The Armour Archive

I recently talked to Barb Snyder from http://barbkat.com about getting some belts for my new grizzly 2X72 belt sander. I was under the impression that the zirconium belts are what I would need for polishing metal but she said that she only carries zirconium belts up to 120 grit. From reading the other posts this is far to low for bring a piece to a nice finish. She said she has high grits of aluminum oxide but will this material be appropriate for metal?

Maybe this thread can be used to talk about the advantages of different sanding materials as well.

Thanks for the input.

I may be misremembering the time I spent working on the Alligator Grit press (yes, seriously.. ), but I think that is the highest grit Zirc goes too.

After the 120-grit Zirc -- a stock removal grit really -- the Aluminum Oxide grits will continue to do everything you need to do in grinding, polishing, and finishing. Aluminum oxide, a/k/a by the old term alumina, a/k/a corundum, is the stuff they make Crock-Sticks of.

The other biggie in abrasives, still in worldwide use, is Carborundum(tm), the name being coined from a mistaken idea as to its composition -- they started making the stuff by baking alumina with carbon at very high temps, at first by mistake, in 1891. It's really silicon carbide. Since its hardness approaches that of diamond, it too has no trouble grinding or polishing ferrous metals of any hardness.

Though if you have a knife with an ATS-34 steel blade, its extremity of abrasion resistance suggests you should use a diamond hone for hand sharpening that edge. ATS-34 is slow and difficult to sharpen with anything less hard.

I use her belts (good belts, good prices, good service).

I have ended up with various grits over the years and somehow I got some smoother ones. I don't use them anyway. Generally just use the coarser up to about 120 and then move over to setup wheels - cotton buffs with abrasive glued to them (several levels - 150ish, 220ish, sometimes to 320). In the past I have used PB-80 etc. greaseless compounds after grinding. Then on to more normal buffing with stainless compounds. I use a real cutting compound on a sisal wheel followed by more normal stainless compound on a tight cotton buff.

I use the zirconium belts because they last longer than the other and (at least from Barb) really aren't much more expensive. I have used aluminum oxide for several years and it does work, it just wears out more quickly.

My goal has been to come up with a reasonable compromise between the (high) cost of abrasives and speed.

At least on armour I don't think that a belt is supposed to get you to a "polished" finish. It is one step in the process toward the final finish.

Wade

I do agree with Wade fully. Zirconium belts are actually best I have used. I use them on slack belt attachment too. My friend used rough ones on lanisher for stock removal on the blades. Cutting like crazy.

Jiri

I've become a big fan of Silicon Carbide. It lasts longer than anything else I've tried (and over the years I've tried pretty much everything on the market), particularly vs. stainless and titanium, and can be obtained in grits up to 600 easily. I know that you can get higher grits, I believe up to 1200 maybe 2000, but I don't remember off hand where that was from.

Zirconium is a good second choice for most things, but if you are going to be working with hardened spring, stainless or titanium I highly recommend you at least try Silicon Carbide; it takes less time to do your surface finishing work as well as the belts lasting longer.


Frederich

We frequently use 120 grit rouge for a nice satin finish, so don't discount its uses for polishing too hastily.

You guys should check out

http://www.trugrit.com/belts4.htm

I've been buying my belts from them for 20 years and they have the best prices and selection I've seen.

I use the Hermes Alum oxide. Tried zircs and found they didn't last any longer and were nearly twice the price. Ymmv.