Polishing Brushes

The polishing brush should have moderately soft bristles. A long bristled shoe polishing brush can be used, although one that is a little stiffer does the job more quickly.

A shoe polishing brush

It is important to keep these brushes free of hardened cement, as a brush containing pieces of hardened cement will scratch the leads rather than darken them. As soon as the polishing is finished, inspect the brush for little balls of cement. Rubbing the brush against a clean rough surface will clean it while the cement is “wet”. Also running the brush at an angle on the sharp edge of your work bench will clear some of the cement adhering to the bristles.

A polishing brush with slightly stiffer bristles

If the cement hardens, you can clean the brush by crushing the hard balls of cement with a pair of pliers. Or you can just get a new shoe polishing brush.

Holding the Cutting Head

Many people hold their cutting head steady with a finger during the scoring process.  This is not necessary.

The axel of the cutting wheel is slightly forward of the centre line of the cutter.  In addition, the cutter is held slightly angled back toward the operator to be able to see the wheel and the cartoon (or marker) line.  Both of these act to ensure the wheel follows the movement of the arm or body in a forward motion. 

In cycling, the distance between the angle of the shaft of the cutter and the axel is called the “trail”.  The greater the amount of trail, the easier it is to keep the bicycle following a straight line. The same applies to the cutter. This trail is created by the extension of the angle of the cutter to the glass.  The axel of the wheel is behind that line. The cutting head has a sharper angle at the back than the front to accommodate this angle backwards. The resultant forward force is in front of the axel and so leads the wheel to follow the direction of the cutter without any need for stabilisation.

There is no need to have your finger on the cutting head. It swivels for a reason. It will follow the direction you are pushing without any angle, so there is a clean score.  If you attempt to stabilise the cutter head you risk the wheel running at a slight angle to the direction of the score.  I talk about this as a skidding score. The result of this is to give a score with forces directed not only straight down but sideways too.   This gives the glass many more ways to break.  And not always along the line you want.

Also when you want to score a tight curve, the slight movement of the head allows the curve to be slightly smoothed again without any skidding.  This means there will be fewer pressure lines sideways to the score line.

Manufacturers have put the play into the cutter heads for a reason.  The above attempts to explain it.  The manufacturers would not include a feature that costs time and effort, as well as cost if it had no purpose.  It seems perverse of us to try to run counter to that by holding the head or even fixing it solid, so it is unable to pivot at all.

Adjusting Cut Runners

There are a number of types of cut running pliers.  These photos show some of them. 

The apparently most popular is this:

Cushions

It is frequently difficult to find replacements for the plastic cushions that come with a new pair of cut runners.  People resort to a number of means to provide a substitute.  Some wrap electrical tape around the jaws, others use fabric bandages (Elastoplast/band aids).  I have even used the liquid plastic that is designed for coating tool handles.

However, if you adjust the cut runners appropriately, you can use them to run your scores even without cushions.  The purpose of these cushions is only to compensate for too much pressure in running the score.

Use without covers

You can run the score without cushions by using the adjustment screw on the top jaw of the tool. Yes, it does tell you which is the top jaw without having to check the end of the runners, but it has a more important use.  It is not just a pretty cool way to tell which is up. 

Its purpose is to adjust the width of the opening so that it provides the appropriate amount of bending force no matter how much pressure you exert at the handles.  If you are running scores in three-millimetre glass, set the jaws to that width by turning the screw until the jaws are that width apart.

Place the jaws at right angles to the score, aligning the mark on the top jaw with the score line and squeeze the pliers.  As you squeeze, the curved jaws provide enough bending force to run the score without over stressing the glass.  It is the adjustment screw that limits the over-stressing of the glass during the running of the score. Yes, you may not be able to run the whole length of the score this way, but you can repeat from the other end and that is usually enough to complete the running of the score.

You can continue to use cushions of various sorts with this adjustment for thickness, but I found that these were not necessary when the runners were properly adjusted.  In fact, I found that soft cushioning made more difficulties than using them with the bare metal.  I discovered this during the period of using the liquid plastic coating as used for tool handles.  I dipped the jaws multiple times to give a cushioning effect and it worked fine.  The cut runners continued to work even after the tool handle coating had worn off.  It was then that I realised I could control the running pressure more directly than by having a cushion between the glass and the jaws.

