I just got that tile saw I mentioned in the "bender mods" post.
Wow. It eats through 1/4 acrylic like nothing, using water as a coolant. The coolant flow is proportional to the water depth, roughly. More like proportional to the arc of blade in contact with the water bath. I overfilled mine and it stayed really cool while generating a small handful of acrylic swarf in nearly no time.
I am a happy camper. I can't wait to cut some steel angle with it using water and a friction blade. Hm. That might be counterproductive!
I am going to add a dry sanding disc to it.
I've cut aluminum, wood, a machinable ceramic, a concrete paver, and tempered glass. The glass blew up when I forced the cut. I think with some patience, coolant, and the right size starting blank, it would work. My blank was oversized, I cut free hand, and I didn't use coolant. No harm done; while spectacular, such blowups are relatively harmless, as am I. :)
On to layout and drilling for an ultracapacitor store of 1000 A and 35 kJ capacity for the MOEPED. Coast down a hill, then weld a stud to a fence post or cut through a lock. What fun.
It's the $59.99 saw from Harbor Freight.
Doug Goncz Replikon Research Seven Corners, VA 22044-0394
Tempered glass is cut and/or shaped as soft glass and is then tempered. If you call to have a piece of tempered replaced, it is usually a 3 day process. You can often tell a piece is tempered by some very small pinch marks on one edge where the grips held it on the way through the oven.
When it breaks, it goes into a bunch of small pieces. The pieces tend to not be sharp or are so small they don't have much cut potential.
You can't cut tempered glass. (For those not in the western hemisphere, this is probably referred to as "toughened" glass.) It's heat treated such that the skin is in tension and the internal mass is under compression; IOW, like a balloon.
Also, look along the surface from a very slight angle and you'll see waviness. It's not flat like float glass. Also, there should be an etching in one of the corners with the ANSI spec, and a logo and/or "tempered."
I cut tempered glass. Yes, it blew up on me, but there was a cut mark several millimeters long before it did, and it blew up right when I forced the cut. I will try again with a proper fence, less feed, and more water. I just have to convince myself. Perhaps any treatment does not extend to the edges completely, and so I am misled by my cutting experiment. But I know I saw a kerf.
Tempered glass is like a balloon, but the insides are rigid, not capable of the large expansion that a gas would present. However, the outside is proportionally rigid. Tempered glass is frequently chemically treated as well. if I remember my materials class correctly.
You certainly can't score and snap tempered glass. That kind of energy input will blow it up every time. Frequently, even a score will shatter it.
I get my tempered glass from the trash when people toss stereo cabinets and the like.
I am interested in a tempered glass top for a project, the SAD Table (Seasonal Affective Disorder Coffee Table). I may learn something from those who sell such tops.
you can't cut tempered glass, if it was well tempered to begin with. the sheet of glass is heated in large kilns on a roller bed. room temp to 1200F in 5 minutes, and back to room temp in another 5 minutes.
in the US, tempered glass is almost never chemically treated.
the skin is in compression, the interior is in tension. this imbalance is what provides both the strength and the energy to explosively decompose.
My shop glasses were toughened and chemically hardened. Tempered sheet glass is rarely treated chemically. I agree on that.
Yes, this is what they taught us in Materials. The opposite of a ballon, so that limited bending in a beam mode leaves the outside still in compression and not subject to fracture.
The energy is more focussed. More concentrated to a single point. It's a stress raiser. There is more energy dissipated in a saw cut, as you imply. Sure. You are doing more work with a saw cut. But it's also more controlled.
Note, I plan to use a smaller saw for my next experiment, a variable speed saw by HF that has a capacity of 3/4 inch. And I will try some drip coolant.
try this: open the yellow pages, call a few glass shops, and ask them if they've ever sawcut tempered glass, or even have heard of anyone doing it successfully.
you shouldn't even sandblast tempered glass past a surface etch. every shop i've ever talked to would refuse to blast tempered glass. once you get anything through both sides of the cut, it will explode. that's what it's designed to do. if it doesn't, then by definition it wasn't well tempered glass.
but hey, it's your time and glass. let us know if it's ever successful.
You're right, of course, a few phone calls would resolve the issue. No point in blowing up my toughened glass "cutting board".
I wonder if I can cut 1/4, 1/2, or 1 inch thick plate or float glass with this saw and water? Do people make lens blanks of plain glass, then grind them? Do you get a useless lens if you do that with ordinary glass? I imagine the 1/2 and 1 inch glass is pretty damnned hard to score and snap.
I dry-ripped some 0.093 inch Lexan, wet-crosscut, and wet-ripped some
1/4 inch acrylic with it yesterday and got a good finish, but I need a magnetic feather board to guide the work against the fence soon, and for the thin Lexan I'll need an even finer-than-plywood blade. More like a jeweler's saw. I think I have one somewhere. I just looked. Where did I put that damn thing? I must have cost as much as the tile saw!
Let's see, 6 inch blade, 18+ inch circumference, 0.093 ~= 0.1 inch material, but off center line might be 0.2 inches, that's a 90 tooth blade, oops, 3 teeth per thickness is 240 teeth, at 3600 rpm, with
0.0005 inch feed per tooth is 0.240 inch per rev, or for this thin material, cutting at around 900 ipm! Yowee. That's 15 inches per second. Did I get that right? Hm....Maybe another parameter limits the process--it's only a 4 amp motor! (Listed at 10 in one place, at 4.5 in another)
I haven't tried cutting any aluminum tooling plate with kerosene coolant yet.
I am making a disc sander for the saw today. Well, I made the disc last night, and I just bought the adhesive sandpaper, but I haven't tried them together
I hope to get a spare fence from HF for ripping dowels down the middle. That'd be useful. A spare miter guide bar, if I can get one, will provide stock for keying a small vise I have for cross cutting dowels. The miter guide seems to be calibrated accurately.
Cut depth is 33 mm fixed. It'll cut through a 2x4--almost! No really, it's that close with a 7 1/4 inch blade. The right side lifts and locks at 15 degree increments to 60 degrees but the left stays fixed. So you double cut bevels. First square, then on the bevel with a fence bracing the waste. What a hassle. We'll see if it has the power and heat resistance for that load. The motor has a nice fan on the end.
I have received a prepaid return label for the saw. It was dropped in shipping and some vent grillwork broke. HF will replace it gratis on inspection. That's good CS in my book.
The stone and concrete dust has a tendency to scratch up the stainless top. Maybe paper under the work would fix that, or less coolant. You can adjust the water flow to the work by adjusting the level in the well, from a mist to a flood.
I really like having a saw that cuts dry or wet. HF doesn't advertise this feature. You just rinse it off and out after wet work, let it dry, and change blades. Before wet work you blow or vacuum it out, change blade, and add coolant. When I get the new one I'll add a shop vac hose port to pull the sawdust down and away, and a motor brake switch.
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