Harnesses and Acid

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Re: Harnesses and Acid

Postby rjack » Jul 8, 2013 1:13 pm

Sulfuric acid is H2SO4. Its fairly strong because the hydrogens readily disassociate from the sulphate group.

Sulphonic acid is an organic acid, with an organic molecule of varying sizes substituting for an OH group. So at best, its 1/2 the strength of sulfuric acid. The reality is that the polarity of the substituted organic group will have a large bearing on how acidic the new organic acid actually is. "Sulphonic" is just a generic name and doesn't provide much info in its potential acidity.

The free hydrogens are what lower the pH, create an "acid", and what attack and weaken the bonds in nylon. In any case, they are wildly different acids despite the similar sounding names.

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Re: Harnesses and Acid

Postby paul » Jul 9, 2013 6:14 am

trogman wrote:I was really hoping some of our more knowledgeable members would explain (in laymans terms) what the difference is between sulfonic acid and
sulfuric acid. If they are essentially the same thing, it doesn't sound like a good idea to be using it on rope and soft vertical gear.

Trogman :helmet:


Basically Sulfonic Acid is Sulfuric Acid with one of its Hydroxyl (OH) groups replaced by an Organic (i.e. Carbon-based compound) substitent (see https://en.wikipedia.org/wiki/Sulfonic_acid.

The important detail from possible damage to harnesses is:

Sulfonic acids are much stronger acids than the corresponding carboxylic acids. p-Toluenesulfonic acid, with a pKa of -2.8, is about a million times stronger acid than benzoic acid, with a pKa of 4.2. Similarly, methanesulfonic acid, pKa = -1.9, is also about one million times stronger acid than acetic acid. Because of their polarity, sulfonic acids tend to be crystalline solids. They are also usually colourless and nonoxidizing, which is convenient. Because of their high acidity, sulfonic acids are often soluble in water or exhibit detergent-like properties.


Hope that helps.
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Re: Harnesses and Acid

Postby trogman » Jul 9, 2013 9:30 am

Thanks for the explanation of the differences. I guess the bottom line is that, while it raises some interesting issues, this little experiment is inconclusive, at least regarding many of the substances they tested. I find it extremely odd that the 30 min. exposure to Woolite caused a 9% decrease in strength, while 72 hours only resulted in a 5% reduction. And then we have the JKKS test, which showed basically no reduction at all. So now I am totally confused. :shrug: I suppose I could just not wash my ropes and gear at all. Then the WNS police would track me down and crucify me. :yikes: Seriously, I can't imagine me not washing my gear.

For the time being I will probably just continue washing my nylon gear, but just to be on the safe(er) side, I will stay away from the Woolite. The Arm and Hammer detergent or just about any detergent w/o sulfonic acid should be fine. Of course I will also avoid anything with added bleach.

Am I worrying about this too much? I don't think so, since my life does depend on the integrity of my rope and nylon gear.

Trogman :helmet:
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Re: Harnesses and Acid

Postby cavedoc » Jul 9, 2013 1:53 pm

trogman wrote:Am I worrying about this too much?:


In my opinion, yes. They soaked for 30 minutes and then dried for 15 and lost 9%. Remember that soaking your rope in pure water can reduce strength up to 15%. There is at least some water in Woolite and it is not going to all disappear in 15 minutes of drying. You could make an argument that Woolite is safer than tap water or cave water. If they had a better control group the relative risks here would be more obvious. The JCKS testing is better done and very reassuring. If you remain worried, never use a wet rope.
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Re: Harnesses and Acid

Postby trogman » Jul 10, 2013 2:37 pm

cavedoc wrote:
trogman wrote:Am I worrying about this too much?:


In my opinion, yes. They soaked for 30 minutes and then dried for 15 and lost 9%. Remember that soaking your rope in pure water can reduce strength up to 15%. There is at least some water in Woolite and it is not going to all disappear in 15 minutes of drying. You could make an argument that Woolite is safer than tap water or cave water. If they had a better control group the relative risks here would be more obvious. The JCKS testing is better done and very reassuring. If you remain worried, never use a wet rope.



Thanks for that insight, Cavedoc! My concern was that the 9% might be cumulative, which would definitely be cause for concern. You make a good point.

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Re: Harnesses and Acid

Postby acountrycaver » Jul 17, 2013 11:08 am

Thanks for the excellent safety information. I keep my climbing gear in a special backpack isolated from harm,,,,,I hope.
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Re: Harnesses and Acid

Postby sgla321 » Jul 30, 2013 8:15 am

Used to really be careful with wheat lamps; not such a problem since batteries aren't carried on belts almost at all anymore.
Always prudent to carry ropes, harnesses, etc. in packs while stored in car tunks etc.
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Re: Harnesses and Acid

Postby Adam Byrd » Aug 21, 2013 8:46 am

I'm late to the discussion, but maybe I can shed a little light on this topic. Other posters are correct in pointing out that the relatively weak sulfonic acids are different than the strong acid sulfuric acid, but an important point has been overlooked in the formulation of detergents. Taking regular Woolite laundry detergent as an example, the MSDS lists Benzenesulfonic acid, C10-C16-alkyl derivatives and sodium hydroxide as two of the ingredients. Some similar detergents list sodium alkylbenzene sulfonate. These are equivalent. It means that the sulfonic acid has been neutralized by the addition of basic sodium hydroxide. Exposing all of your clothing to acid doing normal laundry would destroy your clothes, and that's not what detergents are designed to do. Having neutralized the acidic proton, you end up with some sodium ions floating around and the alkylbenzene sulfonate molecule. The alkylbenzene sulfonate has a nonpolar end (alkylbenzene) and negatively charged polar end (sulfonate) and can trap dirt and oils, behaving as a detergent.
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