Reclaiming Solder

Re-using solder can range from simply soldering the ends of the solder sticks together (if you are using blowpipe solder). This will then form a useable stick with solder blobs on its length.

If you have a number of blobs and splashes, don't throw them out. Collect them together and when you have enough you can make them into another stick of solder.

You can tape two narrow pieces of glass onto a length of marble or heavy steel about 3-4 mm apart. Put the pieces in the channel formed by these two pieces of glass and melt the pieces with your soldering iron. This will form a useable stick.

Lifting the new solder stick from the wood

The same can be done by cutting out a 3mm wide and deep channel in a piece of timber and doing the same as above. The wood will smoke a bit and blacken, but not ignite.  And you can use a blowtorch to melt the solder if you do it this way.

Using the (slightly irregular) solder stick

Assembling Foiled Pieces

Keeping foiled pieces together while assembling them prior to soldering is sometimes a problem.

If the panel is rectangular - or at least one with multiple straight sides - you can use short battens of the length of the sides. Nail or screw them down to a board so that about one half of the panel is contained. So if it is a rectangle, two sides will be enough. If it is six-sided ,three pieces would do.

An assembled piece illustrating the two battens - although with a leaded panel

For ease of assembly, a copy of the cartoon should be fastened to the board first and then the battens fixed on top of the cartoon. The pieces can then be placed against battens and held there with pins or nails until the next pieces are ready.

Illustration of the cartoon fixed by the surrounding battens

Some prefer to tack solder the pieces together as they foil. This can be done in combination with the use of battens. However, leaving the soldering iron idling while foiling and using it only occasionally is very hard on the iron's tip and your electricity bill. I prefer to assemble the whole and then solder all at once.

Illustration of placing pins all the way around an oval panel

For circular or irregular shapes a slightly different approach is required. You can use multiple pins or nails along the perimeter to hold the foiled pieces together. An alternative is to cut a piece of scrap window glass to the shape of the external perimeter of the panel. Hold it is place with nails or pins and proceed as with a rectangular shape.

Placing nails all the way around an irregularly shaped piece

First Ramp Rates

There is a lot of literature about annealing and cooling rates, as they are the most critical elements in producing a piece with minimum stresses within it.  But there is not so much information on initial ramp rates.

It is possible to break the glass by heating it up too fast during the initial temperature rise.  How fast you can increase the temperature is dependent on how even the heat is within your kiln and the profile of the glass.  Any suggestions have to be tested within your own kiln and setup rather than relying exclusively on others' experience.  Some of the considerations relating to the kiln are given in this blog about initial rates of advance.

So with those precautions, I put forward a suggestion based on my experience and information gleaned from the Bullseye site, education section and from Graham Stone's work. These lead me to suggest that the initial rate of advance can safely be the same as the second cooling segment as listed in the Bullseye chart Annealing Thick Slabs (Celsius and Fahrenheit). This ramp rate applies up to the softening point of the glass.

Experiments have shown that an evenly thick piece of glass 6mm thick cooled at 150ºC/270ºF per hour during the second cooling segment - can also be fired up at the same rate. And by extension:

• A 12mm thick piece could be taken up at 99ºC/178ºF per hour
• A 19mm piece could have an initial rate of advance of 45ºC/81ºF per hour
• A 25mm thick piece of glass could be taken up at 27ºC/49ºF per hour.

These rates depend on a number of factors:

• how the glass is supported,
• the nature of the shelf,
• the composition of the mould, and
• the kiln characteristics as well as
• the colour combinations and
• whether the piece is tack fused or full fused.

Slower rates of advance are indicated if  

• the kiln is side fired or has cool spots.
• the shelf has not supported on 25mm/1" kiln posts.
• the piece is tack fused, you need to slow the ramp rate by half.
• there are strongly contrasting colours next to each other   

Remember that these numbers can only be used as a guide in conducting you own experiments.

More information is given in the eBook Low Temperature Kilnforming available from

Bullseye 

and Etsy

Fusing with Painting

Combining Painting and Fusing

Painted oyster catchers with frit and stringer

It is possible to combine glass painting with fusing. Tracing paints are generally powdered iron rust and fused to the glass by the glass powder that carries this pigment. So it is possible to paint and fuse a project at the same time without loosing the intensity of the paint.

In general it is best to work down from the highest to the lowest temperature in your firings. This does require planning of the firing sequence in addition to the usual design considerations.

This sequence of firing depends on the glass stainers' paint you are using. The tracing paints (blacks, browns, some whites, some blue greens) that fire at 650ºC and above can be fired up to around 800ºC without losing much of their intensity. If you use Debitus paints, they can be fired to 850ºC without loosing their depth of colour.

Fused, painted and slumped piece painted both at fusing and slumping operations

If the paint is under glass pieces or under frit, the paint will appear to spread and the lines thicken. This is due to both the lens effect of the covering glass and the weight of the glass over the lines. If you require the lines to be of consistent thickness, you probably should paint after fusing.

You can, of course, use low firing ceramic glazes as they mature in the region of 700ºC to 850ºC. These can be painted on to the unfired glass and taken to full fuse without any fading. You do need to make sure the glaze has time for any volatile materials to burn off, so a slow rate of advance up to the slumping temperature of the glass is advisable.

Painted and fused, then painted and slumped.  Note the paint lines and coloured glass do not always match or need to.

If you are using glass stainers' enamels, you need to fuse and shape before firing. You can fire in the mould for the enamel firing as the temperature range is in the 520ºC to 580ºC range and will not add more mould marks to the glass. Keeping the glass in the mould protects against any tendency for the glass to alter shape.

