zalzal
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Question : Is shellac (kind of gum acacia) good for oud ??
Question : Is shellac (kind of gum acacia) good for wood finishing
as a varnishing - polishing agent ?
http://www.allandetrobert.fr/Technical_Industry.asp
Wasn't gum one of the precious present brought by Balthasar King to 3Issa at Bethleem ?
Gum arabic is an incredible product, coming fm the bleeding of the acacia.
BTW is acacia used in ouds ??
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Jameel
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Shellac is actually the secretion of an insect, not a tree resin.
Gold, Frankincense and Myrrh were the gifts of the Magi. The latter are both resinous excretions of a tree.
Gum arabic is indeed an incredibly versatile material. It is used in certain finishes I believe.
Shellac is a great finish for ouds. It's used extensively for instruments of all kinds. Most often it is applied using a technique called "french
polish", where the shellac is dissolved in alcohol and rubbed on in whisper thin coats over a period of usually many days.
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zalzal
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Merci,
Still i wasn't that far with Magi
http://www.panspantry.co.uk/list.html
..."The Arabic word for frankincense is "Al Luban", meaning "The Milky One" This describes the milky white texture of the oxidised resin -although
many of the best resins are golden in colour. From this we get the European name Olibanum. However, to confuse matters "Luban" tends nowadays to be
used for a wide variety of incenses, some of which are very definitely not frankincense! Most modern frankincense comes from Somalia, although it is
often re-packaged to make it appear to originate from the Arabian peninsula..."
Later on it is said that "coptic frankincense" is the one preferred by...muslim pilgrims...
I am sure oud playing is and sounds better with a smell of frankincense all around...i mean if you play inside heavy steams of frankincense, like in a
sauna
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jdowning
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Interesting question zalzal.
Shellac is made from the lac insect and comes primarily from India so is not derived from gum acacia. It is the basic material used in French
polishing.
It is used traditionally as a finish for guitars (as well as oil varnish and other finishes) so should also be good for ouds. Shellac is soluble in
alcohol so has the advantage - unlike a traditional oil varnish - that a damaged finish can be relatively easily repaired 'simply' by redissolving
the finish. It disadvantage is - it dissolves in alcohol and is not waterproof.
I have examined the finish on an oud that I am currently restoring which - underneath a thick protective layer of wax polish - has a finish that
appears to be soluble in alcohol and which might, therefore, be a shellac finish. However, like you, I am interested to know if shellac is a
traditional finish for ouds.
Is Gum Arabic also soluble in alcohol - not as far as I know but I could be wrong?
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jdowning
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Apparently gum arabic is highly soluble in water but insoluble in alcohol.
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Dr. Oud
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Shellac is certainly a good finish material for ouds and is the most common one used in my experience. The application is critical, however. If it is
merely brushed on it is a poor finish; soft, cloudy, lumpy and not very well adhered. French Polish is the method that rubs successive thin layers of
shellac on, each one infusing with the last coat so that the end result is a clear smooth and hard finish.
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jdowning
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Shellac can be applied successfully with a brush or pad as a spirit varnish but needs to be well diluted if the messy problems that Richard observe
are to be avoided. Shellac has a limited shelf life once made up so is best made from flake shellac as needed. Stale shellac will not dry properly.
The dilution or "cut" usually used for French Polishing is a 2 or 3 pound cut - that is 2 (or 3) pounds of shellac dissolved in a gallon (8 pounds) of
alcohol. This is likely what you get if you purchase ready made shellac from a hardware store.
The store bought shellac should first be diluted by adding two parts alcohol and allowing to stand a couple of days before pouring off the clear
liquid from any residue. The clear liquid is then diluted further by adding one part alcohol. This thin fluid is then applied by wiping along the wood
grain and sanding very lightly between coats after drying. About 5 coats will give a very fine lustrous finish.
I have used this weak shellac solution in the past for finishing instrument soundboards as it seals the surface from dirt but have not tried it on
instrument bodies.
