|
|
|
|
gmggg
Sep 17, 2010, 6:39 PM
Post #26 of 37
(1568 views)
Shortcut
Registered: Jun 25, 2009
Posts: 2099
|
edge wrote: gmggg wrote: What I might suggest (And what I use for plastic holds) is a biodegradable degreaser, I like Orange-Solve myself. It's a citric based degreaser and I have a hard time imagining that it would damage any rock type, but maybe someone with some concrete knowledge could weigh in on that. We have used citrus based paint strippers at Lincoln Woods to remove graffiti* with good results. However you need to flush it with plenty of water, and I can't comment as to how it would react with caked on chalk. It showed no noticeable effect on the rock or it's texture. *They don't make enough to remove all the graffiti at Lincoln Woods...
As someone else noted you really want an alkaline for caked on chalk since it's more of an oil problem than anything else. Orange-Solve works really well for me with greasy urethane holds that have been outside for extended amounts of time with lots of caked chalk and road dust. I imagine it'd be pretty good on rock as well.
|
|
|
|
|
xtrmecat
Sep 17, 2010, 6:43 PM
Post #27 of 37
(1567 views)
Shortcut
Registered: Apr 1, 2004
Posts: 548
|
Easy there big fella. We posted nearly the same time, I didn't mean to ruffle your feathers. Any acid would be too much really.
I was commenting to keep the guy from going down to the hardware store and buying a gallon of muratic and dosing the stone. Yes, that would create a dangerous and potentially disastrous scenario. Same thing as trying to use some old battery electolyte, " Yeah, that should do it,right Jeb?'
If 3% HCL solution is the same ph as coke, why not get in on a 2 liter special for $.99 and save us a few cents also. Feeds the insects at the same time.
Burly Bob
|
|
|
|
|
blondgecko
Moderator
Sep 17, 2010, 10:11 PM
Post #28 of 37
(1542 views)
Shortcut
Registered: Jul 2, 2004
Posts: 7666
|
dynosore wrote: Diluted muriatic acid (say 3-5%) should work well, just wear the right protective clothing and rinse the rock when done to get rid of the residual. Realistically, you're not going to dissolve even a small fraction of a mm of rock with a solution like this. The acid will preferentially attack the calcium carbonate over almost any rock type.
... Unless that rock is calcium carbonate (ie. limestone). And no, a 3-5% muriatic acid solution is not "about as acidic as a can of coke". Diluted from typical hardware stores concentrations, that's still around 0.5M, or below pH 1. That's overabout a thousand times more acidic than Coke (pH 3-4, iirc).
As to the original question, why not experiment with one of the more "creek safe" detergents?
(This post was edited by blondgecko on Sep 17, 2010, 10:52 PM)
|
|
|
|
|
redlude97
Sep 17, 2010, 10:16 PM
Post #29 of 37
(1539 views)
Shortcut
Registered: Aug 27, 2008
Posts: 990
|
Why is everyone talking about calcium carbonate? Chalk is made from magnesium carbonate
|
|
|
|
|
aspiringloser
Sep 17, 2010, 10:40 PM
Post #30 of 37
(1530 views)
Shortcut
Registered: Aug 13, 2009
Posts: 12
|
Castrol Superclean
|
|
|
|
|
blondgecko
Moderator
Sep 17, 2010, 10:47 PM
Post #31 of 37
(1527 views)
Shortcut
Registered: Jul 2, 2004
Posts: 7666
|
redlude97 wrote: Why is everyone talking about calcium carbonate? Chalk is made from magnesium carbonate
I know - but that didn't seem worth mentioning, since the chemistry is pretty much the same.
|
|
|
|
|
gunkiemike
Sep 17, 2010, 11:37 PM
Post #32 of 37
(1519 views)
Shortcut
Registered: Oct 1, 2002
Posts: 2266
|
blondgecko wrote: dynosore wrote: Diluted muriatic acid (say 3-5%) should work well, just wear the right protective clothing and rinse the rock when done to get rid of the residual. Realistically, you're not going to dissolve even a small fraction of a mm of rock with a solution like this. The acid will preferentially attack the calcium carbonate over almost any rock type. ... Unless that rock is calcium carbonate (ie. limestone). And no, a 3-5% muriatic acid solution is not "about as acidic as a can of coke". Diluted from typical hardware stores concentrations, that's still around 0.5M, or below pH 1. That's overabout a thousand times more acidic than Coke (pH 3-4, iirc). As to the original question, why not experiment with one of the more "creek safe" detergents?
