Planten glass problem

J

jtwodogs

Joined
Feb 1, 2009
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421
I have a craftsman 2x42. This makes the second glass platen from usa knife works I have installed with JB weld with the glass centered on the metal. It keeps chipping big chunks off the outer edge. Why this is happening I do not know. I am tempted to go with just plain metal although I know this will wear my belts out quicker, I don't like the thoughts of flying glass chips. Anyone suggest a more durable planten liner.
Thanks
 
There are many things that could be causing your problem so I will offer this fix.
You can use tile from Home Depot or the alley if you find some. Its cheap and hard enough along with very flat. Granite slabs works as well.

I just used a harden steel Platen for years and sometimes still do cause I'm to lazy to clean off the old tile or glass off of one of the two platens I use.
 
I don't believe a glass platen saves on belts. I have never heard that remark before, by the way. What it does do is withstand wear longer than can real crap up your grinding. Frank
 
The other part is that mine doesn't heat up, even when I'm grinding hard enough to stall the grinder.
 
Frank Niro said:
I don't believe a glass platen saves on belts. I have never heard that remark before, by the way. What it does do is withstand wear longer than can real crap up your grinding. Frank
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Frank,
I think that was/is a selling point of the Pryo glass. Dissipates heat faster, so that saves your belts. Since I grind after HTing I do think it help dissipate heat but never really saw any difference in how long my ceramic belts would last compared to a harden steel platen.

elementfe,
I sure can get my platen hot enough to burn by touch after an hour or two of grinding. What size motor/ grinder are your running if you can stop it easily?
 
My glass platen is on a kind of tired Grizz- rated at 1hp, but who knows how much is left. :)
When I'm "surface grinding" on it (flat of knife vertical on the platen) it's pretty easy to bog down, not so much with any other grinding.
I do as much heavy grinding on the wheel as possible- but I do notice a big difference in how much my metal platens heat up vs. my glass one.
 
Lawrence , the ceramic glass was created from a problem of metal platens getting dished and uneven wear.Yes the smoother the surface the less heat build up.Frank
 
elementfe said:
My glass platen is on a kind of tired Grizz- rated at 1hp, but who knows how much is left. :)
When I'm "surface grinding" on it (flat of knife vertical on the platen) it's pretty easy to bog down, not so much with any other grinding.
I do as much heavy grinding on the wheel as possible- but I do notice a big difference in how much my metal platens heat up vs. my glass one.
Click to expand...

The rating on most of these chinese tools can be suspect. I have seen guys fix this by setting up a second motor behind the grizzly and just let the grid spin freely.

Go find any cheap used 1 to 2 HP motor of 1700-1800 rpms that was made domestically, two step pulleys a couple of hinges and some link belt and you can improve that grizzly to an adjustable that won't bog down with normal usage. When you buy new motors you want a TEFC 56C motor so the dust doesn't kill it.
I have a few old open motors I've used in the shop for years one is from the 1940's and still works strong. I have only burned out one from dust I think?


Also you can flatten your platen on any 4 x 36 or 6 x 48 sander. www.trugrit.com stocks ceramic belts in those sizes and 2 x 72 etc…

Glass doesn't transmit heat as well as steel. That's why the run cooler.
 
Maybe be a dumb question here but where is it chipping? The sides or the top/bottom edges? No clue what to tell you if its the edges, but i always round off the top and bottom edges of the glass before epoxying it down so the belt transitions over a smooth radius
 
Keeping my eye on this before I glue my new piece of glass on. Do you find yourself putting more pressure on the spots that chip on your glass, is your JB weld spread out evenly over the entire back? Do you use a lot of water when cooling off a blade being ground? Hot glass and cold water doesn't mix with good results.

What do you use to grind down a radius on your glass CWendling, will our normal grinding belts work well on glass?
 
I believe the glass you are referring to is actually a clear ceramic material that is used in fire rated locations. Water on this material should not be an issue.
 
If I am standing in front of the grinder, it is the right hand side of the planten, the side the belt goes on. That is the side I do most of my work, maybe it is to much pressure, but I tried a lighter touch and still had random chips coming off.
I know this is going to sound crazy, but you have to find what works for you. Instead of grinding all in one direction, I grind blade up pulling to the right, then flip and grind blade down pulling to the right. My grinds seem to be more uniform that way.
 
Yes Setlab. If you are using pyroceram/ceramic glass then belts will grind it down. I usually do it with a ceramic belt but others would probably work. Not sure what to suggest Jack. Ive never had that problem. Is the belt running smooth on your grinder? Not bumping blade off where you bump back on the platen?
 
Yes Cory, it seems to bump around a lot when the belt is fresh. Come to think of it that is when the chips came off. 36 grit ceramic.
 
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