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Couldn't Mr. Robson's ghosting be caused by over burnishing by the scraper? 

 

I read where Bartruff's violin tutortorial said to use glue over the plates before varnish.  Looked sort of yellow to me after applied.  It was a few years ago when I first ran across violin making where I first read that but I couldn't bring myself to do his glue bit on plates.

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Christian,

You are certainly correct...the glue ghost came from the contrast between the Balsam Ground and the glue from the insertion of the decoration.  I just received my 4th viola from this maker and the issue has been corrected. 

However the question still remains.  As Brigette Brandmair once, politely, told me, "Joe, there are many roads to Rome!"

There are a variety of successful ground methods.  I make no pretense of hiding my preference for a deep luminescent ground under a "Cremonese" style varnish.

I am open to being wrong, but I have as yet to see a protein based wood surface preparation that allows for the deep reflectivity.  I believe it is in the nature of the materials and the way they sit on the wood.

I think this is a "compared to what?" situation.  A ground may look good on a particular instrument, but when compared to another your observation may change.

I recently began a project to address this.  Hopefully this will be ready for VSA in November.  I am doing a series of plates...1/2 size violin tops and back...with a variety of grounds so we can look at them side by side.  The list is Balsam Ground, shellac. linseed oil, glue, casein emulsion, POP. mineral ground, and straight varnish.

on we go,

Joe

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Ditto.  :)

 

I tested a lot of things, and found similar results:  other things just look better than glue as a base, if you want to get the most glitter glow and contrast out of the wood.

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Start with hide glue is , according to the "Carteggio" from Cozzio ( I know it was wrote long after Strad death, but, maybe the earliest text about Cremona's varnishing technics) one of the way to varnish in Cremona, supposed to prevent worms.

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Start with hide glue is , according to the "Carteggio" from Cozzio ( I know it was wrote long after Strad death, but, maybe the earliest text about Cremona's varnishing technics) one of the way to varnish in Cremona, supposed to prevent worms.

 

To be fully effective at worm prevention, this would require hide glue treatment of the inside also. 

Is that what the Carteggio says?

Do you do that?

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Hide glue ground:

 

 

And A LOT of other stuff, too. We're not really born yesterday. Not all of us, anyway.

 

 

Yes, they call it "varnish"

 

I see. It's not varnish, it's "varnish". By the way, you are not trying to tell me that all you did there was paint it with watery glue and then "varnish" it ?

I think you should clarify this.

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I see. It's not varnish, it's "varnish". By the way, you are not trying to tell me that all you did there was paint it with watery glue and then "varnish" it ?

I think you should clarify this.

 

Most people who use weak hide glue or gelatine in their varnishing process just use it as a sealer coat to stop whatever gubbins they put on top burning the endgrain. Dunno about Christian, but for my ground the gelatine sealer coat is stage 2 of a 5 stage process (before varnish is applied).

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Most people who use weak hide glue or gelatine in their varnishing process just use it as a sealer coat to stop whatever gubbins they put on top burning the endgrain. Dunno about Christian, but for my ground the gelatine sealer coat is stage 2 of a 5 stage process (before varnish is applied).

 

That would make sense to me and be in line with my own rather extensive experiments.  I'm perfectly fine with "not telling" but am getting a bit blurry on  "confusing". :)

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Glue or egg white I've heard used as a "separation layer" to keep the varnish proper from soaking into the wood, and/or to aid in antiquing.  This usually is NOT the first thing on the wood, though... something to wet the wood and enhance the flames goes on first.

 

Glue directly on the wood can be used, and still come out with a very nice looking finish, as Christian shows.  However, I still firmly believe that some contrast, sparkle, and pop is lost by that process.  Fine if you want a softer look, and perhaps there is some acoustic benefit, but for maple I want to see it show up as luminous, glittery, and contrasty as I can possibly manage.

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Don,

Agreed. Protein coating play a variety of roles in new making and antiquing.  The function of the layer in antiquing is very useful.  However there are always trade offs...gain something and you lose something else. 

Protein based applications on bare wood...and wood that has been "colored"... in some way....in order to have the toughness necessary to be protective, must be to a degree white ie. opaque to the degree which corresponds to their durability.  The more processed...heated...the protein the more protective and the more opaque it becomes.  A secondary factor is the reflective surface.  This type of application transfers the reflective surface from in the wood to the surface of the protein.  Mike Molnars "Optics for Luthiers" article covered this well.  The attached is another way to explain the concept.

When used as a separation layer the optical properties remain the same...although the thinness of the layer, which is often just washed off, tends to interfere to a lesser degree.

on we go,

Joe

SG05-wood.pdf

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2nd color coat applied.  If you look close, you can see the color matches on the inside of the decoration [retouched glue ghost] but it does not match the detail and depth of reflection oustide the pattern.

post-6284-0-45002600-1441936346_thumb.jpg

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da Salo viola

On a decorated instrument I think it is important to be able to see the decoration.

Full varnish...medium brown with some highlights.  I keep seeing that Nicolo Amati violin in the back of my mind.

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