Health Risks from Lead/Tin Solder

"Lead solder – is an open window or an open door in my greenhouse studio required, and in either case do I need some sort of extractor device."

The fumes are not from the lead or solder, they are from the flux.  Eye protection is important.  Gentle ventilation is sufficient.  A small fan to create a current of air to the outside will do of there is no other ventilation.

“If you give items away/sell them. What safety advice do you give to people.”

Lead is only dangerous if consumed.  It is not absorbed through the skin, only by transfer from the skin to the mouth.   Once the piece is handled, wash hands before eating, drinking or touching eyes.

“Is lead free solder a better option for small sculptures, which are not jewellery.”

The risks of lead poisoning are greatly exaggerated. If the pieces are not worn, the risks are minimal. If the pieces are not handled, there should be no transfer to the digestive system. Lead free solder is more difficult to work than a lead/tin alloy.

“What gloves are good to prevent cuts. I’m presuming disposable gloves are best for soldering.”

Skin tight cut resistant gloves are best, but are uncomfortable for long use periods. They can be used for soldering too. Honestly, I don’t use gloves for anything, and my blood lead levels have been below the minimum for the 30 years I have been working with lead and solder.

These are my opinons, of course.

The best guidance on health and safety for stained glass workers, is Greg Rawls’ website.  His career was in industrial health and safety until retirement a couple of years ago. He gives sensible, scientifically researched advice, which is not alarmist.

Care in the Operation of Soldering Irons

The most important element in the deterioration of soldering iron bits is long idle times. This is where you leave the iron on, and not in use, for a long time.

Have everything ready when you start soldering, so the iron will be used continuously, and will not sit there building up heat, while you get ready to use it again. An idle iron will keep heating to its maximum capacity, and without anything to transfer the heat to, it will start burning off the tinning, after a short while. So if you will not be using the iron for a while turn it off until you are ready again.

Even if you have a temperature controlled iron, idling for a long time at the set temperature does have the same but lesser effect as one without temperature control.  

The other elements leading to deterioration in performance come from lack of cleaning and tinning of the tip. When the coating of solder burns off or is coated with carbon you get poor heat transfer from tip to working surface making it appear that the iron is not heating properly.

An example of a heavy stand

It is important to ensure your electrical supply cord is kept away from the hot end of the iron to avoid burning through the cord.  In another studio the supply was from overhead so the cord was never trailing across the work or the bench.  A solid stand to place the iron into is important to both avoiding damaging the electrical supply and melting other things around.  To assist this, all materials not relevant to the soldering process should be put away before the soldering begins.

Protect yourself from burns from the iron or hot solder.  Always keep your hands away from the hot end of the iron.  Always place the iron into the holder when making adjustments of any kind that interrupts the soldering.  Keep burn relief, such as aloe vera by the soldering station.

Eye protection is important, because the flux fumes often contain chlorine compounds that can affect your eyes.  This is more important than breathing protection.  If good ventilation is being used, that will be enough for lung protection, and will reduce the risk to eyes, even then, eye protection should still be used.

Finger Protection While Grinding

 Grinding lots of glass pieces often leads to a number of small cuts on the tips of your fingers. There are several things that can be done to reduce these cuts and the tenderness that comes from lots of grinding.

Various methods of protection are used.

Altering the fingers used to press the glass to the grinding bit.

Gloves –  It is not recommended that you wear gloves around rotating machinery. There is too much risk of injury, even on a small grinding machine. Some of the alternatives to gloves include plasters (band aids), masking tape, electrical tape.

Finger protection you can buy include rubber finger protectors, finger tip pads, finger caps (as used in counting money).

Other tools are made to hold the glass such as the grinder cookie

and Nick's Grinder's Mate 

Prevention
The sore fingers are usually caused by tiny cuts from the glass. So, all these methods are ways of putting something between the glass edges and your fingers. More importantly, you need to think about your practice if you are getting sore fingers while grinding.

