On 21 Sep, 10:35, "steveybar"
wrote:
We have just purchased a new oak table whose care guidance notes say they
recommend applying a thin coat of furniture oil once a month for the first
three months, and once a year thereafter.

Odd. Although this is common advice, it's not usually applied to
tables.

There are two sorts of "oil finish", film-forming and non-film-
forming. A film-forming finish sits on the outside of the wood and it
cures to a skin or film. It soaks in too (that's important for looks
and "depth"), but it does cure, and it does form an external build-up.
This is the sort of oil finish I'd expect on furniture. Although it
takes many coats to apply it well, it's a small, finite number of
coats and once they're done, they're done. These would usually be
applied in the workshop, maybe daily, and don't need to be renewed in
the future.

In fact they _shouldn't_ be renewed afterwards. Particularly where the
"mayonnaise" recipe for an oily "finish restorer" has been used
(National Trust through the '70s) you'll see that repeated
applications build up into a muddy brown finish that's a pain to clean
off afterwards.

One aspect of a film-forming finish is that it's not very wear
resistant. Oil films are weak (weaker than varnishes) and they'll
wear. Sometimes this is seen as patina developing and regarded as a
good thing. However for "working" implements, particularly
kitchenware, it's usually to avoid an oil film finish here in favour
of a non-film finish. This soaks in entirely and doesn't form the
external film. It doesn't need to cure, although some oils do and some
don't. It's your classic "salad bowl" finish.

An aspect of these non-film oil finishes is the advice to refinish
"once a month for the first three months, and once a year thereafter."
or similar.

For a good film-forming finish, I use Liberon's ready-mixed "Finishing
Oil" which is a good quality product and easy to get (Axminster,
many other on-line sellers, maybe local too). Rustins, Bolloms etc
sell similar products.

If you're using a film-forming oil, don't keep re-applying it
indefinitely! If you're going to do that, use a non-film oil that's
also non-curing (or at least, very slowly curing).

Non-film oils are easy too. Simple mineral oil is fine here ("liquid
paraffin" from Boots), or there are some vegetable oils that are
usable. I use camelia oil (from dick.biz in Germany, but not the
Japanese simulated camelia oils for tools). Walnut oil (from a deli,
or even Tesco) is good too, particularly for kitchenware. Be wary of
other oils though, especially olive, as they can go rancid over time -
they oxidise faster than they cure.

You don't need an oil that "feeds" the wood. Wood's dead. Nor do you
need to worry about the wood "drying out" (it'll do this anyway,
that's a moisture issue). Why you need to replenish oil is because the
old oil needs it, not because the wood needs it.

If it were mine, then I'd look at just what finish I wanted (film or
non film) and then move to that. Probably I'd go for a few coats (over
a week) of Liberon's, then leave it at that and maybe wax it annually
afterwards, rather than oiling it. I might even shellac it - most of
my oak furniture is finished as shellac over oil.