If you have consistent difficulty in sliding the glass into the came, you should consider dressing the came before use. Dressing the came consists of running a fid or other hard material along each of the four flanges of the came. In doing this, you are pressing each flange in turn down against the bench or other smooth surface.
Dressing the cames gives a slight bevel or ramp for the glass to slide over the edge of the came and into the channel of the came. You can dress the whole length at once, or as you cut the pieces off from the main length. Dressing shorter pieces is less likely to bend the came.
Of course there is a second stage of dressing the lead came upon completion of the soldering.
Friday 27 March 2020
Structural Reinforcement
Leaded light panels often require additional support against wind pressure or vibration. Whether this is needed depends on the size and location, e.g. if in a door or a ventilating window that is constantly being opened and shut. Large leaded glass windows need some bracing against the force of wind and rain. This can be achieved by using one of the following supports:
- Saddle Bar
- Reinforcing Bar (Rebar)
- Steel Core or Steels
- Zinc Section
Saddle Bars are the strongest method of support and are used in large external windows for preventing panels from bowing inwards. They resist wind pressure in exposed situations. Saddle bars form part of the latteral support structure of the window. These bars are attached to the panel with copper or lead ties. These ties are soldered to solder joints across the narrow width of the panels. The bars are fixed to the perimeter of the opening either by the mouldings or by being inserted into holes in the frame. The sides of the opening provide the ancor points for the bar. The panel is fixed to the bar by twisting the ties around it.
A saddle bar fixed in position at the side and the ties being twisted around the bar. |
Sometimes the opening is divided by sideways "T" bars. Generally the leg of the "T" faces outwards and the panel is set onto the ledge formed by the leg of the "T". This leg often has a series of holes drilled in the leg, for pins to be inserted to hold the panel in place until the sealant has cured.
An example of "T" bars being used on a small side opening window |
Rebar is another external support. It generally is a zinc coated steel strap about 2mm by 10mm and asl long as needed to cross the panel. This tends to be soldered directly to the panel at the solder joints either on the inside or outside. One advantage of this material is that it can be bent to conform to the lead lines of the panel. In consequence it is not as stiff as saddle bars are.
Steel core
Steel cores take two forms - either steel-cored lead or steel strips fitted into the lead cames when leading. The steel cored lead came is less available nowadays. They are mainly used in domestic glazing where support is required particularly in leaded lights with diamond panes when they are inserted in continuous diagonal leads. The steel cores are not adaptable to significant curves.
Steel cored lead came cut away to show the steel core |
Zinc
Zinc section came is often used to frame a panel that is not glazed into a window or frame. It has been used in the past for both straight and curved lines. Using it for curves requires a came bending machine to give good, regular curves. It gives a panel strength for ease of handling, but does not resist sagging or bowing at the centre. The other disadvantage of zinc is that it corrodes much faster than lead.
Image showing a variety of zinc came |
Wednesday 25 March 2020
Scheduling to Room Temperature
Why Schedule the kiln to room temperature? The kiln will cool slowly enough at the
final stages.
How do you know?
Relatively large thick pieces need slow rates of cooling
below 370°C. Complex tack fused
pieces require slow cooling rates as well as the long annealing soaks. These
required rates of cooling may be slower than your kiln’s unpowered rate of cooling.
This means you need to know the natural cooling rate of your
kiln from 370°C down to room temperature to be sure you are cooling at a
suitable rate. The method described in this blog post gives you information on
how to calculate the natural cooling rate of your kiln.
I program my firings to about twice room temperature. Yes,
the kiln does not turn on much during that time, but when I crack my kiln
open to speed the cooling, the switching on of the relay tells me I am cooling
faster than programmed, and I can reduce the size of the opening to avoid too
rapid cooling of the piece.
The following chart is a way to assist in recording your
kiln’s unassisted cooling temperatures against time to give you the natural
cooling rate at various temperatures.
Kiln Name: | Cooling Rate | |||||
observ'n | Time (hr:min) | Temperature | Difference | rate/min | rate/hr | |
1 | : | Time (mins) | Temp. | =temp/mins | .=temp/min*60 | |
2 | : | |||||
3 | : | |||||
4 | : | |||||
5 | : | |||||
6 | : | |||||
7 | : | |||||
8 | : | |||||
9 | : | |||||
10 | : | |||||
11 | : | |||||
12 | : | |||||
13 | : | |||||
14 | : | |||||
15 | : | |||||
16 | : | |||||
17 | : | |||||
18 | : | |||||
19 | : | |||||
20 | : |
Wednesday 18 March 2020
Candle shades
These
kinds of drapes are generically known as handkerchief drops, as they form the
kind of shape that is formed by holding the cloth in the middle and letting it
drape. They can be done as small drapes
over kiln posts, cocktail shakers, and much larger forms.
