Let's talk about Ground

[MikeC]

2 hours ago, JacksonMaberry said:

Wonder if it would be helpful to put down a list of things that could be done in order after the wood surface is ready.

Proposed list, please add or remove as you see fit. Obviously not everyone would do all of the steps, but this is the order I see as useful:

Prime/Stain (in the wood)

Seal (maybe mineral, or not)

Varnish

I think that would be a very long list 

[JacksonMaberry]

50 minutes ago, MikeC said:

I think that would be a very long list 

Agreed! But what else do we have to do? Make fiddles?

[David Beard]

1 hour ago, MikeC said:

I think that would be a very long list 

Early on in thinking finishes and historical possibilities, I did make such a list.  And it was long.

[Peter K-G]

On 6/3/2021 at 10:15 PM, Peter K-G said:

Why should we assume that there was a standard Cremonese varnish/ground formula that lasted 200 years.

 

On 6/3/2021 at 10:24 PM, David Beard said:

Basically, yes.

 

10 hours ago, David Beard said:

And, just imagining now, if Stradivari was asked about 'ground' he might say something like: 'Yes. I still do that sometimes. But this days I quite often do that layer quite differently, or even leave it out.

 

Change of opinion

[Peter K-G]

My opinion is that there is a lot of differences between one old cremonese to another regarding ground/varnish. They experimented just like we do today.

This is also likely why studies contradict

[Davide Sora]

10 hours ago, JacksonMaberry said:

Wonder if it would be helpful to put down a list of things that could be done in order after the wood surface is ready.

Proposed list, please add or remove as you see fit. Obviously not everyone would do all of the steps, but this is the order I see as useful:

Prime/Stain (in the wood)

Seal (maybe mineral, or not)

Varnish

I'd put the wood finish at the top of the list, the real "base coat" of all transparent coating.

Then, the phases "Prime/Stain" and "Seal" could also be reversed in some cases.

[MikeC]

There is certainly a lot of research and a lot of clues.  

[Michael_Molnar]

2 hours ago, Davide Sora said:

I'd put the wood finish at the top of the list, the real "base coat" of all transparent coating.

Then, the phases "Prime/Stain" and "Seal" could also be reversed in some cases.

On target.

[David Burgess]

On 6/28/2021 at 10:14 PM, Marty Kasprzyk said:

Put it out in the sun sometimes.

When I was working in the Weisshaar shop, we had an array of bridges out on the roof, exposed to the Los Angeles sun. The surface color would change to something "more pleasing" rather quickly, but exposed for too long, the wood turned "punky".

[JacksonMaberry]

On 6/29/2021 at 3:18 AM, Davide Sora said:

I'd put the wood finish at the top of the list, the real "base coat" of all transparent coating.

Then, the phases "Prime/Stain" and "Seal" could also be reversed in some cases.

Very fair points.

[Three13]

1 hour ago, David Burgess said:

When I was working in the Weisshaar shop, we had an array of bridges out on the roof, exposed to the Los Angeles sun. The surface color would change to something "more pleasing" rather quickly, but exposed for too long, the wood turned "punky".

Was this from sun or LA smog?

[scordatura]

3 hours ago, David Burgess said:

When I was working in the Weisshaar shop, we had an array of bridges out on the roof, exposed to the Los Angeles sun. The surface color would change to something "more pleasing" rather quickly, but exposed for too long, the wood turned "punky".

How long is “too long”?

[David Burgess]

2 hours ago, Three13 said:

Was this from sun or LA smog?

From the sun I expect, since air pollution would have been about the same indoors and out.

1 hour ago, scordatura said:

How long is “too long”?

Sorry, I don't remember how long these bridges had been outside (under glass).

[Don Noon]

This thread has been dormant for a few weeks, but this is relevant.

I've been playing around with ground formulations to try to get one that I can apply easily, wets the wood well, and doesn't penetrate thru ribs.  For the moment, this is it.

The ground has been applied in exactly the same way, at the same time, to 4 different samples of maple.  It's pretty obvious that the wood itself is a huge player in the result, as you might expect when the ground is transparent with only very slight coloration.  I think you could get away with a little more color in the ground than this, but not much before you start to see color hanging in the flames or burning.  These flames are not burned, and switch color completely depending on angle.

 

[Don Noon]

MN went wonky and posted twice.

 

[Strad O Various Jr.]

It doesn't seem really relevant to me unless you tell us what the ground is?

[Don Noon]

18 minutes ago, Strad O Various Jr. said:

It doesn't seem really relevant to me unless you tell us what the ground is?

Terpene resin primarily.  I have been diddling for years with some in a large bottle with several different sovents added in unknown amounts and then adding some artists medium and then cooking it.  Hope that helps.

[Strad O Various Jr.]

Thank you, makes it more interesting if you have an idea what it is.

[scordatura]

On 7/23/2021 at 8:11 PM, Don Noon said:

Terpene resin primarily.  I have been diddling for years with some in a large bottle with several different sovents added in unknown amounts and then adding some artists medium and then cooking it.  Hope that helps.

By artists medium, do you mean tube color or dry pigments?

[Don Noon]

1 hour ago, scordatura said:

By artists medium, do you mean tube color or dry pigments?

Neither.  Specifically, W/N Blending-Glazing medium, which is perfectly clear.  WIth just resin/solvent, it was too thin, penetrated thru ribstock too easily, and dried way too fast.  The medium was added to slow things down, and cooking (not very hot) was done to evaporate the most volatile stuff and thicken it up so it didn't wick into the wood so far and fast.  Appearance-wise, the thickened version ends up looking no different from the thin version; it's just easier to work with and avoid soak-thru.

Mostly, I posted the photos to point out that the starting color and flame of the wood makes a huge difference.  Gotta test every time.

[Don Noon]

BTW, I checked the edges of the samples posted earlier with an eye loupe to see how deep the flames were.  On the leftmost sample, I estimate about 10 degrees variation from longitudinal.  Middle samples 20 - 30 degrees.  Deep bigleaf:  45 degrees commonly, with occasionally more... some folded 90 degrees.  Wanna guess how much fun it would be to try to bend that one?  Such deep flame I think loses the 3D effect and looks burned, as it takes such a huge viewing angle change for the flames to move.

[Michael_Molnar]

2 hours ago, scordatura said:

By artists medium, do you mean tube color or dry pigments?

https://www.winsornewton.com/na/masterclass/exploring-oil-mediums/
 

 

[joerobson]

On 7/25/2021 at 10:26 AM, Michael_Molnar said:

https://www.winsornewton.com/na/masterclass/exploring-oil-mediums/
 

 

This is Dammar + linseed oil  + mineral spirits...correct?

[Michael_Molnar]

27 minutes ago, joerobson said:

This is Dammar + linseed oil  + mineral spirits...correct?

No pigments. I don’t use it whatever it is. I just have the link.