I have started to get out and collect some rocks, but because of the COVID19 lock-down, I can’t go driving all around my shire doing a full geology excursion.I’m suppose to stay within 5 kms of home. I can go to the shops or Post Office for essentials, but we don’t have a shop or a post office here in our little hamlet. So we have to go the 5km to the next village where there is a small shop and Post Office. Luckily for me, I have walked all this country around here over the past 45 years. So I know where to go within 5 kms to get some glaze stones. There is a small volcanic plug just a couple of kms away, but it is completely kaolinised and has lost most of its alkali, so doesn’t melt very well – in fact not at all. Also, the high levels of iron and magnesia that are left limit what can be made from it. It’s really just a brown soil and is only good as an iron pigment.It would be nice if there were some acid rocks nearby, but there aren’t. So I’m stuck with what is here. There are just 3 volcanic plugs within the 5 k limit around here. All basalts.
I called in at Werner’s house, just a couple of kms further along, on the way to the shops. Keeping my distance of several metres, I reminded him that I had called in there 20 years ago and he let me collect some of the basalt rocks that out crop from a small volcanic plug in his back yard. Werner is a very nice guy. He has retired since I was there last. We went for a well distanced walk around to his back yard. We are both double vaxed, so felt safe to do so.
Mid last century, this was a working quarry, it’s abandoned and quite over grown now, but there are lots of little, hand-sized, small stones that I can pick up from the garden bed near the top of the quarry wall. I can fit about 15 kgs in my back pack and thank Werner and prepare to walk back out. I tell him that I’ll be back for some more stones in another 20 years! He laughs, he will be 100 by then.
I put the stones through my rock crushers. First, I put the fist sized pieces through the jaw crusher to reduce the stones down to blue metal sized pieces.
Then they go through the disc disintegrator mill to reduce the gravel to grit.
I have installed a flexible dust extractor system that sucks the dust from the machine out through a fan installed in a sheet of plywood that fits in the roller door space. It is quick to install and remove afterwards. This was the quickest and cheapest DIY solution to the OH&S dust problem involved in crushing rocks, as i had the sheet of plywood left over from the ceiling of the throwing room.
I sieve out all the over-sized bits, and put the rest into the ball mill. This reduces the grit down to dust that I can use to make a glaze.I know from my previous research that I can make a tea-dust and a tenmoku glaze from this dark rock. Basalt isn’t very easy to work with, as it doesn’t contain sufficient silica or flux to melt properly. It also has far too much Magnesia and iron to make anything other than dark glazes like tea-dust and tenmoku. Even then, it needs extra limestone and silica to get any usable, stable, glossy result at all. But the thing is, it can be done with a little bit of chemical jiggery-pokery using just what is available around here. In fact. It can be done with what is in my back yard!
My initial test tile showed me that I can make a honey brown glaze, a black tenmoku, a green magnesia matt, a tea-dust green/black glaze and an opalescent dark blue/green glaze.
Meanwhile, Janine is at work making larger bowls on the ’Slatcher’ kick wheel.
While the ball mill runs, I spend a bit of time making some new fibre cement pot boards. I use our own sawn and milled pine slats to reinforce and support the fibre cement sheet boards. Some of the advantages of the FC pot boards is that they are cheap, very flat, quite absorbent and light weight.
I made a couple of stillages on castors to hold the pot boards in a compact and movable form. The first set I made from leftover parts of the brickies’ scaffolding. I don’t like to see waste, so i kept the parts after i dismantled the scaffolding. The other set I made from steel, half of which was left over from the shelves and benches that I made for the Gallery and lab rooms. These shelving racks can hold 28 pot boards if they ever get filled. More than enough for us.
Now that we finally have a continuous, flat, level floor, we can wheel our work between the throwing room, kiln room and glazing rooms as needed. So easy and convenient now. What a luxury!