Setting the spacing

An easy way to set the correct opening of the jaws is to test against the glass you are about to score and break.  Place one side of the jaws against the edge of the glass. Slide that corner just a few millimetres over the glass.  Turn the set screw on the top of the jaws anticlockwise until they are fitting the glass snugly.  Back off a half turn (clockwise) so the jaws move easily along the edge.  This is now set to run the score on this glass. 

Open the jaws and place the centre mark in line with the score.  Close them gently and you can observe the arc of the jaws above the score line. Squeeze the handles and the score will run along the line away from the cut runners.  As you have adjusted the opening, no matter how hard you squeeze the cut runners, you cannot add more pressure.  This means you avoid crushing the glass.

The principles

The curve of the jaws is designed to provide the bending force required to run the score.  The radius of the curve has been designed to provide the correct bending pressure for differing sizes of glass.  The most common ones are useful for glass up to, but not including, 6mm glass.  The screw adjustment provides compensation for differing thicknesses of glass.  Setting the width of the gap to match the thickness of the glass prevents the application of too much pressure.

Thicker glass

For thicker glass you need cut runners with wider jaws.  These usually are fitted with three points to apply the breaking pressure - one under the score and one each side of the score on the top.  Again, these are adjusted to be just less than snug to the glass before applying the pressure.

One example of  cut runners for thick glass.  There are a variety of others.

Spray nozzles

Quite a bit of the material we spray is solids in a colloidal suspension. This means that the nozzle can clog easily. Frequent agitation is needed to keep the material in suspension and not building up on the bottom which can clog the screen at the bottom of the tube.

You should not have long delays between spraying in one session, as the solids can begin to solidify within the spray head and so clog it.

When you have finished spraying, take the spray head off and clean it completely and thoroughly to ensure there are no solids left to harden. Then put it back together and it should be clear for the next use as well as sealing the container.

Grinder maintenance

There are several elements in maintaining one of the work horses of many glass studios.

Water

Ensure there is enough water to supply the pump or sponge that wets the grinding bit before starting any grinding. Too little water reaching the bit, fails to lubricate the diamonds and keep the glass cool. If you are getting a white paste or a powder on or near the glass, you need to increase the water supply.

Empty the reservoir daily. This keeps the water from producing a smell, and allows you to clear the glass residue from around the grinding bit. 

If you are changing to a finer grit, it is important to change the water, clean the resevoir, and thoroughly clean the sponge each time you make that change. Otherwise, you risk bringing coarser grit to scratch the finer grinding surface.

You can also buy a additive for the water – often called a diamond coolant – which is intended to provide a kind of lubrication for the diamonds. This may extend the life of the bit a little.

Bit maintenance

Periodic removal of the bit and lubrication of the shaft should be part of the regular maintenance of the grinder. You should make sure that the socket for the grub screw is clear of glass residues before attempting to turn it. I do this by using a needle or other thin sharp object to clear out all the glass powder. When the socket is cleaned, I push the key into the socket very firmly and hold it there while turning. Prevention maintenance is to fill the socket with vaseline or thick grease after tightening the screw.

Inspect your bit carefully for smooth areas showing that the diamonds have been worn away. Also look for dents, and other irregularities on the surface, indicating that the bit is damaged. In these cases, the bit should be replaced.

Before putting the old or new grinder bit back, ensure the shaft is smooth and without corrosion. Then coat the shaft with Vaseline or a proprietary anti seize-compound. This will ease the removal of the bit later. If the shaft is corroded, use a strip of fine wet and dry sandpaper to shine the shaft.

Sometimes bits need to be dressed – removing protruding diamonds, or cleaning and exposing new ones on a worn bit. To dress the bit you can grind some scrap glass, brick, or use a dressing stone to lightly grind some of the abrasive material away. This can extend the life of the bit.

