Just how hard is it??

Thanks for stopping by. The WFB is my 'whatever I happen to be in to at the moment' corner of the web. I have two other Blogger sites which are far more interesting.  

The Lost Canyon Project is the chronicle of my work photographing and cataloging the life's work of my late friend, artist Pete Hampton (1940-2018) 

 

The Lost Era Transcripts is the fruit of the Lost Canyon Project. It is a re-creation in book form of Pete's unfinished master work, The Lost Era. This is a good candidate for the finest work I have ever done.

 

 Just How Hard Is It?

 

 too. 

I bought the chunk of anhydrite from Dodd Roth around twenty years ago. He had a finished piece done in this stuff. I've mentioned this before; it polished up to a beautiful metallic sheen, almost like hematite. But Dodd  often worked in hard stone like calcite, and even onyx. That kind of work takes power tools. Where I have a long row of files and rasps, he had a five gallon bucket holding half a dozen angle grinders, and die-grinders, all with different cutting heads. 

I was looking forward to working this stone. I had a sort of science fiction theme in mind.

 Monday I set the rock up to cut a base. It was a much easier set up than with the big white rock. I got the stone blocked up level, and strapped it down on the table with a ratchet tie down. I started, as always, by scribing the base line out with pencil, then a hacksaw. By the middle of the day the groove I cut in the rock was barely the depth of the saw blade. I experimented with rasps. The material was hard, but the tool seemed to cut OK. I couldn't get a smooth pass with the chisel, though. This was odd, because a few days ago, I rubbed out a corner of this stone with some 80 grit sandpaper, then a few finer grades. It took very little effort to get a nice finish on the stone.

This wasn't looking good. But it coincided with lunch break, and while the burrito was in the microwave I checked the email. There was the weekly email from the Stone Carving Supply gals up north. Coincidence is always important. They recommended an organization called NWSSA, Northwest Stone Sculptors Association. I looked them up, and perused their web site. And, what do you know? NWSSA had a brief guide posted, describing the characteristics of the various minerals popular with sculptors. I read some stuff I already knew, but I also learned some new stuff about my stones.

Now, I'm not going to pretend to know anything about chemistry, here, but this is interesting. Alabaster is an evaporite stone. It is formed in layers from salts that remain on the floors of dried lake beds. Alabaster is hydrous calcium sulfate. The molecule is composed of calcium, sulfur, and, oddly enough, water.  On the Mohs scale of hardness* alabaster generally rates a 2.  Anhydrite is the same molecule only without the water. It is much more dense, and it rates about a 3.5 on the mohs scale, a little harder than marble.

The guide confirmed my experience. Anhydrite, I have learned,  is a poor choice, for working with hand tools. The stone is too hard to work with rasps and files; it tends to be brittle, and fractures easily under the chisel. Another drawback is that, like alabaster, anhydrite will not weather well. Over time, the stone will actually absorb water, and slowly morph into alabaster.  That's why it was easy, at first, to get a groove started, or sand down a corner of the stone.  The surface of the stone had weathered, and softened a little over the years. A few cuts in, and I hit the hard stuff.  This is power tool territory: diamond saws, and grinders. It's an entirely different way of sculpting. I have only some small experience shaping this way, and I don't have the tools to do it. This stone is a no-go. bummer.

So, it's back to the finish.  Before starting in on a new task, it's important to finish the last one. I wasn't happy with the finish I achieved on the big white stone. There were tool marks, and scratches, and dull spots that remained even after two days of sanding and polishing. So Tuesday, I brought the beast back out to the table, and started over from scratch. (ha ha) I started wet sanding, making four passes, each with a new sheet of 320 grit. Each "pass" means going over the stone, head to toe, until I wear out a new sheet of sandpaper. I worked the stone through four or more passes each of 400, 600, 1000, 1500, and finally, half a dozen passes at 2000 grit finishing paper. That's a wet mess of sanding.

 Finally, it was time for the soft cotton polishing cloth, Simichrome polish, and, at long last, carnuba wax. There is something zen-like about going over and over the same surface of the same shape again, and again, and again. The routine becomes hypnotic; with each pass the stone looks just a little bit better. Each improvement is an enticement to make another, and time evaporates. I knocked back about nine hours on this thing.

Much more shinier

Too bad about the anhydrite. And the big white stone was the last of the crystal. Except for some scraps, the crystal is gone. I doubt I'll ever see the stuff again. Even so, I have two very nice chunks of alabaster left. I started this one today.

The picture above is of the flattened base.  Notice the layers. I sprayed the stone with water to bring up the color. This is a softer stone. It'll take a gentle touch, but it's going to be candy store pretty:

 

 I don't have a plan in mind, yet,  except to emphasize the beauty of the material. Lots of surface. Lots of color. Lots of curve. The last piece was kind of staid, and serious. I want to do something a little more fun. We'll see how it turns out.

* The mohs scale rates stone from soft to hard: talc (soapstone) at #1, to diamond at #10.