Moulds for Bottles

One of the many styles of commercially prepared moulds

An alternative to buying moulds for slumping bottles is to use a sand bed. You can place the bottle into the sand and roll it a little from side to side to create a depression in the sand that then becomes the mould.

I use a fine sand (not builder's or garden) and coat it with alumina hydrate (slaked alumina). I use about 1 part alumina to 5 sand, but the mix is not critical, just enough alumina to coat the sand particles. It can go directly on your kiln floor if you have an easy way to pick it back up, as it is re-usable. Or you can put it in a stainless steel tray or any open topped box that will withstand the temperature.



Make your depressions and then sprinkle or sift a fine layer of alumina over the area - I use an old sock to hold some and dust it over the sand. Then lay the bottle in the depression.

The amount of sand impression you get is dependent on the temperature you use - the higher, the more sand texture you get. 





This way of slumping bottles eliminates the need for a mould and it is variable for different sized bottles.

Annealing a Stressed Piece

If a project has not been sufficiently annealed, it is possible to re-fire to do a good anneal.

You need to establish a slow rate of advance; one that is much slower than for the heat up of a fully annealed piece of the same thickness. This is because you can heat shock the glass much more easily than one which is adequately annealed. I suggest going at about half the rate of a normal firing for a piece of the same thickness.

You have to make sure all the glass is above the annealing temperature so it is advisable to go up to near the slumping or softening point of the glass to ensure all the stresses are removed before beginning the annealing process. If you want or need to retain the level of texture of the previous firing, you will need to go to about 20ºC above the annealing soak point of the glass and soak there for at least as long as you plan to soak at the anneal point.

Anneal at a rate (after the anneal soak) that is considerably slower than previously used. Look at the Bullseye annealing schedules for thick glass, or their project notes for annealing bowls to get some good guidance on the rates of cooling.

Thin Glass Uses

• Thin glass is often used in jewelery as it allows more layers of differing colours to be built up. It also is very useful when building a channel in the piece.
• Thin glass allows more layers to be built up before going over the 6-7mm when the glass begins to expand due to the height overcoming the surface tension of the glass.
• This also allows colours that are not present in the manufacturer's palette through combinations made from two or more colours.
• Thin glass versions of dense colours provide a lighter tone which can fit in well with other lighter colours.
• Thin glasses are also useful in tack fusing, as the height is not so great and so can be used over 6mm thicknesses without adding greatly to the volume.

Seams on the Edges of Jewellery Pieces

Sometimes the edges of pieces can show the places where the glass layers join.

This happens when there is not enough heat to completely fuse the pieces together, as in a tack fuse.

It can happen to only some pieces, due to differences in temperature within the kiln. If this occurs take note of the cool spots, or better yet, run a test for the cool areas of your kiln as in this Bullseye Tech Note.  Then avoid those areas for full fused items.

If you run your kiln as fast as it will go, you can be left with seams at the sides if you do not soak for long enough at the top temperature. I usually try to achieve my desired results with a 10 minute soak. Going slower to top temperature can give you fully formed edges at a lower temperature.

You can also get visible seams if you are using iridescent glass, mica, metal or other inclusions that come to or near the edge of the piece. The solutions are to move the inclusions further in from the edges. With iridescent glass, you should remove two or three millimetres of the iridescence to allow the glass to stick together.

If you want to conceal the layers of colour used to build up the piece, you can cut your top piece - assuming it is not clear – 3mm larger all around. This allows the top layer to fold over and enclose the whole piece, concealing the different colour layers.

Fire Polishing Jewellery

Sometimes jewellery pieces come out of the kiln with imperfections that need to be ground away.

You can do a quick shaping on the conventional grinder and then fire polish. However, you will not get a fire polish at a low enough temperature to avoid distorting the piece. The way to get a fire polished surface or edge is to make the edge less rough before putting the glass into the kiln.

After you shape the pieces on the grinder, make sure you scrub them well to remove any particles created by the grinding process. Dry them and then cover the rough areas with a white paint marker. This will indicate when you have removed the scratches caused by the previous rougher grinding.

Get out your wet and dry sandpapers. Start with the most coarse (about 200) and work the ground area until the paint has been removed. Keep the sandpaper and the area being worked damp. When all the white paint has been sanded away, wash, dry, paint and go to the the next finer grit. Repeat this with progressively finer grits – normally use the grit number twice the previous grit (larger numbers indicate finer grits).

Normally, going down to 400 or 600 grit will be enough to enable a fire polish at a low enough temperature to avoid distortion of your piece. This heat range will be at a low temperature tack fuse.

This smoothing process does not take very long and is much cheaper than buying several finer grinding bits - most grinder bits are 60 to 80 grit, although it is possible to get bits up to 600 grit.

Channels for Jewellery

There are many ways to attach jewellery to the wearer.

One of these is to create a channel in the glass to allow a chain or jump ring to be placed through the piece. This is done by stacking the glass around a narrow strip of thick fibre paper – 2mm or 3mm – thick enough to allow the chain or wire to pass through.

Channel formed with 2 layers and fibre paper

This can be built with layers of thin fusing glass. These are normally 1.5mm to 2mm thick. Volume control is important, as enough thickness of glass is required to stop it contracting. The piece might be constructed with a 3mm base, and several thin layers to make a total thickness of 6mmm to 9mm.

For the channel, cut a narrow piece of thin layer about 6mm to 8mm for the top. Then cut another short enough to leave a channel of the desired width. Fill that channel with fibre paper. Then continue to build the upper layers. These layers should be around 6mm to keep the glass around the channel from drawing in.

Pendant formed in the manner described above