Windows and doors
For window panes up to .75 m˛ use 3 mm thick float glass.
From .75 m˛ to 1.7 m˛ use 4 mm float glass and above 1.7 m˛ use 6 mm float glass.
In doors fitted with full length glass use 6 mm “SafetyGlass”, “Shatterprufe” or laminated safety glass.
Always measure the height and width tight against the widest part of the frame opening in which the glass fits and deduct 5 mm to allow for expansion of the glass and frame.
Take these measurements to your glass merchant
or, if you have a spare piece of glass but too big, cut it to size. (See: How to cut glass
Put down newspaper, plastic or canvas sheeting to catch all the debris.
You will need about 400 g of putty per running metre
- With a hammer and an old wood chisel or screwdriver remove all the old putty and broken glass. Be careful with larger pieces and tap the chisel gently to avoid breaking adjacent panes. As soon as larger pieces show any tendency to move remove them by hand rather than let them fall. It is best to wear leather gloves for this operation.
- With the frame completely clear of all putty this is a good time to do some frame maintenance. If there is any tendency to rust remove all old paint, brush the frame with a steel wire brush and apply a good rust converter or rust inhibitor which also serves as an undercoat.
- Roll the putty between the hands, adding some turpentine if it is too hard. Mix a teaspoon of white cement (or ordinary cement if there is no white cement available) per 500 gm of putty as a hardener.
- Roll a “sausage” in your hands and push this with your thumb against the frame rebate as back putty. With a constant pressure push the new glass against the back putty until it is about 2 to 3 mm from the frame all round.
- Fill the front of the rebate with putty. Again roll a “sausage” and press into the frame with your thumb. Ensure that it makes a solid bond with the frame and glass and that you put in sufficient putty to finish off without having to add more.
- Finish off with a putty knife. With constant pressure and the knife at a 45° angle cut away the excess putty from corner to corner, at the same time pushing the putty into the frame. Always work from corner to corner to ensure that you get a smooth finish. The finished putty “bead” should just cover the rebate of the frame. Your putty should not stick to the knife but if it does wipe the knife with turpentine. Under no circumstances use water. If you get just a drop of water between the putty and the glass the putty will not stick there.
- Finish off the back putty by pressing and cutting the putty into the cavities ensuring that there is a slight bevel from the glass to the frame to prevent water from seeping between the back putty and the frame.
The putty can be painted in ten to twelve days.
- Remove the quadrants holding the glass in place with a sharp bevel chisel.
Clean the frame of all old putty, glass and nails.
Back putty the frame, put in the glass and replace the quadrants pushing them up evenly against the glass and nailing down with small panel pins preferably in different places from the old nails. Sink the heads with a No.1 nail punch or a larger, blunted nail.
If the quadrant is to be painted the old holes and the new sink holes may be filled with putty. Otherwise fill the holes with an appropriate colour wood filler.
As there are many ways in which glass is fitted in aluminium frames, study the construction of the frame before starting the job.
Most glass is fitted in aluminium with a rubber insert. Be very careful not to damage this when removing the glass.
If the retaining beading is screwed down, replace the screws with new ones if at all possible; the chemical reaction between steel and aluminium can be corrosive.
If there is no beading that can be removed the glass is fitted in the aluminium sections of which the door is made.
Remove the frame from its hinges.
At the top and bottom on the opening side there will be screws or bolts holding the frame together. Undo these.
Slide the opening side of the frame away and remove the glass, being careful not to damage the rubber insert.
Clean the inside of the insert carefully. Remove all old glass and dust.
Paint the inside of the rubber with turpentine and slip it over the glass. Using plenty of turpentine as a lubricant in the groove of the extrusion, work the glass with the rubber into the groove. A gentle tap with a rubber mallet may be needed.
Reassemble the frame and replace it.
Picture frames are fitted with 2 mm glass. These days non-reflective glass is more readily available and cheaper than float glass.
Allow at most 1 mm for expansion.
Tools used on this page
Undo the picture wire from one of the screw eyes.
With a sharp knife cut through the backing sheet or tape along the frame.
Remove the panel pins or staples with a small pincher or a pair of pliers.
Lift out the backing board.
Lift out the picture with its surround.
Clean the new glass very thoroughly on the inside. Washing in hot water with a liquid dishwashing soap and immediately drying it with a clean dry dishcloth will do the trick.
Place the glass cleanest side up in the frame.
Place the picture on top making sure that it is the right way up. The screw eyes in the sides of the frame are normally one third of the height of the frame from the top.
Replace the backing board and nail into place with 6 mm x .5 mm panel pins using a small panel pin hammer.
Tape the back of the frame across the join with buff packaging tape.
Replace the picture wire.
Panel pin hammer
to top of page