When to Apply Patina?

 Is patina able to be applied days later or does it need to be applied immediately?

The best method is to clean the solder with non-metallic mild abrasives. If the bare solder is left for a while, the solder needs to be cleaned again, as oxidisation begins immediately. Any oxidisation inhibits the patina reaction and provides an uneven finish.

Once the solder has been cleaned with non-metallic scrubbing, wash in cold water, dry at once, and immediately apply the patina.

Can you leave the solder silver with polish/wax until you decide which color and go back later? 

It may be possible, but it is not a complete protection against oxidisation. It will, of course, reduce the amount of oxidisation and make the clean up a little easier. But, any polish needs to be thoroughly cleaned off and the solder scrubbed clean, washed, and dried before applying patina. So it may be most simple to cover the soldered panel with plastic cling film (Saran wrap?), or in a sealed plastic bag until it is time to clean the solder and patina.

In both cases the important elements are to

• clean back to bare solder,

• clean with water,

• dry immediately and

• apply the patina acid right away.

Patina Application for Copperfoil

by Stephen Richard

My observations:

• Wash the whole item, concentrating on the solder lines.

• Use small brush such as a toothbrush.

• Avoid ammonia as it creates the possibility of residue.

• Whiting/calcium carbonate rubbed over whole project will effectively clean as it is a very mild abrasive. It is not good at cleaning acids from under solder though.

• Baking soda – there is some fear of scratching, but in solution there should be no granules. It bubbles in the presence of acids, so there is a visual indication of the presence of acid. But make sure you get it all off the project before applying patina. as it is alkaline, and tends to neutralise the acidic patina.

• Use of an abrasive like fine steel wool, or to prevent transfer or metal, a kitchen scouring pad on the solder to help with a smooth application of the patina.

• Waxing is usually done after the patina application.

• Application of the patina is best done with gentle, light pressure from brush, sponge, cotton buds or rag.  Allow time to react with the solder it is a gradual chemical reaction.

• Buffing or polishing the patina is to be done after it is dry, using light pressure to avoid rubbing the patina off.

• Waxing will polish the patina as well as protect it from oxidisation.

• Note that patinas are acids specific to various metals, so black for zinc is different from that for solder and lead, and both are different from each other.

• Patinas will get darker with time.

More Details

The application of patina to solder and other metals consists of three stages:

• cleaning,

• application,

• protection.

Cleaning

 Flux residues and other contaminants are left after soldering.  Cleaning can be a combination of cleaning with abrasives and alkaline materials.   After soldering, cleaning and drying your piece, use fine (000) or extra fine (0000) steel wool and a brass wire brush to go over all the beads. Use a brush first if you want, and follow with the steel wool, since it will provide fewer scratches. This helps remove any leftover flux that on solder lines.  Some advise metal abrasives as residues can be left. However the plastic abrasive pads used in scrubbing pots can be used to finish the cleaning without leaving metallic residues.

Omitting this step increases the chances of developing whitish blotches later on the solder lines.  Including this step also makes a better base for applying the patina.  After using the steel wool, use a soft brush to remove any residues from the steel wool, brush, flux or solder.  Baking soda – sodium carbonate – can be used to neutralise any of the acidic flux left. It bubbles in the presence of acid,  giving a visual check for any acid left.  It is important to rinse the baking soda off with plenty of clean water.

After cleaning the solder beads, wash the panel off with warm water and a little dish washing liquid to remove oils and other residues. When washing use a very soft scrubbing brush to get in all the little crannies.

Dry the piece with a soft towel. If the piece is framed in zinc, make sure that any trapped water is eliminated and the piece is entirely dry. Often letting it stand overnight will be sufficient. A panel with no moisture will help the polish be more even.

Apply the Patina

As patinas work by chemical reaction, they are specific to various metals. Those designed for solder react with the tin mainly, those for lead react with lead, and those for zinc react with zinc. Although each of these may work with other metals, they work best with the metal they are designed for. Too much rubbing while the patina is wet simply interferes with the action of the acid. Application of enough patina to allow it to "soak" - actually time to react with the metal - is much better than rubbing. It is a chemical reaction, not a buffing process.

