As far as stabilizing goes, I know about PEG, but using that just seems wrong for historical instruments, though my understanding is that it is extremely effective. Cooking whistles in stale ale? Hmmm...
Are you suggesting I look into any of these techniques at this point? The KD wood I am using might not meet the high standards of professional players, but at this point I have a lot of things to improve before I feel like I would be wasting money using high end timber. But I don't want the fipple folk flutes I make now to crack apart in short order either. This time of year I could probably just put a few in the attic in the morning and then wait to oil the bore in the mid afternoon and seal in less moisture and possibly get a little more penetration. Would that help?
"PEGs contain potential toxic impurities such as ethylene oxide and 1,4-dioxane. PEGs are nephrotoxic if applied to damaged skin." Wikipedia
Cure it in the attic for a week , then soak it in either cold pressed walnut or linseed oil(artist grade for less toxins and greater refinement for finish) for a day, also in the attic. If you are concerned about toxins avoid 'boiled' linseed or other hardware brands. Health food walnut works best but health food flax has too many unrefined lipid oils. Artist grade linseed is expensive but good. After the soaking let it drip dry and wipe it down. This oiling is for the wood pore structure not for surface finish. For best results send it back up to the attic or dry it in the sun. Finish the instrument then if wanted a hard oil can be used externally as part of the finish, but keep the internal oiled with almond oil infused with clove oil or vitamin e, again wipe on wipe off.
I think the Wiki entry may be playing up the "potential" problems a bit. Third world industrial grade PEG may have those problems, but in powder form PEG is sold over the counter as the laxative our pediatrician recommends when gentler methods to get things moving have failed - Miralax. I haven't used PEG wood stabilizer and don't plan to, but that's because I am a cranky old traditionalist and it isn't cheap not because of health concerns. The PEG I have seen for sale on turning sites claims to be non toxic.
I don't care for BLO because of the toxins it puts in the air while applying it and during curing. I use tung and turps a lot instead (100% tung and yes I know breathing turps isn't good for you either but at least it is less offensive to the senses).
I have been doing nothing but almond oil on the inside and tung/turps outside. I was planning to add a few coats of amber shellac (using flakes) to better whistles intended for sale.
The reality is that the current batch aren't going to receive that full treatment. I will put them up in the attic a few days and then oil them (probably with some pure artist grade linseed I have maybe barely enough of) and let them dry.
Tung and turp , excellent. Do not confuse pharmaceutical grade PEG with industrial grade. I neither trust wood product use of the term non-toxic, it is not always at FDA standards. I always research the MSDS. As Quality shellac is saliva resistant when cured I find it a great flute coating in conjunction with oil. Even though the rule is fat over lean I have had great results layering shellac and oil shellac and oil. Just be sure the oil is cured.
When it comes to oiling, I am a minimalist. Once the instrument is ready, I simply stuff it into a tank of cold-pressed linseed oil cut with turps, don't ask me what proportion. It starts out roughy 50-50, but due to gradual evaporation of turps tends to get heavier on the oil side, until it feels a bit too thick, when more turps are added to taste. The idea is that it soaks into the surface, rather than sticks to it. If you use good hardwood, and polish it on the lathe to a good finish, there is no need for any further finishing on the surface, it will come out a very pleasant silky sort of surface. Not glassy polished, but kind of antique looking polished. I also tend to leave things in for more than a day, but no hard rules there.
Stephen, drying in th SUN?! What about hairline cracks?
Hmm... talk about finish with luthiers... Isn't there something safer we can discuss, like religion or politics? Maybe religion is redundant; a lot of what people believe about finishes is based on faith in whoever taught it to them. Anyway, all the studies I have seen on finish penetrating wood say it is mostly a myth. But there is an awful lot of wiggle room in that word - "mostly". What the studies I have seen say is that "dip and drip" gets you over 98% of the way there as far as the amount of oil that the piece of wood will ever absorb no matter how long you leave it soaking. I have never seen one that used vacuum bagging; that may change things. Anyway, lots of people have the exact plate thicknesses from some Strads to use a reference and match those exactly using high end tone woods and yet when they complete the violin however good it might be, it is generally not in the same class as a Strad. Does it matter that the old method resulted in an additional .5% oil absorption, but not .7%? (I made those numbers up, but hopefully you get the point) Maybe...
