Coldworking fused glass is a process carried out at room temperature using cold working techniques and equipment.
Many items may require no cold working whilst other pieces can require different finishing processes and tools.
Different glasses can be ground, drilled, sandblasted, etched, cut, sawn, sanded or polished to prepare the item for firing in a glass fusing kiln or as a finishing technique after hot work is complete.
Some methods are applied between kiln firings.
Diamond Hand Pads
One of the simplest methods is the use of different grades of diamond hand pads.
Wet and dry hand pads are very handy for cleaning up faulty edges, baked on kiln wash, as well as edge spikes on frit castings.
Pads or sandpaper can also be used with silicon carbide compound to speed up the process.
Using various pads and compounds can produce a nicely polished surface.
Table Top Grinders
Water cooled table top grinders, wet belt sanders or flat lap grinders are excellent for shaping and edge finishing.
A range of different grades of grinding bits, belts and grinding discs are available for these machines.
Hand held power grinders are another type of tool used for cold working.
Being hand held they are quite portable but require a constant source of running water and can be very messy to use.
Cutting can be done using a water cooled ring saw, band saw or tile saw.
Different thicknesses can be cut with these saws.
Tile saws, with a special cutting blade are usually used for cutting very thick pieces.
Ring and band saws are generally used for shaping and cutting intricate shapes or patterns.
Special diamond coated drilling bits are available for drilling. Drill sizes can range from 1/8" to well over two inches.
Drlling can be carried out with a hand held electric drill or in an electric pedestal drill.
All drilling is water cooled to protect the drill bit.
Small pieces are generally submerged in a water container and then drilled.
Engraving is usually done after fusing as engraved details will disappear during the fusing process.
This also applies to dichroic glasses which are best engraved after fusing.
A number of small engraving machines are available as well as more high powered units such a Dremel or a jewelers flex shaft.
Items can be easily signed with an engraving machine.
Sandblasters are used to impart a finish or design to fused objects
Used after fusing to ensure the finish or design is retained.
It is possible to slump or fire polish sandblasted pieces provided the item does not become too hot.
Sandblasters can also carve deep designs or holes or remove baked on kiln wash.
A full range of cold working equipment and information can be found at DELPHI GLASS - Tools & Supplies.
Whenever using cold working equipment always wear appropriate safety glasses, gloves and face masks to protect against glass fragments and grinding dust and fumes.