Just to update the C&F library, here’s something I learned about, recently.
For instance, on wood flutes I use a product commonly known as cold-pressed linseed oil, or “artist” grade linseed oil, which is not to be confused with common hardware store linseed oil, or “boiled” linseed oil, which contains certain inedible, not-for-flute-use additives, and, until quite recently I was of the impression that a fundamental difference between these two oils was that application materials used with these oils, such as rags, swabs, sponges, etc., could be subject to spontaneous combustion, that is, could suddenly light on fire all by themselves, when used with hardware store linseed oil, but not when used with cold-pressed linseed oil.
However, while oiling a flute with cold-pressed oil, I happened to notice some fine print on the bottle’s label, and I’ll quote it here. “DANGER: Rags, Steel wool or Waste soaked with this product may spontaneously catch fire if improperly discarded. Immediately after use, place rags, steel wool or waste in a sealed water-filled metal container.”
Therefore, apparently all linseed oils must be used with extreme caution.
May be combustible at high temperature - Slightly flammable to flammable in presence of heat. As with all unsaturated fats and oils, some porous materials such as rags, paper, insulation or clay when wetted with this product may undergo spontaneous combustion. Keep such wetted materials well ventilated and in a cool area to prevent possible heat buildup.
If it is that unstable, then you only want to use it on cheap flutes that you don’t care about. Folks down the road were almost completing their new home when the floor finishers left a pile of oil-soaked rags on the open floor. The home burned completely to the ground at about 2 am. Sucks. So be careful.
My understanding is that the major fire hazard is the boiled linseed oil, although treating the cold pressed oil with a little extra caution too can’t hurt.
When I oil my flute, I am always careful that the rags and swabs that are impregnated with the oil are first placed into an airtight ziplock bag, and then stored inside an airtight metal tin.
I’ve never heard of treated wood autocombusting; I think that’s because the wood has much less surface area exposed to the air than would a piece of cloth.
Wood treated with linseed oil NEVER combusts. Before synthetic oils became popular for impregnating boats, linseed oil was used by every wooden boat owner. It’s when the oil is left to oxidize in rags and the like it becomes dangerous. Cold pressed linseed oil is furthermore very good for your health, especially when it’s mixed with yoghurt. Oiling a flute with linseed oil can’t therefore be anything but beneficial . . . just leave out the yoghurt
Oil combusting spontaneously is very, very different from, say, almond - or any cooking oil - bursting into flame when being boiled at a high temp. The difference is the word “spontaneously”. Oil-soaked rags spontaneously combusting in a wastebasket is very different than during the frying of donuts.
Boiled, and even cold-pressed, linseed oils for art generally have additives that make them dry quickly. These are petroleum based and are a) toxic, and b) combust spontaneously. The safest linseed oil for use on a flute is raw (unboiled and pure) edible linseed (also called flaxseed) oil. It is usually found in healthfood stores, and - in addition to adding a wondrous sheen on wood, will give you Omega 7 nutrients, which may or may not prevent cancer. Fish is healthier, but then there’s that mercury issue…
The only drawback to linseed/flaxseed is that if a thick drip is left in the flute, and the flute goes without playing, swabbing before it dries completely, it will congeal and leave, well, a drip inside the flute. So use it very thinly (like all oils), and don’t go for weeks without playing your flute. You shouldn’t, anyway, as playing is good for you, and doing so may prevent cancer, certainly better than playing a fish.
Actually, the particular “Cold-Pressed Linseed Oil” I am using is labeled as nontoxic, although perhaps the very high price of this small, 75 ml bottle of oil could cause injury to one’s bank account. That said, the next time I look for it, I think I’ll check out a nearby health food store, and I thank you for the suggestion.