Adjustment of 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 reduce the height of the bit as it wears.

Kiln 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 the brick floor.

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 placed in the kiln, e.g., mould, with a spirit level.

Example of a small 2-way spirit level

Monthly

Electrical parts: check the elements and their connections (normally at back or side). The screws on the connectors for the element tails should be tight. If they are badly corroded , they need to be replaced.

Any support pins or wires should be firmly seated in the brick work or supported by sound hangers.

Check the level of the kiln and internal shelves on a a regular basis and every time the kiln and its internal furniture is moved.

Brushes for Painting

A quality paint brush will have hairs that form a point and have a good spring to them - they bend while painting but return quickly to their original shape. A good brush will also hold lots of paint and deliver that paint evenly throughout the stroke. Brushes usually have a number to indicate their size - the larger the number, the larger the paintbrush. The larger the brush the wider the line that can be produced, although with a light touch a fine long line can be made because of the pointed nature of the brush.

The best brushes are made from natural hairs, although there are brushes made from a combination of natural and synthetic materials which are adequate.

Sable hair brushes are considered to be the best for painting. The hair comes from a variety of pine martin and the Kolinsky sable from Siberia is considered the best. These brushes are more expensive than others, but are soft and flexible, hold their paint well and can make an expressive thick to thin line.

Ox hairs are normally used for making rigger brushes. This is a round brush with long hairs, said to be used to paint the lines of ships' rigging in the past. The hair is strong and springy making it useful for long lines and thicker paints.

Squirrel hair brushes are useful for applying paint in broad, thin layers for matting.

Goat hair brushes are normally known as hake brushes. These are a traditional, oriental style brush. It lacks spring, but forms a good point and so is useful to cover larger areas quickly with a gentle touch.

Pony hair is made into short round brushes used as soft stipplers.

Hog hairs are made into hard, very economical brushes. They come in flat and round shapes. They are most used for stippling and can be trimmed, shaped, used, and abused for years.

Badger hairs are thicker at the end and thinner at the root, creating a conical shape. These soft brushes are used to blend paint once it has been spread on the glass. The brush is swept across the surface of the paint to blend or move paint and remove stroke lines.

Cleaning Blending Brushes

Cleaning badger brushes just before use, is easy. Flick, gently and rapidly, the very ends of the brush hairs against the side of your hand – but use respiratory protection and be careful not to inhale any dust. If you notice flecks of dust in your paint when you create a grisaille you’ll know it’s time for a thorough and wet cleaning again.

After each use, rinse out the brush tips in cool water. Gently rub the tips of the brush hairs to loosen any extra paint. Grasp he hairs above the tips to keep the water from the main part of the brush. Then wet the exposed ends of the hairs and rub them gently until the water runs clear. 

If you use a blender for oil, you will need to use a small amount of natural soap, if so, thoroughly rinse.

Flick the brush to remove excess water, smooth the hairs into shape and allow to completely dry by hanging the brush with the hairs pointing downward – this avoids water flowing into the brush base where the hairs are attached. If you have round-handled brushes, you can twirl the brush between your hands to remove excess water.

Clearing Small Core Drill Bits

Core drill bits are very useful, as only a thin wall of glass is removed, leaving the main part of the hole as a single piece. This means that it is quicker than a solid drill bit through not having to remove so much glass. However with small diameter core drills they often jam up with waste glass. This is evident when the drill ceases to drill through the glass, leaving a broad circular mark as it moves around on the glass.

Inevitably, at one time or another, the glass core will get stuck inside the drill bit. This needs to be cleared before any further drilling can be successfully done. It seems to be more common with the smaller diameter drills – from 5mm down.

The broken off core needs to be cleared from the back of the bit, not the diamond coated end. So you need to take the bit out of the drill and use a thin nail or piece of wire into the hole to push the glass out.

My collection of core drills.  At the front you can see copper wire and a thin punch for clearing blocked drills

Core drills need a more accurate means of steadying the bit than your hands. Imagine that you are trying to get that core out of the glass in tact. Any wobbling as you drill will break that core. When the core breaks, it is inclined to jam the cylinder. So a drill press is almost essential when using a core drill.

