Your background sounds familiar, I was mainly building molds for the medical industry. Gesswein was the source most shops seemed to use. I had a tool salesman drop by the shop and leave a Falcon Tool catalog and have been quite pleased with their selection an service.
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Sam, thanks for that link. I’ve been buying from Gesswein since the early seventies but now they only sell the stones by the box quantity; other than that they are a great company to do business with.
Richard

what grades and grits work for you? I'm using them for gun work, I haven't polished a mold out for as I said 40 or so years. [/quote]

This question also interests me.  I have some Gesswein stones and occasionally use them but have a tendency to shy away from using them.  Seems like I get a dirty finish when I do use them.   

So, how do you guys use them?  What’s the proper way to use and how far in polishing do you go using them?  There are also quite the variety of types, so what ones are best for gun work?   

I have a feeling a book could be written on the subject but some of this info would sure help.
Bob

Grand slam wrote on May 11^th, 2025 at 9:06am:

Both Gesswein and Falcon sell box qtys by the dozen. Congress Tool sells by the individual as I see it from their website. Although I haven't yet bought from them. We will see.

I use them for shaping stuff, not so much for finishing.  I like wet/dry silicone carbide for polishing much better.  And for flat surfaces and squaring stuff, I use diamond hones.

I had the good fortune to purchase the tooling form a large mold making shop, and got a lifetime supply of Gesswein stones to choose from.  A lot new, many in dozen boxes, and a huge array of unidentified and mixed used pieces.  I passed on a lot of the mixed stuff to others here a couple of years ago, but have a fair amount still to hunt through and use. 

Predominately, I kind of just hunt and choose and try to see what works best.

There's about 4 major hardness types, with varying grits in each type.

What I've found, is there are some that break down fast, and cut very aggressively.  Those are great for fast work, particularly blending and shaping.  In the ones that I have, those are the orange and the white stones.  There are some that are very hard, and don't break down, those are great for sears, precise sharp edges, and such.  Those are the pink and the beige stones, as well as some very dense white ones.  I have a few sintered gray ones, like general purpose grinding wheels, and those seem to be best at putting scratches in the surface that are awfully hard to remove with subsequent grits.

However, there are some that are also color coded by grit, not by hardness.  So, it gets a bit confusing, and somewhat trial and error.

What I ended up doing is putting together sets of similar hardness and color, in the range of grits, and I use those for targeted work, where I know what I need.  I keep those stored by grit size.   

For the trial and error stuff, I just have a miscellaneous bin, and I search for what works.

LRF covered it pretty well, the only thing I would add is be careful as you use the stones, as the oil and grinding waste can get on the printed grit number on the stones, and then you have no clue what you have and they have to go in the trial and error bin.  Unless you're well organized, and have them sorted and identified by grit size in your storage system, and put them back correctly!