Would someone explain tempered glass on a platen???

C L Wilkins

C L Wilkins

Joined
Mar 18, 1999
Messages
2,112
I have seen this mentioned a number of times here lately. Could someone explain to me the way this is done?
1) How is the glass cut to size????
2) Is it tempered after it is cut???
3) If it truly is tempered glass, how does it not lose its temper under grinding conditions???
4) Why and how would this be "better" than hardened steel as a platen???

I am ignorant in this area and would really like to know about the application. I am always looking for a better way to do things if it is possible.

C Wilkins
 
I used plate glass on the platen of my 2x42. The glass store cut me 3 x 3/8" pieces at 2 x 5 inches and slightly radiused the edges - for $5 for all three. $5 Canadian!

The glass is flat and stays that way. I glued it in place with JB weld and it held - even when I leaned too hard and cracked the glass. I heated it up on the stove element to remove it.

The glass I used wasn't tempered and though it didn't fly apart on me in tiny shards, I still prefer to recommend safety glass.

Some of us don't have access to a machine shop or any way to precision flatten a steel platen. Glass is a workable option. I would prefer a good hard tool steel platen if I had the means.

Rob!
 
Tempered glass is made as temper glass. The pieces I have and use were cut for me by a glazzier.A 2"x6" piece costs me $10.The reason to use the tempered glass is that it will last a lot long than hardened steel and it does not warp. It can be simply attached to the platten with two layers of two way tape (yes like carpet tape) that does not contain a fabric. ( (I have only seen one kind that did )A warped platten will not of course give you a flat grind nor will that graphite canvass which may do a great job on convex shaped blades. Sorry, but I can't give you the reason why it does lose its temper.Probably would make a pretty good knife if it wasn't so brittle.
 
The glass you use, is it cut before tempering or does your glazier have a method for cutting tempered glass?

 
You can get tempered glass at local glass houses, or you can use fireplace tempered glass. Either place will have scraps in a pile left over from custom cuts, and usually there will be a piece in there that will work for you, or they are usually very good about cutting it for you. As mentioned in the above replies, here's a few other things using the glass will do. Number one, glass will loose heat much fast than a metal platen. It won't warp or wear down like steel. And, the big thing is this: it will eliminate chatter completely when you go to higher grit belts for smoother grinds. It works wonderfully and I have tempered glass on my Dewalt small platen grinder, my Balder small knife making machine, and on the machine I use extensively, my Hard Core. I love this machine, and it was worth the wait. Took me five years to finally get one. Had my heart set on a Burr King, but we all know what happened there. I must say though for any questions, the Hard Core is much improved. Hard bearings for longer life, solid machined aluminum arm, and is so quiet, you just wouldn't believe it. Variable speed in 220 is the only way to go, as you would have a very difficult time bogging it down. My other two machine bog down if you even think about it! Which is good because I have learned (because I had no choice) to go slow and take you time. Try the glass, you can't go wrong. Regards, Bear
 
Craig,

I was told by a local glazier that he could not cut tempered glass and that it must be ordered to a specific size. I had him cut me a piece of corning glass instead.

Brett
 
You don't need any special glass-I've been using regular plate glass cut to size by my glass guy-cost's a buck or two per piece-I buy 20 at a time-when they break, chip them off, scrape down the platen and bond on another piece. I use the green Zap-a gap and spray the kicker around the edges. works great and it's FAST.
I do all my tapered tang finishing with NEW, sharp belts and at 3000SFM or less, so I don't have to push too hard against the platen. I get great life from the glass-I've seen lots of posts, guys complicating the s*** out of this idea-it's not required-simpleand cheap will work just fine for this one. Just try it!!!!!!!!!!!1

RJ Martin
 
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