DEET and Climbing Ropes

There was an interesting conversation at the RTCUK Sleepover about DEET maybe degrading climbing ropes. It was scary enough to make you think twice about risking Lyme's or a nasty fall. After all, as a solvent DEET will melt plastic and denature your sunglasses, camera and so on.

I couldn't find anything definitive online, but everything you can find points to this quote from a report which now seems to be unavailable:

Summary of Nylon, PET and Spectra Chemical Resistance to DEET

Many climbers have in the past worried about the effects of accidentally spilling bug repellent on their climbing ropes. The following is the result of preliminary testing of deet and other bug repellent chemicals.

Samples of nylon, polyester, and spectra were submitted for chemical resistance testing for DEET (N,dimethyl-m-toluamide). The three samples were immersed separately in “CUTTER” and “OFF” brand insect repellent for a period of twenty-four hours at room temperature. “OFF” contains 95% Deet (N-dimethyl-m-toluamide) while “CUTTER” contains only 7% Deet and probably some oil based solvents as well. The results of the testing indicate no loss of strength as measured by tensile strength retention in any of the three samples.

There was one interesting anomaly that occurred only in the case of Nylon and the “CUTTER” brand insect repellent. As mentioned before there was no loss of strength for any of the samples but here there was a 25% increase in the elongation and a decrease in modulus. This basically means that a rope made entirely or mostly out of Nylon may become “rubbery” with a significant amount of exposure to “CUTTER” or other insect repellents with large amounts of oil based solvents.

However, with regard to the chemical in question, DEET, there appears to be no effect on any of the physical properties of the three samples. Hence as “CUTTER” contains only 7% DEET the change in the Nylon elongation and modulus must come from the other solvents in the product. It is suggested that if a rope has significant amounts of Nylon to use insect repellents with 95-100% Deet instead of ones with some Deet and large amounts of other oil based solvents.

Please keep a major factor in mind in regards to this study/testing. The only two brands tested were OFF and Cutter and were specific formulas of those brands. So we can’t necessarily say that all bug repellent products with DEET will not harm the stated materials. Other brands and other formulas could contain a substance other than what was in the two formulas tested. In other words, it is probably safe to say DEET itself has no effect but there can be other chemicals in other repellents that may.
— Honeywell Performance Fibers

Personally, I'm taking this as permission to not worry. The most up-to-date forum discussion about this I could find was this one, and there seems to be no accounts online of rope failure after DEET contact. Your mileage may vary, but for me avoiding the relative certainty of again having to extract gangs of voracious parasites from my nethers beats the theoretical risk of equipment failure.

Protecting the Free and Open Internet: European Edition

Reddit has summarised the European attempt to destroy the internet for everybody. Here it is in its entirety, though click through to the site for the comments.

Hey Reddit,

We care deeply about protecting the free and open internet, and we know Redditors do too. Specifically, we’ve communicated a lot with you in the past year about the Net Neutrality fight in the United States, and ways you can help. One of the most frequent questions that comes up in these conversations is from our European users, asking what they can do to play their part in the fight. Well Europe, now’s your chance. Later this month, the European Parliament’s Legal Affairs Committee will vote on changes to copyright law that would put untenable restrictions on how users share news and information with each other. The new Copyright Directive has two big problems:

  • Article 11 would create a "link tax:” Links that share short snippets of news articles, even just the headline, could become subject to copyright licensing fees— pretty much ending the way users share and discuss news and information in a place like Reddit.
  • Article 13 would force internet platforms to install automatic upload filters to scan (and potentially censor) every single piece of content for potential copyright-infringing material. This law does not anticipate the difficult practical questions of how companies can know what is an infringement of copyright. As a result of this big flaw, the law’s most likely result would be the effective shutdown of user-generated content platforms in Europe, since unless companies know what is infringing, we would need to review and remove all sorts of potentially legitimate content if we believe the company may have liability.

