Ground coat

ctregan · #1 05-02-2008, 06:33 AM

What makes for a good ground coat on string instruments? Is it done to seal the wood and impart colorful undertones? Or is there a physical component to the ground coat as well? Should it be elastic? or hard like a shell? Is it essential for a good tone?

I am not looking for secret formulas, just an better understanding of the ground coat and how it effects a Bass.

arnoldschnitzer · #2 05-02-2008, 07:06 AM

You have opened a major can of worms. Opinions are all over the lot on this. Mine is that the ground sets the background color, and basically seals the wood, so that colored varnish coats and glazes don't penetrate into the wood surface. I think its elasticity should match the varnish, unless you want a crackled look.

christ andronis · #3 05-02-2008, 07:30 AM

Arnold, how does it affect the tone?. I've got the nuclear shellac on my backup and I just have to believe that it really inhibits the vibration of the bass.

RCWilliams · #4 05-02-2008, 08:57 AM

no one has called meany thing really obnoxious of late so let me fix that by offering a conjecture, what if the difference between the Italian, German, French and English sopunds was the ground?

arnoldschnitzer · #5 05-02-2008, 10:34 AM

Quote:

Originally Posted by christ andronis

Arnold, how does it affect the tone?. I've got the nuclear shellac on my backup and I just have to believe that it really inhibits the vibration of the bass.

Impossible to really know, but I have heard anecdotally that folks report improved tone after refinishing some of these heavily-lacquered or urethaned basses. Tom Martin likes to say "You don't want to run a marathon in a raincoat".

Bob Branstetter · #6 05-02-2008, 10:44 AM

Quote:

Originally Posted by RCWilliams

no one has called meany thing really obnoxious of late so let me fix that by offering a conjecture, what if the difference between the Italian, German, French and English sopunds was the ground?

As I'm sure Rick knows, there are a lot of people in the violin community who feel that the ground (Not The Varnish) is the most important component of classic period violin sound. While scientific analysis of tiny pieces of wood from repaired Cremona instruments has shown there to be a "mineral" layer on many instruments made by the great Cremona makers, there is still huge disagreement on what it is. William Fulton (famous for bent violin plates and terpene varnish) believes that the ground was a propolis soap. The second half of this article discusses the propolis ground. The propolis ground seals the wood and is naturally yellow in color when dry. I don't know if propolis soap is the "real" ground used by the masters, but the evidence shown by Fulton was enough to convince me to use it under the varnish of the instrument I'm currently making. I've seen and heard violins made with the Fulton varnish and propolis ground and to say I was impressed would be an understatement. The ground will not make a poorly made instrument sound good, but it may be one of those things that make the difference between a good instrument and a great one. I don't know for sure, but I'm willing to give it a try to find out for myself.

arnoldschnitzer · #7 05-03-2008, 07:05 AM

Bob, are you putting it on the inside as well? I read that the Rubio mineral ground is supposed to be applied to the interior as well as the exterior. Is it the same with Propolis?

Bob Branstetter · #8 05-03-2008, 09:24 AM

Quote:

Originally Posted by arnoldschnitzer

Bob, are you putting it on the inside as well? I read that the Rubio mineral ground is supposed to be applied to the interior as well as the exterior. Is it the same with Propolis?

The Rubio mineral slurry ground and Propolis soap are quite different. There is historic evidence that would support either one as being "the" Cremona ground, but I personally think the known availability of bee hives and the documented use of propolis in the paintings of the period tip the scales toward propolis. However, there are many experts in the violin world who think that the Rubio ground or something like it was "the" ground.

I had the opportunity to talk to Bill Fulton and to see up close violins that had been made with the Propolis ground and to me, the look was closer to the look of Cremona violins that I've seen at museums than the ones I've seen with the Rubio ground. Naturally, the varnish on top of the ground can make a difference, but that is also true with any other ground.

I plan to use the propolis ground only on the outside of the instrument. I don't believe that Fulton recommends coating the inside with Propolis. I know some makers today who coat the inside with glue or albumin, but I've yet to be convinced that it is a good thing to do in the long run. I've always felt that coating the inside could cause problems later when it is necessary to repair cracks. Plus, I don't think there is any proof that makers in the classic period coated the inside. On the contrary, some violin experts have stated that varnish was applied the instrument originally just to keep them from looking dirty after use.

Martin Sheridan · #9 05-05-2008, 10:19 AM

Bob,
Sacconi said that Stradivari did coat the inside of his violins.
He said that if you put a drop of water on the inside of the instrument it just stood there as opposed to sinking into the wood which would be the case if the inside was not sealed.

Darren Molnar · #10 05-05-2008, 11:36 AM

Hi Martin, I've read that too. But I wonder some days.

Would three hundred years or so of playing an instrument, (with a rosined bow right over top the f-holes) deposit enough rosin dust to give the same appearance? three hundred years is a lot of dust!

I'm feeling that there probably wasn't any coating origionally, but bowing over top the f-holes for such a long time, would deposit enough rosin to become a coating on the inside. They have been cleaned inside many times, which might actually soak, press the rosin into the pores, eventually looking like a thin intentional coating.

Next week I'll probably think something different, grounds tend to be a moving target for me, but I thought I'd throw the idea out there.

Bob Branstetter · #11 05-05-2008, 11:44 AM

Quote:

Originally Posted by Martin Sheridan

Bob,
Sacconi said that Stradivari did coat the inside of his violins.
He said that if you put a drop of water on the inside of the instrument it just stood there as opposed to sinking into the wood which would be the case if the inside was not sealed.

I've seen several articles in the VSA Journal over the years that disagreed with Sacconi on this matter.