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Jonathan
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jdowning, doc, and others: I have been asking some of the local luthiers about French Polishing, because I have an oud that has a French Polish that
is worn off.
I know very very little about the French polish process, however,
some of them have told me that they spray on the first few layers of the shellac. Quite honestly, that did not sit well with me. Again, I know
little about French polish, but it seemed to me to indicate an effort to speed up the process. Do you know anything about this? Is there any
advantage to spraying on the shellac that I am not aware of?
I had another luthier tell me that French polish loses it shine after a very short time, and will "cloud up". I have a couple of ouds with old French
polish on them, and I never saw this. Shouldn't the French polish remain clear?
In preparing the surface of an oud for French polish, what level sandpaper do you go to? I saw a guy recently that refinished his oud. He told me he
sanded it down to 1000+ grit. He had about 17 coats on the oud, and it was one of the most beautiful things I have ever seen. He also told me that
he clocked the hours, and that he spent 360 hours doing it! Sorry, but I just can't imagine it. That entire oud I built probably took me about the
same amount.
In contrast, one oud maker told me that he does not sand beyond 600 grit, because the shellac won't take as well to the wood. Any thoughts on
this?
I know the tru-oil is easier, but I am trying to stay a bit more authentic with this refinish (I actually am not planning on doing it myself, but I
want to learn a bit more before I send it somewhere). Also, I heard that (I don't know if this is true) if the surface wood is not adequately sealed
prior to the application of the Tru-oil, the sound can be deadened somewhat.
Thanks for your help.
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jdowning
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Professional instrument makers often use sprayed lacquer as a production finish so I suppose that they could also spray shellac. The advantage of
spraying is that it is fast and gives an even, uniform coating so is suited to quantity production. However it is also potentially hazardous and needs
to be undertaken in a spray booth with flameproof extraction fans etc. - so not really the method to use in your home.
Shellac is compatible with hide glue and oil varnishes so can be used as a sealer on bare wood that is to be oil varnished.
It is best not to sand the bare wood at all prior to finishing as sanding abrades and plugs the wood grain pores. The best finish is straight off the
scraper. On the other hand when sanding between coats of shellac the objective is not to cut though to the wood underneath but just to remove any
surface irregularities, dust specs etc in the coating. Only very light sanding between coats with the finest grits should be used for this. The final
coat can be polished with fine grade pumice or rottenstone and mineral oil.
A shellac finish will cloud or produce a white stain if it comes in contact with water or moisture. This damage can be removed by repolishing.
My experience with ouds is limited to the old oud that I am currently restoring so I can't comment on how ouds are generally traditionally finished. I
first thought that my oud had an oil varnish finish as it did not respond to testing with alcohol. However I have since found that the instrument is
coated with a wax finish over what may be shellac or other spirit based finish underneath. The wax finish, applied over the course of decades, has
built up and protects the shellac finish underneath from damage but, on the other hand, the soft wax has absorbed dust and grime and lost its original
lustre. I have removed the old wax in one small test location to reveal a rather nice lustrous patinated finish underneath - one that I shall try to
preserve in the restoration work - but that will be another story later.
The attached image shows a small area of damage that was completely filled with wax that was easily removed by scraping with a fingernail.
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Jonathan
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Thanks--that helped a lot.
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Rufi
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Johnathan do not use tru oil except mabey on the back.
I have french polished many instruments guitars, violins, basses, cellos, mandolins, and ouds. It is in my experience the most true sounding finish.
That is that it can be applied really thin and does not effect the sound much.
I always used to apply it by hand from start to finish but I ran into problems early on especially when using a colored spirit varnish over a light
wood. It is very difficult to seal the wood evenly before you begin to apply the varnish with oil.
An old luthier friend of mine ,who gets wonderful results in production guitars with a french polish, told me how to spray the first couple of layers
to get a perfectly even base to begin your buildup. Lee Varis and Mike ouds both have ouds that were finished this way please ask them how they like
them. it still takes as much time to do a proper job, about six weeks, but i find that I get closer to perfect results by spraying the first coat of
two.
