Contents
1
- Squaring panels
2
- Wide edge cames
3
- Mitred Corners
4
- Tucking Cames
5
- Growing Panels
6
- Weaving
7
- Bending wide cames
8
- Leading small circles
9
- Leading Nuggets
10
- Leading tight curves
11
- False Lines in Leading
12
- Silhouettes in leaded glass
13
- Sculpting the came
14
- Copper foil in leaded panels
1
- Squaring panels
When
building leaded glass panels to be placed in existing wooden frames,
you need to make sure the panel is as square as the opening in the
frame. The first requirement is to make sure your cartoon is squared,
or has right angles at each corner.
I
use a “roofing iron” as it is called in the UK. It is a steel
tool about 600mm on one side and 400mm on the other. Its original use
was to work out the pitch of roofs and check the same pitch was
maintained all along the building. The first important thing – now
that all roof trusses seem to be prefabricated – is that they still
are in production. The second thing is that they all have a fixed
right angle.
 |
| Roofing Square |
Using
this roofing iron will ensure your corners on the cartoon are right
angles. This helps in the drawing of the cartoon as you only need set
the iron on the base line and draw the verticals without having to
measure the width higher up the cartoon. Of course you should check
that the width is still correct at the top, just in case there has
been a slip.
Then
you have to stick to the cartoon.
When
you are setting the battens to ensure the sides are held where you
want them while you continue with the leading, the roofing iron again
will ensure that you have placed the battens at right angles. You
choose which line is to be your base, and nail or screw the batten
into place. Ensure it is exactly parallel to your cut line and then
align one side of the iron against it. Place the other batten snugly
along the length of the other leg of the iron and you know you have a
right angle.
When
you are completed leading, but before soldering you can check on the
accuracy of the angles by using the roofing iron again at each corner
to check on the “squareness” of the whole panel. If the panel is
out of square, you can tap on the battens not yet nailed/screwed in
place to ease it all back into “square”
2
- Wide edge cames
The
purposes of large perimeter cames are several.
Easy
adjustment on site. It is often the case that windows are not
totally regular in their dimensions, even though you have taken the
measurements carefully. Variations in width and height can be
accommodated by shaving the lead in appropriate places. This avoids
having to take the panel back to the studio to reduce the size of the
glass and put new perimeter came on the panel.
The
width of the rebate has an effect on the width of the came to
be used. The wider the rebate, the wider came you will want to use.
The minimum width of came you want to use with a 10mm wide rebate is
10mm came. This will give a maximum of 2.5 mm of came showing if you
have a glazing allowance of 5mm. Often 12 mm came is better. In
general the came should be wider than the rebate is, but not so wide
that the heart of the lead is outside the rebate. In church windows,
where the panels are installed into the stone, the cames are
frequently 16mm or 25mm wide to accommodate the variations in width
and the flexibility needed to get the panels into the slots.
Aesthetics
have an effect on the width of the perimeter came too. Various people
want more or less came showing. The important limitation is that the
heart of the lead should be within the rebate.
In
autonomous panels the need for large edge cames is to act as a
framing device. Zinc might be used but there are other possibilities
than using a different metal that will provide as good or better
solutions.
One
option for framing, especially on edges of rectangular panels is to
use lead. The lead touching the glass or copper foiled edge should be
10mm flat came. This allows you to insert a 5mm mild steel rod which
is then covered by a 13mm flat came. The came leaves are smoothed by gentle
pressure on the upper and lower flanges with a stopping or lead knife
to bring the two flanges together. This gives a pleasant finish to
the edge.
3
- Mitred Corners
 |
| Completed Mitred Corner |
There
are various ways to determine where and at what angle to cut the lead
came, especially for panels with more than four corners. The most
common is a four cornered panel. The following method works for that
circumstance very well.
My
preference is to use the battens surrounding the cartoon as a guide
for the placing of the mitres on the first two cames. The battens
are placed
around the cartoon to suit the came width. The vertical came is
placed in contact with the bottom came.
 |
| Setting the perimeter batten |
A
short piece of came – ca. 50 mm – is placed on the external
cartoon line almost in contact with the vertical lead. A second short
piece is placed on top of the short piece and extended over the top
of the side lead.
Mark
the lead lightly with a nail or pencil. Cut the angle from the inside
to the outside corner. This will form a 45 degree angle.
 |
| Lower came marked for cutting from corner to line opposite |
You
can do the same for the bottom came, by removing the vertical came
for the time being and doing the same operation on the horizontal
came. Then they can be place back together for the next operation.
To
determine the length of the came which is already mitred on one end,
put the came in place on the cartoon.
Then place a short piece of lead on the cut line which is at right angles to the came to be measured. Then place a short piece over the two cames as for the first mitre cut.
