Handyman in the Home by Hobby - How Shellac Is Manufactured - The Mail (Adelaide, SA : 1912 - 1954) - 18 Dec 1937 (original) (raw)

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Sat 18 Dec 1937 - The Mail (Adelaide, SA : 1912 - 1954)
Page 31 - Handyman in the Home by Hobby

Handyman in the Home by Hobby

How Shellac Is Manufactured

THE shellac of commerce is a resi-

nous material, produced by an

insect, the only resin known to be of

animal origin. To be more accurate,

it is known as lac, but, as it is mar-

keted in the well-known flaky form, it

is more commonly known as shellac.

Lac is the secretion of the lac insect,

scientifically called laccifer lacca. One

of the scale insects to be found on the

twigs of certain trees in India.

The body of the insect contains a dye,

which must not be confused with the

resinous secretion. It was this dye that

was originally sought after, and not the

resin. Lac dye is seldom used now, and

has lost its commercial importance. The

resin is the only product of the insect

It is interesting to note that the word

lakh means 100,000, and has been ap

plied to the secretion of the insects on

account of such myriads swarming to

gether on the trees. References to lac

having been used as early as 1596 in the

preparation of varnishes for wood have

The lac insect begins life as a minute

creature about 1-40 in. in length. It is

provided with a fine, hair-like tubular

proboscis with which to pierce the soft

structure of the tree and suck out the

The insect lives on these juices, and,

during its life, it secretes the resinous

matter. This provides it with a pro

tective covering against its many ene

mies, both insect and bird.

THE lac insect achieves its life's ob

ject in the propagation of its kind.

After the young emerge from the al

ready dead bodies of the female, the

secretions that provided them with

protection and shelter become the raw

material of the lac industry.

The industry is important in India,

as practically the whole of the world's

supply comes from that country.

The insect is actually a parasite, and,

to prevent the host trees from becom

ing extinct, the industry is carefully

supervised. Trees are selected and

pruned to encourage the growth of

young, tender shoots, which are then

infected with the young insects. Time

for recuperation is given the trees. In

some instances they are fertilised to

When the life cycle of the insect is

complete and the young have emerged,

the old lac-encrusted twigs are

The first stage in the process of

manufacture is to remove the lac from

the twigs, this being done with knives,

the product being known as stick-lac.

On being crushed in special mills, the

stick-lac is converted into seed-lac,

which is washed to remove all im

The next step is to prepare the seed

lac in its various forms for export,

namely, shellac, garnet lac, and button

lac. Of these three, the most import

ant is shellac. It is prepared by melt

ing the seed-lac in long, cylindrical

cloth containers before a charcoal fire,

causing the molten lac to filter through

the cloth on to a stone slab.

By rolling this mass of lac with an

earthenware cylinder, filled with hot

water, it is worked into a sheet of

even thickness. The skllleid nature

workman, holding two corners with

his toes, and gripping the upper edge

with hands and teeth, rapidly stretches

the thick sheet until it becomes very

On cooling, it is broken into the

small pieces with which we are

A N estimate has been made that half

?£i- of the shellac used today goes into

the manufacture of gramophone records.

The preparation of spirit varnishes and

polishes absorbs a large proportion of

the annual output. French polishing as

a trade is entirely dependent on the

shellac industry, there being no other

product to take its place.

Electrical industries use shellac be

cause of its high insulating properties.

It is also used in the manufacture of

munitions on account of its waterproof

ing qualities and in the making of first

Although french polishing has

reached a fine art, it still has some

disadvantages. It is quickly marked

by heat and water. However, these de

fects are being taken into account, and

it is expected that in the near future

a polish containing a chemical hardener

will be introduced. This polish would

be used where increased resistance to

water and heat is required.

For polishing light-colored woods a

specially prepared bleached shellac is

available to give a clear finish to the

nr*HE illustration shows a handy little

-*- article, easy to make and always

useful. It can be made of % in. ply

wood, but one of the softwoods, as used

for packing cases, would be more suit

An important point when making

boxes of any kind is to work the sides

together, and then the ends, to make

them exactly the same size. The ends

When all the pieces are of the cor

rect size they can be cleaned up with

a smoothing plane and glasspapered

in readiness for nailing. Use 1% in.

round head nails, about three to an end.

If they are nailed on the slant a very

serviceable job will result.

Punch the nail-heads below the sur

face and plastic-wood or putty the holes

made. Finish off with glasspaper. A

.stain or varnish would be suitable for

Some form of grip can be attached

if the tidy is to be fitted in a cupboard