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Mark Dolan
01-03-2012, 01:34 PM
I'm looking for a small grinder to just grind and polish punty marks from my pieces. It seems like all the grinders on the market are for stained glass. Are there small grinders out there specifically designed for removing punty marks that don't cost an arm and a leg? Below is a link to Inlands 8" grinder, but it seems like overkill for what I need.

http://bit.ly/yy9oQh


Thanks

David Patchen
01-03-2012, 03:31 PM
If you're only going to remove punties, I'd recommend getting an oxy/propane torch and fix them hot. Any kind of coldworking equipment you're going to buy will cost a whole lot more than a torch setup, and your torch can be used for lots of other things. Also teach your assistant to make punties that come off really clean so they only need a second under the torch to roll any sharp bits. Get good with your punties and a hot torch and you can save a ton of time in the cold shop. I rarely coldwork any cups.

If you really want a cold punty remover, you'll need some spherical miracle diamond wheels (check kingsley north) in 100, 360 and higher if you want to polish. You'll need an arbor for the wheels to run on (see hisglassworks for fancy build your own). You'll need a motor to turn the arbor. You'll need some kind of water feed to keep it all wet. Upside down water bottle is ghetto but works, plastic flexloc tubing on a valve plumbed into your water line is much better.

You should visit a few good shops to see the range of what people use and what works.

Mark Dolan
01-03-2012, 03:47 PM
Thanks David. I have the oxy/propane torch and an assistant but both of us need to get better at what we are doing in order to avoid coldworking all the time.

Guy Kass
01-03-2012, 05:37 PM
If you go the way of the spherical miracles. See if Henry Halem placed his order in China yet. Way better prices than what you will pay locally.

Pete VanderLaan
01-03-2012, 05:44 PM
What I continually fail to understand in this sort of pursuit is that it's clear to me that people aren't shy about pricing their work at all but I see over and over again that the attitude towards their basic materials, like clear glass, or grinding tools are always viewed as somehow being a covert ripoff.

Grinding equipment is a very small custom market for really good quality tools. If you are a serious polisher or engraver, you need tools that don't vibrate. Harbor freight is never going to provide that, yet the move is always in that direction, to cheap it out. Why do glassworkers treat their materials like they are dogshit?

David Patchen
01-03-2012, 06:54 PM
Who said harbor freight? I'd recommend he attach a spherical miracle to a drill bolted sideways on a workbench and a garden hose running overhead before I'd recommend a harbor freight arbor :)

Henry Halem
01-03-2012, 07:28 PM
If you go the way of the spherical miracles. See if Henry Halem placed his order in China yet. Way better prices than what you will pay locally.Yes he did.

Pete VanderLaan
01-03-2012, 10:03 PM
Who said harbor freight? I'd recommend he attach a spherical miracle to a drill bolted sideways on a workbench and a garden hose running overhead before I'd recommend a harbor freight arbor :)
************
I actually think the dumb thing is fine, I would actually grind and polish the entire base using flat tools and finish it properly. Scott what you said was actually just fine. I'm just feeling quite curmudgeonly tonight.

Mark Rosenbaum
01-03-2012, 11:05 PM
************
I actually think the dumb thing is fine, I would actually grind and polish the entire base using flat tools and finish it properly. Scott what you said was actually just fine. I'm just feeling quite curmudgeonly tonight.

Now I'm confused....Scott has not posted on this thread :confused:

Allan Gott
01-03-2012, 11:56 PM
Get good with your punties

Given Mark's experience, this is the best advice he can get. Not only is he going to save coldworking time, but more importantly, he's going to keep his pieces off the floor.

Pete VanderLaan
01-04-2012, 08:43 AM
************
I actually think the dumb thing is fine, I would actually grind and polish the entire base using flat tools and finish it properly. Scott what you said was actually just fine. I'm just feeling quite curmudgeonly tonight.
**********
Actually he did and then deleted it. I can read all the deletions, like the ones from that guy in Canada who sent me hate mail. He basically said it's rally hard to afford good tools and he would rather keep his money to buy color and such.

I just think work should be finished. I like to finish like I'm turning the piece over to the Corning Museum where people will judge my work forever. That takes good tooling.

Dave Hilty
01-04-2012, 09:29 AM
**********

I just think work should be finished. I like to finish like I'm turning the piece over to the Corning Museum where people will judge my work forever. That takes good tooling.

I took to Pete's advice about optical finish bottoms several years ago and the results are several but mostly I get regular complements about the cold-worked bottoms, no fear in pricing higher and I get the pieces to sit absolutely straight, using a bubble level to guarantee it. Assuming you've left enough glass to grind the bottom (and it takes less than you think once you know the secret) once you are happy with the breadth of the bottom on the pipe, you get just enough heat there to puff out a very slight convexity. The center of this slight bump is your target for the punty. Even if you take a slight bite out of the bottom when it exits the punty the convex surface insures a minimum of grinding to finish the bottom.

Scott Novota
01-04-2012, 10:59 AM
After typing it, it seemed a bit, well...already been said more than once so I smoked it knowing that the person I was replying to anyway would read it. It would have shifted the way this conversation went and I was willing to just let that horse kind of die. Mostly because I agreed with Pete once I typed my own response out.

Pete VanderLaan
01-04-2012, 03:52 PM
I am everyone's conscience...nagging.

Mark Dolan
01-04-2012, 08:00 PM
What is a bevel level?