Shellac does not cloud up if it applied properly.
It can be kept shinny if you polish it up from time to time.
Most of us don't sand wood passed about 220 of even 180 grit before the finish is applied in between coats we use 360 to 600 grit wet.
If you are really interested in this you shoul look into two sources
First Luthiers merchantile used to offer a cataloge for about 20 bucks that had an article in it. That was the first difinitave article i read and
got me started.
Then Classical guitar seller Ronald Fernandes has a video that If you would promise to return I will let you borrow.
Let me know what else you have questions about email me at Rufieoud@yahoo.com
and I will send you my Phone number
Thanks
Rufie
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Hosam
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Jonathan, Ron's video is really good.
Rufi, is there any difference between the method you use for French polishing and that of Ronald Fernandes? I understand that everyone has his own
little variation.
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Jameel
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Jonathan, listen to Rufi's advice. The article he is talking about is on LMII's website in full. Or check this if you're really eager http://www.milburnguitars.com/fpbannerframes.html
Keep in mind that French Polish is actually a technique, not a finish per se, although most often it's done with shellac. I don't have much experience
with FP, but I've seen it done quite a bit and talked with a real expert polisher for hours about it. It's the guy that helped me with the sandwich
top. He FP's his classical guitars and they are flawless. Way better than any oud finish I've ever seen. Just incredible. Smooth as a mirror. In
reflection, you could see nothing, no brush strokes, orange peel, dimples, specs, haze, NOTHING. I've seen him do it, and it's not rocket science.
Just kinda laborious. We're learning a lot from each other lately. He's even done a couple classicals without finishing the top. Go figure....
Incidentally, he often begins his french polish by laying down a couple coats of amber or red shellac (button lac) with a cheap hvlp gun to get it
started. Nothing wrong with that. That business of 300+ hours to do a FP is quite unecessary.
Personally, I don't see the point in taking an oud finish to this level. I just don't think it's worth it. Don't get me wrong, the last oud I finished
with TruOil (and that's a more durable finish than shellac) is silky smooth and very uniform, but it can't be compared to a first-rate french polish.
The thing is, after the bowl and neck gets sweated on a few times (I'm not exactly skinny, and sweat fairly easily), and moved around against the
buttons on my shirt and set on a coffee table etc. etc. that perfect FP is gonna be history. I'm of the view of a more practical, yet beautiful finish
for ouds. You see concert classical guitarists drape cloths all over their body and basically only touch the parts of the guitar they have to. How
many of us treat our ouds that way? I sure don't. Just my 2 cents.
One more thing. If you're going to FP the bowl, I was thinking you'll need some sort of jig to hold the oud rigid while you polish over the bowl,
since you wont be able to hold it still with one hand. A guitar is relatively easy since you can do the back while its laying on the face, then do
each side one at a time. But with the oud you'll have to immobilize it so you can polish over all areas without it moving. You'll also need lots of
good lighting. Rufi, how do you keep the oud immobilized?
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Jonathan
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Thanks a lot, guys.
I have seen Rufi's work in person, and it is very nice. As is Viken Najarian's. There was a local luthier (violins?) who has passed on, but whose
work I see from time to time (Bassicon?). I have seen 3 or 4 ouds that this guy did the French polish on, and the job was beautiful. I also own one
oud that he did the polish on, as well.
Jameel--I do love the ease and durability of Tru Oil. I read on another forum, probably MIMF, where somebody stated that the sound on instruments
can be deadened a bit when using Tru Oil if the wood is not first sealed. I don't know if that is true or not--I'm still not sure that the impact
that the bowl has on the tonal characteristics of the oud are all that significant, let alone the finish that is put on the wood.
Rufi, I appreciate the offer. I'll give you a call shortly.
Thanks again, everybody.
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