I use sandpaper glued to glass for sharpening chisels. What kind of sandpaper should be used for this? I’ve always used whatever sandpaper was on hand, from garnet to silicon carbide, but now the glass is scratched up. Don’t know if the scratches were made by the tools being sharpened, or by grit from the sandpaper.
It occurs to me that sandpaper hard enough to scratch glass would make quicker work of sharpening tools.
Janet
Replies
sandpaper
Silicon carbide wet/dry is what is usually recommended. It's available in various grits up to around 2000.
http://pro.woodworker.com/9x11-sheet-60d-ao-mssu-111-122.asp
Would silicon carbide damage a granite slab? I Googled "hardness of granite" and found that granite varies in hardness. Is the granite slab used by engineers harder than silicon carbide?
Janet
relative hardness
"Is the granite slab used by engineers harder than silicon carbide?"
That probably depends on the granite to a large extent, but even the best quality is subject to wear. One way to minimize the contamination, and thus the wear, on the granite would be to mount your paper on a sheet of plate glass (3/8" or so thick), and then rest that on the granite plate. I wouldn't worry about minor scratches on the granite surface, though. They won't affect the overall flatness of the granite, and in the final analysis, you're just looking for a "reasonably" flat surface for the sandpaper.
why not
just buy some stones. it is the more accepted way of sharpening tools
ron
Good point. I went with sandpaper to avoid a large initial outlay, but a granite plate is expensive. When the glass can't be used anymore, I'll upgrade my whole sharpening system.
Janet
Granite surfacing plates are cheap at Woodcraft.
Janet:
A couple of years back I got my granite plate from Woodcraft during a sale and paid $15 for it. About 6 months ago I went back and got my oldest son one for the same price. Woodcraft puts these on sale at least twice a year. Even Woodcraft's normal $32 list price won't break the bank for a decent granite surface plate that gets the job done.
gdblake
Thanks for the resource. I didn't know that granite plates could be found at that price. I had used Google to shop for them, and at the time it listed the Starrett (read "$$$") plates first.
Janet
I bought the Woodcraft granite plate a couple of years ago. It is a nice heavy plate and was on sale.
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