Shellac:
The Perfect Finish for
Wood Shops
My Quest to Find the Perfect
Finish for Student Use
Darin Petzold
Serrano Intermediate Woods
Saddleback Valley USD
My Requirements
When you are dealing with multiple classes
of 30+ students, the process of finishing
becomes a HUGE undertaking. Here are
my requirements when choosing a finish:
Easy to apply
Easy to clean up equipment and spills
Fast drying
Non toxic
My Requirements:
Easy to Apply
This goes without saying, if the finish is not
easy to apply, it will be frustrating for both
the students, and the instructor. If
students do not see success, they will be
less likely to put the effort into achieving a
quality finish, so the learning curve needs
to be fairly “flat” at least for the initial
attempts at using a finish.
My Requirements:
Easy to Clean Up
Let’s face it…this is the instructor’s requirement!
Ease of clean up is not only cleaning of the
equipment, but ease of putting procedures in
place for the clean up process. If the clean up
of a finish product requires a lot of steps, the
likelihood of students successfully completing
the process is very low.
My Requirements:
Fast Drying
Unless you have massive amounts of space
in your shop, storage of student projects is
always an issue, especially when it comes
to storing projects that need to dry. A fast
drying finish will help solve this problem by
allowing students to put their drying
projects in their normal storage area by
the end of the regular working period.
My Requirements:
Non Toxic
Many traditional finishes are soon to
disappear due to recent rulings on the
toxicity and volatility of the finishes. Water
based finishes are the obvious solution to
this growing problem. Though shellac is
not water based (it is typically dissolved in
denatured alcohol), it is FDA approved in
it’s dried form. This also solves the
problem of using a finish on items that are
potentially toxic around children.
The Perfect Finish?
I was reading a recent article in Fine Woodworking
(December 2010 #215) that detailed the
manufacture and history of shellac. As I read, I
realized shellac would be the “ideal” finish I had
been seeking. Here is a video supplement to
that article.
Origins and Manufacture of Shellac
An email to the author, Vijay Velji proved worth the
effort as he invited myself and three others down
to his home workshop for a private workshop on
shellac use and the French Polishing procedure.
Shellac: A Natural Product
Shellac is secreted onto a
branch by insects smaller than
a grain of rice. It takes a
tremendous number of these
insects to create a pound of
useable shellac
The Perfect Finish?
We carpooled down to Mr. Velji’s house and were
warmly greeted. He soon impressed us with his
vast knowledge of shellac, his command of the
French Polishing process, and his ability to
describe the chemical processes that were in
action.
Our goal for the day was to ask many questions
regarding shellac as a finish, and to have Mr.
Velji guide us through the French Polishing
process on a practice piece of Mahogony.
Our Day of Fun
Tom Williams (Laguna Hills HS)
and Mark Mora (Serrano
Intermediate) are readying a
squeeze bottle of denatured
alcohol for use during the
French Polishing process.
French Polishing
Here is a short introduction to the French
Polishing process. One of the many uses
for shellac, and perhaps one of the most
revered.
Introductory Video on the French Polishing
Process
French Polishing:
Surface Preparation
As with most finishing processes, surface
preparation is the all important first step.
Your finished product will only be as good
as the prepared surface. Planing,
scraping, and sanding are all good ways to
prepare the surface.
French Polishing:
Pore Filling
When using an open grain wood such as
Mahogany, pore filling is an important step in
preparing the surface to accept the final finish
product. In this case, very fine pumice is forced
into the surface grain in order to fill the large
crevices. The pumice will not only fill the gaps,
but it will absorb the color of the shellac and
blend in perfectly. An added bonus is that the
process of forcing in the pumice will also finely
sand the surface as well.
French Polishing:
Bodying
Bodying is the process of applying hundreds of
very fine layers of shellac to the surface.
Technique is critical in this step, but easy to
learn. The key to this step is not to be in a rush,
and to realize it is the fine layers that will
eventually lead to the ability of the final mirror
finish. Throughout this process, there is a
wonderful opportunity to tie the concepts of
refraction and reflection into the discussion!
Bodying will take anywhere from a day to several
days to complete.
French Polishing:
Burnishing
This step ties it all together and brings out
the mirror finish. Students were seeing
hints of what the finish would become
during the bodying process, but it is the
burnishing process that will really drive
home the importance of quality work and
attention to detail. Burnishing is the
process of stretching and polishing the
uppermost layers of shellac into a very fine
and flat mirror-like surface.
French Polishing:
The Finished Product
The pictures tell the story! Though we didn’t
go through the full bodying process, we
were still able to produce a pretty fine
finish.
Left to right: Mark Mora (Serrano
Intermediate head custodian, Robert
Sherlock (Serrano Intermediate
Assistant Principal, Tom Williams
(Laguna Hills HS), and myself, Darin
Petzold (Serrano Intermediate Woods)
Final Thoughts
Shellac is definitely a finish worth exploring. I
currently use it as a brush on finish for one of my
introductory projects with my Woods 1 students.
It is certainly not French Polishing, but it does
add a nice finish to their wood. The beauty for
me as an instructor is that it meets all of my
requirements.
I am looking forward to developing new projects
that will allow my students the opportunity to go
through the French Polishing process.
Final Thoughts
Tom Williams (LHHS) was brave enough to
put his woodshop kids to the task of
French Polishing the shop benches! The
sense of accomplishment those kids must
have felt is priceless.
Final Thoughts
I encourage you to visit Mr. Velji’s website.
He sells a wide variety of shellac flakes
and supplies. His DVD on the French
Polishing process is highly rated and well
worth the purchase.
Shellacfinishes.biz