The
very cheapest hair spray works well with glass paint, if you need to
transfer your painted glass to another place for firing. Complete the painting and then spray with cheap hair spray as you would to fix
a charcoal drawing. This will hold the paint firmly during transport
and does not affect the paint during firing.
Glass Tips
A collection of hints and tips gathered from many years working with stained glass, kiln formed glass, acid etching, sandblasting and other areas
Wednesday, 15 May 2013
Friday, 10 May 2013
Tracing on Opalescent Glass
Opalescent
and dense glass presents problems as the usual method of tracing the
image through the glass is not possible. If you first spray the
glass with a cheap hair spray, this gives a “toothed” surface to
the glass. Then using carbon paper an image can be transferred.
However, the carbon paper leaves a greasy residue, so water based
paint will not take, but an oil medium will.
Sunday, 5 May 2013
Matting
Oil,
and Water and Gum as Media for Matting by Dick Millard [edited from a
discussion]
Oil has been used, I believe, since the 16th Century, and certainly up through the 1970's to today. It is used wherever it is determined it should be used, and one is sufficiently informed and facile to use it in a manner of delivering its full and lovely potential.
First
of all, oil is not characteristically employed as a matt, out of
which, by the negative process, one "takes out lights". In
overwhelming instances, with which I am acquainted, it is used as a
shading material applied over a pre applied and "worked"
under matt of water and gum base.
This
provides the required "tooth" to provide both a degree of
adherence and ease of application.
So,
I would suggest an oil matting, or a shading application over a
smooth glass surface, would be generally problematical!
Add
a bit more gum to your water under matt which will reduce the
necessity to fire that matt, which changes the character of the
desired "tooth". The purpose of the "tooth" to
receive the oil matt is also to provide "porosity" as an
"absorbant", which additionally holds the oil mixed paint
to the matt. Otherwise, the oil remains too liquid and does not float
in a controlled fashion. It will require a much dryer application of
kerosene, or increased absorption by additional blending.
I
had a large landscape piece, hills in the back ground, that I matted
and applied an alcohol mat too, but I was lifting the water mat
trying to cover it with alcohol, so I added more gum to my mat and
that did the trick. I also used a very soft Chinese brush. I have
found that firing the mat first and looses tooth.
I
have noticed over time that some people seem to have the impression
that the less gum used, the better. I advise not to use an excessive
amount of gum arabic, as a soft matt, with a soft touch produces a
soft look. This is interpreted to mean 'less is better'. That is
true, but only up to a point. If too little gum is used, or none, it
will come off as if it were flour or mud diluted with water and
applied. Too little gum severely jeopardizes any opportunity to
produce soft gradation from the highlight to the untouched matt.
Tuesday, 30 April 2013
Tracing with a Pen
![]() |
| Example of a pen nib |
Using
paint mixed with essential oil or turpentine and with a fine mapping pen for small lettering
works well, as the oil flows better than water. Although with
practice, a water based paint can be used with a pen, but it is a
little tedious as the pen has to be loaded frequently with a tracing
brush and constantly cleaned as the water dries quickly.
Thursday, 25 April 2013
Radiating Lines
In
designs for leaded and copper foiled glass it is important to avoid
lines radiating from a single point. Some of these reasons are:
It
is important to reduce the number of lines that meet in any design to
avoid a big bright solder place in a panel.
It
makes for large solder blobs, especially on leaded glass panels, and
therefore provides a focus where one may not be wanted or required.
The
difference between the harder solder and softer lead came leads -
over time - to cracks in the lead at the edge of the thick solder
blob.
In
leaded and copper foiled glass it is a point of weakness, as there
are likely to be multiple thin or tapering pieces of glass that are
liable to fracture early in the life of the panel.
Methods
of Avoiding
![]() |
| This umbrella image avoids long narrow pieces by having the ribs and supports crossing to make short narrow pieces |
Narrow
tapering pieces can be compensated for by making the narrow parts
shorter than the wider parts of the taper – although this does add
to the density of lead and solder around the termination point.
There is a difficulty in adapting single radiating points in a
drawing to the practicalities of the medium of glass. Examination of
older panels (in either technique) will show some of the problems of
thin tapering pieces. It is obvious in older windows, especially in
the Victorian Era, when tapered pieces where in their glory. Almost
always, the tips are broken. It is the nature of glass, and goes
back to knowing how the medium will react to the conditions you
create.
Good
design will avoid multiple radiating pieces from a single point of
origin.
It
is not possible to make a neat termination by joining half a dozen
tapers at one point. The finished piece will not look like it did
when it was drawn out with a pencil. You can pencil in a termination
with six points, ending at one point and it may look good, but when
you draw the design with the width of the led or foil will show the
clumsy nature of the design with a large termination point.
As
you can see, the answer starts with the design, before you cut and
foil, or fit the came to the glass. Art is not about the physical
placement of what you see in your mind, as much as it is about the
"illusion" you are creating that you want others to see.
That starts with the design, and avoiding something that you know is
going to give you a problem.
It
is not possible to make a neat termination by joining half a dozen
tapers at one point. The finished piece will not look like it did
when it was drawn out with a pencil.
You can pencil in a termination with six points, ending at one point and it may look good, but when you draw the design with the width of the led or foil will show the clumsy nature of the design with a large termination point. As you can see, the answer starts with the design, before you cut and foil, or fit the came to the glass. Art is not about the physical placement of what you see in your mind, as much as it is about the "illusion" you are creating that you want others to see. That starts with the design, and avoiding something that you know is going to give you a problem.
