Grinder Bit Chipping Glass

Credit: Techniglass.com

A new grinder bit chips the glass excessively, especially with a coarse grit. It can also be the result of a bare spot on the bit.  You need distinguish between these states.   Check the surface of the bit.  If there are any small bare spots, the bit needs to be replaced.

 

Credit: WWGrainger

The best thing to do with a new coarse bit is to treat it with a dressing stone.  This is a block of aluminium oxide which can remove high points on the bit, and clean up the spaces between the diamonds on the bit.  It is relatively inexpensive to buy and lasts a long time.  The dressing stone can be a brick, although it is not as efficient because it is much softer.  

If the grinding bit still chips off too much glass from the edge, you need  a finer grit.  It will not take glass off as quickly as the coarse one, but it eliminates or reduces the chipping.  The three common grades are: coarse, standard, and fine.  It is a good idea to maintain a stock of the medium and fine grit grinder bits as replacements for worn ones.

Core drill bits

Credit: JMbestglass.cn

Using core drill bits needs a drill press. It keeps the drill bit steady and avoids breaking the core which plugs the hollow part of the bit.

Oscillating a core diamond drill bit is not the correct procedure. Oscillating the bit creates two undesirable things.

• It breaks off the core that  is being drilled out, plugging the drill bit, and blocking the cooling water being pumped to the drill bit.  This means the bit heats up and loses some of the diamonds. Additionally, it can heat up the glass so much that it breaks. If you are not using a flushing head with your drill, you will need to raise the bit a little from time to time, allowing water to the grinding surface. 
• Starting at an angle or oscillating with a core bit wears out the sides of the drill bit more quickly than necessary. Core drill bits need to be applied directly and vertically. This is why core bits do best in a drill press. It holds the bit in a vertical position without breaking the core being drilled out, or prematurely using the diamonds higher up the bit.

Credit:  Lawson-HIS

There are generic drill presses available for holding Dremel-type craft motors and hand-held drills. They are inexpensive and make the drilling process so much more certain to regulate the pressure. It also makes an easier start without skipping over the glass. They are so inexpensive that a few holes without skipping will pay it.

Credit: Bhole ST1542 Pico Dril

Drill speeds should be varied according to the size of the hole being drilled. This is important with the high speed Dremel-type motors.  Larger holes need a slower speed than smaller ones. The rim speed of a small bit is nearer the rpm of the drill than a larger one, because the larger one travels a greater distance per revolution than a small one. A listing of recommended speeds is given in this blog.

Hollow core diamond bits are of two types:

•     One, where a heating process attaches the diamond, is called sintered in Europe and other countries.
•     The second, where the diamond is bound with resins, is called bonded in Europe.

They seem to have different designations in North America.

Bits of the first type are longer lasting, and more expensive. These can be “sharpened” with an aluminium oxide dressing stick to expose new diamonds and maintain their effectiveness.

Credit: W W Grainger.com

Bits of the second type wear quickly and should not be “sharpened” with a dressing stone. The normal wearing away of the bonding material exposes the new diamonds.  Dressing them wears away the diamonds that could be used in drilling.

Another advantage to core bits, is that a core drill grinds out much less glass from the hole than a solid drill bit, so it takes less time to drill a hole.

One disadvantage, especially on core drills of 5mm and less, is that the core needs frequent cleaning out of the cores that get stuck inside the drill bit. To maintain efficient and effective drilling, the core needs to be poked out from the bit from the base toward the drilling surface.  This applies whether water is being pumped through the core or not.  Without clearing the core, more pressure must be used to continue drilling, resulting in larger break outs as the hole is completed, and more breaks of the complete piece.

Home Made Frit Maker

Recently, when looking for a small frit maker, no shop had one in stock.  Having heard of making one from plumbing pipes, I went in search of material.  I came across stainless steel pipe and caps.

 

The practical size seemed to be 50mm.  Short sections of threaded pipe were available with matching caps.  That forms the containment cylinder.

 

A threaded 25mm pipe and cap can be fitted loosely into the larger one, and so forms the plunger or piston.