The first thing is just to lightly grind all the way around the piece. This can be quick, and should use minimum pressure. This to is to take the sharp edges off the glass.  You can do a simple, light grind all the way around the piece. This removes the extra sharp edges that often remain after breaking the glass.

You can go a step further and do a light arris around the piece. This is just lightly holding the glass at about 45degrees to the grinding bit and going all the way around on all sides. This does not take off the shape of the piece, but gives a more rounded feel to the piece.

An illustration of the effect of holding the glass at an angle to the grinding head, although it need not be so much.

If you have to press hard to achieve the effect you want, it may be that your grinder bit is badly worn. It may also be that you need to have a coarser bit to achieve the amount of grinding that you need.

You should not be pressing hard in any case. This will wear out bearings on the motor and reduce the life of the bit.  Let the grinder do the work. Many people seem to put huge pressure on the piece to grind away the waste more quickly, but this is actually counter-productive. Less pressure means less fatigue, less chipping at the edges, fewer broken pieces, and most importantly, fewer cuts to the finger tips.

You should use medium pressure to allow the diamonds on the grinding bit to do the work. This will be about the same pressure as scoring the glass.  Fine work requires a fine grit, removing a lot of glass requires a coarse bit, not more pressure.  

If you frequently have to remove large amounts of glass, you need to review the accuracy of your cutting. You should not be relying on the grinder to do more than tidy your cuts.

Remedies
There are several remedies to relieve the soreness:

Cucumber melon
Vitamin E
Tea tree oil
Germolene
Antibacterial hand lotion 

Cutting Glass

Techniques and Safety

Use of the Glass Cutter 

When cutting glass your are first scoring the surface to weaken the glass and then second, breaking along the score line. The glass will always follow the path of least resistance. It is important to keep this in mind when “cutting” glass as it has significant implications for scoring and breaking.

Use the cutter by moving it away from you, so you can see the cartoon lines as you score. When using a straight edge, you can pull the cutter toward yourself or push it away, whichever suits you.

Grasp of the cutter

The classic or traditional grasp is for use with a pencil cutter. The cutter is placed between the first/index and second /ring fingers with the thumb at the back of the cutter. This initially is awkward. Its advantages are that it transfers most of the work to your arm rather than fingers and wrist, and it restricts the movement of your wrist, leading to smoother curves.

Basic cutter in traditional grasp

Oil filled pencil cutter in traditional grasp

The modified grasp is also for use with pencil cutter. The cutter is placed between the thumb and first/index finger. The second /ring finger is also most often used beside the first/index finger. The fingers should be straight to avoid excessive strain on the fingers and possible carpal tunnel problems later.

Modified grasp with straight fingers

The fist grip for use with pistol grip cutters. The cutter is held similar to a gun, with the first/index finger pointing down the shaft holding the cutter head. This pointing action seems to aid the accuracy of cutting. This applies to cutters with right angle handle attachments also.

The palm grasp is for the small Toyo and other palm cutters. The cutter is placed on the pad beneath the thumb and held with the first/index finger and thumb.

Scoring Glass

Cutting glass is done by “scoring” the surface of the glass with a glass cutter, then breaking it along the score line. The break you make will always follow the path of least resistance, so you want to be sure that the score you make becomes that easy path and glass breaks the way you want it to.

Moving the Cutter

Generally, you use the cutter by moving it away from you, so you can see the cartoon lines as you score. When using a straight edge such as a cork-backed ruler to guide your cutter, you can pull the cutter toward you, or push it away as suits you. The cutter should always be held at a 90 degree angle (left to right). You can determine this by looking down the cutter to the wheel and to the cartoon line below.

Alignment

The cutter should be held so that your dominant eye looks along the cutter to the cut line just in front of the wheel. This ensures you are looking directly to the line and that your cutter is not tilted to one side or the other. Looking down the side of the cutter only ensures that it is tilted with the effects indicated above.

