Linseed oil darkening...
Bill K
or missed the answer to this. I know that linseed oil will darken with
time, but does this happen only when it is used as the only finish, or
does it happen if another finish is used over it? I have seen many
professional wood workers recommend using it under shellac to bring
out depth, but if it will eventually turn dark it seems like a bad
idea. I am making some maple furniture and would like to use it under
something, but I don't want it to turn black. Thanks
John McGaw
a couple of hundred years so it is just a matter of time... If you are
worried about the darkening, tung oil will pop the grain also and has less
tendency to darken the wood -- of course you will have to allow for the
longer hardening time in your finishing schedule.
--
John McGaw
Knoxville, Tennessee, USA
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Bill K <use...@spamattention.com> wrote in article
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Paul T. Radovanic
>I have read all the "classic" books on finishing, but I couldn't find
>or missed the answer to this. I know that linseed oil will darken with
>time, but does this happen only when it is used as the only finish, or
>does it happen if another finish is used over it? I have seen many
>professional wood workers recommend using it under shellac to bring
>out depth, but if it will eventually turn dark it seems like a bad
>idea. I am making some maple furniture and would like to use it under
>something, but I don't want it to turn black. Thanks
There are good reasons that many professionals recommend using boiled
linseed oil under shellac.
I've heard all sorts of theories on the darkening issue. One such
states that the "turns black" reputation came from days of yore, when
people used straight flax oil, which remained tacky and therefore
attracted dirt.
It's also true that mildew critters feed on the oil, so a straight oil
finish in an outdoor or damp environment would indeed turn black from
the mildew.
I've never had a linseed-oil finish turn black. One very wise
finisher invited me to apply some linseed oil to half a piece of wood
and set the piece outside (in the full Florida sun) for a week. I
did, and I didn't see any difference in the degree of darkening
between finished and unfinished wood.
Now, your maple will darken over time anyway, and so will most any
finish. But it won't turn black.
Jeff Jewitt continues to use linseed oil. He is not only an
accomplished expert and a savvy finisher, but he works on antiques as
well. So, if it's good enough for Jeff, it's good enough for me.
Personally, I think that linseed oil really makes maple come alive.
For the record, I never use straight boiled linseed oil as a final
finish. I usually cover it with shellac. But if I want the look of a
straight oil finish, I use either Watco or, more likely, a homebrew of
oil, varnish, and turps.
John mentioned that tung oil has less tendency to darken, but it also
costs six times as much, takes much longer to dry, and has a flat
sheen to boot.
Paul Rad
Aslam Hassan
>
> Personally, I think that linseed oil really makes maple come alive.
Second that point.
>
> For the record, I never use straight boiled linseed oil as a final
> finish. I usually cover it with shellac. But if I want the look of a
> straight oil finish, I use either Watco or, more likely, a homebrew of
> oil, varnish, and turps.
>
> John mentioned that tung oil has less tendency to darken, but it also
> costs six times as much, takes much longer to dry, and has a flat
> sheen to boot.
>
> Paul Rad
What he said. Listen to the man. I know from experience what he says is
right.
Aslam
jim mcnamara
1. If used as the only finish and exposed to a lot of UV light, it will
usually turn black or dark grey. This will happen regardless - well,
almost regardless - of any film over the linseed oil. Some UV blockers are
used in varnish films, and these prevent linseed oil from darkening, shrot
term. However, the blockers will degrade over time and the linseed oil will
darken after that. You have to refresh the varnish about every 12-18
months to keep things shipshape.
2. A linseed oil only finish will also darken on exposure to a polluted
environment. Linseed oil fully polymerizes over a long period (even when
it has added driers), so soot can embed in the still-uncured finish. It
will remain there. You see this in Antique English-made furniture -
because they burned a lot of coal for heat when the piece was new. A clear
film topcoat over the oil prevents this from happening.
Linseed under shellac or some other film will not pick up soot.. Unless you
are making patio furniture, linseed oil will not darken very much in your
lifetime due to UV in your house.
Most furniture darkening that happens is from changes in the wood itself.
Plus lots of film finishes change color (usually beome more ywllow or
orange) over time. When you add the film & wood color changes together the
tone shift can be significant in 10 years or less.
Maple is much less prone to darken than woods like cherry. If you're
worried about tone shift from film finishes stick with either shellac or
water-base varnishes.
jim mcnamara
domingo rose