Commercial muriatic acid is almost as concentrated as what we buy for chem lab use. A 3% solution of it will be 0.3 M, and yes, that's a pH less than 1. Compared to Coca Cola which is pH 2.5. So almost 200X stronger acid. Icks-nay on the uriatic-may. At 3% anyway.
To rgold's point re. oils mixing with the chalk. I suggested a few years ago that the fatty acids from skin oils in the sludge may react with the chalk (which may contain small amounts of magnesium oxide) to form insoluble magnesium soaps. These are not easily cleaned off with alkaline or acidic water solutions. Some really strong grease cutting products would be needed. It should be straightforward to identify Mg soaps by IR spectroscopy, but I'm not in the analytical end of chemistry any more, and my chemist friend who has a lab doesn't seem to climb rock much any more.
|
|
|
|
|
blondgecko
Moderator
Sep 18, 2010, 7:57 AM
Post #33 of 37
(1476 views)
Shortcut
Registered: Jul 2, 2004
Posts: 7666
|
gunkiemike wrote: blondgecko wrote: dynosore wrote: Diluted muriatic acid (say 3-5%) should work well, just wear the right protective clothing and rinse the rock when done to get rid of the residual. Realistically, you're not going to dissolve even a small fraction of a mm of rock with a solution like this. The acid will preferentially attack the calcium carbonate over almost any rock type. ... Unless that rock is calcium carbonate (ie. limestone). And no, a 3-5% muriatic acid solution is not "about as acidic as a can of coke". Diluted from typical hardware stores concentrations, that's still around 0.5M, or below pH 1. That's overabout a thousand times more acidic than Coke (pH 3-4, iirc). As to the original question, why not experiment with one of the more "creek safe" detergents? Commercial muriatic acid is almost as concentrated as what we buy for chem lab use. A 3% solution of it will be 0.3 M, and yes, that's a pH less than 1. Compared to Coca Cola which is pH 2.5. So almost 200X stronger acid. Icks-nay on the uriatic-may. At 3% anyway. To rgold's point re. oils mixing with the chalk. I suggested a few years ago that the fatty acids from skin oils in the sludge may react with the chalk (which may contain small amounts of magnesium oxide) to form insoluble magnesium soaps. These are not easily cleaned off with alkaline or acidic water solutions. Some really strong grease cutting products would be needed. It should be straightforward to identify Mg soaps by IR spectroscopy, but I'm not in the analytical end of chemistry any more, and my chemist friend who has a lab doesn't seem to climb rock much any more.
That actually makes a lot of sense - and there's no need for magnesium oxide to do it. Magnesium carbonate will raise the pH of pure water to ~8.3, which is enough to slowly hydrolyse fats over a period of days to weeks. And, as I learned to my consternation when doing a reaction involving Grignard reagent, magnesium complexes with amphiphilic acids to produce solids that are insoluble in just about everything.
Considering the environment that the chalk residue is in - in particular, regular sun exposure, it's quite likely that there'd be polymerization reactions going on (rather like what goes on on the walls of your oven).
In any case, the solution is pretty much the same: either use something to compete for the magnesium (e.g. EDTA, citrate or other chelators) or reduce the pH to ~3 to remove the affinity of the fatty acids for the magnesium, then wash away with a mild surfactant solution. That's probably the secret behind the citrus based degreasers above.