Tilted Cutter Effects*

A tilted glass cutter has the effect of changing the angle of the cutter wheel. It narrows the angle on one side and increases it on the other side. So on the side tilted away from vertical (which is what happens when you look down the side of the cutter) has an sharper angle with the glass. This is likely to produce chips along the cutting line. The side which is tilted toward the glass has a more blunt or shallow angle with the glass. This produces high stress along the line.

The combination of these two effects make for a rough edge when broken and for break failures because of the stresses being at angles to the desired vertical fissure line.

Steering the Cutter

It is important that the work be done from the forearm rather than the fingers or the wrist. The elbow should be held closely to the body. This reduces the freedom of movement, giving clean flowing score lines. It also reduces the actions that can lead to repetitive stress injuries. Of course, for long cuts your arm will have to extend from you body in a parallel direction with the score line.

All these instructions about holding the cutter are reasonably straight forward when cutting straight lines, but become more difficult when applied to curves. The temptation is to use your wrist to make the curve. However this both tilts the cutter – giving the results described – and risks the cutter sliding across the glass.

You should attempt to be behind the cutter at all times. This means that the steering action should be from your body. Most times, turning your torso from the waist is sufficient to enable the cutter to follow the curve. On curves which are deep or go through more than 90 degrees, it is best to place the glass at a corner of the work bench and “walk” around the piece by both twisting at the waist and moving your feet around so that you can make a 270 degree cut without moving your forearm from your side.

Scoring Pressure

The second and very important element in scoring glass is the amount of pressure used. Very little pressure is required. You should hear no more than a quiet hiss on transparent glass and almost no sound on opalescent glass. However some manufacturer's transparent glass has almost no sound either. So the important element is the pressure, not the sound. Most people start with applying far too much pressure. Tests have shown that only about 4 kg of pressure is required for a clean score.

You can test the effect of this amount of pressure on a bathroom scale. Place a piece of clear glass on the scale and without touching the glass with your other hand, score it noticing how much weight is being recorded. Keep trying until you are consistently at the 4 kg area of pressure. Try breaking the glass. Score a curve with the original amount of pressure and break the glass. Then using the same curve score the glass with the 4 kg pressure and break the glass. You will see and feel the lesser scoring pressure provides a clean break.

Excessive pressure leads to breaks showing significant stress marks on the edge of the glass. Too little pressure has no effect on the glass, making it impossible to break along the score line. The correct pressure (ca. 4 kg.) leads to almost vertical stresses being put into the glass which assists the breaking along the score line. Too heavy pressure creates stress marks which are at increasingly large angles with the increasing pressure. This will still break cleanly on straight lines, but when working around curves the glass can follow one of the lateral stress marks away from the score line. Excessive pressure is often the cause of glass breaking away from the score line on a curve, especially a tight one.

The pressure needs to be applied consistently throughout the length of the score. Uneven pressure leads to inconsistent breaks.

Scoring Opalescent Glass

Cutting opalescent glass often gives difficulties in getting clean breaks along the score line. You need to remember that the opals do not make much if any sound when cut with the correct pressure. If you are scoring so that you hear the ziiip sound, you probably are pressing too hard. When the score is too hard, the opals do not break easily or truly. Only the same pressure as used on transparents is required. Feel the pressure rather than listen for the sound.

Speed

The speed of the cutter needs to be consistent too. If the speed is not nearly constant, different pressures are transmitted to the glass. This also leads to inconsistent breaks.

Where to Start Cuttng the Glass

As a general rule, always make the hardest cut first. Glass tends to run in a straight line. This means inside curves should be done before any other cut is made. This avoids excessive wastage should the break come away from the score line.

Glass placed to make the inside cut at the right first

It will be most efficient to place the glass to be cut with the inside curve facing the raw edge of the glass. If something goes wrong, the glass can be moved and tried again, resulting in less glass and time wasted.

It is also hard to run very thin strips of glass without getting ragged, chipped edges. Allow a 6mm minimum distance from the edge of the glass when placing the glass on the cartoon unless the edge glass is going to be used for the whole edge of the cut piece.