Yeah, I think the key word I meant to emphasize, rather than the cold-pressed, was “for art”. I’d guess flaxseed is turned into linseed oil by being pressed, one way or another, cold or hot. The main point was that the additives in oil-paint linseed oil (for art) helps the oil dry in days, rather than weeks, which is useful when trying to complete a painting. And, yes - it will be more expensive in smaller quantities. I understand that some makers will use these treated oils in the shop, initially, to seal the wood of a new flute (I think Loren mentioned this a while back). But, when you’re oiling your flute on a semi-regular basis, it’s probably a bad idea to keep treating your flute with a super-fast drying (and solidifying) substance - sort of a semi-natural polyurethane. Much better to have an oil that will swab out over time and need to be replaced with regular oiling.
An old boatbuilder told me once that even raw linseed-oil would solidify and sort of crystallize inside the wood if given a long enough time. He also said that it would weaken the wood. Oils solidify or harden by bonding with oxygen. This process can be slowed down considerably by adding an anti-oxidant like vitamin E to the oil.
Linseed/flaxseed is a “hardening” oil (as opposed to almond, which isn’t, but, for that reason among others, many people feel it’s virtually useless as a barrier oil in the first place) - which is why it is used in oil painting (you’d want it to dry eventually). Raw takes much longer than boiled to do so, and that’s why art linseed is boiled. Some hardening is a good thing, as the absorbed oil acts as a barrier. Since we’re talking flutes, which are played regularly, swabbing and condensation, etc., the likelihood that a hardened drip will be permanent inside the flute is not really an issue, unless the oil dries prematurely fast, as in the case of linseed with distillates added to hasten hardening.
Ihe old, old days, there were no distillates added, and the paintings in question are largely intact after hundreds of years, so I wouldn’t worry too much about crystalization in your lifetime. As for ruining wood, I’d imagine sailing a wooden vessel in water, not to mention salty water, is probably doing the wood a lot more damage than any oil used. Also, keep in mind that flutes do not actually soak in water, in spite of regular condensation, and the point of oil is merely to slow water absorption, not to stop it (as in the case of a boat). Also, no boat is made from heavy, naturally oily hardwood (grenadilla sinks, for example), so I’m not sure by what method a boat maker would be able to discuss the effects of linseed on the exotic woods used for instruments. Like the aforementioned paintings, many flutes bathed in linseed oil are now hundreds of years old, and still in playing condition.
Oh, and yes - adding vitamin E will help preserve organic oils from going rancid. Not sure it does much to slow or speed hardening.
And you ride yourself over the fields..
And you make all your animal deals…
And your wise men don’t know how it feels…
To be thick as a drip…
That’s an interesting thing to consider, as until now I’ve thought of Vitamin E as an additive to keep linseed oil from going rancid. However, apparently a combination of linseed oil and Vitamin E could somehow chemically “balance” each other.
I am looking at two bottles of oil that I was thinking about moving to when my bottle of almond oil runs out. They were in the house for other reasons.
One is labelled as “refined linseed oil for oil colour” and the label on the back says “A pale, alkali refined, linseed oil, derived from the crushing of flax seed. Free from the mucilage normally found in commercial raw oil”
The other is “Organic fresh cold pressed linseed oil (flax seed oil)” and it says “the delicious nutty flavour of this oil is ideally suited for use on salads… etc” In the bottom the oil is clouded by something that might well be mucilage (actually that was last week, the bottle is now almost empty, it tasted just fine).
No mention of boiling but do I go for mucilage or alkali refined ? Or neither ? As people say, the almond oil soon seems to get removed by a few hours of hot breath and wiping.
Just on the basis of an unscientific hunch, I myself would be more at ease with food-grade. I mean, hey, it’s un-messed-with. The idea of leftover alkali on my flute doesn’t sit well with me. I’d rather reapply than regret. But, maybe the paint-grade stuff is acceptable. I defer to wiser heads in this matter, although I’m probably not going to change my practices.
As it is, I’m really out of the discussion, anyway, as I use almond or walnut oils - when I do. Can’t stand the smell of linseed oil.
Folks down the road were almost completing their new home when the floor finishers left a pile of oil-soaked rags on the open floor. The home burned completely to the ground at about 2 am. Sucks. So be careful.