 

There needs to be a handle.  It could be a turned piece of wood to fit the inside of the pipe.  In this case, I obtained a reducing connector to fit a 12mm pipe to the plunger and topped it with another cap. 

The whole was put together in less than a minute, once all the parts were assembled.

The completed frit maker

Galvanised pipe would be cheaper but carries the possibility of introducing zinc into the frit.  Stainless steel risks introducing non-magnetic particles into the frit.  As I sieve out powder from my own frit making before washing, I am not too concerned about steel contamination.  If you want powder, use uncoated mild steel so the contamination can be drawn out with a strong magnet.

Silberschnitt Runners

 
The use of the highly acclaimed Silberschnitt cut runners requires a bit of experience to get the best from them.  They are at their best on inside curves and thin strips.  This is a few notes on how to make best use of the runners.

 

 
Always use the runners with the name visible to you.  This is the right way up.
 

Make use of the adjustable bar at the top of the runners.  Rotate the adjustable bar to be at right angles to score line.  This means the pliers do not have to be at a particular angle to the score line, which has advantages in tight areas.
 

Each press of the handles opens only a small run of the score.  Excessive pressure risks breaking glass and reducing the life of the pads

 

Move the runners along to the front edge of the opened score and press again.  Work your way all along the curve adjusting the angle of the bar as you go.  This progressive opening of the score line gives a break with almost no flares.
 

These runners are much better than the plastic ring star breakers, because there is much more control over angle of pressure.
 
Note: make sure you get replacement pads when you buy, they are robust but do wear out over time.).
 
 
Silberschnitt running pliers are excellent but require some experience to get the best from them.

Hake brushes

Hake (ha-kay) brushes are made from goat's hair. Their advantage over other brushes for applying kiln wash is that they hold a lot of liquid. Proper ones made from joined bamboo work better than the ones with flat handles.

Traditional Japanese hake brush

People often note that these brushes tend to shed hairs. The solution to stray hairs (given to me in a Bullseye workshop) is to invert the new brush and apply super glue at the point where the hairs emerge from the handle.  This holds the hairs in place. It will work on flat handles too.

Inexpensive goat's hair brushes of the hake style.
As can be seen by comparison, there are fewer hairs in these.

Renewing the Grinder Bit

When to replace the grinding head?

An obvious time is when the grinding becomes much slower than previously.  Adjusting the bit up or down to expose a new diamond grinding surface is the obvious first step.  When there is no more adjustment available it is time to replace the whole bit.

Another time to replace the bit is when a bare spot appears.  

One style of wear on these bits is not just the general, even wear all the way around the bit, but where all the diamonds are lost, and the metal is exposed.   

This bare spot can be observed upon inspection.  But most of us do not regularly inspect the bit before turning the grinder on.  There is another way to tell something is amiss.  What you may notice is an unexpected vibration during grinding.  When you experience this vibration, it is time to inspect the bit.  You will most likely find a patch of bare metal.

You do not have to throw the bit out.  If there is space above or below the bare spot that will provide a grinding surface for the thickness of glass you are grinding, you can do something to extend the life of the bit.

Simply raise or lower the bit until the bare spot is below the surface of the grinder grid, or in the case of this illustration, raise it sufficiently high to be above the thickness of the glass you are grinding.

Why do the bare spots appear?

It may be due to manufacture. The bonding of the diamonds may not have been completely even.  But it can also be due to grinding while there is little water – when a paste appears.  This leads to heating of the grinding bit as much or more than the glass.  A hot grinding head, especially those which are resin bonded, can lead to loss of diamonds either in one spot or generally around the bit.

Hake brush

Bamboo handle hake brush

The hake (pronounced hah–kay) brush was developed in the far east.  It has several variations – the original consisted of a group of bamboo brushes bound together in a line.  These are still made and used. Many modern hake brushes have a broad wooden handle with a wide line of hairs.  These brushes are made of very fine, soft hairs - often goat hair is used. 

Flat wooden hake brushes

The flat hake brushes are most often cheaper and in a wider variety of sizes than the bamboo ones.  I prefer the bamboo for the feel in the hand that the broad handle gives.  With the longer hairs, it holds more moisture and delivers even amounts of kiln wash even with long strokes. 

