When you are looking for kiln firing schedules, you will always find these three different types of schedules in books or online. Most glass manufacturers have their own temperature ranges to follow to achieve these three contours, so it's best to check with each individual manufacturer. Don't forget to take firing notes to keep track of what works best for you and your kiln.
Now when you are new to fusing, you might be confused as to the difference between tack fusing, contour fusing and full fusing. We thought we'd write a little about these three different techniques today.
Tack Fuse 1350º- 1370º
Contour Fuse 1400º-1450º
Full Fuse 1460º- 1480º
The tack fuse contour comes in handy when making pendants or other glass art where you want multiple layers to look as though they are only laying on top of others. It can look nice when done with dichroic glass tack fused on top of a non dichroic base glass. Also when you need to lightly fuse multiple elements together, without melting down (and melting together) the entire piece, you will want to use a tack fuse schedule. If you have a piece that will need many firings and you want all pieces to keep their original shape when completed, it helps to tack fuse the pieces until the last firing. Remember, the thicker the piece you want to fuse, the slower you need to heat up the piece until you get to the final heat desired!
The contour fuse is a more rounded off version of the tack fuse. The edges are not squared like what happens when tack fusing.
A full fuse completely melts down multiple layers of glass so that the piece looks flat and seamless. When making pieces like dishes and bowls, etc. that have multiple design elements placed side by side, typically laying on top of one piece of base glass, you should full fuse the piece first before slumping into the mold you intend to use.
Finally, a little info about slumping glass into or over a mold. It is possible to slump and fuse a piece at the same time. If a piece has a lot of design elements, some of which could possibly move when slumping, it is best to fuse first before slumping. To slump you will need to heat your kiln up to between 1200 and 1300 degrees Fahrenheit.