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Diluted Oil Varnish used as a Sealer


pt3
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It is said that oil varnish diluted in turpentine can be used as a sealer, originally I use Vernice Bianca (white varnish), but it is hygroscopic, so I want to make a try. What is the proper proportion (by volume) of the varnish and turpentine? I use Marciana varnish. But I am worried about that the penetration of the diluted varnish into the wood maybe too deep and harmful to sound quality.

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I too wouldn't think dilute varnish would "seal" very well. Maybe extremely dilute to add some color or accentuate flame, but for sealing I'd think about something that doesn't soak in, and/or dries rapidly.

Sealing with varnish, dilute or otherwise, is a fairly common way to ground. I use a dilute varnish as the final procedure in the Balsam Ground. Reading between the lines in Don and lyndon's remarks ........... you will need to do some experimenting as there are lots of possible outcomes.

on we go,

Joe

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I too wouldn't think dilute varnish would "seal" very well. Maybe extremely dilute to add some color or accentuate flame, but for sealing I'd think about something that doesn't soak in, and/or dries rapidly.

Thank you both for your immediate replies!

So, using dilute spirit varnish may be a better alternative. I want to know the degree of duluteness, i.e., how much seedlac should be added to 100 c.c. of alcohol.

Another alternative is gelatine plus alum. The concentration of gelatine solution is generally 2 ~ 3%, but how much alum should be added to this gelatine solution (e.g., 100 c.c.)with such concentration. It is said that alum is used as a hardener and makes the sealer not so hygroscopic as vernice bianca.

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Thank you both for your immediate replies!

So, using dilute spirit varnish may be a better alternative. I want to know the degree of duluteness, i.e., how much seedlac should be added to 100 c.c. of alcohol.

Another alternative is gelatine plus alum. The concentration of gelatine solution is generally 2 ~ 3%, but how much alum should be added to this gelatine solution (e.g., 100 c.c.)with such concentration. It is said that alum is used as a hardener and makes the sealer not so hygroscopic as vernice bianca.

The ratio of solvent to varnish has a lot to do with the varnish. What solvent will you use? What is the oil to resin ratio of your varnish?

Gelatine will act as a barrier. I think of sealing as in the wood, rather than a shield.

Joe

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The ratio of solvent to varnish has a lot to do with the varnish. What solvent will you use? What is the oil to resin ratio of your varnish?

Gelatine will act as a barrier. I think of sealing as in the wood, rather than a shield.

Joe

Thanks a lot!

The varnish I use is Marciana according to an old Italian Recipe, which consists of colophony, mastic and linseed oil. The ratio of oil to uncooked resins is 1:1 by weight. I intend to use turpentine to dilute the varnish and want to get your directions of the proper ratio of solvent (turpentine) to varnish.

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I believe M. Darnton is sealing (or was sealing) with shellac. He recommends to dilute it 4 times before applying it to the wood (so I guess he meant using a 3/1 cut shellac diluted a further 4 times). I did try this with my latest violin even though some people think the worst about this procedure. I will have to wait 1 or 2 more weeks to know :)

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Ok, vernice bianca is hydroscopic. But has anyone actually tested the effect on wood? I mean on the damping quality or durability of the sealer. It brings up the the sugar seal idea. jezzupe contends that the sugar seal is thin and really does work, in spite of it hydroscopic nature.

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Thanks a lot!

The varnish I use is Marciana according to an old Italian Recipe, which consists of colophony, mastic and linseed oil. The ratio of oil to uncooked resins is 1:1 by weight. I intend to use turpentine to dilute the varnish and want to get your directions of the proper ratio of solvent (turpentine) to varnish.

Given the 1:1 oil to resin ratio I would not thin this varnish and then apply it to bare wood. A high oil varnish in direct contact with the bare wood will wet the fibers in a manner similar to using linseed oil on the wood. Try this on a sample: Put a little varnish on a piece of cheese cloth. Rub a small amount on to the surface. Then using a separate cloth wipe and then buff the surface until the varnish tacks up so that is does not absorb too much. Let it dry and take a look.

on we go,

Joe

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Given the 1:1 oil to resin ratio I would not thin this varnish and then apply it to bare wood. A high oil varnish in direct contact with the bare wood will wet the fibers in a manner similar to using linseed oil on the wood. Try this on a sample: Put a little varnish on a piece of cheese cloth. Rub a small amount on to the surface. Then using a separate cloth wipe and then buff the surface until the varnish tacks up so that is does not absorb too much. Let it dry and take a look.

on we go,

Joe

Thank you very much for your valuable guidance!

I have a further question: What's the difference between using this kind of varnish and using linseed oil for this purpose?

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A 1:1 oil to resin ration varnish will have a consistency of cold honey and it will not soak in the wood, it is too viscous.

manfio,

True, in the way that you would prefer....but not all varnish is made that way! Putting it on and immediately wiping it off avoids the possible problems.

pt3,

Wiping linseed oil on to the bare wood....the commentary on this would fill an encyclopedia. It is worth searching the back threads on MN to get an idea of the issues involved. Personally I do not think it is a good method.

on we go,

Joe

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I too wouldn't think dilute varnish would "seal" very well. Maybe extremely dilute to add some color or accentuate flame, but for sealing I'd think about something that doesn't soak in, and/or dries rapidly.

