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05-02-2009, 12:37 PM #1
OT- How much does plexiglass cost ?
3/16" and 1/4" standard issue clear plexiglass... how much should this cost per square inch in cut sizes appropriate for typical CNC coolant guarding ? Reason I ask is in this town we have only one supplier of such and the prices are so high I'm wondering if I'm paying a monopoly premium for the stuff.
05-02-2009, 01:16 PM #2
Well, you really don't want plexiglass, you want Lexan (polycarbonate).
It is costly, McMaster carries it to give you an idea on price.
05-02-2009, 01:20 PM #3
For example (from a search) My experience with Lexan is that oils and/or solvents will cause it to
become very brittle and crack at any machined edges, including drilled
Below is the sort of enclosure I mean. That one was refurbished with standard issue plexiglass.
05-02-2009, 01:38 PM #4
Ac $ thickness dependent but runs from ~2-$4/sqft/1/4".
05-02-2009, 01:38 PM #5I'm wondering if I'm paying a monopoly premium for the stuff.
05-02-2009, 02:33 PM #6
What a cool little machine!
05-02-2009, 02:46 PM #7
What would a machine like that sell for in operable shape?
05-02-2009, 04:06 PM #8
I get it in smoked for $181 a sheet (4'x8'x1/4") from TMX/AIN Plastics in Ny.
TMX/Ain Plastics-Subsidiary of Thyssen NA
249 E Sandford Blvd
PO Box 151
Mount Vernon , NY 10551-0151
Contact: John Collelouori
E-Mail Address: email@example.com
Phone Number: 914-668-6800
Additional Phone Number: 800-431-2451
Fax Number: 914-668-8820
05-02-2009, 04:33 PM #9
Last piece of 4x8' 1/4" acrylic I bought was $112 + $20 to rip it lengthwise into 2 18" strips (plus the drop).
I deal with an outfit called Cope Plastics. They have offices around the country.
05-02-2009, 04:53 PM #10
My wife is a sign maker and I just happened to be with her when she picked up some clear pieces of 1/4" Plex. yesterday at Cope Plastics in St. Paul. Two pieces cut to 28"x48", edge finished, and flame finished were $102ea. I'm guessing the cutting, edge finishing, and flame finishing cost as much as the material itself. The edge finishing means milling or routering the rough saw cut edges, and the flame finishing is what gives the edges their smooth, glossy, factory looking, finish that you can see right into. Unnecessary finishes for machinery splash guards (except maybe for frameless sliding doors), but sometimes useful in her sign applications.
05-03-2009, 10:23 AM #11
I know you have your opinions and probably won't change it. But if you have ever seen some of the marks in these types of shields you know you should be using polycarbonate. Also the pieces plexiglass "shatter" if impacted, this can also be fairly dangerous if an operator is standing in front of it.
If you look at the pieces you having made they appear to be radiused on the corners. This is obviously more time consuming and I am sure adding a significant cost.
05-03-2009, 12:25 PM #12
Would tempered "windshield" glass work? You know, the kind with the high-strength laminate. Or wired glass? I'm just thinking that real glass would scratch less. If it was tempered and laminated or wired, just as safe. And with the cost figures plastics the guys are talking about, it may be about the same cost. Downside might be weight.
These guys are in Greensboro:
05-03-2009, 02:01 PM #13
The purpose of wire glass is to keep a person's hand (and arm) from passing thru if they happen to push on the glass and it breaks. As far as the actual breaking goes, its only slightly stronger than plate of the same thickness. Its also extremely expensive in the US because its not produced here due to some environmental reg that makes its production too expensive. My brother in law is in the glass business and IIRC most of the wire glass he gets comes from Germany. He mentioned a while back 1/4" wire glass cost him about $8/sq ft delivered.
1/4" laminated glass has typically cost glass peddlers about $3.50/sq ft over the last few years, but that price has dropped a bunch in the last few months. so its closer to $2 now. The labor in cutting laminated glass is at least double the labor for cutting sheet or plate. It has to be scratched on both sides, and then alcohol is poured along the break and set afire to soften the plastic. The piece is then "bent" slowly to expose the plastic, and the plastic is cut with a razor.
The waste tends to be higher since any glitch in the scratching process can cause a runout in the break, rendering the piece useless. The same applies to monolithic glass, but the laminate has to be scratched twice, doubling the chance for a boo-boo. In anything other than very small pieces, cutting laminate becomes a 2 man job, mainly because it takes such careful handling in turning it over to make the scratch on the 2nd side.
I've seen laminated glass used in machine tool windows, but overall its probably one of the most expensive options. It'd be rare to find a MT window that didn't have rounded corners, and those add further complications in the cutting of laminated, both in difficulty and in the likelihood of scrapping the piece due to a runout.
Glass shop material markups tend to be very high as compared to the sorts of material markups we're accustomed to being able to get in our own businesses. My b-i-l does quite a few replacement MT windows to customer patterns, and he can sell the plastic for 2-1/2 times what he pays for it, add the labor, and still be the cheapest in town among 3 or 4 glass shops that stock plastic sheet. Some of his customers use acrylic for replacement and others want polycarb.
Shipping costs can be a killer on plastic sheet since none of the major warehouses run their own trucks. Everything has to be skidded and cardboard wrapped, and it still gets probably the worst common carrier rates on the planet since the truckers can't pile anything on it or stand it on edge to take up less space. Its not unusual for my b-i-l to drive from here to Charlotte to pick up a half dozen sheets of plastic. Round trip is about 220 miles, but he can save about $250 in skidding and shipping costs for his effort. That figure is probably down somewhat now with fuel costs lower, but the shipping on this stuff is still high in comparison to most things.
About the only way you can likely save any real money on window replacements is to pick up a few sheets of material from one of the warehouses next time you're near Columbia, and cut the stuff yourself. That'd likely save you on the order of 2/3 to 3/4 of what I'd imagine you paid for the windows in the pic. The cutting is fast and dirt simple with a vertical bandsaw or even with a good handheld jigsaw. Saw 'em out and buzz around the edge with a DA sander and about 100 grit open coat paper, and they're ready to go.
One thing you didn't mention was whether you installed them or if you took the panels to a glass shop and had them do it. If they did it, a good portion of the cost could also be in installation labor since some gaskets can be hell to deal with, particularly if they have some age on them. There are tools made specifically for the job, available from C R Laurence, that make the job go much easier, and they aren't particularly expensive. If you installed them yourself, you did all the hard work, so it'd be well worthwhile to stock a few sheets of material and keep the profit off the gravy end of the work for yourself.
05-03-2009, 02:51 PM #14
MR-10 Is what you want it has a scratch resistant coating and is lexan. You can get it smoked as well if you desire. Two company's come to mind Kmac GE Lexan and Bayer makrolon.
05-03-2009, 08:19 PM #15
Looking at that enclosure I have to wonder if over half the plexi could be replaced by sheet metal. Who needs clear on the back and sides? maybe for lighting?
05-03-2009, 08:24 PM #16
05-04-2009, 08:56 PM #17
Both my lathes have a acrylic/polycarbonate laminate, the acrylic on the inside where the coolant/chips etc hit, and the polycarbonate on the outside for penetration resistance, seems to be two sheets of 3mm glued together.