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Ben Solwitz
02-11-2012, 04:52 PM
I haven't had much luck getting a murrine chopper like this (http://www.redhotmetal.net/glassblowing-cane-cutter/) to work well. Any guidelines on sizes/shapes that will work? I can cut them with a saw but it takes a comparatively long time.

Pete VanderLaan
02-11-2012, 05:00 PM
I think that to be a really nice cane cutter but it has to be cutting compatible annealed cane. When you try to cut a cane, either manually or with a chopper whacker, first just try cutting a straight clear one that is annealed. If it cuts clean, it ain't your cutter. There was this rule of thumb that the cleaner the cane cuts, the less trouble you will have with it in terms of compatibility. If the cane justs crumbles, or worse, splits horizontally, you have compatibility issues, or annealing, or both. Anything bigger than about 3/8th inch needs annealing. .

Ben Solwitz
02-11-2012, 06:36 PM
Yeah I always anneal it. Does it work with square canes? How big do you think you could go with properly annealed, compatible cane? I know David has talked about cutting and polishing all of his tiles in the past, but I assume they are pretty big.

Pete VanderLaan
02-11-2012, 07:22 PM
Most of what I did with mine was cased in a fluorine white and 1/2 inch was the crunchy point. That stuff can make you crazy.

Ben Solwitz
02-11-2012, 07:49 PM
It's ok I have antibodies from previous infections.

Eben Horton
02-11-2012, 09:18 PM
Make your pulls thinner.. a chopper likes round cane better than square and i agree with Pete... 1/2" is max. I can do almost 3/4" on mine, but i loose a lot and there is a lot of waste

David Patchen
02-12-2012, 02:00 AM
Totally agree. If you're making 1/4" circular murrine (like using filigree cane for murrine) then you can get away with not annealing and use a chopper. If you make thin circular or square murrine (3/8" diameter or less) and anneal you can still use a chopper as I did for years. Like Pete said, if you have stuff crumbling or splitting down the middle you probably have a compatibility problem and/or didn't anneal correctly. Been there, done that and stopped using all German color as a result.

Anything larger than 1/4" I anneal to get good cuts. I cut all murrine with a 8 x .032 blade of this model and get great cuts:
http://www.kingsleynorth.com/skshop/product.php?id=46658&catID=113
I keep it wet while cutting it, then rinse it all really, really well. You'll get micro bubbles if you don't fuse it in the glory and fire polish the surface before you pick it up.
I built a jig that my assistant uses so the cuts are quicker and consistent thickness.

If the colors you're using don't fit well, then all bets are off for both clean cutting and making work. Figure out compatibility before making a ton of murrine, chopping/cutting it, composing your piece and blowing it. It sucks to have them crack from incompatibility that can be sorted out before all that work. I've been there, but thankfully it's really rare to lose one from bad fit now.

Pete VanderLaan
02-12-2012, 02:46 AM
David: What clear glass do you use? That in my opinion also matters. What exactly do you mean by " fuse it in the gloryhole?"

Ben Solwitz
02-12-2012, 09:40 AM
I assume he means to get it pretty hot and squish it all together on the pastorale plate, making sure the surfaces all get hot enough to fire polish, before picking it up on a bubble or a collar or whatever. What are the dimensions of the tiles you typically use? Have you tried thinner blades? Seems like it would be nice to remove less material if you can.

David Patchen
02-12-2012, 10:26 AM
Sorry--I meant "fire polish", not fuse.

I had some students picking up murrine off a plate that was in the garage and kept getting a scum on the murrine. It wasn't really scum, just tiny bubbles that get trapped where the glass had been cut. Fire polishing the surface of the murrine in the glory hole before picking it up makes the top surface that touches the bubble glassy and viola--no scum. The other side gets flame polished on the glory as it's now attached to the outside of your bubble.

I've not tried thinner blades but .032" was sufficiently thin for me. Seemed like a good size to balance stability and thinness.

I use murrine in diameter from 1/2" to about 1". I cut them to 5-6 mm thick.

Ben Solwitz
02-12-2012, 10:46 AM
Do you do many collar pickups?

Pete VanderLaan
02-12-2012, 10:52 AM
Sorry--I meant "fire polish", not fuse.

I had some students picking up murrine off a plate that was in the garage and kept getting a scum on the murrine. It wasn't really scum, just tiny bubbles that get trapped where the glass had been cut. Fire polishing the surface of the murrine in the glory hole before picking it up makes the top surface that touches the bubble glassy and viola--no scum. The other side gets flame polished on the glory as it's now attached to the outside of your bubble.

I've not tried thinner blades but .032" was sufficiently thin for me. Seemed like a good size to balance stability and thinness.

I use murrine in diameter from 1/2" to about 1". I cut them to 5-6 mm thick.
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This issue has always confused me. I don't see why fire polishing wouldn't just trap bubbles as well. With ground surfaces, the ultra fines from SiC would always cause problems. When Lenny Di Nardo was doing his grall series he always said he had to scrub the shit out of the blank to keep bubbles out and I never believed him. Scum is scum. It's a combo of glass and something else. When people say cut the murrini but always keep it wet, my chemistry head explodes...When you fire polish a murrini, are you holding it up to a torch or what. This seems profoundly awkward and slow.