Direct or Trace cutting

Place the glass over the pattern and run the cutter along the cartoon lines you see by looking through the glass. There's no need to draw lines on the glass. For translucent glass you may need a light box.

You should be aiming to cut glass efficiently and accurately. Trace cutting is the most efficient, as it completes in a single operation what other methods – such as drawing on the glass or making templates from the cartoon - take several steps to accomplish.

It is more accurate because each extra step required for other methods increases the possibility for error. The fewer times you copy the original pattern lines, the less likely you are to diverge from the original pattern.

It is very important to keep the cutter at right angles to the glass - as seen from side to side, not vertical. This of course is true of all cutting. It makes the cutting inaccurate, because the light is bent when coming through the glass much like water changes the apparent angle of sight into its depths. Tilted cutters also have undesirable effects when breaking the glass.

Cutting with Patterns or Templates

When scoring around a paper pattern it is necessary to steer (turn) the cutter in the proper direction. The paper will not turn the cutter for you. You should steer the cutter by turning your upper body rather than your fingers, wrist or elbow. Failing to do this may allow the cutter to run over the pattern and so fail to score the glass.

Alternatives to using the paper pattern directly as a guide in cutting glass are to outline the pattern paper on the glass with a pen or to draw the pattern on the glass while it overlays the drawing. You follow the inside edge of the pen line with the cutter. However this results in cutting glass much as when cutting directly over the cartoon and so merely introduces an additional step in cutting glass.

This shows a set of templates in use for repetitive cutting. The template is drawn around for subsequent cutting

Directly cutting the glass over the cartoon avoids the time spent in making patterns, and the difficulties and inaccuracies in multiple transfers of the shape. Often a light source is required under the cartoon to enable the lines to be seen through the glass. There will always be times when the glass is so dark or opalescent that the lines cannot be seen and therefore a pattern is required.

Keep the pattern cutting restricted to the times when nothing else will do. The only times I use patterns for cutting are when the glass is too dense for the cartoon lines to be seen through the glass with light behind or for repeat shapes where a pattern can speed the process.

I draw around the pattern pieces, as that avoids the possibility of the cutter riding up on the card that I use for templates. This comes from several occasions when the cutter did go over the template which prevented the score and so created a bad break. Others do score successfully around the template stuck to the glass.

Pattern Scissors Usage

The purpose of pattern shears/scissors is to cut out the space between pattern pieces equivalent to the came heart or the space needed for foil.

The scissors come in two thicknesses – one for leaded and the thinner for copper foil.



If you must use pattern scissors, use them in short cutting motions. Use only the first 50mm of the blades which are closest to the pivot point. Otherwise the paper jams in between the blades. It remains difficult to cut long straight lines without quickly having an “accordion” of paper blocking the cutting action.



Some suggestions to make things easier:


• Clean the blades regularly. If you are cutting anything with adhesives, clean the blades after each use with spirits.

• Often running a little soap along the blades helps to lubricate and smooth the action of the blades.

• Use stiff high quality paper so you do not catch fibres in the scissors. Waxed paper or stencil card are good materials to use.



Organising pattern pieces. 


You have made a second and third copy of the cartoon haven’t you?
 Now that you have a lot of pieces need to decide how to organise them

• Mark any grain direction before you cut the pieces apart.
• You need to code the pieces in some way. 
Numbering with reference to the main cartoon is most common. 

• It is a good idea to colour code the pieces and if the surface will take it, a shading of the colour makes a quick visual reference.

Keeping the pieces together
Envelopes are easy to write on for colours, or areas such as borders, background, etc.

• Freezer bags that are transparent and have a band to write on are very good, as you can see the pieces without opening the bag.
• You need a labelled bag or container to keep all the envelopes together.




Alternatives to pattern scissors


For copper foil, you can use normal scissors, by cutting to the inside of the pencil or inked line. You can also use a scalpel or craft knife to cut to the insides of the marked lines.