Pour a small amount of the patina into a small container so as not to contaminate the rest of your patina. Do not pour the remainder back into the bottle, as it will begin to neutralise the main supply.  Apply your patina with a small flux brush reserved for the purpose, or a piece of a rag. If you use a rag, renew it frequently. Do not be afraid of putting too much on. If you are not happy with the colour when dry, you can rub the solder over with a 400 (also known as 000) wire wool or an abrasive scrubbing pad to abrade the surface. Then give it a further coat.

Once the patina is dry, you can use the baking soda solution again to neutralise the remaining acid on the metal, but it is not absolutely required.. Rinse well, and rub gently with a dry cloth to assist the drying, do not scrub. When dry again you can re-wax the metal.

Sometimes a white residue appears alongside the solder bead after a piece is finished, covered in patina, and waxed. This seems to have two causes.

Residual acid

As there is a possibility of some acid remaining on the piece, rinse with a bit of bicarbonate of soda added to the water. This will neutralise the acids from the flux and patina that may still be lurking under the foil and solder beads. If you get a frothing while cleaning with the soda, you will know there is still acid present. Wash - rather than scrub - those areas again with the water and soda solution until there is no foaming.

Trapped moisture

Moisture can also produce this white residue, as it allows minerals to migrate from under the solder seams. The advice centres on cleaning. Do not use much soap in the initial cleaning solution. After rinsing ensure the piece is completely dry by setting it aside in a warm dry place for a day or two before waxing or sealing.

Preservation

To preserve the desired finish, a coat of beeswax, carnuba, or other car wax helps, but remember that copper will oxidise over time no matter what you do. It is this what gives it a rich deep antique lustre.

Some allow the waxed piece to sit for 24 hours and then re-wax it. The applicator should be a soft object such as a cotton bud or soft cloth. Do not polish it until it no longer is showing black or copper. Rather allow it to sit undisturbed for several days. The patina will get darker and smoother over time. Don't worry too much about getting it pitch black, or bright copper the first day.

Those that use paste waxes seem to have less difficulty than those who use thin or spray on waxes. The heavier waxes seem to seal any moisture within the structure. The moisture seems to be able to migrate through the thinner waxes. Still, it is not optimum to have moisture sealed within the panel, as it will eventually come through the wax as it ages. It seems the best long term result will be achieved by ensuring everything is absolutely acid free and completely dry before waxing.

Use a good quality furniture polish or wax. Shake the bottle well if it is a liquid, then apply liberally to a soft cloth, or good quality paper towel, rubbing all over solder. If you have a glass with a deep texture, try to avoid this all over process, as it can be hard sometimes to remove all of the polish from th edepth of the undulations afterwards, and it is noticeable when it dries. Alternatively, mask off the glass from the solder.

Immediately after applying the polish, take a clean, dry soft cloth or new paper towel, and begin to gently rub the solder seams. If you are using paper towels, you will need a lot of them, as they tear up quickly. When both top and bottom sides have been polished, check for any missed spots, especially along the edges of your solder seams. Also check for polish residue in tight corners and along the edge of the solder. An old toothbrush often works to remove it. If you need stiffer bristles, make sure you keep this new toothbrush separate from all the others in the house.

Observing these methods should provide long lasting patinaed pieces.

Revised 4.8.2025

Glass Grinder Maintenance

by Stephen Richard

Glass grinders are often the main machine used in stained glass.  They are important machines to many of us and so need proper maintenance and use to give us long service.  This note is about the things you need to keep in mind about maintaining the grinder.

Glass grinders are very handy tools. They mainly consists of a spinning diamond coated cylinder (the bit) extending above a grid surface that can rapidly and accurately grind glass to the desired shape.

