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I have started making large vessels using 24" sq. kiln shelf into which I have cut a 12" hole (monster job with carbide jig saw blade.) The vessels are 8" deep by 12" diameter plus the flange at the top. The glass started as a 19" sq. by 5/8" thick. This one I finished by cutting the rim into an octagon and cold worked with an Alpha polisher using 5" diamond pads. The first one I made, the glass was only 3/8" thick and got too thin. When I tried to trim off the flange with my wet saw as shown in the Bullseye online lesson the vibration caused the glass to separate in an undulating line near the top. I was able to smooth the top into an artful wave and save the piece. My question is,what alternative ways do people use to accomplish this task? I do have a large diamond band saw but if I were able to saw around it the unfinished edge would face outward, not upward. Help. Thanks.

Warren

Hi Warren,

I don't have the experience to talk about such large, thick vessels.

On the smaller ones I tried a couple of years ago - using a large rail type saw with 10" blade - the edge was perfect. To achieve this I hold the vessel flange absolutely parallel to the saw blade. It is quite a job, slow and wet, leaving quite a bit of - expensive here - waste glass. The risk of loosing the piece is always there. And I don't know if it works well because of the saw, or simply because the vessels are smaller and thinner.

Cannot imagine this being easy to do on a large and heavy vessel without a rig to hold the vessel firmly in the right position.

I also have the set of 3 molds, was intending to do something with them this winter. Would you care to share why did you decide to go the way of dropmold/tile saw instead of using the 3 molds?

One benefit I can see is that the outside of the vessel would be shiny. Where I live glass does not sell very well unless it looks "glassy" (shiny and at least partially transparent).

After the blank is ready, one firing in the drop ring instead of three in the molds is tempting, but the work with the tile saw is still to be done, so I am wondering

It would be very interesting for me to hear your thoughts, since you have tried both ways.

Hope someone with experience will answer your query...I have been checking every day to see if there are any replies.

Good luck and best regards, seachange

Hi Seachange,

What is a railsaw?
The 2 reasons I went with the drop out were the shiny both sides that you mentioned and the overall size. The 12 hole with an 8" drop produced a much larger vessel. Also, in my one trial with the 3 molds the final slump was not a uniform height. Apparently, one side of the bowl dropped ahead of the other side.

Thanks for your reply.

Warren

Thanks Warren,

Hadn't thought about the possible difference in size between the two methods....interesting. Worthwhile knowing. And the risk of the last mold not working properly. I thought that possibility had been solved by the gradual shaping of the glass in the previous two molds, but obviously not.

I have the small cone bowl http://shop.bullseyeglass.com/cone-bowl ... -mold.html. The shape is deep and nice, for the few times that the glass drops straight. I got tired of the failures (in spite of super slow firings) and stopped using it.

A rail tile saw looks like this. I live in Australia, many of the tiling specialists here are originally from Italy. This is the type of saw they recommend and is easy to find locally. Mine is made in Italy, but there others. Many years ago I participated in a class with Patty Gray in Sydney. I have the idea that Patty said to me she has a rail tile saw and is (at least was then) very happy with it. She mentioned they are expensive (they are or at least were when I bought it).

This is a picture of a Husqvarna tile saw, from CRL

Many thanks for your reply, have learned from it.
Best regards, Seachange

Hi Seachange,

We have a railsaw, (we actually bought it for tiling our floors) and I've bought a thin kerf diamond blade for it., Do you invert the vessel so the flange to be removed is flat on the deck of the saw, push it into the blade while turning it, or do you hold the vessel steady, slice off a section, reposition and take off another slice then finish by grinding or do you somehow hold it on its side and freehand the cut?

I'd really appreciate a description of how you do this, please. Jen

aka bridge saw, being sold more and more for larger tile work. I got cheap thin wood blades as stiffeners for thin kerf diamond blades.

Mine's got a lock to keep the saw from moving on the rail so I could push work into the blade but I'd rather hold the work on the table and take successive cuts and finish on the flat lap and WBS.

If I were challenged to cut a circle out of a hard kiln shelf, I'd take it over to the waterjet shop and have them cut it out, perfectly in a few minutes.

That's a different issue. I'd considered waterjet for the rims of finished stuff but they don't like to do 3D- there are clearance issues for the abrasive nozzle assembly.

Marty wrote:aka bridge saw, being sold more and more for larger tile work. I got cheap thin wood blades as stiffeners for thin kerf diamond blades.

Mine's got a lock to keep the saw from moving on the rail so I could push work into the blade but I'd rather hold the work on the table and take successive cuts and finish on the flat lap and WBS.