Two heights of new cocktail shakers |
A well used cocktail shaker with kiln wash |
A kiln post wrapped in preparation for firing |
Two short kiln posts after firing |
When
preparing several drapes to be fired at one time you need to consider several
factors.
Higher in the kiln is hotter.
The heat in a kiln, as in an oven, is greater the higher in the kiln is
supported. This means that taller
supports will drape quicker than shorter ones. The consequence is that all the
drapes should be of the same height.
A single layer that has begun to stretch at the shoulder of the former |
Larger spans fall quicker than
smaller.
The more of the glass that is unsupported, the quicker it will fall,
even at the same height. This is because the larger amount of unsupported glass
has more mass than a smaller one and so falls quicker. Plan for all the glass to be of similar
sizes.
These two were fired at the same time. The back one is larger than the front |
Different shapes fall in different
ways.
Squares and circles are the most common shapes used in a drape. The corners of squares are points that
are further away from the centre of the support than the sides. These points begin to fall first, drawing the
sides in later in the firing. Circles
form a taco shape before the ends of the “taco” begin to fall. This deformation of the circular “taco” takes
longer than a square takes.
Care needs to be taken that the glass does not thin excessively at the
shoulder of the support. There is less
difficulty, if the same shapes are fired together as different heat work is
required for each shape.
Observation by peeking is required to
stop free drops at the right time.
As in all drapes, it is important to observe the progress of the drape
at intervals. This is best done by quick
peeks to note the development of the shape and to move to the cooling segment
when the drape is complete. This also requires a scheduling of a long soak and
knowledge of how to advance the kiln controller to the next segment of the
schedule.
Wednesday 11 March 2020
Kiln Maintenance
Switch off the kiln before doing any maintenance.
Before or after each use
Vacuum the inside of the kiln. Use a low suction setting, especially on
fibre walls and ceilings. Stronger suction is possible when cleaning a brick
floor.
Example of vacuuming around elements |
Example of vacuuming lid without elements |
An alternative to vacuuming the elements is to use the air compressor hose at low power to gently blow out any dust settled in the element grooves. Do not do this for fibre insulated kilns, only brick.
Check on the kiln furniture – including shelves, boards, supports. Are they kiln washed and without scrapes, scratches, gaps? Has the kiln wash been fired to full fuse temperature? In both cases, clean the used kiln wash off the shelf and renew.
Check that the shelves and other kiln furniture
are without cracks.
Clean kiln furniture of dust and
debris.
Check the level of any item newly placed
in the kiln - e.g., mould, or shelf replacement - with a spirit level.
When the shelf paper is exhausted lift
out the thicker papers and vacuum the shelf.
The Thinfire and Papyrus papers can be vacuumed directly or gently swept
up and placed in a container for disposal. Do not introduce any moisture to help reduce the dust. This is not good for the kiln or you, as it could induce shorting out of the elements.
Monthly
Electrical parts: check the elements
and their connections (normally at back or side).
First unplug or switch off the power to
the kiln.
Check the screws on the connectors for
the element tails are tight. Loose connections cause the
wire to vibrate at the connection during the power phase. They heat up enough
to melt the wire at the connection. For a single element kiln, it will simply
lose power. In multiple element kilns
the remaining elements work much harder to achieve the temperature and provide
uneven heating.
If the connectors are badly corroded ,
they need to be replaced. This can be
done without replacing the elements. Unscrew the connectors and put new ones
on. If the connector is fused to the element
wire, you need to cut the wire as close to the connector as possible to
maintain a length of wire for the new connector to be fixed.
Check the condition of leads and plugs
supplying power to the kiln. Make sure
they are sound, not frayed and not kinked. Replace any frayed parts. Take out any kinks in the power supply cable.
Any support pins or wires should be
firmly seated in the brick work or supported by sound hangers.
Check the level of the kiln floor and
internal shelves on a regular basis and every time the kiln and its internal
furniture is moved.
Making a schedule of maintenance checks
and noting on it the dates checked is a good idea for those who need reminders.