They also need water like any other drilling of glass. Normally this is supplied through the hollow core of the bit, which is beyond hand held drill motors.

For something as small as 3mm, a solid drill that removes all the glass rather than a core is more likely to be most successful. You can get diamonds bonded to piano wire that will give you holes from a fraction of a mm up to 2 or 3 mm and these can be used in dremmel-like tools that take small diameter bits.

It is absolutely NOT recommended to use a core drill at an acute angle to start the hole. The wall of a 3mm core drill is very thin and easily damaged. It is ok to start a solid drill that way, but not a core drill.

There are a number of related posts beginning with this one which give advice on the many ways to drill holes in glass.

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.

Example of top of bit almost too low for the glass

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.

Example of nicely adjusted bit

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.

Grinder Chipping Glass

There are a number of reasons that may cause the grinder to chip the glass surface. Some of the things to check are:

Too much pressure

It may be that you are pressing the glass into the grinder head too hard. The grinder head should do the work. Firm rather than hard pressure should be applied. If the grinder slows, it is an indication that far too much pressure is being applied.

Insufficient water supply

There may be too little water reaching the head to lubricate the diamonds and keep the glass cool. If you are getting a white paste or a powder on or near the glass, you need to increase the water supply.

Worn or damaged grinder bit/head

Inspect your bit carefully for smooth areas showing that the diamonds have been worn away. Also look for dents, and other irregularities on the surface, indicating that the bit is damaged. Any dents or smooth places on the bit cause a vibration that is similar to a tiny hammer tapping the edge of the glass.

Grit size

It is possible that you may be using too coarse a grit on the grinder bit/head. The more coarse the grit is the larger the chips will be taken off the edge surfaces. Smaller grits take smaller chips off the edges, and so are less obvious.

New bits

Examples of the range and grit differences in grinding bits

If it is a new bit that is causing the chipping, consider dressing it. New bits often need to be dressed – removing protruding diamonds, or cleaning and exposing new ones on a worn bit. To dress the bit you can grind some scrap glass, brick, or use a dressing stone to lightly grind some of the abrasive material away. This most often settles the bit and avoids chipping.

Cutting thick glass

Use the correct angle of cutter wheel for the thickness. 

Use a similar pressure to cutting 3 or 6 mm glass. It is natural to think that as the glass is thicker, you need to use more pressure. The different angle of the cutter wheel is designed to transfer the standard pressure more directly downward.

Use cut runners made for thick glass to help break the glass. Run score from both ends of the score, especially on curved scores.

Example of cut runners for thick glass

Alternatively, turn the over and use hammer and rounded screw driver to run the score (similar to tapping method for thinner glass). Place the screw driver blade directly over the score line and tap it with a hammer. This will start the run. Continue it by placing the screw driver over the score at the end of the open score and tap again to continue the run.

Orientation of Cutter Heads

In addition to the alignment of the cutter, you need to be sure you are moving the cutter forward in the way it was designed. If you look at the cutter from the side you will see two things. The most obvious one is that the angles of the cutaway on the head are shallower at the front and steeper at the back. In addition if you look carefully, the axel for the wheel is slightly forward of the centre line of the whole cutter.

Cutters aligned to score to the left

So it does not matter where the fixing screw on the head is. It may be at the front or at the back. What matters is the cutaway at the back which allows the cutter to be used with a shallower angle, than if reversed. This is most obvious on wide cutter heads.

Cutters arranged to score to the right

Repair of a Plastic Barrel Cutter

Generally, there are two parts that can break or be damaged – the wheel and the barrel.

Wheel

If the wheel is damaged or worn, you can replace the head. When considering that, look at the cost of the head and consider whether the small cost difference indicates you should buy a new cutter instead.

The most common damage is a flat spot on the wheel. You can check for this, immediately after dropping the cutter, by lightly moving the cutter across a smooth piece of glass. If you hear a regular ticking sound, the wheel is probably “flat spotted” and will need to be replaced.

