How To Cut And Shape Rubber

Many types of rubber items can be hand made if the shape is simple. Non-available body mounting pads, axle bumpers, door and trunk lid bumpers, etc can often be fashioned in the restoration shop. Lens gaskets, etc can be cut from sheet rubber, using an exacto knife

Layout using an ordinary wax crayon to draw lines on rubber.

Slab rubber pieces 6mm or over can be cut to rough size on a band saw. Teeth should be fairly course and have some set. Spread the cut to avoid jamming the blade. Thick rubber can be easily cut with a course sharpened knife if tension is applied to spread the cut. If the knife sticks, dip it in water.

Finish the parts to shape on a bench grinder or a small disc sander held in a jig or vice. Keep the part in constant motion to finish evenly and to avoid burning the surface.

Polish the parts on a cloth mop buffing wheel using jewellers rouge or simonize cleaner as the polishing agent. Wash in gasoline when finished.

Holes can be drilled in rubber. Parts must be firmly held in the jig or drill bed vice. Speed should be set higher than normal. Placing rubber in a freezer before drilling will make it a little easier to work. The hole size will be smaller than the drill size. Experiment on a waste piece. If the rubber is less than 6mm thick, use a punch.

The other way of making up rubber mouldings, is to go to your local friendly tyre retreader and ask for a piece of uncured rubber that is used for retreading tyres. The slab of uncured rubber can be cut quite easily with a Stanley knife or a scalpel.

After cutting and shaping the rubber the area can be sanded or lightly buffed to smooth out any cutting marks. Uncured black retreading rubber is in a semi plastic state and does not resist the parring as does cured rubber. The uncured rubber can be worked just the same as the cured, but, after being shaped, the raw rubber needs to be cured.

There are several degrees of hardness for rubber, from soft to hard depending where it is being used, so all that is necessary to tell the retreader is where the rubber moulding is going to be used. I prefer to have the rubber soft for areas where the moulding is sealing off around windscreen pillars to body panels and the rubber hard for axle snubbers. To get the rubber cured your friendly retreader should have one of those steam heated ovens for curing tyres.

Both methods have there use, and I have cut door snubbers from solid rubber and I have used the uncured rubber for the more complicated shapes.

Acknowledge "Veteran Torque" (V.C.C.A.Q.) and "Early Auto", the official organ of The Veteran Car Club of Western Australia (Inc).