Yuri,I have found as long as the wood is freshly oiled it will withstand a great deal of sun or direct heat without checking, that is providing it is well cured. Your finish looks great by the way. Andy , Charles Colliers method of injecting oil in a vacuum does indeed penetrate deeply in the wood relitive of course to the density of the wood. However heated oil does penetrate better than cold oil. The test is easy , try both methods and weigh before and after. I run a violin shop as my day job and rarely do I need measure more accurately than .1 mm however as concerning recorder voicing and bores I measure .001 mm. The reason that one simply cannot copy measurements on a violin is that they lack the understanding what the measurements mean and how they relate to various densities of wood. Most just lack skill. Recorders and many woodwinds often lack a building finish that extends much if any beyond the surface. On violins we do not want the varnish to penetrate but stay on top of the wood. Different needs for different purposes.
I guess a lot depends on what "deeply" means also. One article I read had an interesting test; they tried to get water to bead on the back side of veneer using a bunch of different finishes that claimed to penetrate into wood. 1/16" was an impervious barrier but they had limited success at 1/32". There was a sidebar on the physics of trying to get large molecules through the small pores without clogging. It was a brand test rather than a method test though; I don't think they used heat.
I think lack the skill and means to work at .001 mm tolerances even if I could measure them. I tried my hand at string instruments; I made a folk fiddle, some string dulcimers and I still have a half finished citole/gittern (yes, I mixed things up as badly with string instruments) in a box waiting for me to decide what to do next. My crowning achievement was a flat top mandolin that I put a considerable amount of time in and ended up with a playable instrument that was no better than an entry level import.
Successes in penetration of finish depends on the wood density. 1/32 is very good, but one can do better, again depending on woods and method. There is as well a chemistry of making the molecule smaller.
I wish I could locate the article, but it was in a physical magazine that has been decluttered away and I didn't have any success Googling for it. I am a bit of a cynic - I suspect magazines don't run that sort of test very often because nearly all the finish vendors have one or more "penetrating" finishes and it is a pretty well known secret that none of them work all that well. Anyway, I thought the test was slightly misleading because veneer has 2 surfaces and almost no "middle" so I think penetrating through 1/32" veneer is easier than penetrating into solid wood 1/32".
I have been teaching a general wood finishing class for next to 20 years. Still for historic finishes I mix my own. I have read many conflicting reports, even highly scientific ones, that I tend to take everything with a grain of salt. The tests I believe in are the one's I do myself, but I attempt to keep abreast with what is in print. Still your turp and tung sound good as well as shellac. Lets focus on that which you are having problems with. As you are already using a gun drill how about we close this subject for now and work on the other subject you have started.
I have to say that .001mm is beyond my hmm..., skills? either. I don't think it's about skills, really. In the case of recorders a .001mm difference in the windway height won't last very long after you start playing. The wood's expansion/shrinkage rate is far larger than that. I make these things by eye, mostly, just as those long-dead makers used to. (And no, I'm not claiming anything like their abilities, or anything. The reason for emulating them is not because it's "sacred", but because it works.) Obviously, before starting out on this method, you need to get a good idea of what exactly you are going to do by eye...
My bad, I got zero happy and forgot to proof. I measure bore and voicing to .01 mm and make templates from that. Wether my end results are that consistently accurate I cannot say as I as well depend on visuals for overall balance.
My research has led me to believe that precise measurement in historic times of instrument building was employed, but it is arguable how it was used.
Individual trees will vary in density, some species have larger resonses to moisture change than others. I have seen a lot of poplar, some too soft to hold screws well, others quite a bit tougher; growth conditions varied a lot more 40 years ago, todays lunber is more likely to be plantation grown, especially when gotten from a lumberyard rather than a local mill.
