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On 5/14/2024 at 9:19 AM, tpistor said:

Trying to make "linoxin".  Started in March, 2021.  Will this work?

It works for what? If you want to use it to make a varnish like I use, it has to be soluble in alcohol. I don't think it is at the point you're at, but you can test it by putting a small piece in alcohol to see if it dissolves.
If I were you, I'd grind it up with a meat grinder to break it up and expose more of the surface to the air and any uncured, unoxidized oil trapped inside. But I think you will need a few more years if you want to only use natural oxidation like I do. A clear sign of complete oxidation, in addition to perfect solubility in alcohol, is the color becoming dark brown.

Grinding:

DSC_6129ridLinoxingrinding.thumb.jpg.31d2d0b95747acb18ecddae9bf58cd50.jpg

 

Fully cured and oxidized Linoxin:

linossina86ridlogo.thumb.jpg.d1c01d38c6568cc06eb5906de900e668.jpg

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On 5/15/2024 at 10:49 AM, Davide Sora said:

It works for what? If you want to use it to make a varnish like I use, it has to be soluble in alcohol. I don't think it is at the point you're at, but you can test it by putting a small piece in alcohol to see if it dissolves.
If I were you, I'd grind it up with a meat grinder to break it up and expose more of the surface to the air and any uncured, unoxidized oil trapped inside. But I think you will need a few more years if you want to only use natural oxidation like I do. A clear sign of complete oxidation, in addition to perfect solubility in alcohol, is the color becoming dark brown.

Grinding:

DSC_6129ridLinoxingrinding.thumb.jpg.31d2d0b95747acb18ecddae9bf58cd50.jpg

 

Fully cured and oxidized Linoxin:

linossina86ridlogo.thumb.jpg.d1c01d38c6568cc06eb5906de900e668.jpg

Or you follow the receipe by Lapo Casini who dissolved the ground linoxyn in a solution of natriumcarbinate (or was it natriumhydroxid?)  As a result this red brownish slurry will float up. After letting evaporate the water which adheres to it it can be dissolved in alcohol. However in solution it is not very stable. Therefore Casino advises to blend it in the desired amount with other resins such as shellack and let the alcohol evaporate. Then it can be stored for years.

i made such a ‘Casini varnish block’ long long ago and still use it to imitate fatty oil varnishes in touch up. 
 

note: I might have remembered the procedure not 100% exact. 

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1 hour ago, Andreas Preuss said:

Or you follow the receipe by Lapo Casini who dissolved the ground linoxyn in a solution of natriumcarbinate (or was it natriumhydroxid?)  As a result this red brownish slurry will float up. After letting evaporate the water which adheres to it it can be dissolved in alcohol. However in solution it is not very stable. Therefore Casino advises to blend it in the desired amount with other resins such as shellack and let the alcohol evaporate. Then it can be stored for years.

i made such a ‘Casini varnish block’ long long ago and still use it to imitate fatty oil varnishes in touch up. 
 

note: I might have remembered the procedure not 100% exact. 

Remember well, Casini saponifies with sodium hydroxide or sodium carbonate, then "desaponifies" with hydrochloric acid or another acid, to neutralize and recoagulate the linoxin. Then wash it well to remove traces of chemical substances. I prefer the natural oxidation system precisely because it is difficult to get rid of residual traces of chemical substances, which could cause problems. Or maybe not. In doubt, I prefer to have a lot of patience and use the natural method, the result still seems different to me, in the color (darker and redder) and especially in the behavior of the linoxin once dried in the varnish, which remains less soft. But it also works with the chemical system, only you can use less in proportion to the resin because otherwise, the varnish will be decidedly too soft.

This is the Casini book: https://archive.org/details/verniceliutailapocasini

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16 hours ago, Davide Sora said:

Remember well, Casini saponifies with sodium hydroxide or sodium carbonate, then "desaponifies" with hydrochloric acid or another acid, to neutralize and recoagulate the linoxin. Then wash it well to remove traces of chemical substances. I prefer the natural oxidation system precisely because it is difficult to get rid of residual traces of chemical substances, which could cause problems. Or maybe not. In doubt, I prefer to have a lot of patience and use the natural method, the result still seems different to me, in the color (darker and redder) and especially in the behavior of the linoxin once dried in the varnish, which remains less soft. But it also works with the chemical system, only you can use less in proportion to the resin because otherwise, the varnish will be decidedly too soft.

This is the Casini book: https://archive.org/details/verniceliutailapocasini

Hey Davide. Does the linoxin varnish antique well? Does it chip and shade okay? 

Just curious. Thanks. 

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31 minutes ago, Nick Allen said:

Hey Davide. Does the linoxin varnish antique well? Does it chip and shade okay? 

Just curious. Thanks. 