Don't purposely cut glass large with the intention of grinding. Ideally no grinding would have to be done. It should be used only for minor adjustments or for grinding tough-to-cut inside curves.

Cleaning

The water reservoir should be emptied each day after use.  It is not advisable to have standing water in your grinder for some health reasons, avoiding unpleasant smells, and as moving a grinder with water risks damaging the grinder’s motor and other equipment and materials in the studio.  Even if you do not move your grinder about, the water needs changing just as frequently as the glass grit needs removing.  Some people line their reservoir with aluminium foil to catch the grinding residue.  This may not be possible on all grinders, but does reduce the effort of cleaning the grit from the bottom of the reservoir.

Ensure you clean your sponge (if the grinder uses one) when cleaning out the reservoir.  If you do not clean it regularly, it will become hard and stop bringing water to your grinding head.

The accumulated glass grit should be cleaned out with scraper or paper towel and disposed of in the waste, not down a sink.  The glass grit is relatively heavy and will become solid and block your drains.  If you have a garden, the glass grit is a good soil modifier, by helping the drainage.  Without regular cleaning, the glass grit will accumulate and restrict the flow of water to your grinding head.

Clean any plastic eye shield with running water, as rubbing it will scratch the surface.

Ensure there is water in the reservoir before starting any grinding, but do not over fill as the excess water could get into the motor. Empty the reservoir at the end of the day's use. 

Grinder Head Maintenance

Wear - There seem to be two main indications of wear – chipping of the glass, and slow grinding.  There are a number of reasons that may cause the grinder to chip the glass surface and not all are indications of wear. Some of the things to check are:

• Too much pressure will cause the glass to chip.  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 motor slows, it is an indication that far too much pressure is being applied. It will also lead to cuts on your fingers. Run the glass lightly against the grinder all the way around to remove any overlooked sharp shells on the glass.  Then light pressure will not cut your fingers while grinding.

This shows some finger protection being used to protect fingers from cuts.

• Grit size has an influence on the way the edge appears.  It is possible that you may be using too coarse a grit on the grinder bit/head. The coarser 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 can be a source of chipping.  Oddly, new bits can cause chipping. 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.

• A worn or damaged grinder bit/head can cause chipping.  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.

This range of possible causes shows that chipping of the glass is most often comes from the way the machine is used rather than the grinder head needing replacement.

Lubrication

Water for the grinding head.  Insufficient water supply can reduce the life of the grinder head.  If there is too little water reaching the head to lubricate the diamonds and keep the glass cool it can reduce the life of the grinder head, by overheating it too. If you are getting a white paste or a powder on or near the glass, you need to increase the water supply. This may indicate a low water level, too much grit in the reservoir or sponge clogged preventing sufficient water reaching the grinding head.

The white reside on the grinding head shows there is insufficient water reaching the grinding surface

Use Vaseline or other grease on the shaft and grub screw.  Smooth any corrosion from the shaft with fine wet and dry sandpaper and lubricate the shaft. Periodic removal of the bit and lubrication of the shaft should be part of the regular maintenance of the grinder.  Also ensure the grub screw is kept clear of glass grit by putting some Vaseline in the recess.  This keeps the threads and the slot for the alan key from clogging up with glass grit.

Removing the Head

The first step in removing the grinding head is to loosen the grub screw that fixes the head to the shaft. This is often full of glass grit, so clean the recess for the alan key first. I do this by using a needle or other thin sharp object to clear out all the glass powder from the recess in the screw and the threads.  When clean, insert the alan key as far as possible and while holding it in turn the key in an anticlockwise direction.  If it will not move, you need more leverage.  If the alan key simply spins in the recess, you need a stud bolt remover tool. 

This is a tool that many mechanics and tool shops have. It is normally square or triangular. It is used by drilling into the broken off bolt. The tool is tapped into the hole and then with a wrench/spanner the grub screw is loosened. In the case of the grub screw the recess is already there so you only need to hammer the removal tool into the alan key recess and proceed as normal.

