|
Home
Adhesives
Beverages
Confectionary
Candles
Chewing
Gums
Cosmetics
Lacquer
Formulations
Detergents
Disinfectants
Dyes
Fertilizers
Fluorescent
Liquids
Fruit
Preserving
Fumigants
Gold
Hair
Preparations
Inks
Insect
Bites
Insecticides
Insulations
Perfumes
Soaps
Polishes
Shoe
Dressings |
For earth cables
and exposed strong
1.- Melt 2 parts of asphalt together with 0.4 parts of sulphur, add 5 parts
of linseed oil varnish, linseed oil of cotton seed
oil, keep at 320° F. for
6 hours, next pour in oil of turpentine as required.
2.- Maintain 3 parts of elate rite
with 2 parts of linseed oil varnish at 392° F for 5 to 6 hours, next melt 3
parts of asphalt,
pour both substances together, and again maintain the
temperature of 392° F. for 3 to 4 hours, and then add 1 part of
linseed oil
varnish and oil of turpentine as required.
3.- Insulating Varnish for Dynamos
and Conduits with Low Tension Shellac, 4 parts, sandarac, 2 parts, linoleic
acid, 2 parts,
alcohol, 15 parts.
4.- An insulating material which
contains no Caoutchouc is made by dissolving natural or coal-tar asphalt in
wood oil adding
sulphur and vulcanizing at 572° F. The mixture of asphalt
and wood oil may also be vulcanized with chloride of
sulphur by the ordinary
process used for Caoutchouc. Before vulcanizing, a solution of rubber scraps
in naphthalene is
sometimes added and the naphthalene expelled by a current
of times added and the naphthalene expelled by a current of
steam.
Substitutes for hard rubber are made of natural or artificial asphalt
combined with heavy oil of tar and talc or infusorial earth.
Most of the insulating materials
advertised under alluring names consist of asphalt combined with rosin, tar,
and an inert
powder such as clay or asbestos. Some contain graphite, which
is a good conductor and therefore a very undesirable
ingredient in an
insulator.
|