Showing posts with label Sand. Show all posts
Showing posts with label Sand. Show all posts

Wednesday 4 March 2015

Texture Moulds

Texture moulds are popular but expensive and with limited designs. You can make your own unique ones with only a few items of equipment. 

An example made by someone else



Clay

Various forms of clay can be used. Roll out a flat piece using boards of 8-10mm thick to support the rolling pin and give consistent thickness to the clay. The board underneath should be covered in paper or cloth to make an easy release. I have found that grease-proof paper as used in baking works very well.  It releases easily from the clay.  

Paper clay provides light weight moulds that do not hold a lot of heat, but any standard clay will do the job. There are two approaches to developing the pattern. You can stamp the pattern into the wet clay with any prepared design on a stamp or other textured material. The other is to dry the clay to leather hardness. You can then incise the pattern you desire directly into the clay. Fire to bisque temperatures, and sand to remove any rough areas or undercuts. Kiln washing the mould before use is essential.



Using a patterned roller to impress the design on the clay



Fibre board

Various fibre boards can be used. Ceramic fibre board, Kaiser Lee board, Vermiculite board, insulating ceiling tiles such as Armstrong, and calcium silicate boards can be incised and marked as desired. The advantage to the ceramic fibre, insulating ceiling tiles, and Kaiser Lee boards is that they allow air to pass through the material. Kaiser Lee board of these three provides the easiest surface for incising. Calcium silicate has no fibres, but requires a separator. Ceramic fibre and Armstrong ceiling tiles have fibres, requiring a bit more work to get a smooth surface. Armstrong tiles require a separator, but ceramic fibre boards do not unless you harden them for durability.


Fibre paper

Three millimetre fibre paper gives a easy material for cutting with craft knives or scissors to the design wanted. You can draw through an existing stencil or copy the design with carbon paper. It is not easy to produce designs with lots of detail.  It is quick, does not require separators, but is probably a single use material, unless you use mould hardener and then kiln wash, although it still will be delicate. For large projects, the paper should be fired first to ensure the combustion of the binders do not produce gasses to cause bubbles or fogging.


Loose Material

Sand, whiting, and kiln wash provide easy materials for one-off designs. You can quickly draw the design you want into the flat loose material with your fingers, or tools. You can also use found items to press into the loose material. Place the glass gently on top of the material and fire. If you use sand, you should dust it with kiln wash or aluminium hydrate to ensure the sand does not stick to the glass.


Unique Designs


All of these methods will provide unique designs which will distinguish your work from others.

Tuesday 30 July 2013

Moulds for Bottles

One of the many styles of commercially prepared moulds


An alternative to buying moulds for slumping bottles is to use a sand bed. You can place the bottle into the sand and roll it a little from side to side to create a depression in the sand that then becomes the mould.

I use a fine sand (not builder's or garden) and coat it with alumina hydrate (slaked alumina). I use about 1 part alumina to 5 sand, but the mix is not critical, just enough alumina to coat the sand particles. It can go directly on your kiln floor if you have an easy way to pick it back up, as it is re-usable. Or you can put it in a stainless steel tray or any open topped box that will withstand the temperature.



Make your depressions and then sprinkle or sift a fine layer of alumina over the area - I use an old sock to hold some and dust it over the sand. Then lay the bottle in the depression.

The amount of sand impression you get is dependent on the temperature you use - the higher, the more sand texture you get. 

This way of slumping bottles eliminates the need for a mould and it is variable for different sized bottles.