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Sealer - an old question re asked.


Alex_E

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After using local hardwoods where no sealer/ground is required, just sand to a fine finish and then varnish for a magnificent glowing shine, using Maple for the first time is a new experience.

After reading sundry old posts on sealers, ground, varnish etc I called into the local Chemist shop and inquired about Potasium Silicate, they directed me to the Hardware Shop who in turn suggested the Chemist.

I've been advised that thin hide glue can be used but havn't seen this mentioned, the egg white method is of interest but my chances of buying Gum Arabec or Shellac flakes locally would rate lower than winning Lotto.

Are there any simple methods I can use, bearing in mind that it will only be for the neck/scroll rather than the entire body.

Some of the methods I've seen to date seem that involved that I half expect the formulae to include Bats eggs, Mountain dew gathered at midnight and having to face precisely two degrees from true North while carrying out the mixing.

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Hi Alex,

If all else fails, use two coats of clear violin varnish, let it dry and sand it. On your neck and scroll, it will act as a sealer.

If you lightly wash your wood with a solution of sugar soap, let it dry and sand it, this will also give it a better finish. It may also add a yellowish tinge to the wood.

Cheers Wolfjk

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I have tried the egg white (VB) and it made an excellent sealer, dried fast, and was very easy to sand. I made mine with a very small amount of gum arabic and I have heard some say they used egg whites only. At this point, I cannot attest to any acoustic advantages but it is very easy to prepare and I would experiment with it even in the absense of the G. Arabic. I did use a small amount of honey but not sure if it's really needed either.

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Quote:

Some of the methods I've seen to date seem that involved that I half expect the formulae to include Bats eggs, Mountain dew gathered at midnight and having to face precisely two degrees from true North while carrying out the mixing.


This is misinformation. It's magnetic north, which in your part of the world is likely to be quite different.

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Hi,

-----can you explain what sugar soap is?-----

In Britain it is a cleaning material some woodworkers use to clean the wood prior to sanding and polishin. It is sold under the brand name of "Sugar soap" and is widely available.

It seems to be similar to "lye", which in days of old was made by boiling wood ash in rain water for about two hours, letting the ash settle, and collecting the liquid on top in bottles.

The liquid lye was used for cleaning, and for making soap. (or varnish?)

Cheers Wolfjk

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Hi,

Thanks for your post. Yes, that is the right name for lye: potassium hydroxide. However it should be used at the reccommended solution. Using it neat is dangerous and might turn your spruce into cardboard. One should always read the instructions on the bottle!

Cheers Wolfjk

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The distinction is between potassium carbonate and potassium hydroxide. The latter is the lye sold as a drain cleaner. It is one of the strongest bases. I certainly would avoid it as Michael Darnton suggests.

Potassium carbonate is "potash" and a much weaker alkali. Still you need to ask yourself if you want even this in your wood.

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Regarding vernice bianca (gum arabic, egg white, sugar and honey) - if one leaves out the sugar and honey which are hygroscopic, the gum is also hygroscopic. Would there be any merit in adding alum to the gum arabic/egg white mix to make it less hygroscopic?

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Hi Jmasters,

Thanks for your post.

The sugar soap I recommended in my first post on this thread is an alkaline solution and used to clean wood prior to polishing to remove grease and other stains. It also raises the loose grain, and the wood needs to be sanded and buffed again after use.

I mentioned lye because in Stradivari’s time that would have probably been the only cleaning material available. According to a talk given by a varnish, and pigment dealer, it was used in making violin varnish.

I am giving my age away here!? But my experience with the making and usage of lye goes back to 1945-46-47. After the Second World War, it was impossible to buy any soap, and using lye was the only way to produce any. As a young boy, it was my job to collect the wood ash, boil it in a cauldron, and make the wooden boxes for the soap. Making the actual soap was done by the adults.

In European villages, wood ash was a useful commodity, was collected, and used for many purposes, including bleaching linen, fertilisers, and cleaning. ( although some people might have only washed if they fell in the water)

It is difficult to imagine what life was like for ordinary people in the 17th and 18th, centuries, and what materials they would have used to achieve the brilliant varnishes, so some careful experimentation will not go amiss.

