Linseed oil

[big h]

I am having a new mando built for me and have been looking at different finishes for it. the guy who is building it suggested linseed oil for the finish. Would this be unwise to do?

[Bill Snyder]

Just straight linseed oil? Raw? Boiled? Polymerized?
Tru-oil is a polymerized linseed oil product that is not uncommon among amateur luthiers because of its ease of use. Most professional luthiers go ahead and get set-up for something else though.

[Lefty Luthier]

Linseed oil is fine on open grained woods like walnut but it tends to get a bit gummy on tight grained woods like maple so I don't recommend it. Though Tru-oil is a fine product, I don't believe it rises to the level that a good French polish or lacquer finish does for professionally built instruments.

[big h]

Ok thanks a ton!

[Bill Snyder]

Is your builder an experienced builder? What does he normally do? Have you seen any of his previous instruments?

[big h]

He is a experienced builder. He thought it would be a good idea. He thought it would be alt like a varnish. He also said something about tung oil. I don't know what to think really.

[big h]

and yes I played his brothers walnut that had linseed on it and thought it was an outstanding mando.

[sunburst]

I've seen finishes of 100% Tru-oil that were of professional quality. I've used it with good results, but not for complete instrument finishes like those I've seen.
"Boiled" ("polymerized") linseed oil can be a good finish if well applied. It is basically linseed oil with metallic driers added to speed up and improve the polymerization that is the mechanism by which "drying" oils harden.

If your builder is experienced and has done the finish before with good results, if you have played instruments that he/she has finished with linseed oil and liked them, I'd say place your trust in the builder.

[woodwiz]

There are three problems with linseed oil ("bolied" or raw) that I can think of.

First it doesn't build a film. It soaks into the wood but doesn't build. Many luthiers find that oil soaking into wood deadens the sound, which may or may not be desirable.

Second, it never hardens. Room temperature is below its "glass transition point", so it is always soft. Since it never hardens, dust and dirt penetrate into the film over the years.

Third, it darkens with age - a lot. I've seen furniture that was finished and maintained with linseed oil that has turned completely black. Took a long time, but black it was.

I haven't seen the same problem with Tru-Oil. It is a good gunstock finish, and some luthiers report success with it. It certainly is easy to use.

Linseed oil based varnishes work fine because the oil is cooked with a resin that gives much better hardness and allows a film to build. It's just straight linseed oil that is a problem.

[Stephanie Reiser]

I have in the distant past used only linseed oil as a flintlock gunstock finish. The problems were that it takes about 20 coats, and then it takes forever to dry.
The violin builders making their own varnish use either linseed or walnut oil as the base, the other ingredient being a resin of some type.

[billhay4]

Tru Oil is a gunstock finish. It does dry as the oil in it has been treated so that it dries.
It does take a lot of coats, but patience produces a very nice finish.
As for oil penetrating and deadening sound, I'd put this in the realm of anecdote. Oil only penetrates a few thousandths of an inch, no more than a varnish itself.
Bill

[Soupy1957]

One other characteristic of boiled Linseed oil is its volatility. It is VERY combustable!!!!

I have a can of it that I use VERY light amounts of, when oiling the ebony fret board, but I can't imagine a finish made of the stuff.

If you play really hard and fast, I wonder if it would ignite? (lol)

-Soupy1957

[Stephanie Reiser]

"I have a can of it that I use VERY light amounts of, when oiling the ebony fret board,"

I use mineral oil for that purpose.

[big h]

Thanks!

[raulb]

There are three problems with linseed oil ("bolied" or raw) that I can think of.



Third, it darkens with age - a lot. I've seen furniture that was finished and maintained with linseed oil that has turned completely black. Took a long time, but black it was.

I have never used it on anything fine, like guitars or mandolins, but over the last 40 years, I have applied gallons of boiled linseed oil on wooden ladders. Not one of them turned black. Until the oil finish degraded (sunlight, weather, use) the ladders remained wood colored (hickory) and when the finish got old, they just turned gray as any weathered wood would (alliteration not intended).

The problem I might see is that as an oil, it does soak into the wood, and I don't know how advantageous that is on a musical instrument. All finishes do soak in a little, but more or less than linseed, I don't know. This soaking in is, or course, why we used it on wooden ladders.

It also stinks to high heaven (and is why I hate it). Plus it does take a long time for it to dry to where you don't get oil on your hands if you touch it. Even putting the ladders out in the sun did not seem to help.

[7777777]

Both raw and boiled linseed oil cure to a very soft finish and penetrate the surface of the wood fairly deep. It would stand to reason that they would be poor choice because they would greatly deaden the resonance of the wood - forever. Polymerized oil such as Tru Oil does cure very hard and does not penetrate nearly as deep, partly because it cures so much faster. Many builders report excellent results with Tru Oil. The Luthiers Merchantile International (LMI) discusses Tru Oil on their website - check it out.