A worn wheel is more difficult to detect and is also much less likely to occur. I have been using some of my cutters for 15 years without any sign of being worn.

Plastic barrel

Sometimes the plastic barrel cracks or breaks. This will mean that the oil in the cutter will leak out. So you can consider continuing to use the cutter without oil, or by dipping the head in an oil soaked bit of cotton wool or similar material before each cut.

If the break is at the threaded end and you want to continue to use the ball at the end for tapping purposes, you can glue the barrel back together with an epoxy resin. Make sure the pieces are free from oil. Then glue and allow to cure. After curing, sand down any excess resin to make the cutter comfortable to handle.

Then for additional strength you can wrap with dental floss or extremely fine wire. Start below the glued area and go to the end of the break and back again. You could coat this wrapping with epoxy again both to secure the wrapping and to further increase the strength.

Another solution is to cut the cracked end off and re-thread the remainder. It makes the cutter a little shorter, but will continue to hold oil and give good service.

Or, you could buy another cutter.

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.

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 that the flat came of the same width.

The technique for finishing a curve around a single piece of glass can be seen in the tip “Leading Small Circles”

Soldering Zinc

Brass, copper and zinc are heat sinks. That is, the metal conducts the heat rapidly so more heat has to be applied than for lead and tin to keep the soldering site hot enough to accept the solder.

The important elements are:

Use a hot iron. If you use a rheostat, turn it up to full. If you can, change the tip/bit to one rated at 800F – it will have an “8” stamped on the end that goes into the barrel of the iron.

Apply the flux liberally at the soldering point to ensure the area is “wetted”.

Keep the iron in contact with the came for a few seconds to heat the metal. If you are using zinc as your border around a leaded panel, make sure you do not heat up the lead came so that it begins to melt.  Keep the iron on the zinc.  It will transmit heat to the lead came without getting it hot enough to melt.

When the came is hot, apply the solder to the bit. 

Keep the bit on the metal until you see the solder begin to flow on both the zinc and the lead or onto the solder bead (on copper foil), then gently lift directly up. 

Cut Running Pliers

Cut running pliers are intended to assist with the running of long straight or gently curving scores.  Sometimes they are referred to simply as running pliers.

There are a wide variety of these made for different purposes.  The following are illustrations of some of the styles.

This plastic cut runner is an economy version of the metal one below

 To use these cut runners, you align the raised line on pliers with the line of the score and squeeze gently.  The single line on the bottom jaw acts a fulcrum, allowing the two raised parts on the upper jaw to provide pressure to the score and run the break along the score line.

Metal cut running pliers

The metal cut runners are pliers with curved jaws. When looking at the pliers from the nose toward the handles you will see the curve like a down turned mouth. These assist the breaking of the score by putting tension on the glass.

Cut running pliers almost always are supplied with covered jaws. This are normally two pockets of flexible plastic that fit snugly onto the slightly flared, curved jaws. Keep these on. When worn they can be replaced by buying more, or by wrapping the jaws with tape using "liquid plastic" or sometimes even using them bare.

There is a spacing screw on top which allows adjustment for different thickness of glass. It is intended that the jaws should not close completely – which can place excessive pressure on the glass – but be adjusted so that there is about 1mm less opening than the thickness of the glass. So when cutting 3mm glass there would be a 2 mm gap. On 4 mm glass the gap would be 3 mm, and so on. experience will show what relationship is best for you. The principle is that the pliers perform a gentle tensioning of the glass. Using your hands exerts more tension on the glass and cannot be so delicate.

Use

Align the centre of the top of the jaws - often the pliers have a centre line on the top to assist – along the direction of the score. Squeeze gently and the score will begin to run.

I have found my best success when using cut running pliers is to avoid trying to run the whole score from one end. With a bit of practice you get the feel for how much pressure you should be applying and so when to stop. Then turn the glass around and start the run from the other end. Usually the open ends of the score will meet and the break is completed. Occasionally the two runs will not meet. Then it depends on how complicated the curve is as to whether you use your hands to complete the break or start tapping the score line to finish the break.