The more modern and safer method is to use a tool with a reverse thread on it. This means that as you turn anti-clockwise, the tool thread bites into the recess and brings the grub screw out.

If the grinding bit is already seized, the method of removal is based on how fast it is stuck. If there is a bit of movement around the shaft when the grub screw is removed, you can probably remove it with simple tools. First use very fine wet and dry sandpaper to remove all corrosion and roughness from the upper, exposed part of the shaft. Put a thin film of lubrication or penetrating oil on the shaft and then you can hold the top of the shaft tight with smooth-jawed pliers while you twist the bit. Be careful not to mark the shaft or you will create another obstacle to removal of the bit. Alternatively, while pulling up on the bit, you can tap the top end of the shaft gently with a plastic hammer to shake the bit loose.  Be careful with this method as the shaft is directly connected to the motor and excessive pressure can damage the motor.

If this does not work, remove the grid and turn the dried grinder upside down and spray WD-40 or other penetrating oil to the bottom of the grinder bit.  This should be left for a few days with renewal of the penetrating oil every half day. Then try the methods above to free the bit from the shaft.

If the bit is still firmly stuck, you will need a small wheel puller to get the bit off the shaft.  Small wheel pullers are available from most DIY or mechanics suppliers.  They are often called faucet pullers.

Once you have the bit off, smooth any corrosion from the shaft with fine wet and dry sandpaper and lubricate the shaft. Periodic removal of the bit and lubrication of the shaft should be part of the regular maintenance of the grinder.

Adjusting 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 lower the bit as it wears.

This bit is only just high enough for this style of grinding

An example of  the right height,although too much pressure is being applied

Here the head is only just low enough to catch all the glass. 

Be certain that you secure the grinding head with the grub screw facing the flat part of the shaft.  Failure to do that will both mark the shaft, making removal difficult, and potentially allow the shaft to spin while the head remains stationary.

This shows the minimum level for 3mm glass

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.

Care in Use

Lubrication

Water is the primary lubricant.  It washes the grit from between the diamonds and keeps the head cool.  It also cools the glass, of course.

You can buy an additive for the water – often called a diamond coolant – which is intended to provide a kind of lubrication for the diamonds. This may also extend the life of the bit, but is not necessary.

Grinding head/Bits

The diamond bit must be kept wet to prevent glass dust from developing and being inhaled.  Also, importantly, it keeps the bit cool and so avoids overheating the bit and extends its life.  There are several grits available. "Fine" grinds slower but leaves fewer chips out of the glass. "Coarse" grinds very fast but leaves larger chips. "Standard" is a central compromise.

Shaft

Smooth any corrosion from the shaft with fine wet and dry sandpaper and lubricate the shaft. Periodic removal of the bit and lubrication of the shaft should be part of the regular maintenance of the grinder.  The maintenance is not only on the shaft but also on the fixings. Putting a dab of Vaseline or thick grease into the grub screw socket will help keep it clear of the glass residue. 

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 too much pressure is being applied.  That kind of pressure also puts a lot of wear on the bearings of the motor.

Extending the life of your grinder bits is a matter of recognising that you should not force the glass into the grinding head. Excessive pressure against the head heats the bit and allows the diamonds to become free of the binding material, so reducing its life. 

If the grinder is not taking glass off fast enough for your purposes, you should put a coarser bit on the grinder, rather than press harder. The bits do come in a variety of grits. Try out some different grits to find the one that works best for the speed at which you want to remove the glass.

Maintenance routine

A maintenance routine for your grinder is a practice that will reward you with longer lives for your grinder heads and the machine itself.  A sample routine might be like the following:

Daily

Empty the water reservoir 

Clean out all the glass grit 

Clean the eye shield

        

        Weekly

Inspect the bit for wear. Adjust up or down or replace
Inspect that grub screw is free of glass grit. Clean and re-fill with Vaseline
Check head moves freely up and down on shaft.  Tighten the grub screw after.