Week 7 (Week Beginning 08/03/10)

Kiln Casting With Gaffer Casting Crystal

The image to the left is that of the glass that came out of the cast I put in at the end of last week. The effect isn't really what I wanted but it is really pretty. The jade green and clear have mixed quite a strange way creating waves of colour within the piece and the jade green has split in to lots of different shades of green.
I have another couple of moulds for this shape I will try another method of casting them with the other billet and a half of clear and jage green I have left to see what different effects I can get.
I have already started cold working this piece getting the excess cut off and flat bedding the surfaces at 120 and 220 grits, I would like to get this to a finely polished standard so I get more practice for future pieces. And i wrote in my proposal that I would need to practice my pollishing skills.

Viralap

After a couple of days of hand lapping I started to lose the feeling in my hands and the will to live so I inquired to the use of this little piece of kit, the Vibralap. It's like a flat bed but you leave your piece of work on it and it grinds the surfaces down for you, but it takes a lot of time. I had gone through the grits 120, 220, 320 and started on 400 but for some reason it was taking ages to get all the permanent pen cross hatching off (you cross hatch with a permanent pen or using a china graph pencil so you can tell when you have ground the layer back to a flat surface) I think it's because I started using a different sheet of glass than I had the day before so one of them mush have been ground down too much in one spot making the sheet uneven. So I set up the vibralap, it needed to be level so the bottom of it was propped up in places and the legs adjusted while a spirit level was sat on top so I could tell when it was level moving it around occasionally to check the whole thing was level. Next I needed to clean off the bed that the glass piece vibrated on, to get rid of any bits of glass dust or old grit. When that was all clean I poured on some 400 grit and mixed it with water, I was told to make it a little thinner that I would if I were hand lapping then when it was turned on come back to it every 10Min's or so to check on the glass or top up the grit or water if I think I need to.




The image too the right shows how much was ground down after about twenty minuets. I returned again to the piece every 10 - 15 minuets during the day and the amount ground down didn't seem to be very much. It would probably work a lot faster if there was some more weight to the piece also the glass that I had been hand lapping on to begin with may not have been that flat. It seems this may take a few days just to get this one surface flat, think I may go back to hand lapping but for now I'll leave it on a little longer to see how it gets on, and I'll get on with something else...

Casting Billets (Second Attempt)

It's not that I don't like the other piece, it's just not how I thought it might look. So I'm going to try popping the billets straight into the mould. I have been told that with this method I will be able to see a seem between the two layers of glass, but you might be able to make them blend together the two colours the longer you hold the kiln at the top temperature. I'm going to use the same kiln program as I did for the first piece as it seemed to cast quite well, I shouldn't have to hold this as long because it hasn't got a resiwar to flow through but the longer time might help the colours blend. Again I have used a billet and a half to cast with and like the other there will be excess which is a shame. It might be worth trying with the gaffer frits at some point so that I don't end up with as much waste.


Here is the kiln program I used:

50 ⁰C/hr → 500 ⁰C → Pass hrs
Full ⁰C/hr → 830 ⁰C → 3.00 hrs
100 ⁰C/hr → 600 ⁰C → Pass
15 ⁰C/hr → 440 ⁰C → 4.00 hrs
10 ⁰C/hr → 360 ⁰C → Pass
20 ⁰C/hr → 310 ⁰C → Pass
50 ⁰C/hr → 21 ⁰C → Pass
End

More Plaster Models

Here are some of the plaster pieces I got from using the two part mould I made last week, I am strating to use them to think about how to arange and carve my final piece.

And here is a nice bit of carving I did...