Use

These brushes can hold a lot of moisture and deliver it evenly.  This makes it good for laying  down large areas of even colour in watercolours, and in glass painting. The same characteristic makes it very good for coating shelves with kiln wash.  The brush should be filled liberally with the paint or kiln wash. The brush should be gently shaken to remove any excess. Hold the brush nearly vertical and let the bristles barely touch the surface as you move along in smooth sweeps across the surface.  This allows the kiln wash to be evenly spread with very few brush marks.

Maintenance

One drawback of these brush is that the fine soft hairs are difficult to bind into the ferrule.  This results in the brushes often shedding hairs onto the shelf as it is being coated. A tip I learned from Bullseye is to treat the new hake brush with superglue at the base of the hairs. It does not have to be super glue.  It can be any runny glue, or diluted PVA.  I prefer super glue, even though it is reported to have some sensitivity to moisture. You can work the glue into the centre by using a needle to poke at the hairs to move the glue toward the centre of the bristles.  The glue binds the hairs in addition to the binding at the ferrule, and so keeps the brush from shedding. 

I did this on my bamboo handle hake brush a couple of years ago and it is not yet shedding hairs during applications of kiln wash.

Make sure you clean the bristles immediately after using to avoid any material drying among the hairs and causing them to break when next used.  To clean the brush, you only need running water run through the bristles.  Do not scrub the bristles against anything.  The hairs are delicate.  Set the brush aside horizontally to allow water to drip off and the hairs to dry.  Setting the brush upside down when wet allows water into the bindings of the hairs.  Putting it with the hairs down onto a surface deforms the hairs, making it difficult to straighten them later.

A hake brush is among the most useful tools to put kiln wash onto shelves and moulds because it holds so much moisture.  It does require maintenance to ensure the hairs do not shed and that the delicate hairs are not broken.

Adjusting Cut Running Pliers

Typical cut running pliers

Cut running pliers are very useful tools if used correctly.  The pliers must have the curve in a “frown” rather than a “smile” to operate properly.  The knurled screw at the top and the scored line on the top jaw help place the pliers the right way up. They must be placed directly in line with the score. They should be only a centimetre or so onto the glass.  Holding them at the end of the handles, apply gently increasing pressure until you hear a click or see the score running.  If it does not run completely, turn the glass around and apply the pliers to the other end of the score.

Use of the Adjustment Screw

It is important to make use of the adjustment screw to get the best from the pliers.  If this is not adjusted properly, it is possible to crush the glass, or at the other extreme, not run the score at all.

The jaws need to be adjusted for the thickness of the glass.  The method I use for this is to place the edge of the runners on a corner of the glass to be scored.  

Loosen the screw until the glass is gripped by the jaws.  

Gradually tighten the screw until it resists your gentle pressure on the handles.  This gives you the correct opening of the jaws for that piece of glass.

When the pliers are properly adjusted to the thickness of the glass, you will not crush the glass and it is easy to use the pliers without cushions.

Rakes for Combing

It is of course, possible to buy commercial tools for combing hot glass.  But with a little ingenuity, you can make your own for a small amount of money and some effort.

My raking tool is a metre long round stainless steel rod, 8mm in diameter. I sharpened it on a  grinder for metal rather than my glass grinder. Then I bent a right angle to give me 75mm "hook". The handle is a piece of broom handle. I drilled an 8mm hole in the wood and hammered it on.

A longer metal and shorter wooden handle works better than the one I made with a long wooden handle, as there is no wood near enough the heat to burn. If you do have a long handle,  soak it in water to keep it from burning.

It is possible to make a rake using mild steel rod, but it is more likely to spall and drop flakes into the glass.  Both metals need to be kept cool.  Rest the rake in a bucket of water before the first pass at combing.  As the glass stiffens and you need to wait for the glass to come back to a combing temperature, put he rake back into water to cool it.  If you try to comb with a hot rake, it will stick to the glass.

It is important to have a handle made of an insulating material to avoid any possible electrical shocks.  It also makes for a more comfortable handle that does not heat up.

