used for many applications in woodworking. From making gesso to be
used as a decorative finish or as a grain filler etc. to use as a
lubricant and fine abrasive, this is a versatile product, with
uses that are only limited by your imagination.
gm Powder shaker
page is an taken from... "A Polishers Handbook" written by Neil Ellis
Gesso is a mixture of glue and talcum powder or
calcium carbonate, and is used as a base for other finishes, notably gold leaf. When dry
the gesso is extremely hard and durable. It can be sanded to give a silky smooth finish
and burnished to produce a shine.
The uses I will describe to you in the
following pages have nothing to do with gilding, but will give you some ideas for finishes
that will open up a whole new world of possibilities to you.
Many of the gesso finishes are particularly
well suited to woodturned items and can be used on both spindle and bowl work. They are
also suitable for use on most furniture, especially vertical surfaces. Some can be used
for table tops etc. but take the time to experiment with them first & know their
WHAT YOU WILL
A plastic or glass container with lid (water tight) - Talcum Powder (super fine)
- PVA glue - Water - Small paint brush approx. 25mm wide, or an artists oil brush about no
14 (buy cheap ones from the market - A piece of timber to work on. (for this exercise it
is a good idea to use s small square of 18mm custom-wood or chipboard) - Shellac and
universal tint (colour of your choice) Some 00 steel wool
In your container mix (by volume) 1 part of
PVA glue with approx. 4 parts of water. When completely mixed, slowly add and blend in the
talc (approx. twice as much talc by volume as there is liquid) keep adding and mixing talc
until you have a mixture that resembles a pancake batter. If the mix is too thick add a
little water if too thin add more talc.
You have just made your first batch of
gesso. This will keep in an airtight container for a long time, at least twelve to
GESSO effect no. 1
1/ Paint your piece of timber with the
gesso. Just slop it on to cover the whole surface. Dont worry too much about brush
marks these will disappear later on. This first coat keys the gesso to the wood and will
be the base for the final coat.
This first coat could take anything up to a
couple of hours to dry. I sometimes help the drying process along a little through the
application of heat by way of a small hair dryer. This can speed up the drying time
considerably to around ten to fifteen minutes.
2/ Once the first coat is dry you can apply
the second and final coat. Once again just slop it on but try and get a reasonably even
coat. Leave this second coat to dry for a little while, say five minutes. By this time the
gesso should have a slightly tacky feel to it. If you touch it with your finger it should
peak like beaten egg-white when your finger is removed.
3/ Now take your brush and with the handle
in a vertical position tap the bristles down and then up on the surface of the tacky
gesso, continue to do this over the entire surface of the wood until the whole thing is
covered with little peaks. This is called a stippled effect. Leave this to dry overnight.
4/ To a small quantity of shellac add some
universal tint. e.g.: 4 tablespoons of shellac plus 4 drops of green tint. Mix thoroughly
then apply an even coat of the coloured shellac to the surface of the now dried gesso.
Leave this to dry thoroughly. (approx. 15 minutes) You should now have a green coloured,
stippled gesso, board.
5/ Next make a tight wad of steel wool
about the size of a golf ball and briskly rub the green stippled surface until the white
of the gesso start to shine through on the peaks, this white highlight is the effect you
are after. Make sure that you keep the steel wool in a tight wad throughout the rubbing
You have finished your first gesso effect.
I will wager you haven't seen anything quite like that before.
To 1 part pearl hide glue add 2 parts water
allow the glue to soak in the water for about 15 minutes to half an hour, until it has
expanded and soaked up some of the water, now place the mixture in a double boiler (as for
making glue page 36) and heat the glue until it is liquid, stirring occasionally.
Once the glue has become liquid slowly add
talc (whilst constantly stirring) and keep adding it until you have a mix resembling
batter. If the mixture is too thick add some more water.
An example of
quantities for a gesso mix is as follows - 0.25 cup pearl glue,
0.5 cup water, 1 to 1.5 cups of talc.
Keep the mixture warm to keep it liquid, as
it cools it will start to thicken and get hard. More water can be added to retard the
drying process, if required, this could be up to an extra 0.5 cup for the above mix.
Unfortunately there is no exact science to
making gesso. Each job and application can demand a slightly different mixture, just as
different users will find they have a preference for their own consistency of mix. I
suggest that you experiment with the base mixtures described herein until you have a mix
that suits your particular application.
Take a piece of white Oak, water down some hide glue gesso to make a runny batter, mix in some red
universal tint until you get a bright red, then apply the gesso to to the oak using a wad
of hessian or a piece of old towel. Rub the gesso hard across the grain, pushing it in to
the open pores of the timber. When the whole piece is done, put it aside to dry
When completely dry sand the surface back
to clean bare timber you should now have a white piece of Oak with a magnificent red grain
that almost leaps off the board at you. Make sure that the board is free from dust and
polish with white shellac or whatever finish you desire.
These are just
a couple of very basic ideas. The decorative effects that can be done
using gesso are just about limitless.
Talc is also used as a very fine abrasive, a lubricant on
bench-tops, machinery, drawer runners, etc. and can be added to
shellac as a grain filler. Our talc is much finer than ordinary body
talc and completely free from perfumes that may harm a finish. It is
also ideal for use as a body talc for people who are allergic to
perfumes and other additives. There are many more practical uses for this
amazing powder, from soaking up oil spills to ................ well,
let your imagination run wild.