![]() |
| Example of a design that will present difficulties at the centre |
You can pencil in a termination with six points, ending at one point and it may look good, but when you draw the design with the width of the led or foil will show the clumsy nature of the design with a large termination point. As you can see, the answer starts with the design, before you cut and foil, or fit the came to the glass. Art is not about the physical placement of what you see in your mind, as much as it is about the "illusion" you are creating that you want others to see. That starts with the design, and avoiding something that you know is going to give you a problem.
Tuesday, 23 April 2013
Aperture Drops Blank Sizes
As the glass drops through the aperture, it stretches, but the whole substance of the piece is drawn toward the hole. If there is not enough spare glass around the hole, the whole piece will be drawn through the aperture.
There is a minimum size of the glass in relation to the size of the drop out hole. Up to some maximum size, the greater the diameter of the hole the
greater the amount of spare glass there needs to be.
greater the amount of spare glass there needs to be.
Also relevant is the depth of the drop. A shallow drop needs only a few centimetres larger than the hole. While a deeper drop needs a greater amount of glass surrounding the hole.
I have found that for a 300mm diameter hole, with a 150mm drop the glass needs to be 35mm larger all around. Thus an aperture of 300mm needs to be at least of 370mm diameter for this 150mm drop. I have done drops with 550mm diameters with only a 650mm diameter blank. This indicates to me that there is an amount of spare glass that will be sufficient even for larger diameter drops, but I have not found it yet.
One element that can reduce the size of the blank is to make an inclined collar around the aperture of the drop mould.
This idea is based on the observation that as the glass begins to fall through the aperture, the outer edges of the glass rise from the mould surface so the glass is resting only on the inner edge of the drop out mould.
This inclined drop out mould will be like a shallow bowl rim, but without a bottom. The glass blank then rests with only its outer edge on the collar. When the temperature increases to the point that the glass begins to slump, the glass will conform to the slope and so create enough friction to restrict the glass from falling through the aperture, although it is with a smaller than normal rim. The actual size of the rim for each size and depth will need to be determined by experience.
More information can be found here
Saturday, 20 April 2013
Temporarily Securing Panels
When installing panels into an window
opening or frame, you often need to secure it while you finish
puttying or use other forms of weather proofing.
If you use sprigs (headless nails) or
even carpet tacks, use them where there are leads meeting the
perimeter. There us less chance of a stray hammer strike hitting the
glass. It is more likely to strike the lead and so cushion the
impact to the panel. I also use a straight putty knife behind the
nail or sprig to avoid even the chance of a strike directly on the
lead.
These precautions, with suitable
modifications, are applicable to copper foiled and fused panels.
Monday, 15 April 2013
Initial Heat Up Rates
![]() |
| Example of a graph of a heat up for industrial purposes |
There is quite a lot of information on
the annealing cool rates, but not so much on the initial heat up
rates. This is probably because the cooling rates are more critical
than the heat up. But everyone knows that you can heat the glass up
too quickly for its thickness.
My experience leads me to suggest some
heat up rates to 50C above the annealing temperature for circular and
nearly square full fused pieces. These have worked for me, but of
course, may not work in all kilns.
6mm heat up at 160ºC/hr
12mm heat up at 110ºC/hr
19mm heat up at 50ºC/hr
25mm heat up at 30ºC/hr
In general, these heat up rates are no
more than twice the initial annealing rate for the relevant
thickness. That is, the initial anneal cool for 6mm is 80C/hr; and for 12mm is 55C/hr. When you get to 25mm, my initial anneal cooling rate is only 15C/hr. So you can see how the doubling of the initial anneal cool works.
Tack fused and pointed pieces require
much more careful heating because of the differing thicknesses within
the piece, or the relative narrowness of one end or area in
comparison to other areas. The suggestion is that the heat up for
these should be at the rates suitable for items at least twice as
thick as the thickest part of the tack fused or tapered piece.
Wednesday, 10 April 2013
Grinder Bit Height
If your grinder bit is too low or too
high the diamond surface will not grind the whole of the glass edge.
This can lead to chipping of the surface of the glass at the edges.
A good practice is to start with the
bit as high as possible to allow for differing thicknesses of glass.
As high as possible is with the bottom of the diamonds just below the
platform of the grinder. This will ensure that you can deal with
varying thicknesses of glass without immediate adjustment. You can
then lower the bit as it wears.
Of course, you need to ensure there is
adequate water reaching the grinding bit to avoid overheating the
glass, and to keep the dust from grinding from getting into the air.
Friday, 5 April 2013
Mobile Glass Storage
Sometimes
people consider placing their glass storage onto wheels. It
is better to avoid wheels on glass storage for several reasons.
You
would need heavy duty wheels to cope with the weight. Glass is 2.5
times as heavy as water, so it does not take much volume to make a
really heavy glass case.
You do not need to move all your glass at once - a piece at at time is all that is needed. It will be safer, and in the end easier, to build your work bench nearer the glass.
There
are risks breakage while moving. The heavy glass store will vibrate
the glass within the storage, and any snags or obstructions while
moving the glass will increase the risk of breakage.
The
structure can become too heavy to move and so defeat the original
intention.
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