Safety gear is required to protect eyes and clothing from the heat.  It is not possible to have the kiln open at around 900C without it.  This is the face, hand and arm protection I use.  The coated visor protects your eyes against the infrared radiation from the kiln.  The gloves can be the aluminised silver colour ones or the kevlar ones.  The alminised ones are easier to manipulate things with.  The arm protectors are aluminised too. They are easy to put on and give additional safety to the body.

Natural fibres should be worn to avoid clothing bursting into fire.  I use a denim jacket reversed for additional chest protection.

Soldering Lead Came

Soldering lead came is different from soldering electronics or copper foil. For electronic soldering less heat is needed, cleanliness is all important, suitable flux is required, and the iron is held differently, among other things.

Soldering lead came The lead needs to be clean and bright to start with. If it's fairly new lead it should be solder-able without more than a scrubbing of the joints with a brass wire brush. However, if the lead is dull and oxidized, you should scrape the lead in the area to be soldered with a nail, the blade of a lead knife or other sharp edged tool until the bright metal is revealed.

an example of paste flux

Example of a tallow stick.  It has the appearance of a candle, but without the wick.

Example of the application of tallow to a joint

Then the flux can be applied.  Paste flux or tallow works best as neither flows in its cold state.  This means that you can flux the whole panel at one time without the liquid flowing away or drying.  Once the whole panel is fluxed, you do not need to stop during the soldering process.

Example of a gas powered soldering iron. The flat face of the soldering bolt is held in full contact with the joint.

An electric soldering iron is held over-handed (as you would a bread knife) in order to get the handle low enough to have the tip flat on the lead. This will be a 15 to 20 degree elevation from the horizontal. Allow the weight of the soldering iron to do the work for you. 

Let it rest on the joint after you apply the solder between the lead and the iron. In order to heat both pieces of lead you may have to rock the tip slightly to contact all leads being soldered. Take the solder away from the iron so it doesn't become attached to the joint. As soon as the solder spreads, lift the iron straight up. This process will take only a few seconds, much less than 5.

Example of smooth flat solder joints.

Avoid "painting" or dragging the iron across the joint. The object is to have a shiny, smooth, slightly rounded solder joint. Moving the iron and solder around does two things.  It makes for a weak joint as the solder does not have the chance to become stable and so forms a "pasty" joint.  Moving the iron around during the soldering of the joint often provides sharp points where the iron was moved quickly off the join. There should be no points sticking up from the solder joint. If a solder joint is not satisfactory you can re-flux and re-heat. Don't apply too much solder. It's easier to add more solder than to remove excess.

Soldering Irons and Rheostats

People often want to have variable temperatures for decorative soldering.

It is recommended to use a rheostat in circumstances where the soldering iron does not have an internal temperature control.

A rheostat is NOT a temperature controller.

Action of a Rheostat
A rheostat actually reduces the power supplied to the iron, thereby making it take longer to heat or re-heat after a period of soldering. Without a rheostat, if an iron is left idle, it will eventually reach its maximum temperature. This is usually too hot for soldering lead, but OK for joining other metals. With a rheostat, if an iron is left idle with the rheostat set to (say) '6', it will still reach its maximum temperature but very much slower than the one without a rheostat.

Action of a Temperature Controlled Iron
Temperature controlled soldering irons attempt to maintain a set temperature. This is controlled by the combination of the microchip in the iron and the tip. So to adjust your temperatures all you need is a few different tips. For example, a number 7 tip lets your iron heat to 700F degrees. For decorative soldering your need tips of lower temperatures, usually a number 6 or 600F degree is enough of a reduction for most decorative stuff. A number 8 tip (800F) will let you work at a higher temperature if you work quickly.

Differences in Soldering Speed
Using an iron without a rheostat, provided you work relatively quickly, you will probably be able to solder all the joints in a small or medium panel without stopping to let the iron 'catch up'. In this case the temperature is controlled by the heating power of the iron balanced by the cooling effect of making the soldered joints.Using an iron with a rheostat, you will need to slow down a little if you are to do that same panel without stopping to let the iron re-heat. In this case the temperature of the iron is controlled by the (reduced) heating power of the iron balanced by the same cooling effect of making the soldered joints.This difference is caused by the fact that a temperature-controlled iron, if it is left idle, it will quickly reach its maximum operating temperature - just as quickly as an un-controlled iron of the same power. When you start soldering, the cooling effect will trigger the temperature controller to provide full power until the operating temperature is reached again.

