Marking. In order to save materials and facilitate the marking of parts,
templates should ideally be used. These may be made from tin or
cardboard, and are placed on the steel sheeting to be cut, with a minimum
separation between parts of 1/8" when cutting, attempting not to waste
materials. One method of marking out the housing and suction tube parts
on a sheet of 1.20 m x 2.40 m is presented in the following figures: Fig. 5
and 6 for the housing and Fig. 7, 8 and 9 for the suction tube.
Oxygas cutting. Oxygas cutting is performed by positioning the cutting
nozzle at the outer part of the indicated part markings, with the quantity of
oxygen and acetylene regulated appropriately. If there is too much oxygen
the flame tends to go out, while if there is not sufficient oxygen the flame
turns yellowish and the cut will be defective.
If the cut parts become warped as a result of heating during the cutting
process they will need straightening, using a mallet and wooden blocks,
attempting to avoid denting the metal.
The nozzles used in cutting the steel plates will depend on the thickness of
the metal. For the 3 mm sheeting, nozzle number 1 should be used.