More that one tool

There is a second variety of cut running pliers designed to run long scores near the edge of the glass.  These can be used in the same way as the cut runners pictured above.

The Ring Star cut runners

These cut runners made from plastic have a pad with a central raised point on the bottom jaw and a circular pad on the top jaw.  Placing the point directly under the score line will begin running the score.

 A more durable, but also more expensive version is the Silberschnitt cut runner.

Moveable pad oriented to run scores in line with the pliers orientation

The advantage of these is that the upper pad can be rotated to accommodate any angle, allowing shallow curves to be broken out.  If progressively deeper curves are scored, this too can assist in breaking out deep inside curves.

Pad oriented at about 60 degrees for running score at an angle to the plier's orientation

This allows a score to be run gently over a long distance. This is especially advantageous when the score is a curving one.  

Use
The upper pad is rotated so that it is at a right angle to the score.  The lower pad has a point to act as the  pressure point when the pliers are squeezed.  As you move along the score, you continue to adjust the upper pad to maintain a right angle to the score.  This is a much more gentle breaking action than the standard cut runners and runs the score in shorter distances.  However these short runs make it more certain to run the score successfully. 

Tools for Thick Glass

There are a variety of tools for breaking thick glass - usually 6mm and thicker.  Some examples are illustrated.

Note: these running pliers are pictured upside down.  The two plastic pads should be on the top of the glass.

These are used in the following fashion:

Adjusting cut running pliers for different thicknesses of glass.

Pounce Wheel

The pounce wheel is used in reproducing images and comes from a time before photocopying or carbon papers. It gets its name from its use together with a pounce bag. In the past the pounce wheel would make holes through the paper or card along the design lines. The paper or card is put over the material which is to have the imaged copied onto it. A small bag of black powder would be dabbed (pounced) on the cover paper leaving black dots on the surface below. These could then be used to trace the same image many times in what ever medium was being used.

Two Pounce Wheels of Different Sizes

As the photo shows, the pounce wheel consists of a pencil-like holder with the spiked wheel at the end. The wheel is on an angled axle similar to a bicycle to make it easier to follow straight lines by pushing away from your body. This allows a clear view of the line being copied. The smaller wheel is useful for tight curves.

The pounce wheel still retains a use in transferring images through opaque materials, although the full pounce process does not need to be used.

To copy part of one stage of a design onto a new one without using tracing or carbon papers you only need to layer a new sheet of paper under the current design and run the pounce wheel over the parts you want to copy. As you move the wheel along, it punctures through the top layer into the lower layer. Normally, the puncture marks are all that are needed to be able to reproduce the original lines.

A crude pounced design

You can also get symmetrical images by folding the paper along the centre line and running the pounce wheel over the line. Unfold the paper and use the puncture marks to make lines symmetrical to the other side.

You can use the wheel to create mirror images by running the pounce wheel over the card, turn the card over and draw using the puncture marks.

Lead knives

The advantage of lead knives over lead dykes are that a wider variety of angles can be made with the knife. There are a number of varieties of lead knives - ranging from adapted paint scrapers to specially made sophisticated tools.

The technique in using a knife is to wiggle or rock the blade with some moderate pressure down through the lead came. Excessive pressure will twist the came rather than cut it cleanly and squarely. When you find the effort or time required to cut through the came has increased, it is time to sharpen the blade. The sharpening angle should be very acute. You can use a fine oil stone or wet and dry sand paper to hone the cutting edge. You can also use a little bit of wax or soap on the blade to ease its passage through the came.

The most simple knife is a stiff paint scraper. The blade should be of good steel so that it takes and retains the sharpening that is needed from time to time. This blade works best by wiggling through the came.

Another style of lead knife has a curved blade. This has a number of variations. This knife works both by wiggling and by rocking.

Experience and personal preference will determine which style you settle on. The important elements are to make sure it is made from good steel and that it fits your hand comfortably.

You can add a metal end to the handle to provide a tool with more uses, especially as a hammer to put the nails into the board, or to snug up wooden borders, sometimes even gently tap the glass into place.

Also look at the use of lead dykes.