Tensile tester in London

Does anyone know where I could get some tensile testing done in London?

Basically I want to find out what exposure to Permethrin does to climbing soft goods such as slings and quickdraws made of nylon, dyneema or a blend of the two.

It would involve pulling the slings until they break and recording the force it took to break them (preferably in kN). Something similar to what they are doing in this video:

https://www.youtube.com/watch?v=5o0b5rL9WgA

I'm based in London, but I can also post you the stuff to test if you're willing to help.

Thanks

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Originally Posted by asteclaru

Does anyone know where I could get some tensile testing done in London?

Basically I want to find out what exposure to Permethrin does to climbing soft goods such as slings and quickdraws made of nylon, dyneema or a blend of the two.

It would involve pulling the slings until they break and recording the force it took to break them (preferably in kN). Something similar to what they are doing in this video:

https://www.youtube.com/watch?v=5o0b5rL9WgA

I'm based in London, but I can also post you the stuff to test if you're willing to help.

Thanks

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Have you thought about asking a university ? Sounds like an interesting experiment for a dissertation, etc.

Imperial have a climbing club and a physics lab..

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Originally Posted by joe narvey

Have you thought about asking a university ? Sounds like an interesting experiment for a dissertation, etc.

Imperial have a climbing club and a physics lab..

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My first thought was 'university', but I don't have a clue on how to go about asking them. I was half-hoping that someone on TZ would be working for one and would be willing to help, or 'make introductions'

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Originally Posted by asteclaru

My first thought was 'university', but I don't have a clue on how to go about asking them. I was half-hoping that someone on TZ would be working for one and would be willing to help, or 'make introductions'

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Google Imperial college climbing club and you get 8 names and contact details. They should be able to connect you with right department.

They also have a large climbing wall set up, etc.

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Originally Posted by joe narvey

Google Imperial college climbing club and you get 8 names and contact details. They should be able to connect you with right department.

They also have a large climbing wall set up, etc.

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Cheers, I'll look into it.

Maybe ask one of the machine manufacturers to point you to a friendly customer/lab that would be willing to help you?

I used to know this company (as a supplier to them), might be worth an approach: https://www.tiniusolsen.com/tinius-o...achine-company

It’s pretty much my field, but I’m in Germany so can’t really help directly. To cut to the chase do you have a budget ? You’d need to pay for the actual testing plus the fixtures to hold the slings correctly. Do you plan on pulling them apart in karabiners, or you want a nice smooth radius bar so that there’s less influence from the ends.

Edit to add: I could conceivably try and organize something here but you’d be paying full commercial costs. Once set-up it’d be very quick work, but you might have expenses for the fixtures depending on what you want to hold everything with. I’d guess circa 2k euro for up to 10 slings including fixtures.

I'm sure I can get someone to do this for you where I work in Sheffield, as long as it's not too time-consuming. Be good if you'd support the fundraiser as I / we wouldn't want payment for this.

If not, I can point you in the direction of someone in W London who may be able to help, whether they'd charge I'm not sure.

PM me if you like.

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Originally Posted by HookedSeven

It’s pretty much my field, but I’m in Germany so can’t really help directly. To cut to the chase do you have a budget ? You’d need to pay for the actual testing plus the fixtures to hold the slings correctly. Do you plan on pulling them apart in karabiners, or you want a nice smooth radius bar so that there’s less influence from the ends.

Edit to add: I could conceivably try and organize something here but you’d be paying full commercial costs. Once set-up it’d be very quick work, but you might have expenses for the fixtures depending on what you want to hold everything with. I’d guess circa 2k euro for up to 10 slings including fixtures.

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As this is strictly out of personal curiosity, that's way more than I'm willing to spend. Thank you for the offer though.

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Originally Posted by ism123

I'm sure I can get someone to do this for you where I work in Sheffield, as long as it's not too time-consuming. Be good if you'd support the fundraiser as I / we wouldn't want payment for this.

If not, I can point you in the direction of someone in W London who may be able to help, whether they'd charge I'm not sure.

PM me if you like.

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A contribution to the fundraiser would of course be made if we can work something out. I will PM you.

Another thing to add, I'm not expecting a professional setup like the one in the video I've linked. I've seen gear tested using a forklift, an attachment point and a dynamometer. A garage setup such as this would be more than enough to satisfy my curiosity.

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Originally Posted by asteclaru

As this is strictly out of personal curiosity, that's way more than I'm willing to spend. Thank you for the offer though.

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You’ll find it’s going to be broadly similar going through commercial test centers. If you want to do it on the cheap then finding a university to help seems a reasonable suggestion, although they may well want to charge unless it aligns with something they’re researching.

What sort of loads are you expecting by the way ? You could rig something up that applies increasing static loads fairly cheaply and easily, but without a force cell you wouldn’t get your nice force/displacement plots, plus you’d have to incrementally increase the loading until it fails, and that in itself may influence the result vs. a single load application.

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Originally Posted by asteclaru

A contribution to the fundraiser would of course be made if we can work something out. I will PM you.

Another thing to add, I'm not expecting a professional setup like the one in the video I've linked. I've seen gear tested using a forklift, an attachment point and a dynamometer. A garage setup such as this would be more than enough to satisfy my curiosity.

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Please consider the safety of the tester(s). There’ll be a lot of energy stored in that sling when it finally decides to let go.

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Originally Posted by HookedSeven

You’ll find it’s going to be broadly similar going through commercial test centers. If you want to do it on the cheap then finding a university to help seems a reasonable suggestion, although they may well want to charge unless it aligns with something they’re researching.

What sort of loads are you expecting by the way ? You could rig something up that applies increasing static loads fairly cheaply and easily, but without a force cell you wouldn’t get your nice force/displacement plots, plus you’d have to incrementally increase the loading until it fails, and that in itself may influence the result vs. a single load application.

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The stuff I'm looking to test are rated for 24 kN. What I want to find out is whether exposing them to Permethrin affects the strength.

Basically, what happened, was that I've sprayed my rucksack with Permethrin to keep bugs out. Only after I've done it it occurred to me that I carry climbing gear in it. I'm fairly sure that Permethrin doesn't affect the metal bits, but I can't find anything conclusive about whether it does anything to Nylon or Dyneema (which what most climbing soft goods are made of).

My plan was to test a brand new sling, and a couple that have been soaked in the substance and see if there is any reduction in strength. I've already bought another rucksack, so I'm not that bothered about that, but this did spark my curiosity as to whether Permethrin affects nylon. I know, for example, that DEET doesn't affect nylon, but it does affect other plastics, but, unfortunately, no one seems to have tested Permethrin.

All that being said, I'm not curious enough to spend thousands to find out.:smiley:

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Originally Posted by ism123

I'm sure I can get someone to do this for you where I work in Sheffield, as long as it's not too time-consuming. Be good if you'd support the fundraiser as I / we wouldn't want payment for this.

If not, I can point you in the direction of someone in W London who may be able to help, whether they'd charge I'm not sure.

PM me if you like.

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Am sure that in the Engineering Dept must have several machines that they use for steel tensile strength, and can be easily recalibrated for an afternoon.

I am not in London but, if for some reason Sheffield cannot do this, I am fairly certain that my university can test a few samples for you.

Feel free to PM.

Regards Gary

Sent from my moto g(7) power using Tapatalk

I would be willing to say that the exposure to bug spray will have zero impact on the capacity of the equipment.

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Originally Posted by rico

I would be willing to say that the exposure to bug spray will have zero impact on the capacity of the equipment.

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Agree, whatever it's dissolved in will have larger effect (probably still none).

DEET might be a 25% solution permethrin is more like 0.25%.