For leaded glass you can use a felt tip pen (a bullet point is almost exactly the right width when new). Cut with scissors or craft knife at the sides of the line.



Alternative to pattern pieces


Use the European or trace cutting method as described here.

Breaking glass with your fists 

For scores with significant, but not necessarily equal, amounts of glass on each side of the score this is a quick simple approach to breaking glass. After scoring, raise one edge of the glass and put your fingers under the glass on each side of the score. Curl you fingers into your palm, and put your thumbs on top of the glass. Turn your wrists outward while holding the glass firmly, and the glass will break cleanly.

With practice, the initial part of a curved score can be run by applying light pressure. Then you can turn the glass around and run the score from the other end to the opened score. This avoids lots of tapping and gives clean edges to the cut glass. It is just as simple as using cut running pliers and avoids the flare often associated with using cut running pliers.

This technique works best with glass that has at least 50 mm each side of the score and on gently curved lines. For tight curves and narrow strips other methods need to be used.

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.

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.

Refining rough cuts and sharp edges

You can make the freshly cut glass safer to handle by gently wiping the edges of the cut piece with the waste piece. This removes the sharpest edges without chipping the glass.

After the glass is scored and broken, you can remove small, unwanted chips with grozing pliers. The serrated jaws of these pliers are used to gently nibble away at the jagged edges.

Rough edges can also be smoothed with a carborundum stone. You rub the stone along each edge, upper and lower, to remove any sharp edges. You can remove more glass with the stone if you wish by a little more aggressive grinding action or just a more sustained light rubbing of the stone against the edges.

A diamond smoothing pad removes glass in much the same way as a carborundum stone, but does it more quickly with the coarser grades. You can use a number of grades to get an almost bright polish to the edges. These pads must be used with water.

A glass grinder is used by many people. Many models of grinders are available. The grinding surface of the bit is covered with fine diamonds, which grind away unwanted glass very quickly without chipping the edges. In addition, they are water-fed which keeps the glass from cracking due to heat, prolonging the life of the diamond bit, and preventing the powdery ground glass form flying around.

A glass grinder is NOT a substitute for accurate cutting.

*This section has been prepared from information provided by the Fletcher-Terry company: http://www.fletcherviscom.com/home.shtml

Other sections:

Tools

Soldering Techniques

Soldering Techniques 

Soldering - how it works

Soldering is a well known and widely used process where two or more metal items are joined together using a fusible alloy with a melting temperature that is lower than their own. The most commonly used solder is a fusible alloy consisting essentially of a tin and lead mixture.

The solder actually dissolves a small amount of the metal’s surface, at a temperature that is well below its melting point and joins with it. It is this solvent action of the solder alloy that causes it to fuse with and attach to the surface of the metal items being joined.

The solvent action that takes place, between the solder and the metal, makes the joint chemical (not just physical) in nature and causes the properties of the joint to differ from the original solder’s properties and from those of the surface of the metal items being joined. When metal parts are joined by solder, a metallic continuity is established as a result of the interfaces where the solder is bonded to the metallic surfaces.

Courtesy of American Beauty Tools

Soldering vs. Welding

The metal joining process that is generally referred to as soldering (or soft soldering) requires temperatures between 183 to 445°C. The joining of metals at temperatures above 445°C (and below the melting point of the metals being joined) is more commonly referred to as brazing (or hard soldering). The actual melting and fusing of the metal items that are being joined together is considered welding. There are, of course overlapping situations that may occur when classifying a process.

The actual joining characteristics that take place are physically different in each of these processes. Soft solders attach to metals by what is referred to as a solvent action that takes place at relatively low temperatures. Hard solders, or brazing alloys contain metals that require higher temperatures to cause the solvent action to take place and fuse the alloy with the metal being joined. Because welding involves actually melting and fusing the surface of the metals that are being joined together, a filler, or fusible material is not always used.

