164 
KERAMIC STUDIO 
HOW I DO MY GLASS FIRING 
D. M. Campana 
IF you wish to use somebody else's experience, if you wish to 
do as successful people do and have good results, begin 
correctly and have the necessary equipment on hand before 
you start. 
Bear this point in mind. A carpenter needs the proper 
tools, so does an architect, a painter, or a blacksmith, and you 
will also find yourself hampered if you do not have the neces- 
sary articles to carry out your glass firing in a safe way. 
I spoiled many a dozen of fine glasses for that very reason, 
and having now everything in the proper place I spoil none of 
them. Every piece comes out of the kiln perfect in shape and 
as bright as a diamond. Follow my advice and you will be 
surprised to see what beautiful effects can be worked out on 
glass ware. 
In my experimenting or glass killing, I happened to re- 
member that in Venice glasses were fired within an iron-drum 
and following this idea I made myself a protecting Muffl,e (as 
I call it) with removable shelves, and made it in such a way that 
the heat of the Kiln can spread easily around it, giving an even 
temperature to top, bottom and sides, making the glasses per- 
fectly safe. 
I give an illustration on this page of my Muffle and of 
the way I work it with removable shelves, and even with space 
for hanging two or three glasses. It is very helpful and since 
I use it I have never spoiled a glass. I would call this Muffle 
a necessary part of the Glass Decorating equipment. 
I can place it into the kiln when I fire glass and take it out 
when I fire china. Of course, I place my glasses after the muffle 
is in the kiln and made solid and stable on its feet. (See that 
it stands straight on its feet.) 
Previous to this, I had tried to protect the bottom and 
walls of the kiln with iron, asbestos, etc., but found always 
difficulty, and uncertainty. Sometimes the result was good 
and sometimes bad. 
I place my glasses here and there, the thin stem glasses 
right in the centre of the muffle, on the middle shelf, my thicker 
and low glasses on the lower shelves or in any other place. 
I never place hollow glasses, such as goblets, tumblers, etc., 
head down, but stand them on foot. I am careful to have my 
shelves very flat, and if they warp occasionally, I make them 
straight again. This is very important, as crooked flooring 
will make your glasses crooked at the foot. A good piece of 
stacking board, or a perfectly straight piece of sheet iron will 
do well. 
Do not allow one glass to lean against another, and of 
course do not stack glass, do not use stilts, or have any sup- 
port. When your glasses are well placed and touch neither 
glass nor the walls of the muffle, close the door and start the 
fire. I let go full blast at once. 
It is difficult to give any definite time for the firing of glass, 
as much depends on the flow of your fuel, on the weather and 
on the size of your kiln. If you have fired china, you know 
about how long it requires for your kiln to begin getting red. 
When it begins to show a low red glow, be on the look-out. As 
to fire tests, I have tried fire test 0.22, which is the softest 
of all firing cones, and found it a little too hard for general 
use. I have tried zinc pyrometers and found them a little 
too soft, I have tried a piece of common glass as a fire test, and 
could not quite depend on it, but in all this experimenting I 
learned that a very good way to determine the time to stop 
is when I can see right through the glasses in the kiln, in 
other words, when glasses look transparent. 
In looking through the peep-hole when the red glow begins, 
your decorated glasses look black, gradually they lighten up 
and become hazy-dark, and then a little lighter until you can 
see through them. This is the time to stop your fuel and promptly 
open the door of your kiln about one inch or two and leave it 
open. This opening of the door will stop the after heat, will 
keep your glasses firm, and will injure neither kiln nor glass. 
I do my firing in a place that can be made dark at the pro- 
per moment, as in the dark I do not become confused when 
I look into the kiln, and my eyes have in this manner become 
correctly accustomed to the dark red glow inside the kiln. 
All these small points, apparently of little consequence, 
give me the results. I have said that I stop firing when my 
glasses look transparent and I wish to warn you also that it 
is far safer for you, in the few first times you fire glass, to stop 
your firing a few minutes before the glass can be seen right 
through. You will gradually learn by yourself, provided you 
observe closely, to remember the shade of the dark red glow 
required. 
The little opening of the kiln door will not injure your 
kiln nor the glasses. In fact, for curiosity's sake, I have several 
times opened the door wide, while the glasses were red hot, 
and with a flat spoon drawn out glasses without having break- 
ages. However, you should not open the door more than one 
or two inches, this being all that is necessary to stop the after- 
heat. 