Advantages of a Temperature Controlled Iron
You can buy an iron (not temperature controlled) and a rheostat but buying tips for the temperature controlled iron is cheaper. The big advantage of the temperature-controlled iron is that you know it will never get too hot for the work you are doing, and that it truly provides that 100 watts (or whatever) power to keep it hot even when you are soldering at top speed.

Choosing a Soldering Iron

The iron used to solder must be of a high enough wattage to readily melt the solder and be able to reheat fast enough to maintain the necessary melting temperature. The tip can't be so small it can't maintain the heat nor so big it covers more area than wanted.

For example a 75 or 80 watt iron is sufficient to begin soldering with, but it will continue to get hotter, as it has no temperature control. An iron of this type should be used with a rheostat in order to prevent overheating while it is idling.

Most temperature controlled irons seem to be produced in 100 watts or higher. These internally temperature controlled irons maintain a constant temperature. They are normally supplied with a 700F° bit (number 7) and is sufficient to melt the solder without long recovery times. You can obtain bits of different temperature ratings, commonly 800F° and 600F°. You can also several sizes of tips for different detail of work.

  For volume work you can obtain temperature controlled irons of 200 watts and more.

It is also possible to obtain a Japanese made soldering iron with the rheostat built into the handle.

Soldering irons

General
Historically soldering tips were copper, placed in braziers. One tip at a time was used; when the heat had transferred from the tip to the solder (and depleted the heat reserve) it was placed back in the brazier of charcoal and the next tip was used.

Much later gas irons were in common use. These used a gas jet to heat the soldering bolt/tip. They are very fast, but require significant amounts of experience to properly regulate the temperature.

Currently, electric soldering irons are used; they consist of coil or ceramic heating elements, which retain heat differently, and warm up the mass differently, with internal or external rheostats, and different power ratings - which change how long a bead can be run.

Selection
The soldering iron used must be of a high enough wattage to readily melt the solder and be able to reheat fast enough to maintain the necessary melting temperature. The tip can't be so small it can't maintain the heat and not so big it covers much more area than wanted.

For soldering leaded panels a 100w iron with a 3/8" temperature controlled tip that maintains a constant 370°C (700° F) is suitable.

For copper foil a higher temperature controlled tip is used. This normally runs at 425°C (800°F). Sometimes a tip of ¼” is used where more delicate beads are being run. But there is little difference in the resulting bead - only that the smaller bit takes slightly longer to heat up.

If a lot of soldering is required that has sustained heat requirements, you might consider a 200W iron. These can deliver heat more quickly and evenly than those with lesser wattage.

Care of Soldering Tips

Many soldering stations come with a sponge which, when wet, is used to wipe the iron's tip clean. A small amount of fresh solder is usually then applied to the clean tip in a process called tinning.

The copper that forms the heat-conducting bulk of the soldering iron's tip will dissolve into molten solder, slowly eroding the tip. As a result of this, most soldering iron tips are plated to resist wearing down under use. To avoid damaging the plating, abrasives such as sand paper or steel wire brushes should not be used to clean them. Tips without this plating or where the plating has been broken-through may need to be periodically sanded or filed to keep them smooth.

a common block form of sal ammoniac

To avoid using abrasives, cleaning with sal ammoniac is recommended. This comes in a block. You rub the soldering iron bit on the surface. As the surface becomes hot, it begins the cleaning process, noted by the smoke rising from the block. When the block under the bit becomes clear, the bit will be clean and can be tinned as above. If this is done at the end of each session of soldering, the bit will last and will be ready for soldering immediately when you next need to use it.

Other posts on maintenance are:
https://glasstips.blogspot.com/2008/08/care-of-your-soldering-iron-tip.html

https://glasstips.blogspot.com/2019/11/soldering-iron-maintenance.html

Breaking Pieces from Large Sheets

Breaking a piece of glass from a large sheet is often a frightening prospect. It doesn't have to be. It is better to cut a straight line piece from your larger sheet than it is to try to cut a curve. This describes a straight line cut from a large sheet of glass.

