torching the granite dry?

[Anders Ourom]

Thank you Brendan! Apparently my fingers are seizing up in the lovely cold weather. Not sure how an "n" became a "d" though - finger dyslexia?

[Brendan]

lol no prob anders... i usually like to type in the warmth of my house
say, do u need a warm place to stay

[csg]

The Chief is granodiorite or monzogranite, haven't looked under a microscope to tell for sure. You can call it granite, and geologists won't make fun of you. At least this one won't.

The melting point of granite is much lower than the melting point of quartz, even though quartz makes up 20-40% of the granite. Its similar to salt+ice having a lower melting point than just ice. Anyways, granite will begin to melt between 600 - 800 degrees C, with variation due to pressure, presence of water, and composition.

Its tricky, meaning pretty much impossible, to get a blowtorch to melt a granite, though you can do it with a properly constructed oven. However you shouldn't blowtorch rock, because you can easily make the granite exfoliate -- that is, peel off a layer and therefore damage the rock. It doesn't need to come anywhere close to the melting point for this to happen, its a purely brittle process driven (and here is just my best guess on this) by expansion of clays found along mineral grain boundaries. Oftentimes you'll see this happen where people make campfires beside a boulder.

[erock]

csg has a point there about the exfoliation. not sure if it is due to clay mineral boudaries though. There was a big debate amongst geologist a long time ago about desert rocks being cracked and exfoliated. Some argued that it was chemical weathering disputing that it was thermal expansion causing the exfoliation. So some geologists decided to put some of the desert rocks in an oven and heat and cool them a bazillion times. Fat lot of good that did. It was later found that the sun heating the rock at the beginning of the day from ONE SIDE caused differential expansion of the rocks and therefore exfoliation.

One other thing, granite can contain some very small amounts of water, so when you heat it, you get lots of pressure. just like you would if you blowtorched popcorn.

Anyways! i was never a fan of the blowtorch method myself, but if you just want to go and climb some discrete boulder problems, or are killing to get back on your project for one last try and it's wet, bring some towels and maybe take it easy with the torch.

[Tyrone Brett]

This is really interesting. I remember Patch Hammond coming here in the late 90's (maybe later, I'm getting old) and he was super anti- torches. At the time I wasn't sure if it was a grit thing or some sort of mystic appreciation of the rock. Anyways, I tucked my little "boulder blower" away after that 'cause something struck me as weird about the whole thing. Given the comments around exfoliation etc..., maybe The Patch was right.
So the big question is..... should Squamish climbers develop a local ethic around this issue (kinda like no pof on grit).
Tyrone
SAS

[XXXX]

Ok so here's the deal as I see it. You can't burn a paper bag if it is full of water, right? (High school science class). You have to dry it out first, then it burns

So as long as u are just evaporating water, the rock never warms above 100C... its when you go the extra few seconds with the torch, after the hold is dry, that you start to cause damage.

Just like - your carefully placed foot does not cause polish on the foothold - your buddy flailing up after you on toprope in his muddy shoes is what causes polish. That bastard. If I ever catch him...

If worst comes to worse you can etch the rock with acid to restore texture when it's polished but it's hard to restore holds when they exfoliate and break off, especially when they are so small that the rebuild would be more glue than hold (right Ty?)

[David_Trippett]

A couple problems with torching....one, is differential expansion of the minerals in the rock. When you heat the minerals, they will expand and contract at different rates. This expansion can cause tiny micro-fractures between the different minerals in the rock that may eventually lead to the breaking of the crystals, or even a whole hold.
Secondly, some minerals have water bound up in the crystal lattice, as these minerals are heated the water molecules can also aid the fracturing as the super heated water vapour tries to escape the the mineral.
This is just anecdotal, but when Sharma was here working Dreamcatcher, he was asking a bunch of us if it was OK to torch the holds...I thought about saying something about what little I knew about the subject...but I didn't....later I heard that a small hold broke at the crux, where he'd been torching it. I guess it ended up lowering the grade? Anyway....this is all like 3rd hand...so who knows whether or not the torching was the cause.
I personally think that it's not a good idea...particularly if it potentially damages the rock.

[rich k]

Ok so here's the deal as I see it. You can't burn a paper bag if it is full of water, right? (High school science class). You have to dry it out first, then it burns

cool analogy XXXX. your brain's made up of water too, so would you take a torch to your head? probably polish your skin a bit, eh!

[Mike C.]

im glad someone came along with a qualified argument against torching. ive been bouldering during the "off season" in squamish since '99 and ive never used a torch. i just bring a couple towels and several chalk balls. gets anything i need dry and it does it way faster than a torch. in situations where you have a sloper with seepage coming from above i sometimes make a dam of chalk several inches above it. you laugh, but it works. and sometimes there are some problems, in the forest no less, that just dry fast. i did the weasel on saturday without even having to use the towel that we brought in. tried that new thing behind Sticky Fingers aswell and if we hadnt have lost ligh(and motivation) No Troblems was bone dry.

(using the voice of Wilford Brimley)trade your torches in for towels. you'll be glad you did.

[Mike C.]

didnt notice that erock had made mention of the towels. sage advice my friend....shouldnt you be aid climbing in the rain right now?

[5.4 Slayer]

Rain? Where the hell is it raining????

[Tyrone Brett]

xxxx: Glue?! I said Pof! Hell, I'm going in there tomorrow to finally fix that damn flake on Tatonka! (just kidding...) But whether glueing, bolting, vegetation management, torching, drytooling on sport climbs... it is interesting to wonder at what point a community might want to agree on norms (which, with climbers, might be like juggling eels) or instead leave self management and regulation in place.

By the way- has any body been in there over this last cold spell? Is it dry? I watched The Real Thing again recently and was inspired by Jerry.
Tyrone

[Mike C.]

Rain? Where the hell is it raining????

yeah, i realised that after i wrote it. its just that i always imagine squamish aid climbers in the rain for some reason. misery loves company.

[erock]

shouldnt you be aid climbing in the rain right now?

Well! first of all i'm living in the arctic wasteland called Calgary (this whole week has been -30) and if i was in squamish i'm pretty sure it would be raining...so i might as well be aid climbing.

[Mike C.]

oh yeah...another fallen soldier claimed by Calgamerica. hows that going, despite the cold? get any climbing in before winter descended?