Thanks for that Marty. Great tip about the el cheapo (or worn out blades that are not worth sharpening) stiffeners.

Thank you, too, for the info about locking the blade. I was going to try a couple of clamps if using it for glass was feasible.

Bert, I did use the waterjet option for cutting shelf material. It did a great job and wasn't expensive.

Jen

Hi Jen

Trying to see if I have some pictures of how I did it (a couple of years ago). Will post again if I find any. I am a bit of disaster when it comes to keeping pictures organised .

First I cut the corners of the flange to get an octagon shape. Then held the vases (made with 3 layers of 3 mm glass) by hand with the flange parallel to the saw blade. Locked the blade in place and move the vase slowly against it, letting the saw do the work, rotating as necessary, removing the whole flange in one cut.

Had 3 to do, twisted the first one slightly and broke it. The other two worked well.

However these were tallish drop vases (about 10 to 12 cm from memory), and not very wide at the rim, therefore not too difficult to hold, and not very heavy.

Warren's piece is much larger, heavier, and I would think a different shape (probably more like a wide cone), I picture it would be difficult to get the hands around it. Everything gets wet and slippery. Also being 5/8" thick, one would have to hold very steady for much longer.

However, I would think it is possible. If i have any time this winter, vases (drop and slumped) are my "project"...will be interesting

When I researched this on the internet at that time, came across some posts were people scored around the rim, tapped and removed the flange this way...sounds to me pretty difficult to do, specially with thick glass, but - from the posts - it is doable.

Best regards, seachange

Thanks for that detailed reply, Seachange. Along with Marty's information I now have a much clearer idea how the rail saw can be used. For now, I don't think I'll be tackling any as heavy as Marty's projects given the difficulty holding the wet glass. Jen

Dry the glass thoroughly and add a duck tape handle or two where you'd normally hold on.

The only drawback that I've found to my bridge saw is the narrowness of the table. Some brands have extensions you can buy- I'll be making one.

Red Green's secret weapon, I'd forgotten. Thanks Marty.

Hi again, found my pictures

This orange/blue small vase I cut further to remove the flare at the rim...was after a more or less straight side.

Here is a picture of my tile saw, first practicing by cutting some old shelves.

Plus cutting a slightly larger vase.

Hope this is useful.

Cheers, seachange

I have cut quite a few larger three dimensional pieces of glass with the sandblaster. I usually mask the cut area with monument stencil (on both sides) and then cut a 1/8" line out where I want the cut to be (on both sides). I then blast half way through from both sides. After the blasting, I grind down the feathered edge that results from the blasting. I find this to be the gentlest and safest way to make a cut in something that I definitely don't want to lose.

Thanks all for the good ideas. The sandblasting sounds interesting and safe, although 5/8" might be a lot to cut through. Here are some photos of the drop.

Some good info in this thread. Thank you for the photos, Seachange. I now see that is the method BE shows in their video. (Wireless B’band has been too slow to buffer videos lately so, although I have a subscription, I haven’t been able to view much of all that good stuff and missed that one).

I’d visualized the vase, sitting upright on its flange, being pushed under the blade, rotated a bit and repeated till the flange was roughly cut off, to be finished by other cold-working.

Could it be done that way? My recovering right paw still can’t reliably hold anything aloft that’s bigger than an eggcup. I’d like the stability that resting it on the saw’s deck would give.

is that how you cut the octagonal shape, Warren, or was that cut out before the drop/ (Nice bowl, by the way). Jen

Thanks Jen,
The drop started with a 19" square blank, so it had a square rim. With that large rim it was too high to hold it on its side and run the blade parallel to the rim for a cut off (Bullseye method.) So, I first cut off the 4 corners on a 45 deg. angle with a 2" rim left as that was as close to the blade as I could get. Still too wide so I cut off each of the new corners to end up with an octagon. I decided it looked good that way so I finished the sawed edges with my Alpha wet diamond pad polisher. One of the reasons I liked it that way was that the inside design continued out on the top of the flange. The alternative was to spend 2 months weight lifting training and then attempting the Bullseye method.

Warren

I’d visualized the vase, sitting upright on its flange, being pushed under the blade, rotated a bit and repeated till the flange was roughly cut off, to be finished by other cold-working.

Rereading the older posts in this thread I realize that is the method Marty described.

Warren, having finished with an octagonal rim on your vase would you, in future for this design, simply start with an octagonal blank? It's very elegant. Of course you haven't removed the rim but that's a different design outcome. Jen