Courtesy of American Beauty Tools

Creating a Quality Solder Joint

Soldering is the process that uses solder (a metal alloy usually consisting of tin mixed with other metals) for the metallurgical joining of metal components to form an electrical, mechanical or hermetically sealed bond at temperatures (less than 449°C) that are well below the melting temperature of the individual components that are being joined. The soldering equipment used to create the required heat and other materials (solder, fluxes, heat sinks, fixtures, etc.) should always be properly matched to the intended soldering application. The equipment and materials used may vary, but the basic soldering techniques that are required will usually remain the same.

One of the most important rules to remember about soldering is "keep it clean". This includes, not only the items being soldered, but also the materials used. Choose quality solders and fluxes without unnecessary impurities. Surface oxidation, contaminants and other impurities are some of the most common reasons for poor quality solder joints. The use of fluxes does not eliminate the need for pre-cleaning the surfaces you are joining, especially if heavy oxidation or large amounts of grease, oil or dirt are present. The stages of soldering are:

Clean: Thoroughly clean all surfaces to be joined, removing any dirt, grease, oil, oxidation, paint, coatings or other impurities that may exist before attempting to solder. Proper wetting can only occur when the intended solder joint area has been properly cleaned. Soldering should be performed as soon as possible after cleaning to eliminate the possibility of re oxidation or contamination of the items being soldered. [So leaving pieces fluxed overnight is not good practice. Flux only the area that can be soldered in the next few minutes.]

Flux: Apply flux sparingly to each of the intended joint surfaces. Flux is primarily used for the removal of light oxidation and to protect against re-oxidation during the actual soldering process. Make sure you have the right flux for the application being performed.

Heat: Apply heat directly to the intended joint area. The correct application of heat is important and should be consistent with the operating requirements determined by the type of equipment being used. Fast and accurate heating will minimize the risk of thermal damage.

Solder: Add solder to the heated surfaces you are joining (do not apply solder directly to the tip, or other heat source being used). The solder should flow uniformly over all of the surfaces that are being connected. Stop feeding solder as soon as you have applied an adequate amount and then remove the heat source. The amount of solder is important because too much will create unnecessary waste, while too little can affect the mechanical strength and conductivity of the finished solder joint.

Cool: Allow the finished solder joint to remain undisturbed until it has completely cooled. You should never attempt to speed up the cooling process by blowing on the solder joint. Even minor vibrations or disturbances during cooling, can cause micro fractures or other types of damage that may severely weaken the solder joint.

Inspect: Check all finished joints for proper wetting, the right amount of solder, a good physical appearance, and the required mechanical strength.

Skills


A quality solder joint is not achieved solely by the equipment and techniques being used, but also by the operator being trained to use them properly. An operator should know how the physical appearance of a finished solder joint helps to determine possible flaws that may exist.

A quality solder joint appears bright, shiny and smooth with all components appearing well soldered. The surface of a finished joint should never look rough, grainy, dull, or flaky (these are signs of what is commonly referred to as a cold solder joint). Problems with proper wetting (solder balling up and not adhering to the components surface) are sometimes associated with too much heat, but are more often related to cleanliness issues.

Courtesy of American Beauty Tools

Exhausting Soldering Fumes

Making a fan


Exhausting fumes while soldering is a safety issue of some importance. If you happen to have an outdoor screened-in studio a simple fix can be had with a computer fan You can scavenge such a fan from an older used computer ready for disposal. Simply cut four timbers 50mm square or 25mm x 100mm to fit around it as a box. Attach a long electrical cord to it with an approved plug;. Attach a screen to both sides. Plug in. An additional feature is to attach an activated carbon filter (as used for cooker hoods) to the front of the fan. This removes particles and some fumes.

Positioning

Always set it to draw fumes away you, generally pointing it so that it is blowing the fumes in the same direction as the larger air flow in the studio. In general a very large fan doesn't always do the job alone, since the fumes always seem to rise up and find your nose. However, with the additional tiny computer fan sitting right next to where you are currently soldering, the fumes just move away.

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Materials
Tools