The unmistakable impact of both these measures would be an incredible chilling impact over free expression and the sharing of information online, particularly for users in Europe.

Luckily, there are people and organizations in the EU that are fighting against these scary efforts, and they have organized a day of action today, June 12, to raise the alarm.

Julia Reda, a Member of the European Parliament (MEP) who opposes the measure, joined us last week for an AMA on the subject. In it, she offers a number of practical ways that Europeans who care about this issue can get involved. Most importantly, call your MEP and let them know this is important to you!

As a part of their Save the Link campaign, our friends at Open Media have created an easy tool to help you identify and call your MEP.

Here are some things you’ll want to mention on the phone with your MEP’s office:

  • Share your name, location and occupation.
  • Tell them you oppose Article 11 (the proposal to charge a licensing fee for links) and Article 13 (the proposal to make websites build upload filters to censor content).
  • Share why these issues impact you. Has your content ever been taken down because of erroneous copyright complaints? Have you learned something new because of a link that someone shared?
  • Even if you reach an answering machine, leave a message—your concern will still be registered.
  • Be polite and SAY THANKS! Remember the human.

Phone not your thing? Tweet at your MEP! Anything we can do to get the message across that internet users care about this is important. The vote is expected June 20 or 21, so there is still plenty of time to make our voices heard, but we need to raise them!

And be sure to let us know how it went! Share stories about what your MEP told you in the comments below.

PS If you’re an American and don’t want to miss out on the fun, there is still plenty to do on our side of the pond to save the free and open internet. On June 11, the net neutrality rollback officially went into effect, but the effort to reverse it in Congress is still going strong in the House of Representatives. Go here to learn more and contact your Representative.

Rookie DdRT Error. How not to tie yourself to the top of a tree.

I got stuck up a tree on Sunday. Kinda. I was with somebody who descended and resolved it, but it was a learning-point - particularly when I usually climb alone...

I had ascended with a doubled rope, and then hauled up the tail and dropped it elsewhere to get it out of the way of my climbing partner. The way I did that was to pull up the tail incrementally and allow the taken-up bight to descend down where I wanted it to go. What happens if you do that is you end up holding the free end with the weight of all the slack rope pulling it down. The natural inclination then is to drop it. On this occasion the weight of the rope pulled the end with enough force to cause it to wrap completely around a limb much lower down, leaving it as in the image.

All seemed well until I tried to descend DdRT, when the standing end of the rope would not come up, thus preventing me from descending at all - and preventing me, therefore, from untangling the tail. To compound the problem, the single wrap meant that gravity would pull any slack out of the standing end, essentially acting as a progress-capture device, allowing me only to ascend.

Lessons learned:

  • This is why you should climb with a partner. Thanks Jos for descending and unwrapping my rope.
  • Don't drop the bight. You are probably ok to allow it to descend until you have the tail-end (though take care! The alternative is to bag the rope as you pull it up...) but then feed the tail down where you want it until all the slack follows it down and is deployed. This takes the energy out of the system, reducing the possibility of wrapping.
  • If you do get in this situation, anchor the working end to a limb near you and climb down SRT to unwrap the rope. If you have a throwline with you you can tie a retrievable anchor and not have to climb back up, but if not the extra climb serves you right!
  • Climb with a backup system. I always have a hand-jammer and foot-ascender, but I've added a gri-gri to my always-on harness-kit. With the progress-capture effect of this wrap it would have been tricky to tie a munter or super-munter for descending, and that wouldn't have been great for stopping at the wrap anyway.

Stay in school kids!

How Technology Keeps Us Hooked.

This is a great article in The Conversation.

Digital technologies, such as social networks, online shopping, and games, use a set of persuasive and motivational techniques to keep users returning. These include “scarcity” (a snap or status is only temporarily available, encouraging you to get online quickly); “social proof” (20,000 users retweeted an article so you should go online and read it); “personalisation” (your news feed is designed to filter and display news based on your interest); and “reciprocity” (invite more friends to get extra points, and once your friends are part of the network it becomes much more difficult for you or them to leave).
— The Conversation

Read it here.

