Oil & Varnish: A Refresher


On the left is a dried puddle of wiping varnish. On the precise
is a dried puddle of a mix of oil and polish. Clearly a
big sensible distinction between the 2.

Should you return to the early problems with U.S. woodworking
magazines within the 1970s and ’80s and examine oil finishes,
you’ll come away confused. The extra you learn the extra confused
you’ll turn out to be. I do know this as a result of I used to be there. The claims and
explanations have been all around the map. Most of the time they
have been contradicting one another.

The issue in fact started with the producers and their
labeling. What was Danish Oil? What was Seal-a-Cell? What was
Waterlox? What was Salad Bowl End? For that matter, what was
“tung oil,” when manufacturers clearly carried out in a different way? All of
these have been (are) wipe-on/wipe-off finishes, all are thinned and
cleaned up with mineral spirits (paint thinner), and all are
highly regarded with novice woodworkers. However what are they? How
do they differ?

In 1990, in the beginning of my writing profession, Jeff Greef
requested me to jot down an article on tung oil for Woodwork
journal (its archives at the moment are owned by Well-liked
). I labored for 3 months researching that
article throughout which the subject morphed into the broader topic
of “oil” finishes usually.

I purchased all of the manufacturers and adopted all of the instructions,
making use of these finishes to varied woods. Nonetheless complicated. The
breakthrough got here when a chemist buddy advised that I put
puddles of the finishes on glass and see how they treatment.

Voila! Some cured very slowly to a smooth and wrinkled movie.
Others cured pretty shortly to a tough, clean movie.

vboiled linseed oil

As a reference, right here is the best way a puddle of boiled linseed
oil cures on a non-porous piece of glass. Gentle and wrinkled.

So there was an enormous distinction in these merchandise. Some needed to
have the surplus wiped off after each coat or the consequence would
be a gummy, sticky mess. Others could possibly be left damp or moist and
constructed as much as a tough movie with a number of coats; this would supply
a lot better water resistance. Some have been clearly oil, or they
have been a mix of oil and polish as a result of together with oil with
the varnish causes the end to treatment smooth and gummy. Others
have been merely varnish, thinned with mineral spirits so the end
could possibly be wiped somewhat than brushed.

Right here’s the place the confusion begins as a result of varnish is made with
oil. How do you outline the distinction between a mix of oil
and polish (Watco Danish Oil, for instance) and thinned varnish
(Waterlox, Seal-a-Cell or Salad Bowl End), which is made
with oil, aside from by how they carry out?

varnish linseed oil

You’ll be able to’t simply combine a pure resin, on this case amber, with
oil and count on to get varnish. The resin will simply sink to
the underside and stay there. It’s important to prepare dinner the combination to
get the 2 to include and make varnish.

The important thing phrases are “prepare dinner” and “combination.” Varnish is oil and
resin (assume amber, used as jewellery) cooked to trigger the 2 to
mix chemically and make varnish. You’ll be able to’t merely combine the
two; the resin will simply sink to the underside and stay there.
It’s important to prepare dinner it. (Varnishes at the moment are made by combining
chemical substances and heating as an alternative of mixing pure merchandise and
heating, however the course of is best to image with the pure

After you have the varnish you’ll be able to combine it with oil (linseed or
tung) to make an oil/varnish mix. This mix acts like oil in
that it by no means cures exhausting. The argument for mixing these, which
you are able to do your self if you need, is that the addition of
varnish makes the end just a little tougher and extra water
resistant than boiled linseed oil or tung oil alone. However my
exams point out that the distinction isn’t a lot.

By no means thoughts, there are nonetheless two very totally different merchandise on the
market represented as oil or unclear what they’re.

Why did writing about this topic happen to me now, after I’ve
written about it so many occasions earlier than? As a result of I simply acquired
a woodworking journal with an article that didn’t distinguish
this distinction. Varnish was outlined as a “combination” of oil and

One of many issues I’ve been most gratified about since 1990 is
that woodworking magazines have all purchased into my explanations
and even adopted my time period “wiping varnish” for thinned varnish
to differentiate it from oil and oil/varnish mix.

tung oil

On the left is Previous Grasp’s Tung Oil. On the precise is
McCloskey Tung Oil. Two well-known corporations promoting two
clearly totally different merchandise, calling each tung oil. What
might illustrate higher why ending could be so complicated?

OK, producers haven’t budged a bit. They nonetheless mislead as
they at all times have. However I’ve come to the conclusion that they
don’t truly understand they’re doing this. They’re advertising and marketing
corporations. So long as their merchandise are shifting off the
cabinets, every thing is OK with the world.

The results of their not caring, nonetheless, is that the burden is
on us to determine what it’s we’re shopping for. That’s what made
it so miserable for me after I realized that right here was a
journal that was nonetheless dwelling within the 1970s and 80s.

— Bob Flexner


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