Some
framing options for free hanging stained glass panels are given here. They are not exhaustive, of course, but do give some principles to be considered when making frames. Wood and metal are the two traditional materials for framing panels to be hung.
Wood
A wood
frame requires joints of some kind. These joints are important to
the durability of the frame. The two main kinds of joints are glued
and screwed.
Glued joints
Lap joints seem to be
strongest. An odd element relating to the strength of this joint is
that placing a wooden pin in the joint weakens, rather strengthens
the lap joint.
Mortice and tenon is also
a strong joint. It requires considerable skill to make a good joint.
A mitred is among the
weakest, but can be strengthened with a biscuit or fillet in the
joint.
A mitred joint with biscuit ready for glueing. |
Screwed joints
These have a lot of
movement before failure, but do give a lot of resilience to the joint
as they can stretch rather than immediately give way. They also can
be used with any of the glued joints if appearance is not of prime
importance.
Frame style
The
width and thickness of the frame are interrelated – thicker
frames (front to back) can be narrower, thinner frames need to be
wider. So the desired appearance of the frame width has a
significant effect on the dimensions of the frame.
Metal cames or angle
Lead can be an
adequate framing material, but if strengthening is required, you can
use copper wire within the came and fold the leaves closed over it. You can also use steel rod within the came, as shown in the posting.
Zinc is a stronger
metal than lead – about 8 times, but still has a weak tensile
strength. I corrodes easily, but accepts solder as a joining method.
It is more expensive than lead.
Some of the variety of zinc came available |
Aluminium is a
little stronger than zinc, but does not take solder. It has similar
costs to zinc.
Some of the aluminium profiles available |
Copper is about 1/3
stronger than zinc and also takes solder. It corrodes to a
verdigris, but can be protected by clear varnish or paint. It is
more expensive than zinc, but can be used as wire which is less
expensive than other forms of copper.
Brass is over two
times stronger than zinc and also takes solder. It resists corrosion
well, and is a little cheaper than copper.
Some of the brass came options. |
Mild steel is over
3 times stronger than zinc, but does not take solder at all well. It
is relatively cheap and welds easily, making it a good framing
material, although a method of fixing the panel into the frame is
required.
Stainless steel is
about 4.5 times stronger than zinc, but does not take solder and
needs special welding. It resists corrosion very well, but is
expensive in relation to zinc.
Hanging and fixing
options
Two point hangings are the
most common as they prevent twisting and distribute the weight to the
sides of the panel.
The hanging material is straight up from the zinc framed sides to the fixing points |
The hanging material
whether line, wires or chains should be straight up from the sides to
two separate fixing points. A triangle shaped hanging puts a bowing
stress on the panel or frame.
A variation where the chain is taken to the corner of the window, is less secure, as it stresses the joint away from the sides |
Loops or holes for screws
should be placed in the frame rather than the panel.
The hanging is from reinforced corners directly to fixing points on the overhead beam |
Ensure the fixing points
for the hanging wires are sound and secure.
If the panel is fitted
tight to the opening, consider ventilation requirements to reduce
condensation between the primary glazing and the hung panel.
No comments:
Post a Comment