honegrown- Geological Specimen Supply (GSS) - ODC

October 26

I am trying to record this in order of discovery because I find it useful to follow along with the thought process. This might be tiresome if a person just wants answers (whatever THOSE are), but might save someone the thought of "well did he think that...why" didn't he....?" I may have. This is warts and all.



"Roll yer own" waterstones. At least, that's my thought. Here we go....

Abrasive personalities.

 Descriptions are paraphrased from Geological Specimen Supply.

First the white volcanic ash...

 Tuff- slightly lithified volcanic ash, mined as the scouring agent in Old Dutch Cleanser (ODC), blasted from a vent as ash, uniform uncrystalized groundmass. Hardness varying with temperature and degree of welding, clean and not welded. Cudahy mine, El-paso range, kern co. CA

White volcanic ash - ODC

Set of 5 student samples. I asked Rudy for a range of density/hardness. The two closest are VERY fine and white, with the closest being slightly "softer" in the hand. Similar to chalk in feel but less dense. They leave a slight dust on your hands, at least until you get them shaped. They seem to firm up with use. The 3 in the rear feel more dense, but rougher and have very small grains of darker particulate material. They are too scratchy for my intended use, so I'll set them aside for now.

I took each of the samples and briefly rubbed them against the rusty (patinated!) surface of the chisel to test the relative abrasiveness of the samples. Sample 1&2 no scratching at all, moderate polishing effect. Sample 3 was strong polish, light scratching maybe JIS 8000 grit. Samples 4&5 moderate scratching around JIS 4000-5000 grit.

Smooth, not scratchy (and safe for porcelain, too!)

This picture is the result of rubbing the #1 sample against the basalt block like a nagura stone and briefly rubbing. The basalt is NOT abrasive. It burnishes but the grains don't really cut, they just smoosh the metal around. The spots are rust pitting. Polishing effect is strong, slightly hazy.

NOTE: I'll do better tests soon. This material is turning out to be VERY interesting.