Grinder Bits

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 motor slows as you press the glass to the bit, you are applying too much pressure. That kind of pressure also puts a lot of wear on the bearings of the motor.

If the grinder is not taking glass off fast enough for your purposes, you should put a coarser bit on the grinder, rather than pressing 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.

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 also extend the life of the bit.

Replacing Grinder Heads

The best action is to prevent difficulties from the start. Before putting the grinder bit onto the shaft, coat it with Vaseline or a proprietary anti seize-compound. This will ease the removal of the bit later.

If the 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.

If this does not work, remove the grid and turn the dry 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 firmly stuck, you will need a small wheel puller to get the bit off the shaft.

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

Leading Nuggets

To use nuggets in leaded glass panels, just wrap the came round the nugget. If the came leaves are oval, it works better than the flat. If the nugget is thick and does not want to fit securely in the channel, you can also use a fid to open up the top leaf of the came.

There also is a technique to cut the came to give a smooth curve given here.

Edges for Copper Foil

When doing a foil project which does not have a zinc or lead came frame, do you use a wider foil so it has a wider solder line? 

You do not need to use wider foil on the edges, but I have often done so to give the edge just as much "line value" as the internal beads. However this needs to be planned from the beginning. If you simply add a wider line on the outside, many times you will compromise the integrity of the design at the sides. You need to cut the glass a fraction larger to accommodate the thicker foil. Two millimeters added to the outside edge should be enough.

Foil not Sticking on Edge

An enquiry arrived the other day:
I’m working on another irregular shaped suncatcher and I have just completed the soldering. Now I've found one small section the copper foil is not sticking. How can I fix this?

The adhesive on copper foil tape is not a permanent one. It only sticks to the glass long enough to apply the solder to the foil. The heat of soldering often degrades the adhesive so much that it no longer sticks. What holds the solder down is the solder bead. So you probably do not have a full bead on the edge. Placing a bead on the edges of pieces is difficult but you can find a method here.

You can make the edge beading a bit easier by putting thin copper wire around the edge of the piece. This strengthens the whole piece. It allows you to attach a hanger without risk of pulling the whole suncatcher apart. It also allows you to form a bead on the edge more easily.

The bead formed on the edge curves around to the front and back faces allowing the solder to hold the copper tape more firmly to the glass.

Tie Wires

Tie wires for glazing bars are to keep the panel from rebounding due to wind pressures on the window. There also is some pressure created within the house by the opening and closing of doors, although this is minor in comparison to the weather.

The tie wires should be securely soldered to the panel at solder joints. Placing ties elsewhere leads to the tearing of the lead. The soldering of the tie wires requires more heat than simply soldering the lead joints. The tie wire needs to be heated enough to melt the solder of the joint to which it is being attached. Then an additional dot of solder needs to be added so that the wire cannot simply pull out from the joint by being only sweated to the joint.

At installation, when the panel is fully seated in its opening and fastened by nails or sprigs, pull the tie wires out at right angles right at the edge of the solder attachment before twisting the wire. Do not use any more than firm pressure. Then you are ready to cross the wires over the glazing bar. This ensures there is no excessive give in the copper tie.

Do not over tighten the tie wire twist. Only twist until snug against the bar. Then continue to twist the loose ends until you have them a satisfactory length. Cut off the twist rather than the tail ends to provide a neat finish. Then tuck the twist under or over the bar, just as you desire.