Use a cutting square or other non-slip straight edge to guide the cutter. You can push as in normal stained glass cutting, or you can draw the cutter toward you as glaziers do. In either case, the pressure needs to be even and the speed consistent.

When moving large scored sheets, avoid pulling the sheet by one end. The score may run suddenly and not always along the line. Instead, move the sheet with support on both sides of the score. After the glass is scored, you have choices about how to run the score.

One easy way to break off large pieces is to move the sheet so the scored line is just inside the edge of the bench. The biggest piece will be on the bench and the smaller piece in your hands. Give a quick, sharp downward push with both hands on the overhanging glass. This action will separate the piece from the main sheet. Having the glass score inside the bench edge gives you a place for the broken off piece to rest, rather than pivoting toward the floor.

Or you can slide the straight edge under the glass on one side of the score, and press firmly, but not sharply on each side of the score. The glass will break evenly along the score line. This is a more gentle method of breaking the glass. A variation on this is to place a couple of matchsticks or glass painting brushes at each end of the score and apply the pressure.


If the glass sheet is of a size that you can hold it in both hands with the score between, you can draw it off the bench, let it hang vertically, and bring your knee up briskly to hit the score line, and it will break easily. This is a showman’s way of breaking glass sheets when the score line is approximately centred on the sheet.


Cut running pliers often do not work very well for long straight scores on large sheets of glass. However, if you use this method, tapping at the start and at the end the score line before squeezing the running pliers will help the score to run the way you intend. This is sometimes the only way to achieve the break of the score.  A note on the adjustment of cut running pliers. 

Care of Your Soldering Iron Tip

Wipe your hot iron tip on a wet sponge on a regular basis while soldering.  It must be done on a natural sponge, not a plastic based one. This should be a quick pass, rather than a lingering one to avoid cooling the tip of the soldering bolt.  This keeps the tip clean of carbon and other contaminants that can reduce the effective heat from the tip.  

There are also brass wool tip cleaners.  These are a bit more agressive than the sponge, but do not cool the tip. 

If you have any dark gunk build up that won't come off on the sponge, rub the hot iron tip against a block of sal ammoniac until the block clears. If the dirt is difficult to remove with the sal ammoniac, use a brass wire brush to scrape the dirt off and then go back to the sal ammoniac block. When it is clean, add a touch of solder to re-tin the tip, and then wipe against your wet sponge.
  

Remember, all this is done while the iron is hot, so be careful.

Other links to Soldering Iron Maintenance:
https://glasstips.blogspot.com/2019/11/soldering-iron-maintenance.html

https://glasstips.blogspot.com/2010/01/maintenance-of-soldering-bits-periodic.html

https://glasstips.blogspot.com/2009/12/soldering-bit-maintenance-wiping-bit.html

https://glasstips.blogspot.com/2009/12/soldering-bit-maintenance-tinning.html

Use of Sal Ammoniac block

A block of sal ammoniac is an excellent aid to keeping your soldering iron tip (or bit) clean and able to hold a small blob of solder.

A description of what sal ammoniac is and the safety precautions in its use are here. 

You should place the block in such a way that it cannot slide around as you rub your iron over it.

Place your hot soldering iron tip on the block until it begins to smoke. Then move your iron slowly back and forth along the block.  Initially, the block will be black from the contaminants coming from the soldering iron bit.  As you rub the bit along the block, it will begin to clear. As it does, you can add a touch of solder and turn the bit over to check whether there are still any black spots on the face of the bit. 

If there are still black spots, return to rubbing on the block for a time.  If these spots are persistent, you can use a brass wire brush to help clean the contaminants off.  Then add a touch of solder and return to rubbing along the block.  Repeat this check until the whole bit is bright and holding a small blob of solder.

Repeat this process for the other side too.

Leave a small blob of solder on each side of the bit to protect the bit from oxidising.  This cleaning process should be done at the end of each soldering session if the bit is not clean.  But it does not substitute for the frequent wiping of the bit on a damp sponge to clean the bit as you work.  The sal ammoniac block is for cleaning persistent contaminants off the bit.