David Patchen
02-12-2012, 11:09 AM
Here's my theory on what's going on:

When the murrine is cut on a diamond blade, the cut surface has a texture that reflects the grit of the blade. The blade I use is ungraded, but probably around 220. So surface of the cut murrine then has a microscopic coarseness and porosity to it--like the surface of a sponge. So if you just warm up the murrine to hot enough to pickup (but not fire polish) when you slap a bubble on it traps a zillion tiny bubbles on the rough/porous surface. However, if you flame polish the surface of the murrine, the surface melts and the rough sponge-like surface is now perfectly flat and glassy and unable to trap bubbles.

I fire polish murrine all at the same time in the heating/squeezing process on the plate just before I pick them up. Never one-by-one; that would be madness.

I'm sure SiC would trap grit in the porus surface of the murrine. When cut on a diamond blade, I find it only traps glass dust. I keep them wet because if you let them dry out it's hard to get this glass dust out of the porous surface where it was cut. If you keep them wet, when you rinse them under a hard stream of water and agitate them (I use a strainer) this dust will mostly wash away.

Make sense or ?

Eben Horton
02-12-2012, 11:20 AM
Here's my theory on what's going on:

When the murrine is cut on a diamond blade, the cut surface has a texture that reflects the grit of the blade. The blade I use is ungraded, but probably around 220. So surface of the cut murrine then has a microscopic coarseness and porosity to it--like the surface of a sponge. So if you just warm up the murrine to hot enough to pickup (but not fire polish) when you slap a bubble on it traps a zillion tiny bubbles on the rough/porous surface. However, if you flame polish the surface of the murrine, the surface melts and the rough sponge-like surface is now perfectly flat and glassy and unable to trap bubbles.

I fire polish murrine all at the same time in the heating/squeezing process on the plate just before I pick them up. Never one-by-one; that would be madness.

I'm sure SiC would trap grit in the porus surface of the murrine. When cut on a diamond blade, I find it only traps glass dust. I keep them wet because if you let them dry out it's hard to get this glass dust out of the porous surface where it was cut. If you keep them wet, when you rinse them under a hard stream of water and agitate them (I use a strainer) this dust will mostly wash away.

Make sense or ?


Thats exactly what is going on. oils from your skin can leave a film on the glass too

Rosanna Gusler
02-12-2012, 11:25 AM
' When people say cut the murrini but always keep it wet, my chemistry head explodes ' i think that part of why keeping ground (sawn) edges from drying out is that water is not just water. water is water plus chlorine, flourine, lime, nitrates, arsnic (my well) , salt ........ . mix that up on a rough substrate with finly ground glass and oxygen then let dry and i think that there are probably reactions/precipatations occuring on that surface that can not be just washed off. i know that i have removed most of my surface issues (in the kiln) by using only distilled water in anything that comes in final contact with the glass. kiln wash included. rosanna

Ben Solwitz
02-12-2012, 01:51 PM
Yeah you want to keep oils from your skin off of it too. Mark Matthews cleans all of his cane with alcohol and then only touches it with a paper towel when he is making a cane setup.

Franklin Sankar
02-12-2012, 01:56 PM
Rosanna Rosanna Rosana, I could not have down a better job at asking the question. I
Love the analysis. Is your head back together again. Thank you
Franklin

Ben Solwitz
02-12-2012, 02:02 PM
I think the chemicals stay encased in the glass pretty well. They say not to leave acidic substances in lead crystal for a long time because the lead will eventually leech out, but it takes months or years of sitting on a shelf. Anything that isn't part of the glass though will potentially burn up and turn into scum, or create fine bubbles in the glass. Fine bits of powdered glass will also trap unsightly bubbles.

Pete VanderLaan
02-12-2012, 02:09 PM
Rosanna Rosanna Rosana, I could not have down a better job at asking the question. I
Love the analysis. Is your head back together again. Thank you
Franklin
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Franklin, Franklin, Franklin, you need to read and follow the posts better.

Franklin Sankar
02-12-2012, 02:14 PM
I was posting while the response came.
From others. But you are right. Thanks for the warning.
Franklin

Pete VanderLaan
02-12-2012, 06:06 PM
Nevermind...

David Patchen
02-12-2012, 06:34 PM
I have my hands all over both cane and murrine while setting up the work and I've never had a problem with dirt or oil from my hands. Maybe my hands are super clean and dry but I've never had a problem vs. all the other variables. I also wash murrine with tap water and if chemicals in the water were a factor then the paper, blocks, etc would impart it too. I put rod in the garage wet from removing the label and in my experience I've never seen anything w/water being an issue.

Travis Frink
02-12-2012, 10:16 PM
I wonder if water might be more of an issue in areas with real hard water or just really unclear well water- my wife lived in an old farmhouse 30 minutes east of Seattle that had brown water from a lot of iron.

I think one of the keys that has been mentioned in previos threads on this topic is clean water in your saw reservoir and really spraying it clean after. This has made a big difference for me.

A good blade makes things easier. Would a finer/higher grit blade be better?

A jig to keep a standard thickness is a great idea. Gotta see if I can rig something like that up.

Ben Solwitz
03-16-2012, 02:44 PM
Just found this thread from a few years ago while searching, we had a similar conversation:

http://talk.craftweb.com/showthread.php?t=6577

Has anyone tried an ultrasonic cleaner? Might be less work for lots of murrine at once.

David Patchen
03-17-2012, 02:36 AM
Good old times. I haven't used a chopper in years...perhaps since 2008. Figured out a lot since then.