Platens- how long will it last?

H

Hulkie

Joined
Oct 22, 2012
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30
I've been working on the same platen for over 4 years. Recently I noticed a difference. I'm having more difficulty getting even bevels. I use quality belts and tried to flip the platen over, using the other side. It's cold now so it may be a factor but I've used it in the winters past. It just feels different! I don't have a surface grinder, although, I'm sure someone on the site can help with that.
For all you experienced blades smiths , do you have to resurface your platen? Mine seems smooth and plum but something just feels off. Thanks
 
I have used the glass platen liners. They are much harder and don't dish the way steel will, even hardened steel. I can usually get a couple years out of my glass liner. I am guessing that you have some pretty serious dishing in your platen if you have been using it for 4 years.
 
I tried using the platen on a HF 1x30 and when I press down with the lightest pressure against the platen, I get terrible edges. I just hear the belts catching on little nicks and stuff. Anyone ever had that problem, and if so were you able to fix it?
 
sintro said:
I tried using the platen on a HF 1x30 and when I press down with the lightest pressure against the platen, I get terrible edges. I just hear the belts catching on little nicks and stuff. Anyone ever had that problem, and if so were you able to fix it?
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I also used a 1x 30 in the past. My platen was fixed to one bolt on the bottom, so any excessive pressure made grinds difficult. I was thinking of a way to stabilize the platen with some jig but then I upgraded.
When I used the 1x30, it took a much longer time for me because I applied minimal pressure. I found it easier to use on thin stock versus 1/8 " or larger. So I was limited to the kind of knife I wanted to make. I'm sure others, with more experienced, have better results on the 1x30 than I . Maybe someone will chime in
 
Platens will wear over time regardless of what material they are made off. Graphite and mild steel platens will wear in a heartbeat. Hardened steel (depending on type and hardness) will wear much slower, but still dish out, and glass is probably the slowest, but starts to dish and mark up as well.

By the way, it will likely still feel fairly smooth, since the back of the belt is slowing "polishing" the metal or glass away, and I've noticed almost imperceptable blemishes on a platen start cropping up on finer grits.

I assume you are using fresh belts? Dull belts will make things seem off too....
 
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It happens. Take a square egde and place it on the platen. Look for hollow places - usually where your table came up top. Placing a light to one side will often help show up wear. Frank
 
I usually just grab the biggest Mill file I have and draw file the platen flat. The stock KMG platen files pretty quickly
 
I glue glass on all my flat plattens, it really heps and lasts much longer than the mild steel flat platten plate.
CW
 
I have gone through two glass platens and have one in the drawer - glass is great and flat, but to try something new to me, I will be testing three new A2 platens. One is 8", square sides, the others are 8" and 10" with rounded sides. My observation has been that folks like glass or A2 for flat grinds. Glass is super flat, but like a brake pad, disposable over time. A2 wears also, but can be re-ground flat. I used mild steel for about two weeks before confining it to backing steel.

If your platen is steel and you have a granite slab (thanks, Stacy), use some 3m feathering adhesive (thanks Nick W.) and stick your sandpaper (120-280) to the granite. A few passes with your platen and you will how flat it is or isn't.

Here's my new A2 platen, flat as glass today.

IMG_0281_zps9a76ab89.jpg
 
This may very well be the dumbest question ever, but have anyone ever tried using a granite platen on your grinder? The reason I´m asking is that I have almost unlimited access to completely flat slabs in various thicknesses, that I could get cut to shape. Mounting it may require some thinking but should be possible.

Or am I missing some issues here?

Brian
 
Gody said:
This may very well be the dumbest question ever, but have anyone ever tried using a granite platen on your grinder? The reason I´m asking is that I have almost unlimited access to completely flat slabs in various thicknesses, that I could get cut to shape. Mounting it may require some thinking but should be possible.

Or am I missing some issues here?

Brian
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Good question, after a search I could only find one person on another forum who mounted a granite platen to his grinder, but he didn't return to share his results. Mounting it would be the same as glass - adhesive and sitting on a ledge in case of bonding failure. Many people swear by JB weld, I would say no way in hell. High-Temp Red RTV Silicone is the way to go.
 
I have used the same mild steel custom platen on my Burr King 2 / 72 for over 30 years, have not had to resurface it once. I just keep the blade moving.
 
John Frankl said:
Erik,

I have an 8 inch A2 platen. Where did you get the 10 inch model?

And is this what you are talking about,

http://www.amazon.com/Permatex-81160-High-Temp-Silicone-Gasket/dp/B0002UEN1A

and why do you like it better than JB Weld? I am about to attach some glass and so I really appreciate the info!
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I got the 10" platen from a friend as a favor, I don't believe he is selling them. It's much thinner than the one I pictured, but I think it is about 3/16-1/4." That Permatex is the stuff. One caution, you will only get to use one side of the glass, because you will have to break it to get it off the backing. I don't like the JB weld because I tried it. Cleaned both the glass and the backing with acetone, and then followed with denatured alcohol to remove any residue. I even scored one side of the glass with a Dremel for better adhesion. I let it cure for 24 hours - during my first grind it began to show signs of breaking free. After less than an hour, air was making its way between the bond. I put a light heat gun to it and it came off in less than a minute with no complaint. I cleaned it up and used the RTV which someone else recommended - totally fail safe. I have a ledge to support the glass just in case, but with properly applied RTV, it's not necessary. Ed must grind better (surely) or differently (surely) than me, but I need harder surfaces than mild steel. I learned I should hog on a wheel and save the platen for bevels, even then, I can score the crap out of platens over time. Red looks cool, too.

IMG_5645.jpg
 
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