Mr. Don Noon,

I remember that you have recommended using sandarac as a sealer. Could you tell me the ratio of sandarac to alcohol? Is it better than shellac for this purpose?

Thanks!

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Joerobson,

After reading your comments on this thread I clicked through to your website which is quite interesting. I wondered, though, if you could clarify two things for me: are the aged wood colours simply colouring the wood to mimic the results of ageing, or do they somehow speed the actual chemical process that would happen naturally over time? And is the balsam ground that you mention similar to rosin oil grounds?

Thanks,

Laura

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Mr. Don Noon,

I remember that you have recommended using sandarac as a sealer. Could you tell me the ratio of sandarac to alcohol? Is it better than shellac for this purpose?

Thanks!

No, that wasn't me. But I have tried shellac, and don't think it looks as good as some other resins.

And, as long as I'm here...

I've also heard the term "isolation layer", which apparently is a "sealer" in that it forms a barrier to keep the subsequent oil varnish from penetrating the wood (egg white, hide glue, and a zillion other things could work). However, it is not necessarily the first thing that goes on the wood, that being some other coating (thin solution of resin in turpentine, for example). The purpose of the first coating is mostly aesthetic (I think), to wet the wood and bring out flame. What does one call this first wash coat? A sealer, to be followed by an isolation layer?

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Wouldn't a resin in turpentine tend to seal the wood? Henry Strobel used to use a wash-coat of an aqueous colorant to stain the wood a "salmon" color (his term...I never saw it). Probably about like a tea-wash, only more intense color. But that had no effect toward sealing-- just color, and raising the grain. His sealer/ground coat came afterward.

Propolis adds color, and tends to seal the wood. Makes it smell nice, too. :)

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Wouldn't a resin in turpentine tend to seal the wood?

I'd say how well it seals would depend on how thick you make it. Personally, at the moment (subject to change), I'd use it rather thin, then use something else over it to keep the oil varnish out.

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Yes, I would say very thin-- but I was of the (possibly unfounded) opinion that the resin residue in the pores would effectively seal the wood after the turpentine had evaporated. Especially if two coats were employed.

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No, that wasn't me. But I have tried shellac, and don't think it looks as good as some other resins.

And, as long as I'm here...

I've also heard the term "isolation layer", which apparently is a "sealer" in that it forms a barrier to keep the subsequent oil varnish from penetrating the wood (egg white, hide glue, and a zillion other things could work). However, it is not necessarily the first thing that goes on the wood, that being some other coating (thin solution of resin in turpentine, for example). The purpose of the first coating is mostly aesthetic (I think), to wet the wood and bring out flame. What does one call this first wash coat? A sealer, to be followed by an isolation layer?

You have said that the first coating may be a thin solution of resin in turpentine. Could you kindly tell me what resin and what ratio of the rasin to turpentine (I mean how many grams of the resin in 100 cc turpentine)? I will follow your advice. I agree with you that thin varnish diluted in turpentine will do the same, but which one is better, thin solution of resin in turpentine or thin varnish diluted in turpentine? What about thin solution of dragon blood in alcohol? Dragon blood produced in China is quite transparent.

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You have said that the first coating may be a thin solution of resin in turpentine. Could you kindly tell me what resin and what ratio of the rasin to turpentine (I mean how many grams of the resin in 100 cc turpentine)? I will follow your advice. I agree with you that thin varnish diluted in turpentine will do the same, but which one is better, thin solution of resin in turpentine or thin varnish diluted in turpentine? What about thin solution of dragon blood in alcohol? Dragon blood produced in China is quite transparent.

I think these questions should be answered by someone who really knows what he's talking about. I'm not an expert, and perhaps our resident expert (Joe) might not want to give away secrets of his business. My last 2 violins I had to strip and revarnish, as they were disasters, and my latest ideas (resin in turpentine) has only been tested on a scrap of wood (although I did recently chat with a real violin maker, and found that he does something very similar). There are several turp-soluble resins; my personal preference is congo copal, for no particular reason other than it has a nice-looking amber color, and seems pretty hard and stable. I haven't tried everything. Resin/solvent ratio is something I haven't determined yet; I'll do a few more scrap tests (eventually) to see what it takes to keep the "wet look" after it dries.

Joe? Any help here?

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Joerobson,

After reading your comments on this thread I clicked through to your website which is quite interesting. I wondered, though, if you could clarify two things for me: are the aged wood colours simply colouring the wood to mimic the results of ageing, or do they somehow speed the actual chemical process that would happen naturally over time? And is the balsam ground that you mention similar to rosin oil grounds?

Thanks,

Laura

Laura,

The Aged Wood Colors mimic the results of the aging process, but they are just color...not chemical reactions. As such they give us control over the color and intensity of the ground in the way we are used to with the varnish.

There is little [or no] similarity between using rosin oil and the Balsam Ground. Rosin Oil is the destructive distillation of colophony [pine resin which has already had the turpentine removed] at high temperature [ 300 - 360C]. The components of the Balsam Ground are fractions of raw pine sap followed by a thin, very resin rich Balsam Ground Varnish.

The Balsam Ground seals the fibers without filling the pores and it dries in a predictable way. Rosin oil is usually a surface application and not predictable in drying.

on we go,

Joe

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