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Cutting THICK glass demo

Posted: Sun May 19, 2013 6:00 pm
by The Hobbyist
This may be old news but I ran across it today on Youtube.com.

http://www.youtube.com/watch?v=x-84Sdq7jaE

Jim

Re: Cutting THICK glass demo

Posted: Sun May 19, 2013 6:38 pm
by David Jenkins
Are you sitting down? Now check the prices on that kit ...

Re: Cutting THICK glass demo

Posted: Sun May 19, 2013 7:23 pm
by Morganica
Uhm...wow. I like that little thumper-thingee...

Re: Cutting THICK glass demo

Posted: Mon May 20, 2013 8:31 am
by Bert Weiss
There are ways to accomplish this with a less expensive set of tools. My tapping tool costs a dollar. I get a cheap screwdriver, and heat it red hot with a propane torch. Then grind the edge to a convex arc. After the score, I flip the glass and place the tool directly over the score and strike it with a small hammer. This technique requires the skill of knowing how hard to strike the tool. I do a lot of work on 10mm and 12mm glasses with my approach. This said, I would like one of those Bohle tappers.

I use kerosene and a paint brush under the cutter wheel to apply the cutting fluid. $4 will buy you a lifetime supply. The evaporation rate is a good one for me. Cleanup requires no extra effort.

Instead of striking the top of the score, I run the propane torch around it. Glass does like to break on the easiest path, so the heatshock over the started break goes to the shortest point, or 90º up from the start. Note, you must start the break 360º around before using the torch. I will note that Bohle's approach is more environmentally friendly as fewer hydrocarbons are involved.

I use the Toyo circle cutter, which is also a good one.

One of the most important tips I can give is to start the score for the external cutout lines well outside the circle. The glass will continue to break to the circle, but if your score goes even the slightest way inside the circle, it can easily break right through the circle.

Re: Cutting THICK glass demo

Posted: Tue May 21, 2013 1:21 pm
by Alexis Dinno
Bert Weiss wrote:There are ways to accomplish this with a less expensive set of tools. My tapping tool costs a dollar. I get a cheap screwdriver, and heat it red hot with a propane torch. Then grind the edge to a convex arc.]
Bert, how would you compare the quality of the breaks you get with your tool to the 'floppy-finger' technique with a small ball-hammer (if you understand the technique I am trying to describe)?

Best,
Alexis

Re: Cutting THICK glass demo

Posted: Tue May 21, 2013 3:50 pm
by Bert Weiss
Alexis Dinno wrote:
Bert Weiss wrote:There are ways to accomplish this with a less expensive set of tools. My tapping tool costs a dollar. I get a cheap screwdriver, and heat it red hot with a propane torch. Then grind the edge to a convex arc.]
Bert, how would you compare the quality of the breaks you get with your tool to the 'floppy-finger' technique with a small ball-hammer (if you understand the technique I am trying to describe)?

Best,
Alexis
I have never heard of "floppy finger". The theories are pretty simple. If you strike the glass directly beneath the score, the break starts directly beneath the score. If you strike the glass off center of the score, the break starts off center. So the finished shape of the glass depends on accuracy of where you hit, or push with your thumb, or tool. the Morton M-80 is a great tool for centering the force directly beneath the score. Unfortunately, it is best for 3mm glasses. Running pliers have a mark on top that centers the force.

I have the hand strength to break out up to 6mm glass with my thumb, much of the time. I do not have the strength to do this on 10mm or thicker glasses. So, I use a tool. With my homemade tool, it is up to you to place the tool and to strike it with the right amount of force.

A key part of my technique is to only strike once in each spot to move the break along. If you hit the glass again, you will be able to see marks representing that second hit. Once you have the start going all around, the torch finishes the break to the shortest point. If you ignore this step, you get flare where ever the start didn't finish. The Bohle technique uses a blow from the tool on the score side after the start has been initiated.

Since the glass I use most often is 10mm, the shape of the glass after breaking it, is often critical to what I do. When I make a shower door, I rely on the fire polish and my skill to cut the glass perfectly square. This allows me to compete with fabricators who are charging for their edgework. Sinks and countertops I make use 2 layers of 10mm, and again, I have a technique to end up with a finished edge without having to grind and polish.

Re: Cutting THICK glass demo

Posted: Tue May 21, 2013 5:13 pm
by Jerrwel
Morganica wrote:Uhm...wow. I like that little thumper-thingee...
Wow, I found the tapper on Amazon http://www.amazon.co.uk/SILBERSCHNITT-O ... B00422VVSM @ L788 which converts to $1,198, I believe. Am I right? Wonder if a chiropractic 'activator' adjustment tool @ $148.00 http://www.thefind.com/appliances/info- ... sting-tool might marginally serve the same purpose; I've had these used on me from time-to-time and they don't seem to 'thump' with the same force as the tool in the video.

Re: Cutting THICK glass demo

Posted: Tue May 21, 2013 5:32 pm
by Bert Weiss
Jerrwel wrote:
Morganica wrote:Uhm...wow. I like that little thumper-thingee...
Wow, I found the tapper on Amazon http://www.amazon.co.uk/SILBERSCHNITT-O ... B00422VVSM @ L788 which converts to $1,198, I believe. Am I right? Wonder if a chiropractic 'activator' adjustment tool @ $148.00 http://www.thefind.com/appliances/info- ... sting-tool might marginally serve the same purpose; I've had these used on me from time-to-time and they don't seem to 'thump' with the same force as the tool in the video.
You are way off. It only costs $699 at Bohle America. The thick glass kit including aluminum case is $1299. Good though...