Wearing of ceramic glass platen

[SHARPCO]

   

This is ROBAX glass(heat resistant ceramic like pyroceram) on my Viel platen. I thought it was very hard and hardly worn out. But it has worn like this in a few months.

I know there are people who use pyroceram here. How much wear is your glass?

[Bud]

Sorry Mr. Sharpco but I don't speak Viel and am no help to you but I am curious. Is the wear from the business side or the backside of the belt?

[SHARPCO]

Sorry Mr. Sharpco but I don't speak Viel and am no help to you but I am curious. Is the wear from the business side or the backside of the belt?

Hello Bud, 

Of course it's because backside of the belt. I applied light pressure.

[Bud]

Ok and thanks. Picture just looks more like a piece of fiberglass to me than ceramic glass unless it only has a thin veneer of ceramic on it and the veneer peeled off.

[SHARPCO]

Ok and thanks. Picture just looks more like a piece of fiberglass to me than ceramic glass unless it only has a thin veneer of ceramic on it and the veneer peeled off.

I understand you. The reason it looks like fiberglass is because I use epoxy glue to bond it. The ROBAX is 4mm thick.

[Ken S]

Is it possible that the platen might be placed a bit too forward? That would put more pressure on the back of the belt, thus generating more heat.

That's easy to do. (I speak from actually having done it......)

Ken

[Mark Reich]

I agree with Ken. Perhaps the top of the platen is tipped forward...? Hard to tell.

To me it looks like someone properly chamfered the top edge of the glass. The rest of what I see looks more like residue from the back of the belt. I have to scrape residue like that off my platens, especially if I use too much pressure with the blue Deerfos belts that have the white padding on the backside of the belts.

[SHARPCO]

Is it possible that the platen might be placed a bit too forward? That would put more pressure on the back of the belt, thus generating more heat.

That's easy to do. (I speak from actually having done it......)

Ken

Not too forward. I made it just contact with the belt. The reason why the edges of the glass are worn seems to be because I use the slack belt.

[Ken S]

Sharpco,

Looking closely at the photo you included, your ceramic glass platen appears to extend higher and closer to the top pulley than the original metal Viel platen. If you are using the small separation between the top pulley and your ceramic glass plate as your slack belt area, you would be creating the same effect as having your plate extended too far forward. By placing a knife in this small slack span area of your belt, you would have your belt in too close, thus creating the bend. 

If you use the diamond plate I sent you to create a slight radius on the top edge of your ceramic glass plate, that should lessen the effect of the harsh corner on your belt.

I bought a piece of pyroceram intending to use it with my Viel. I had it cut 188 x 25mm (7 1/2” x 1”) to match the platen of the Viel. I do not use my Viel enough to need it. The longer distance between the top of the platen and the top pulley makes a more gradual convex grind in the slack belt area. Perhaps this convex curve is more gradual than you wish for knife blades. Fairing the top edge of your ceramic glass plate with the diamond plate should allow you to keep the tighter convex curve on your knife blades. You would be using your diamond plate to do what your belt is already doing ,but in a more controlled way without the wear on your belt.


Ken

[SHARPCO]

Sharpco,

Looking closely at the photo you included, your ceramic glass platen appears to extend higher and closer to the top pulley than the original metal Viel platen. If you are using the small separation between the top pulley and your ceramic glass plate as your slack belt area, you would be creating the same effect as having your plate extended too far forward. By placing a knife in this small slack span area of your belt, you would have your belt in too close, thus creating the bend. 

If you use the diamond plate I sent you to create a slight radius on the top edge of your ceramic glass plate, that should lessen the effect of the harsh corner on your belt.

I bought a piece of pyroceram intending to use it with my Viel. I had it cut 188 x 25mm (7 1/2” x 1”) to match the platen of the Viel. I do not use my Viel enough to need it. The longer distance between the top of the platen and the top pulley makes a more gradual convex grind in the slack belt area. Perhaps this convex curve is more gradual than you wish for knife blades. Fairing the top edge of your ceramic glass plate with the diamond plate should allow you to keep the tighter convex curve on your knife blades. You would be using your diamond plate to do what your belt is already doing ,but in a more controlled way without the wear on your belt.


Ken

Thank you Ken. 

I'm not sure that using ceramic glass for platen is a better choice. Rather, I think it's better to buy extra platen and replace it.