Dave Hilty
01-04-2012, 08:23 PM
Mark, "bubble level" - just a cheap 50 cent piece size plastic round liquid-filled level with a couple round target circles on the top where you locate the bubble on the center target.

I spent way to long eye-balling level on the coarse grind of my pieces, always going too far on one tilt or another until the obvious use of this cheap little device came to me. The "secret" here is to use a wad of modeling clay under the level to stick the gizmo to a convenient place near the top of the piece, usually on the lip. The clay allows you to compensate for oddball shapes/lips and lets you strike a compromise of "level" to your eye, first at 0 degrees, then 90, then etc. This way you really don't have to go back and forth striking a compromise other than once and before you go near the grinding wheel. I take just enough to get a flat surface and then check to be sure I like "level" at that plane.

Hugh Jenkins
01-05-2012, 01:59 PM
Bubble levels are a great tool. You do have to be sure that the grinding plate is level first or the bubble doesn't make things right.

And, I have four different brands and they all have different sensitivities. One goes off the edge with only a slight tilt, while another only goes to the first circle. Setting them all on a glass sheet and tilting it will show how different they read.

Eben Horton
01-09-2012, 09:07 PM
Dont discount the wonders of a piece of plate glass and a little 80 grit silicon carbide slury... just slide your piece around for a minute and presto.. you have a flat bottom.

Franklin Sankar
01-10-2012, 06:09 AM
Why does the silico grit choos to eat your piece rather than the plate glass?
Can you go to 160 grit on the plate?
Franklin

Pete VanderLaan
01-10-2012, 06:50 AM
It grinds both. It only works so long, it doesn't work well and it looks like you were grinding the bottom until you lost interest. Doing it right would be a novelty. I'm looking for quality this week.

160 would just take a long time but it would grind it.

Glenn Randle
01-10-2012, 08:11 AM
Why does the silico grit choos to eat your piece rather than the plate glass?
Can you go to 160 grit on the plate?
Franklin


Plate glass grinding works well for the grits after the piece has been flattened & trued with 80 grit on a wheel.

220 and 600 on the plate, then cerium on felt wheel can give you a nice finish pretty quickly.

The plate glass lasts a surprisingly long time, since it is a much larger & smoother than the pieces you're grinding. It's the "roughness" that you're removing and the plate isn't rough.

Pete VanderLaan
01-10-2012, 08:29 AM
It's a relative flatness Glen. When we were making a lot of cut and beveled pieces, we would 400 them on a rougher and then actually go to a piece of plate glass and put down a slurry of water soap and 1500 grit aluminum oxide. That saved hours on the pumice stage. The piece of plate we used would go far enough out of true in only five or six pieces before we had to trade it for a new sheet.

But that is on the obsessive compulsive level.

Glenn Randle
01-10-2012, 04:47 PM
[QUOTE=Pete VanderLaan;102229]It's a relative flatness Glen.


Of course everything's relative. I figured it's "flat enough" for anyone who'd be asking about using it.

Also, it probably depends on whether you're making art or craft. ;)

Travis Frink
01-11-2012, 12:14 AM
What Glen and Pete said.
I use this for work that is just a little off on the bottom.
600 slurry on plate glass to pumice to cerium.

A friend here uses
600 then 1000 slurry on plate glass to cerium

600 to polish takes a while and uses more cerium so the punice/1000 are good.
Really off stuff get the lap and or a diamond lathe first
A slightly concave (not convex) bottom makes the process a lot faster, more stability( pieces seem to not tip over as easily az a flat bottom but it is probably just my take and experience with plate glass that was in use for too long and had gotten dished) and reduces surface area that might get scratched in the future.

It isn't the fastest but it does a nice job.

Glenn Randle
01-11-2012, 08:26 AM
A slightly convex bottom makes the process a lot faster, more stability and reduces surface area that might get scratched in the future.

It isn't the fastest but it does a nice job.



"More stability"?

I'm not sure I understand what you mean. Also, "how" do you achieve a "slightly convex" bottom precisely? Do you mean "concave" ? Like you get with a punty wheel?

I have a couple of those, but am not set up to take them to a full polish. That would look nice, but would definitely take a lot more time, equipment, and skill.

Pete VanderLaan
01-11-2012, 08:29 AM
More like a diode instead of a resistor.

Language is such a pesky specific thing.

Travis Frink
01-11-2012, 09:53 AM
Language is such a pesky specific thing.

Think left say right
What side o the road am I supposed to be driving on?!
Sorry, my brain is shoting out. It has all been down hill since they switched the blinker and windshield wiper switches on me (In Japan, they are opposite sides as they are in the states and are the hardest habit to break when learning to drive on the left)

Sometimes it is important to listen for what people mean and not what they are saying.

Even with that as a standard, I don't have a clue what is going on with those guys leaving New Hampshire.

Pete VanderLaan
01-11-2012, 11:38 AM
Oh I'm glad they left!

Just remember Lefty loosey, rightie tightie. That's girl talk for tightening bolts and nuts....

Rosanna Gusler
01-11-2012, 01:13 PM
Oh I'm glad they left!

Just remember Lefty loosey, rightie tightie. That's girl talk for tightening bolts and nuts.... grroooaaannn. rosanna

Pete VanderLaan
01-11-2012, 02:34 PM
Sorry Rosanna. I have two lesbian friends down the road. One is a State Police Captain. The other is school teacher.They are the ones who told me that's how they remember.

We report, you decide...