Overheating and prolonged heating, even at low temperatures, quickly looses glue strength. It is
advisable to have the glue pot thermostatically controlled to minimize the time that the glue is kept in the
melted condition. At the end of the day the glue pot and brush should be sterilized so bacteria are not
carried over to contaminate the next day's batch. The correct proportion of glue and water will vary with
the strength of the dry glue and the size of the abrasive particles to be held. When the type of hide glue
has been selected from a reputable supplier, exact proportions of glue and water should be decided
upon for the size abrasive to be used. This proportion rigidly adhered to measuring the glue and water
by weight rather than by guesswork.
The following condensed table gives approximate proportion, which will help in determining the final
figures after the brand of glue has been selected.
When glue stirring is required, a preliminary coat should be applied by a bristle brush and allowed to dry
before putting on the coating that is to hold the abrasive. New wheels should be rinsed on both the face
and sides.
To prevent chilling the glue, the wheel and the abrasive should first be heated to approximately 1200º
Fahrenheit. The coating for the first head should then be brushed on and the wheel immediately rolled in
a trough of the proper abrasive.
After allowing to air dry well for one to two hours, the second coating if required is applied in a similar
manner. In order not to contaminate the wheels with wild abrasive grains, separate brushes and
separate glue pots should be provided for each size abrasive.
After the final coatings, the wheels are dried in a well-ventilated room at about 200( Fahrenheit, with a
relative humidity of about 50%. Wheels should be dried for 24 hours for each abrasive head applied.
After drying, the wheel is balanced and the surface broken up to provide resilience and free cutting by
hitting with a round bar diagonally across the face of the wheel.
GRIT SIZES
GRIT SIZE % by weight