Wednesday 4 March 2020
Instagram as a place to sell
What it is
Instagram is a place to show work and get followers. It is a photo and video sharing site owned by
Facebook. It is a place to tell visual
stories that lead to direct message conversations that can lead to sales. But it is not a direct selling site.
Developing a body of followers is a slow process requiring
continued commitment. Audiences tend to
focus on the Instagram stories and videos. Talking to camera, showing your workspace,
showing and telling about favourite products are some of the things you can do
to make stories for Instagram. Posting these
images and videos is way to get feedback on new products by inviting people to
react.
Using it
Instagram’s value is largely as a marketing tool. It is not a place to do frequent or blatant
selling. There is a general lack of
response to posts with an overt selling message. But occasional on-line sales to a group of
committed followers seem to work. Beware of the effort and cost of packaging
and posting, though.
What to post?
Frequent posting is essential to developing and maintaining
your group of followers. Remember the
title - Instagram. Instant reporting of developments
is important. It develops the connection
between what you are doing and your followers.
The things to concentrate on are such things as how the day has gone, stories,
new venues and products. Ask questions
of followers to get feedback and conversations developing.
Some use Instagram as their main social media source. Share anything in your life that you are
comfortable with everyone knowing, and of course, how the business is
developing. In all this sharing be
yourself, have your own voice. Your
postings need to be when there is news rather than at set times. Your account becomes livelier and more
personal when spontaneous.
Images
Good photographs are essential. Photos and videos are the essence of
Instagram. Your photos need to have
clear captions. The captions need to provide the context for each image. Some
suggest that concentration should be on the captions, and then finding a photo
to fit. The captions and hashtags are
the ways people find their way to your postings. You need to think about the terms potential
customers may use to find out about your kind of work. There is no need to overload the images with
hashtags. A few well thought out terms
will give better results. Look at the
kind of tags you would use to find items of interest outside your craft. The
really important element is an emphasis on providing a story in all the
postings.
Sharing
In addition to creating content, reciprocation of likes and
comments is important. This means you
need to spend some time on the platform to help develop followers. Instagram does assist in creating a community
of followers and makers, especially if you connect with makers of similar
things and exchange supportive chat.
Time commitment
There are suggestions that 80% of your time on Instagram
should be building your brand, and partaking in the community. The rest of the
time you can tell about new products, promotions, and answering questions that
will help people in deciding on the purchase.
But, generating sales is difficult by use of only Instagram.
Location of Outlets
Galleries use Instagram too.
But it is mostly about raising awareness of their businesses, so sales on
Instagram are incidental to them. They
use it to let people know about news of the gallery and artists, their interests,
and promote their exhibitions. For them
it is about publicity.
Their secondary use is by browsing and getting a sense of potential
exhibiting artists as persons and what their expertise and audience may be. This means that getting galleries as
followers can be a way to maintain contact with galleries and get invitations
to participate in events.
How Can Glass Enthusiasts use Instagram?
It may seem the emphasis of this post is on full time craft
artists, but these things are applicable to any craftsperson who wants their
work to be more widely known and purchased.
Anyone who is going to craft fairs needs to do a lot more
than turn up with product. Many times, I
hear of people lamenting the poor attendance at an event. Or, the concern that people don’t seem
interested in buying your work.
The organiser of the craft event can do only a limited
amount of promotion. Their promotion
will be largely general and untargeted.
Your promotion will be much more targeted, because it will be directed
at your followers – an already interested audience. If you can get your followers to attend the
event, or spread knowledge of your attendance at an event, you have a greater
chance of having a good event.
In summary, Instagram can be an element in building an
audience for your glass work. This can
increase attendance of interested people at the events you are involved in, if
you put effort into getting followers who appreciate your work.
Wednesday 26 February 2020
Incompatibility or Annealing Stress?
It is sometimes difficult to determine what the cause of
any cracks might be. There are a variety
of possibilities with pot melts and other high temperature processes.
Surface of slumped melt |
Cracks only on the top of a piece indicate a stress
problem. Yes, there may have been a shift in compatibility, due to long soaks
at high temperature. It would be a small shift though, or the cracks would have
progressed to be more obvious.
Possibilities of healing the cracks
relate to the kind of stress. If the stress is from incompatibilities, there is
no means of healing the cracks. Further
firing may worsen the problem.