A
nail or other pointed implement is used to scratch a line on each
side of the overlapping lead. When this overlapping lead is removed,
a diagonal is drawn from the inside mark to the outside mark. Cut
along this diagonal.
There
are other methods for panels with more than four right angles.
4
- Tucking Cames
It
is most usual in many countries to butt lead cames against one
another. In continental Europe the tucking of cames is more common.
In this process, which has the advantages of speed and accuracy, the
came is first fitted to the glass and then cut at the edge of the
glass.
The
first step is to cut the came to the appropriate angle to meet the
lead to which it is to be joined. However before presenting the cut
came to the joint, one end is lightly tapped with a small hammer to
slightly curve the end of the came. This allows it to slip inside the
leaves of the came to which it will be soldered. [overlap-leading]
The
came is then shaped to the glass as normal. However, rather than
removing the came for the next cut, the came is cut to the length of
the glass, often using the glass as a guide. This end is then
supported on the lead knife and tapped with the hammer to curve the
end, ready for tucking into the next piece of came. Care is required
so that you don’t crush the came and break the glass, nor miss the
came and hit the glass or your fingers. With practice, there are few
accidents.
Diagrammatically,
the tucked lead looks like this
 |
| Leads tucked into the perimeter came |
Tucking
lead provides very accurate joints with no gaps for solder to fall
through. Some argue it provides a stronger panel as the hearts of the
jointed cames almost meet. The main immediate gain is quicker
soldering.
5
- Growing Panels
What
can be done to keep leaded glass panels from growing beyond their
original cartoon lines?
I
find that most people, who are not used to lead came, cut the
crossing pieces too long so the whole panel grows. Each piece of came
that is a fraction too long pushes the passing came out, making the
glass apparently too large. Of course, this is an occasion to use the
tucking method to reduce this cause of enlarging the
panel. You can and should make sure that you have pressed the came
snugly against the glass.
If
the next piece of glass you place goes over the line allocated to it,
something is wrong with the previous piece. Undo the came and check
the size of the glass against the cartoon. If the glass fits inside
the lines allocated, the problem is the way you have fitted the came
to it.
 |
| Pressing along the heart of the lead with an All Nova tool |
Another
check you can do is to run a felt tip pen at the side of the came
onto the glass. Take the glass out and examine the space between the
line and the edge of the glass. This will tell you where the glass
and came are not fitting equally. A narrow space does not immediately
mean the glass is too large, it may mean the came is not tucked
against the glass properly. So check that first, before any grozing or grinding.
 |
| Oversized piece marked against the came |
 |
| Glass piece removed from the came to observe the area that needs trimming (where the nail points) |
Nails,
push pins or other things that you can push into the work board will
keep things stable. If you are working with a rectangle you can use
wood battens. If not, multiple close spacing of nails will help. Also
you could cut a piece of glass into a shape that will hold the
outside of the panel.
6
- Weaving
"Weaving"
is only easily and fully done where there is a grid. The example
below shows a restoration project where the main part of the panel is
a grid.
[photo
weaving 1-3]]
This
image shows the starting of the weaving. A short lead covering only
one quarry has been placed horizontally - although you can start with
a short vertical, both are fine. The next lead is vertical and covers
two of the quarries. As you can see here the two quarries at the
right are ready for the longer horizontal to be placed.
You proceed in this fashion - alternating long and short leads throughout the grid area.
As you can see this builds up in a diagonal fashion with each vertical and horizontal line being interrupted after every second piece of glass.
If
you look closely you can also see that these leads are being tucked.
This is easier with leads of 7mm and greater than of 6mm and less.
This
method of leading gets its name from the similarity to
representations of weaving in illustrations where a broken line
represents the thread or reed going under another. Its purpose is to
avoid hinges and so strengthen the whole panel. This avoidance of
hinges makes the turning of the panel during soldering and cementing
much easier.
Of
course, you must remember that the glass is still the strongest part
of the panel.
7
- Bending wide cames
The
way to bend larger leads such as flat outside leads around pieces of
tracery or other curved shapes in window panels is to lay the lead
upon the bench, and use a curved, preferably wooden, lathekin or
oyster knife.
Progressively
manipulate the lead into the curve. Hold the lead steady by keeping
your fingers spread on the top and back of lead and manipulate the
curve between your extended fingers. Gently push the curved lathekin
along the heart of the lead with small, smooth, circular strokes.
Smooth the lead flanges by pressing down on the flanges on the inside
of the curve as you go. If you try to do it too quickly the lead will
probably buckle.
Frequently
turn the lead over, applying the process to both sides.
If
the flange crimps or buckles, put smooth jawed pliers inside the lead
and squash the flange flat. The pliers can be used to flatten any
kinks that develop in the lead.
The
key is to handle the lead gently and in stages, gently flattening the
complete lead and not flattening completely one spot before moving on
to the next.
The
advantage of round over flat in this circumstance is that round came
of the same size can be bent into smaller curves than the flat came
of the same width.