I have finished a banjo neck with Tru Oil and had good results with a very hard, durable finish. I have also finished furniture with boiled linseed oil and had it remain gummy for years. Just press your finder nail into the “dried“ spilled droplets on any linseed oil can and you can see how soft it is - even after several years.

[lone-woodwose]

Don't know if it will help at all but I have used something called salad bowl oil on a maple highchair once. It has held up well and it came out looking nice. Not sure if it would effect sound though...but it does not deaden the sound of a three year old banging on it.

[Jude Reinhardt]

The dumbest thing that Birchwood-Casey ever did in my opinion was to call their linseed oil based varnish Tru-Oil. It's not an oil finish but a varnish finish.
Good marketing ploy though as a lot of amateur gunsmiths wanted to put a genuine oil finish on gunstocks and kept failing when trying to use boiled linseed oil.
Yes, a good oil finish can be had using linseed oil, here's the instructions- the wood has to be smooth as glass. Apply the oil sparingly, a few drops at a time rubbed into the wood with the palm of your hand. The wood should feel dry, not oily wet when your done.
Do this once a day for a week, then once a week for a month, then once a month for a year and then once a year for life.
Or as Birchwood-Casey used to claim, "you can oil finish your gunstock in a day with Tru-Oil".

The end result mostly depends on what you do to the wood before the finish is applied.

Jude

[Charley wild]

"I have a can of it that I use VERY light amounts of, when oiling the ebony fret board,"

I use mineral oil for that purpose.

Me too! Murphy's soap and water to clean to whole mandolin and mineral oil for the finger board. Been doing it since the 60's.

[Martin Jonas]

One other characteristic of boiled Linseed oil is its volatility. It is VERY combustable!!!!

That's not quite right. What you're presumably thinking of is that rags soaked with linseed oil, e.g. from mopping up the excess when applying a finish, are very dangerous indeed if thrown into the bin or put in a heap. That's because the oil oxidizes when in contact with the air, a reaction that produces a lot of heat. In a soaked cloth, there is lots of surface area, and thus lots of oxidation, but little heat conduction or convection to get rid of the oxidation heat. Thus, the temperature goes up, and as the reaction rate increases with higher temperature (it roughly doubles for every 10 deg C increase), this sets up an ever accelerating process of self-heating which rapidly leads to the point of ignition and can set off a really nasty spontaneous fire without an external source of ignition.

However, that won't happen on your instrument: the exposed surface area is vastly smaller than in a soaked rag (where every fibre is an exposed surface) and whatever reaction heat there is while the oil dries can easily be conducted away, so there is not risk of spontaneous ignition. Once the oil is dry, the treated wood is not significantly more combustible than a wooden instrument is in any case -- if you really try, any mandolin will burn.

Martin

[Keith Newell]

Nice post Martin and I agree with you. Linseed is an excellent finish and once you learn to work with it then you will love it even more. Most builders that use it don't just start with it, they seal the finish somehow with either shellac or another sealer so it won't penatrate. Don't worry about it changing your sound much on an instrument unless you dip it in it and get heavy coats and anything you put on the mando in that heavy a finish will effect it the same.
Keith Newell
http://www.newellmandolins.com

[Ed Lee]

Linseed oil??? If at all possible I'd avoid it on any wood instrument. Yes, it penetrates and thereafter induces a coefficient of expansion and contraction that would be intolerable to tone stability. Antonio Stradivari and his renown apprentice Nicolo Amati finished their fine violins with chitin varnish (made from the wings of bees) set over a light rectified (purified) fish oil (specie unknown). Artificial (???) chitin varnish is made from shell fish (lobster, prawn, shrimp). ... Ed lee

[woodwiz]

Linseed oil??? If at all possible I'd avoid it on any wood instrument. Yes, it penetrates and thereafter induces a coefficient of expansion and contraction that would be intolerable to tone stability. Antonio Stradivari and his renown apprentice Nicolo Amati finished their fine violins with chitin varnish (made from the wings of bees) set over a light rectified (purified) fish oil (specie unknown). Artificial (???) chitin varnish is made from shell fish (lobster, prawn, shrimp). ... Ed lee

Got a source on that? Any data to substantiate? Any historical references, chemical analysis?

How was this varnish supposed to be prepared and applied?

Edit-----------

Nagyvary, 1984 - Never mind. Made varnish from shrimp shells or something. No historical data. I think he abandoned that quite a while back.

BTW, shellac is almost pure chitin.........................

[Keith Newell]

Build some, try it, hear it.
Keith
P.S. Linseed is not un-natural.
For some reason I can't get my web-site of http://www.newellmandolins.com to show right on my sig....let me try it again...

[Keith Newell]

This is a test (also known as shameless self promotion) of my signature.
Keith