... This all makes me think: there's a number of cheaply-available minerals (titanium dioxide, for example) that, on exposure to sunlight, catalyse the breakdown of organic molecules adsorbed to them. I wonder if spiking a little bit of those into the chalk mix might help reduce the caking problem?
|
|
|
|
|
Nick864
Sep 18, 2010, 5:40 PM
Post #34 of 37
(1447 views)
Shortcut
Registered: Feb 29, 2008
Posts: 17
|
Super soaker (mentioned above). While the chemical discussion above is interesting, are you sure you wan acid of any type near your gear? I realize its a quarry, but lets not jump onto dumping chemicals into the watershed. (I make no claims as to knowing anything about the above chems or the enviro effects). Super soaker and some nylon brushes (if its not sandstone) should work. Maybe a truly natural citrus degreaser (citra solve) would work. Lets keep in mind that cleaning gym holds is done on the ground, away from climbing gear, and on plastic not rock. Not sure if gym "techniques" apply here
|
|
|
|
|
the_climber
Sep 18, 2010, 6:57 PM
Post #35 of 37
(1431 views)
Shortcut
Registered: Oct 9, 2003
Posts: 6142
|
blondgecko wrote: dynosore wrote: Diluted muriatic acid (say 3-5%) should work well, just wear the right protective clothing and rinse the rock when done to get rid of the residual. Realistically, you're not going to dissolve even a small fraction of a mm of rock with a solution like this. The acid will preferentially attack the calcium carbonate over almost any rock type. ... Unless that rock is calcium carbonate (ie. limestone). And no, a 3-5% muriatic acid solution is not "about as acidic as a can of coke". Diluted from typical hardware stores concentrations, that's still around 0.5M, or below pH 1. That's overabout a thousand times more acidic than Coke (pH 3-4, iirc). As to the original question, why not experiment with one of the more "creek safe" detergents?
Side note about HCl and Carbonate minerals - Ie. Calcite (CaCO3), Dolomite (Ca,Mg)CO3, MagnesiumCarbonate MgCO3, ...
React most effectively with a cool dilute solution of HCl, not strong/concentrated solutions. Calcite (ie. the mineral that Limestone is composed of) is the most reactive mineral to HCl. The most effective concentration for diagnostic and identification purposes (ie, that concentration which produces the best reaction) is 0.1mol/L HCl, and reaction is near complete is very short order resulting in the acid being neutralized.
Higher concentrations typically result in a sludge.
Carry on
|
|
|
|
|
dynosore
Sep 18, 2010, 7:11 PM
Post #36 of 37
(1425 views)
Shortcut
Registered: Jul 29, 2004
Posts: 1768
|
blondgecko wrote: dynosore wrote: Diluted muriatic acid (say 3-5%) should work well, just wear the right protective clothing and rinse the rock when done to get rid of the residual. Realistically, you're not going to dissolve even a small fraction of a mm of rock with a solution like this. The acid will preferentially attack the calcium carbonate over almost any rock type. ... Unless that rock is calcium carbonate (ie. limestone). And no, a 3-5% muriatic acid solution is not "about as acidic as a can of coke". Diluted from typical hardware stores concentrations, that's still around 0.5M, or below pH 1. That's overabout a thousand times more acidic than Coke (pH 3-4, iirc). As to the original question, why not experiment with one of the more "creek safe" detergents?
I should have worded that better. 3-5% muriatic acid in water i.e. 97 parts water and 3 parts muriatic acid solution will give you a safe solution to use, and a pH of about 1.5, which is close to what I recall coke being, 2.5ish. I was trying to keep it simple for non chemist types and confused the issue, my bad.
|
|
|
|
|
mojomonkey
Sep 18, 2010, 8:44 PM
Post #37 of 37
(1409 views)
Shortcut
Registered: Aug 13, 2006
Posts: 869
|
Nick864 wrote: I realize its a quarry, but lets not jump onto dumping chemicals into the watershed.
Another item to consider about the location is that the area is also a reservoir. Some of the walls are fairly close to the water, thought they are not the most chalked.
Good luck with the cleanup and thanks for organizing it again. I will be out of town for it this year.
|
|
|
|
|
|