Box will always be difficult because of its extreme slow growth. Historical instrument makers were in competition with bowyers for Box suitable for larger instruments, and because England and other states had an interest in the longbow, there were issues of state to contend with, one couldnt just outbid, one needed permission to export/import the stuff in any quantity. Consider the woods seen to be used in surviving instruments, box for most smaller instruments, maple or 'fruitwood' for tenors and larger; box on some of those, but not always 'choice' pieces when it is seen. This holds true with other instruments as well - shalms etc.
When working with wood one must always consider the hygroscopic nature of the stuff, and, with recorders, the high moisture content of human breath. Grain orientation matters.
Riving is more efficient than sawing, far easier to sharpen the froe than any saw blade. But, some woods (eg, elm, mahogany) dont rieve well, so the saw is necessary.
I know that from at least the 17th century boxwood was imported wholesale into at least France from Turkey. There still are companies there that sell box (octopus is one that springs to mind). Boxwood is growing wild in the highlands there, and seems to have been growing in much larger areas in the past.
I know a lot of people worship boxwood. It does take fine detail, carve well. It does mellow to such a nice brown, or stain well if you want the brown to hurry up. But it moves so much with humidity, warps and cracks. The instrument collections of museums around the world are filled with boxwood instruments that are now bent, crooked, flutes that have tenon joints that are now out of round and so unplayable. I'm sure you can do better buying the big boxwood stock from Turkey and being more selective than you can cutting up stock from winter-killed box hedges here in the US. But I think the stuff is just too treacherous for the price.
If you do want to try a real penetrating finish- put the whistle/recorder whatnot into a can of linseed -cold pressed if you like- so that it's immersed. Put that into a strong tight box ( I use a capped length of 8" heavy PVC pipe) and put a vacuum pump on it. If it's tight, and the pump is good enough to draw close to 30 inches of mercury, you will get air bubbling out for ten minutes or so, followed by water vapor. After about fifteen to twenty minutes total, after the foam dies down, I shut off the pump and let the air slowly bleed back in for twelve hours or so. This forces linseed into the wood, and as there is no longer any air or much water left in the wood to obstruct it, it penetrates very deeply indeed. My guess is, the wood is much more resistant to changes in humidity as a result.
I've only tried this with linseed, but likely any liquid that has a high boiling point would work.
Nicholas,
Good point on the PVC oil treatment. My variation is using a venturi vacuum device (as used with vacuum bag gluing) along with my compressor, then letting in the oil after the vacuum has begun. I only use hard drying oils of cold pressed linseed or walnut.
Concerning box wood, be carful not to create misinformation, it is true box can warp but not true that it always does. I consider it one of the best for winds. Though there are many warped instruments, there are many more unwrapped instruments. All wooden woodwinds go oval in time. I believe it is a matter of properly culling and curing the wood, and yes the price is high, as it should be, but of little relevance in the price of quality instrument.
I do not want to sound alarmist, and defer to your greater experience. However, repeatability is an important aspect of instrument making- if you you make very nice sounding instrument, you want to know how to make it again. Do you think that the quality of the box on the market now is such that that's as possible as it used to be? That there's enough good stock available?
That is a great question. I know good sources of box still exist, some commercial and some thru friends and not public. However, I agree alternatives should be sought out, especially in the learning years. Crocus, Ebony, African Blackwood and the other high end rosewoods are going up and up in price, as well as require greater scouting out. I myself have found a wonderful box substitute in Cercocarpus betuloides, A little denser but same color. Unfortunately it has a higher silica content and is a bit abrasive on steel compared to box. It is abundant, but has not a lot of commercial availability. I cut my own as I can cut box in France and Germany where it grows wild( with permission of land owners of course). In winds the difference in adapting between woods is in no way in comparison to string instruments. The tooling as well as dimensions remain constant.
Other woods warp, too, you know. A friend bought an alto recorder, pear, even waxed, as far as I can remember, from one of the more prolific makers, like Moeck. (But not Moeck, I really can't remember which one). Well, half a year down the road the wall of the upper joint was taking on the shape of the fiddleback that was in the wood.