If the stress cracks are due to the
annealing being inadequate, a very slow rise in temperature to about 40°C above
the annealing point before going to a full fuse is required. To heal the crack,
you will then need to go to full fuse temperature. This may require dams to reduce the expansion
of the piece, if that is critical. Then follow with an annealing that has a
longer soak and slower anneal cool than previously used.
Slumping will not help. Yes, the
compression may bring the open cracks together, but temperatures are not high
enough to heal (if possible) any cracks or imperfections.
The pattern of splits on the bottom of the slumped piece |
In this case splits developed on the
bottom during the slumping. The splits on the bottom - if not due to
incompatibilities - are usually due to a too rapid rate of advance in
temperature in the early stage of the heat up.
If it is thought that the cracks
occurred as a mistaken combination of, say Bullseye and Oceanside, the stress
would have been great enough to break the piece completely. There is too
great a mismatch of these two glasses to co-exist in one piece. Of course, if only one or a few pieces were
mixed in, this kind of small crack could occur, but it will normally be around
a particular colour.
It is possible that different
manufacturers’ glasses were used in this piece. The differences in
compatibility can produce mild stress within a piece that do not break
immediately. In high temperature process
like this, the incompatibilities will be exaggerated more than in thinner
pieces fired at lower temperatures.
More detailed information is available in the e-book: Low Temperature Kilnforming.
Monday 24 February 2020
Lead Light Cement
You can make your own lead light cement as the materials are fairly common and safe to use. I have altered the original recipe through experience. Too much of mineral spirits dries out the mix so quickly that the linseed oil cracks early in its life. This results in the possibility of water leaking through the cracked cement. One third or less of the dryer (mineral spirits) reduces the chance of too rapid drying. I no longer use a drier at all. This is my modified recipe.
Recipe
7 parts whiting/chalk
2 parts boiled linseed oil
(measured by volume)
1-2 Tablespoons colorant
This can be lamp black (carbon), black poster paint, concrete colorant powders, or black oil paint in sufficient quantity to give a black or dark gray colour to the otherwise off-white colour of the whiting and linseed oil.
Do not use water based colorants, such as acrylic paint. This does not mix with the linseed oil. Instead it forms a collodial mixture that interrupts the formation of the long linseed molecular chains that make it so good as a long term sealant.
Method
Add the whiting (reserving about one quarter) to the linseed oil. Mix this well, by hand or with a domestic mixer capable of mixing bread dough. When these are mixed thoroughly, check the consistency. It should be like molasses on a cold morning - barely fluid. At this point, add the colorant, so you will know the current colour and can adjust to make it darker.
Add more whiting as required to get the consistency you want. Experiment a little to find what suits you best. If you have to deliver the panel quickly, for example, you need to increase the proportion of whiting to make it stiffer.
Comment
You should make only what you will be using on the current project, as the whiting separates from the linseed oil and sinks to the bottom in only a few days. The commercial cements have emulsifiers to keep the whiting from settling and so extend the life of the product. Since making your own is cheap and quick to make, there is no saving in making a lot.
Lead light cement is a simple, inexpensive sealant for leaded glass that you can make for yourself.
Recipe
7 parts whiting/chalk
2 parts boiled linseed oil
(measured by volume)
1-2 Tablespoons colorant
This can be lamp black (carbon), black poster paint, concrete colorant powders, or black oil paint in sufficient quantity to give a black or dark gray colour to the otherwise off-white colour of the whiting and linseed oil.
Do not use water based colorants, such as acrylic paint. This does not mix with the linseed oil. Instead it forms a collodial mixture that interrupts the formation of the long linseed molecular chains that make it so good as a long term sealant.
The mixed leaded light cement |
Method
Add the whiting (reserving about one quarter) to the linseed oil. Mix this well, by hand or with a domestic mixer capable of mixing bread dough. When these are mixed thoroughly, check the consistency. It should be like molasses on a cold morning - barely fluid. At this point, add the colorant, so you will know the current colour and can adjust to make it darker.
Add more whiting as required to get the consistency you want. Experiment a little to find what suits you best. If you have to deliver the panel quickly, for example, you need to increase the proportion of whiting to make it stiffer.
Comment
You should make only what you will be using on the current project, as the whiting separates from the linseed oil and sinks to the bottom in only a few days. The commercial cements have emulsifiers to keep the whiting from settling and so extend the life of the product. Since making your own is cheap and quick to make, there is no saving in making a lot.
Lead light cement is a simple, inexpensive sealant for leaded glass that you can make for yourself.
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