The
technique for finishing a curve around a single piece of glass is
given next.
8
- Leading small circles
Putting
came around small circles such as lenses and small bullions often
leaves an irregular curve. There is a way to avoid this.
Use
oval or round came to reduce the kinking of the leaves of the came.
As there is less material at the edges of the leaves of oval came,
there is less kinking than on flat came, where the thickness of the
leaves is constant.
Begin
to form the lead round the circle, about half way. Then take the
circle out of the came and cut, at a right angle to the length of the
lead, at an angle from top to bottom. The degree of the angle is not
important at this stage, only that you can repeat the angle – so it
must be fairly shallow and natural for you.
Put the circle back into the came and continue to form the came round it until you meet the angled cut at the beginning. Again at right angles to the length of the came, cut a repeat of the angle.
[photo]
Then fold this end toward the other end. Push the two angled ends together. If they slip up and down from each other, the came is too long. Open the came and cut a sliver off.
Try again until they meet with very little “slippage”.
Then the piece is ready to put into the panel. Place the join at a lead joint so you don't have an additional solder spot.
This
technique can be used for small ovals too.
9
- Leading Nuggets
This
is a special case of leading small circles. To use nuggets in leaded
glass panels, just wrap the came round the nugget. If the came leaves
are oval, it works better than the flat. If the nugget is thick and
does not want to fit securely in the channel, you can also use a fid
to open up the top leaf of the came.
10
- Leading tight curves
When
leading tight inside curves, it helps to bend the came into a tighter
curve than is needed for the glass. Then roll it into the glass.
Finally, run your fid or stopping knife along the heart of the came
to ensure it is firmly against the glass. All this helps the came to
fit snugly into the curve.
11
- False Lines in Leading
False
lines are used in leaded glass where the design calls for an angle
that cannot be cut into the glass. This includes right angles and
even more acute angles. E.g., the petals of a fuchsia flower. The
design would call for an angle of about 60 degrees. This is
impossible to achieve through cutting. So the glass is cut in a curve
and the cames on the side and bottom of the petal have their hearts
cut out so they overlap each other. The overlap is then trimmed to
the shape of the outside of the petal. When soldered, the appearance
is of the glass being cut at the angle required for the flower.
At
other times, the requirement is for a line to go into a piece of
glass, but not all the way across. Again you cut the heart out of the
came, and overlay the smoothed lead onto the glass. You can use just
a little silicone to hold the lead in place until you finish
cementing. After this you can lift the piece of came and use silicone
or epoxy resin to firmly attach the came to the glass. You do not
want to do this before cementing as any excess of glue will be made
dirty by the cementing process and be very difficult to clean up.
12
- Silhouettes in leaded glass
There
are times when you may want to have a silhouette. You could use a
dark piece of glass, or if it is a complex shape you can cut it out
of lead foil or thick copper foil and solder it into place. This
allows intricate shapes to be made when a dark representation of the
shape is required. If the panel can be seen from both sides, the
overlays should also be on both sides. These should be glued to the
glass just as for cames.
These
principles can be applied to copper foil too.
13
- Sculpting the came
It
is not essential that the came always have parallel edges. In some
cases you may want to have tapering cames to represent perspective.
This can be done simply by trimming the flanges of the lead so it
gradually thins, possibly to meet a thinner lead at a joint. Both
sides of the lead came need to have the same trimming. You can also
create an irregular shape to the edge by carving out portions along
its length. The permutations are numerous.
In
all these cases this should be done after soldering but before
cementing, as you will leave a track of putty at the previous edge
which will need additional cleaning. Of course, if you don't mind
that extra cleaning, you can do the sculpting after cementing, but
probably before polishing, so any scratches from slips of the lead
knife can be polished out in one operation.
14
- Copper foil in leaded panels
It
is possible to combine copper foil in a leaded glass panel.
The
copper foiled piece should be soldered before inserting it into the
lead came. In this way the soldered together pieces become very like
another piece of glass.
There
are some special considerations, of course.
The
copper foiled piece should be designed as though it were a single
piece of glass and so can be accommodated into the surrounding pieces
of glass.
The
copper foiled piece should not have severe undercuts which would make
it difficult to insert into the surrounding glass. It may be
necessary to incorporate a piece of the surrounding colour to make it
fit into the panel.
The
copper foiled piece should be finished with all the beads on both
sides. If one side is left flat, it will collect water if on the
outside, and catch on any cleaning processes whichever side it is on.
However, the piece should be tinned only on the outer edges. This
will ensure that the copper foiled piece will slip into the came.
The
image below illustrates a copper foiled piece incorporated into a
leaded panel.
This
section of the panel shows the accommodation of the main leaded panel
with the copper foiled piece with a line from a petal to a leaf.
Otherwise, it was fitted as one piece.