The irony of blogging it is not lost on me. At least I'm not tweeting it.


Why America is the World's First Poor Rich Country

America fills me with utter terror. The absolute lack of interest the state takes in the well-being of its citizens, and the total private ownership of every service that would provide the foundation of a caring society wishing to invest in those citizens (cough... healthcare) leads to an undervaluing of human life and an over-emphasis on individual financial success. The actual ability for an individual to become successful (which in American English is synonymous with wealthy) is a dream bordering on delusion. The American Dream. As Cory Doctorow said in 2014:

Human beings are the gut flora of immortal, transhuman corporations.
— BoingBoing

This is chilling in its ten-word horrific truth.

This article in Eudaimonia expands nicely on the economic system that drives this paradoxical move towards poverty-despite-wealth.

All the things that really elevate people’s quality of life — healthcare, finance, education, transport, housing, and so on — have come to consume such a large share of the average household’s income that they have little left to save, invest, or spend on anything else. And what’s worse, while the basics of life have seen massive inflation, wages and incomes (not to mention savings and benefits and safety nets and opportunities) for most have stagnated. The result is an economy — and a society — that’s collapsing... Predatory capitalism coupled with total economic mismanagement of social investments has made the basics of life ruinously unaffordable.
— Umair Haque, Eudaimonia

Read it all here.

RTCUK Sleepover 2018

The Recreational Tree Climbing UK annual Sleepover is always good and, as usual, failed miserably to disappoint.

By no means everybody. Lots of shirts were in evidence. Kerry, Lawrence, and I had nice high hammocks...

This is the canopy above my bed...

The dawn chorus was amazing, but that early in the morning I was all zipped up and snuggled down. Later on (7:30 - very respectable) I recorded this:

This is how to get out of bed in the morning. It does rather mean the route to bed the night before is a right pain in the arse.

Rachael Talibart's Amazing Seascapes

Rachael Talibart

Newhaven never looked better. Rachel Talibart uses superfast shutter speeds and telescopic lenses to pick out these dramatic solid-looking waves.

Growing up in southeast England, Rachael Talibart spent several weeks every summer on her father’s sailboat, exploring the coastlines of France and the Netherlands. These family voyages were meant as a vacation, although Talibart never had much fun—she was a “shockingly bad sailor” who was almost constantly seasick. Because her nausea was worse inside the boat, she spent most of her time alone in the cockpit, looking out over the ocean.

’I spent ages staring at the waves,” she remembers. “I used to imagine creatures in the sea.’

Found on Wired. See them all there.


Can it ever make sense to talk about 'art' or 'craftsmanship' in the context of a computer-machined hunk of aluminium?


Designed by Nendo:

Firstly, grooves of 5mm deep, 1.8mm width were carved in constant intervals on the vase’s exterior, resulting in two different levels on the surface. The first pattern was then carved 2mm deep from the external surface, while the second pattern was carved 6mm deep from the deeper immersed surface.

This calculated process results in the creation of a four-layer surface with different depths, allowing the patterns to appear visually according to the angle in which the vase is viewed. The dimensions and proportions of this process were carefully examined and tested due to the effects of deviations; if the initial grooves are too deep, the dark casted shadows will visually block the pattern, conversely if it is too shallow, the two patterns will blend together without a distinct separation.

By using multi axis machinery, some grooves were carved to 1.8mm in width, and only 1mm thickness at the edge. These narrow dimensions cause complications, as the grooves can easily break due to clogging of scraping material. Furthermore, if the cutting speed is too high, the temperature of the cutter rises, and can cause metal distortions. Accordingly, the production’s duration and dimensions were carefully adjusted, and milling was done gradually in 0.5 mm deep layers.

This delicate process originated from a 100kg block of aluminum, that after 7 months, resulted in a 15kg vase.