Cheers Wolfjk

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Hi, all,

Not that it really matters, but for the record, the lye sold in US groceries and hardware stores as a drain cleaner is sodium hydroxide, NaOH. It is freely available to anyone with a dollar or two in hand. The last time I bought potassium hydroxide, KOH, I had to sign the pharmacy's poison book. 6 of this, 1/2 dozen of that, though; a strong solution of either compound will dissolve flesh in my experience. KOH was recommended to me for clearing away soft tissue from dissections but commercial lye works about the same. A mild solution of either caustic compound will also dissolve flesh, but takes longer to do so.

Commercial laundry machinery doesn't use a single detergent, but meters bits of this and that in sequence. One of the this'n'thats is a caustic solution, one of those alkali metal hydroxides, which may be later neutralized with a sour rinse such as phosphoric acid.

Now some speculation: the caustic hydroxide may not attack cellulose very much, since it is used on cotton fabric without massive damage. I bet its job is to go for the protein and grease, and I suspect it would also do a number on the lignin or whatever it is that holds wood together. Plausible recipe for cardboard?

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Possibly. The several violins I did that way didn't go all at once--one took about 10 years to become useless. The same problem has been reported with ammonia, and lots of violin makers like ammonia, not being aware of the potential problems. I imagine the process is the same, whatever it is, except that though it's weaker, it's easier to get ammonia all the way through the wood.

The color they both give to the wood is very seductive to someone trying to solve varnish problems, but the people who've been around a while know what happens. Likewise for nitric acid and the "ozone" box.

I've had any number of people assure me these things were all safe--the thing they had in commmon was that they all had no actual experience with them--it was just stuff they'd read or heard somewhere. Lots of garbage travels by word of mouth in the fiddle business--actual working makers are relatively scarce, but opinions about making never are.

It's usually not apparent right away that something's going wrong, so new ideas spreading fast are no better than old ones that never worked as they were advertised. I've done a lot of stupid things to violins, and I'm much more careful now. :-)

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Both boxwood and pernambuco have proven themselves over more than 100 years to be OK with nitric acid and ammonia. Both are extremely dense--the staining in either case is surface only.

With 2.5mm of spruce, treatments easily march straight through the wood and out the other side--that's why they're so potentially dangerous--and spruce is a marginal wood, anyway, for the work it has to do in a violin. Likewise maple--it's more like spruce than boxwood. I've seen broken violin heels that have been stained by nitric acid fumes (from an "ozone" box) right through the entire heel, which is quite a distance!

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I once custom-made a set of fittings for a lady in the orchestra using French boxwood in natural color. The wood was only lightly hand-rubbed with tung oil. Her first reaction was really a shock and the comment was: " It would be embarrassing for me to play the violin with such light colored fittings". After 8 years, the chinrest and the pegs developed beautiful patina. The chinrest was carved based on the indentation she made on the play-dough and she never had any hicky on her neck since. The box wood was highly flamed, why would I use nitric acid or cover it with dirty color?

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Hi All,

I know your people (experts) talked about "ground" and "sealer" before varnishing the instruemnt. I have a different question along that line. Do you seal the inside of the instument too? I have never noticed such undertaking until 2 years ago

I noticed my Chinese made violin ( I believe it was not

only hand made but a international award winner maker, so claimed ) by Shan Jiang of Beijiang, the inside seemed been coated with something.

I have seen 5 or 6 American makers violins, none was coated

(bare wood). I have no idea if this is a new practice. Any advantage or disadvantage in either case ? I take the liberty of throwing this in for your discussion. I hope you don't mind my question. Thank you

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"The box wood was highly flamed, why would I use nitric acid or cover it with dirty color?"

In all humble honesty you wouldn't, David, because you likely do nicer work than I do.

After lightly shaving the shafts of boxwood pegs on "step-up" trade violins, I used to darken them to match their heads because that's what the boss wanted.

As far as sealing the inside, Yuen, I remember one American maker who used to show up near here 7 or 8 years ago, who was known for varnishing the insides of his boxes. At least one local teacher and one local maker mentioned the practice was unusual. I do not know the rights or wrongs of it, just something I heard. He was asking $3000 for his fiddles, which seemed high at the time, especially for the work of "a good carpenter."

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