analysis: tie a 550 lb paracord with a .50 strength factor knot has a strength of 225 lbs. If you tie the top end to a secure tree limb and a 200lb individual steps up into a loop tied at the bottom end with this knot, the force during the step up (the shock load) can easily exceed 225lbs. The cord could break. Add degradation due to age, sun, and/or abrasion and the cord might not even hold a static load of 225lbs.

There are also issues of manufacturing variances--a manufacturer is going to be much more careful about making sure his product exceeds the ratings if he knows it is intended for supporting humans than if the product is just random rope.

Doug

 

[Lawn Sale]

Here is another analysis: tie a 550 lb paracord with a .50 strength factor knot has a strength of 225 lbs. If you tie the top end to a secure tree limb and a 200lb individual steps up into a loop tied at the bottom end with this knot, the force during the step up (the shock load) can easily exceed 225lbs. The cord could break. Add degradation due to age, sun, and/or abrasion and the cord might not even hold a static load of 225lbs.
Doug

I did not intend for this to turn into a debate about shock loading, which I am well aware of due to my college courses on stresses and strains. But, to clear the air here (hopefully), I would only use it in an emergency, as I stated before. The posts regarding the 550 cord to date are theoretical in nature, and while generally correct, sometimes empirical testing goes beyond theoretical knowledge. I agree that abrasion, age, and degradation are all factors that will decrease the working load of the cord in question, as are manufacturing tolerances.

I just went outside to a tree and duplicated the test DougPaul described above and despite doing a pullup and then falling, I could not break the 550 cord. I weigh 205 pounds with my clothes on (hey, I'm not Pete Hickey here! ) and the tree was a hibernating maple (interjected for humor, some of you are taking this way too seriously ). The top and bottom knots were bowlines, and there was about 6' of cord between me and the tree limb. At no time did I touch the ground. That being said, I now have a sweet headache due to the rebound of the cord and the collision of my head with the tree limb, a factor I had not considered in my experiment .

So, ladies and gents, if you're going to "try this at home", please take all necessary safety precautions, including a helmet.

As I stated before, this has gotten out of hand, I never intended this to become a debate. Theoretical data is worthy of study, but empirical data is also worthy of the experimentation. How many times do we look for alternate uses for everyday equipment in a never ending quest to save weight? How often do we push the limits of our equipment past their intended uses? I would not recommend people do something unsafe, unless the risk of the act outweighs the risk of not doing it. But, we have to know the limits of our equipment to know what they will and won't take.

So, let's get back to our regularly scheduled thread topic and off this dichotomic interaction, shall we?

 

[DougPaul]

I just went outside to a tree and duplicated the test DougPaul described above and despite doing a pullup and then falling, I could not break the 550 cord. I weigh 205 pounds with my clothes on (hey, I'm not Pete Hickey here! ) and the tree was a hibernating maple (interjected for humor, some of you are taking this way too seriously ). The top and bottom knots were bowlines, and there was about 6' of cord between me and the tree limb. At no time did I touch the ground. That being said, I now have a sweet headache due to the rebound of the cord and the collision of my head with the tree limb, a factor I had not considered in my experiment .

1. A bowline has a strength reduction factor of about .7 giving an approximate system strength of about 385 lbs.

2. Sounds like the 550 cord might be dynamic (it stretched and rebounded).

3. (And most important) How did the tree fare?

Glad to hear you survived--gear testing is hazardous and there are certain risks which are inherent in these activities...

Doug,
who carries 6 or 7 mm accessory cord (much safer--no bounce ) if he anticipates supporting a human with it.

 

[Lawn Sale]

I don't know about the tree, I'll check in the morning and ask!

Where do you find the knot factors? I've always wondered what knots are stronger than others, but can never find the chart or database. Maybe I'm just entering the wrong words in the search criteria.

Back to the list...what about a hotglue stick?

 

[DougPaul]

I don't know about the tree, I'll check in the morning and ask!

Where do you find the knot factors? I've always wondered what knots are stronger than others, but can never find the chart or database. Maybe I'm just entering the wrong words in the search criteria.

A small chart can be found in Freedom of the Hills--In the 7th ed: climbining fundamentals > basic safety system > pg 141. I suspect it also depends on the rope construction and material. IIRC the strength reduction factors can range from about .7 to .5. (People test these things by putting them on an appropriate machine and pulling until they break. The break typically occurs at the not. Places where a line runs over a sharp edge are also potential failure points.)

Doug

 

[rhihn]

Here is a page that might be helpful for someone with a background in physics, and one that is more for a general reader.

Dick

 

[skiguy]

Back to the list...what about a hotglue stick?

A hotglue stick in combination with some shredded steel wool makes for good hole repair on a torn screw from something like a backcountry ski.

 

[Neil]

In order to get independant verification of Lawnsale's data I decided to repeat his experiment using a slightly different design.
I climbed up into a maple (I wanted to keep that part of the apparatus constant) and tied one end of the rope around around a limb of 8.5 cm diameter. Then I coiled the other end of the rope around my neck and was all set to jump when my neighbour came running out of her house waving her arms and screaming, "Who do you think you are? Pete Hickey?"

I guess she lurks here. Who'd a thunk it?