GeologyRocksHysteresis
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That's interesting. I
Wed, 03/28/2012 - 06:52That's interesting. I thought the sole reason for water/oil in cutting rocks was to protect expensive blades from the heat. Sounds like there might be more to it.
John
“Civilisation exists by geological consent, subject to change without notice.” - Will Durant
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Oh no, you're quite right
Wed, 03/28/2012 - 07:42Oh no, you're quite right John, the water is just to cool the blade to prevent warping from heat build up. As you probably know the blade is used to wear a groove through the stone rather than actually cut. Sometimes the water level in the tank gets too low and the blade is running 'dry' then the marble breaks up completely, I imagine the heat shatters it (I'm cutting 4mm thick pieces).
1hat I'm refering to is the effect of water specific to green serpentine.
Lawrence
Lawrence Payne
http://www.romanmosaicworkshops.com/blog.html
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Yes, we do use 'cut' rather
Wed, 03/28/2012 - 09:18Yes, we do use 'cut' rather than 'wear'! Sounds so much nicer!!!!
Do you have a URL for this effect of water on serpentine please?
John
“Civilisation exists by geological consent, subject to change without notice.” - Will Durant
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As I understand it
Wed, 03/28/2012 - 11:26As I understand it hysterisis involves drag induced in magnetic materials which would, under the conditions you describe, produce a similar effect. However, since all the serpentines I've come across are non-magnetic, I think the term has created a bit of confusion. I think what you're describing is the result of friction spalling tiny flakes of material in the cuts.
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Hysteresis
Sun, 04/01/2012 - 09:49Gus,
What's being refered to is just cutting using either tiles nippers for the thin stuff or a hammer and hardie for the thick stuff and not the effects of the wet saw on the surface.
I wonder if there is any technical evidence for this that has been written up?
John, if you want a couple of pieces let me know and I'll put them in the post and you can try it out.
Lawrence Payne
http://www.romanmosaicworkshops.com/blog.html
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Thanks for the offer. I
Sun, 04/01/2012 - 12:38Thanks for the offer. I actually got some a couple of weeks ago up in Anglsey (outcrop beside the road on Holy Island). I only wanted a bit for teaching. They love to get their hands on a bit of rock.
I was actually more interested in the other aspects.
Thanks anyway.
John
“Civilisation exists by geological consent, subject to change without notice.” - Will Durant
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Hysteresis
Submitted by musivarius on Tue, 03/27/2012 - 11:24.i posted a little while back about green marble (serpentine as I've now been corrected) being easier to cut when wet (it was in relation to my work as a mosaicist). I've since found out that it is due to hysteresis, the water acting to release internal stresses.
I'm trying to find out some more information on this as all the search results seem to be thermal hsteresis acting on external stone cladding on buildings causeing them to warp.
Anyone know any references?
Ta
Lawrence Payne
http://www.romanmosaicworkshops.com/blog.html