As some test tiles just came out of the kiln, it is a perfect opportunity to tell you about it.
First, about the test tiles:
This is my extruder die ( for 2 different extruders):
When I extrude the tiles, I score a line at the bottom of the vertical surface, just above the angle. That makes it easy to break the bottom off for filing:
Once I forgot to do the score line and had to use the angle grinder for this step.
I store the tiles on A4 size 3 mm thick MDF board fitted with stapled elastic on both sides:
I use the same format to write the recipes on the A4 page, and that way I have clear visual reference:
Every now and then a glaze catches my attention that I want to explore fully, so I came up with a series of test that will give me the widest range of colours with the least amount of effort and repetition.
I have mixed 2 kg of glaze base (removing the colourant) and sieved it.
Protect your lungs!!
After dividing the glaze into smaller batches ( see bottom of the chart on the top of the post)
I use precision scales to accurately weigh the colouring oxides. As per chart, I need 1% chromium oxide, which is in this case equivalent to 1g.
This is Triaxial A:
Then the fun begins. I use a syringe to accurately measure 15 ml into second row cups, 10 ml into 3rd row, 5 ml into 4th row and none into 5th.
Tuesday, 26 May 2015
Materials and equipment:- model
- mould release (I use soft soap or watered down clay slip)
- containers for mixing and measuring
- plaster (I use Gyprock Superfine Plaster)
- paper pulp ( available in bulk from roof insulation places)
optional: kitchen timer
A word about undercuts:
1) Preparing the model
2) Mixing the plaster
4)Mixing the paper plaster
Usually you will need more volume of plaster for the second layer, as it is larger.
Start the same way as for the first layer:
5) Preparing the second half
I usually apply it to the sides of the mould as well as the top edge, as some plaster is likely to spill over the side. This will make it easier to clean
6) Repeat steps 2, 3 & 4
And here it is, finished mould. You don't even have to wait fort he plaster to cool down. Gently tap it onto the ground on the seam and it should crack open like an egg. I love this moment.
I tend to let the mould dry for a few days before using it. If you are going to use it for slip casting, you will need to wait for a week or more as the mould needs to thoroughly dry out in order to absorb the water from the casting slip.
If it will be used for a press moulding, it can be used almost immediately.
Did you find this tutorial useful?
Is it similar or different to the way you make moulds?
Do you have suggestions or tips to share?
I would love to hear your comments.