KERAMIC STUDIO 
m 
GLASS FIRING (Concluded) 
Laura Holtz 0' Neill 
A LEVEL is as necessary to the person who fires glass as 
-**• it is to the surveyor or carpenter. Perhaps when 
your kiln was new it was perfectly level, but try a level on it 
now and you will find how irregular it is. I always have on 
hand plenty of platten or firing boards. Two sheets of platten 
placed on the floor of your kiln will serve the double purpose 
of protecting your glass and of leveling the surface on which 
you are to place your glass. You can use small pieces of platten 
or if you need thinner pieces use firing board or if it is to be 
raised still less you can use asbestos shavings placed under 
these sheets of platten until your floor is perfectly level. The 
idea of this is that your glass will be less inclined to bend out 
of shape, if it stands perfectly straight. 
Glass cannot be stacked as we do china with stilts or firing 
board between, therefore it is not possible to get as many 
pieces in the kiln and the price for firing should be double what 
is charged for china— for instance the price of firing goblets 
or good sized tumblers should be twenty cents instead of ten 
cents, the usual price for same pieces of china. The price 
for larger pieces should be in same proportion. 
When glass about which you know nothing, as to its firing 
qualities, or the decorating of.it is brought to you to be fired, 
always put a few pieces in with it that you know are safe to 
fire. I place one of my pieces, on which I can depend, in the 
back of the kiln and one in the front, if both of these pieces 
come out with a good glaze and the stranger's glass comes out 
unglazed you will know the colors she used were not sufficiently 
fluxed. If your pieces come out straight, clear and sparkling 
and the others come out bent, frosted or in any way defective, 
you can feel sure that the fault is not yours but in the compo 
sition of the glass. 
When you fire glass for anyone it is just the same as in 
firing china, at the owner's risk. You have performed your 
part carefully and your test pieces show it is no fault of yours. 
Glass firing requires much closer attention than firing china. 
You have intrusted to you the firing of all kinds of glass, the 
one who brings them to you should take that risk and not 
expect you to be the loser of the price of the firing. 
I have been told by persons who are not experienced that 
glass requires so little heat it must be done quickly and must 
require but little oil. I do not find it a quick process. I turn 
the oil on very gradually so it is over an hour before the kiln 
begins to show any signs of being red. After I seethe least 
hint of red I place a chair where I can sit and watch through 
the mica of the door until the glass is fired. It consumes about 
two-thirds as much oil as for firing china. In firing jugs with 
handles, and flat on the bottom, you should place a sheet of 
platten or firing board against the side of the kiln and let the 
handle rest against it, it will serve as support to the handle which 
is usually pretty heavy and might crack the jug unless sup- 
ported. To protect the bottom of the jug, or any flat bot- 
tomed article, place two triangular bars under it which gives 
a circulation of air underneath and is a great protection. These 
triangular bars come in about six and ten inches in length and 
are useful in many ways. 
In firing goblets or any articles that have a heavy top and 
slender stem I usually turn them upside down. I always wipe 
off the gold edge even if there is a gold band at the top for it 
is so much safer to fire these articles upside down and the gold 
edge might be marred and it is equally pretty to have the 
clear glass edge. 
When there is a compote or any fancy piece with a rolled 
rim and the stem supporting it is very delicate, you can use a 
couple of same height vases or anything on which you can rest 
the ends of two triangular bars and let the article to be fired be 
suspended from these bars by placing the bars under the rolled 
rim. However I find many beautiful dishes of this nature 
that have good substantial standards which it is safe to fire 
standing upright in the kiln. But if the edge is not a rolled 
one, they can be turned upside down like a goblet. 
The easiest firing I ever did was when I was getting my 
glass ready for the St. Louis Exposition. There was an acci- 
dental little opening in the muffle of my kiln, in exactly the 
right place to form a torch by which I could see perfectly all 
the developments of the decorations on the glass. I could see 
the gold turn from a dark streak to a shining line of gold and 
the instant there was a glaze on the colors I could see it; but 
these conditions only come occasionally, so I will tell as well 
as I can, just how I judge when to turn off the oil or gas. All 
the glasses shown in this illustration, excepting two, were fired 
in a Revelation kiln No. 6. The other two were fired in a gas 
kiln. 
When firing glass our instructions have been to use Cone* 
022, but I have not found it necessary to fire until the cone 
bends over as we do in firing pottery. If I am firing imported 
glass I fire until the cone lacks just a trifle from being perfectly 
vertical. If I am firing American glass I place the cone in the 
hottest part of the kiln, where I can see it when looking through 
*Firing cones may be purchased from Prof. Orton's School of Ceramics, 
Ohio University, Columbus, O. They cost 1 cent apiece. 