If you make the varnish with linoxin and colophony the wear is quite similar to an oil varnish, but it depends on the resin/linoxin percentage, but the same goes for the oil/resin ratio of oil varnish, the wear is different depending on proportions. However, I prefer to use seedlac instead of colophony, to have the varnish more resistant to sweat and therefore the wear will be less and slightly different. I wouldn't recommend it for making copies, faking the wear is more complicated.

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23 hours ago, Davide Sora said:

If you make the varnish with linoxin and colophony the wear is quite similar to an oil varnish, but it depends on the resin/linoxin percentage, but the same goes for the oil/resin ratio of oil varnish, the wear is different depending on proportions. However, I prefer to use seedlac instead of colophony, to have the varnish more resistant to sweat and therefore the wear will be less and slightly different. I wouldn't recommend it for making copies, faking the wear is more complicated.

Hmm. Thanks for the concise info. 

I am on the trajectory to make copies/forgeries(not for nefarious purposes) primarily. But having info about all types of varnishes is nice because I can have more tools in my belt when I need them. 

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1 hour ago, Nick Allen said:

Hmm. Thanks for the concise info. 

I am on the trajectory to make copies/forgeries(not for nefarious purposes) primarily. But having info about all types of varnishes is nice because I can have more tools in my belt when I need them. 

I'm not saying it's not possible, in fact you can control the percentage of linoxin well and how the chips and cracking behave, but you have less time than with an oil varnish, even if the latter is probably less predictable in its behavior over time. But I am not at all an expert in antiquing, and only for fun on small samples, such as this one with 1:1 linoxin/colophony varnish colored with madder lake, never on whole violins. So please don't take me too seriously...

DSC_8360rid.thumb.jpg.1a309cadfee0eb77ace05103a66f4be1.jpg

DSC_8360rit.thumb.jpg.d86c0f329a0cfd0fca28e171581d5a2e.jpg

DSC_8358rid.thumb.jpg.ed9f23ecf7003a5ff21a8d22f2708d76.jpg

DSC_8357rit.thumb.jpg.80996669e20a79051872cf5468fab52a.jpg

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Thanks for the replies!  I guess I wasn't expecting anybody to respond.  Sorry for not being specific about "Will this work?"

@Davide Sora Yes, I'm trying to make linoxin like you do.  (love your videos!)  Those photos above where I'm holdup up the skinned-over oil were from Sept. 2022 (about 1.5 years into the aging process).  After taking those photos, I did grind up the skins from 2 of the 8 trays I have in my attic.  You can see the current-day (3 years into the aging) images of these ground-up skins in the photos below.

Out of curiosity, I tried to take some and dissolve it in alcohol, and found it to be completely insoluble.  Not even a little!  I was thinking that maybe some of it is start to get a little bit soluble, but I guess not.

I used "Tried and True Polymerized Linseed Oil".  Does the fact it was "Polymerized" present any problems?  Should I have started with completely unprocessed linseed oil?

Also, should I pile up the ground-up oil skin higher?  I've spread it out sparsely hoping it would oxidize faster.  But, I can't imaging it forming a nice thick brown toffee-like layer like yours.

Next time I'm in my attic, I'll snap a photo of the un-ground (3 year old) skins for comparison.

I'll continue to report the progress of the aging.

I was just looking for some reassurance that I'm on the right track.

linoxinGroundUp2.jpg

linoxinGroundUp1.jpg

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5 hours ago, tpistor said:

@Davide Sora Yes, I'm trying to make linoxin like you do.  (love your videos!)  Those photos above where I'm holdup up the skinned-over oil were from Sept. 2022 (about 1.5 years into the aging process).  After taking those photos, I did grind up the skins from 2 of the 8 trays I have in my attic.  You can see the current-day (3 years into the aging) images of these ground-up skins in the photos below.

Out of curiosity, I tried to take some and dissolve it in alcohol, and found it to be completely insoluble.  Not even a little!  I was thinking that maybe some of it is start to get a little bit soluble, but I guess not.

I used "Tried and True Polymerized Linseed Oil".  Does the fact it was "Polymerized" present any problems?  Should I have started with completely unprocessed linseed oil?

Also, should I pile up the ground-up oil skin higher?  I've spread it out sparsely hoping it would oxidize faster.  But, I can't imaging it forming a nice thick brown toffee-like layer like yours.

Next time I'm in my attic, I'll snap a photo of the un-ground (3 year old) skins for comparison.

I'll continue to report the progress of the aging.

I was just looking for some reassurance that I'm on the right track.

 

 

At the point you are at it is normal that it is not soluble in alcohol, it takes longer. Using prepolymerized oil shouldn't cause any problems, at most it shortens the oxidation time a little (but not much). With the natural oxidation system it is difficult to establish a time to reach solubility in alcohol because the type of oil and environmental conditions can influence, but I estimate that more or less 5 or 6 years will be necessary. The only way to shorten this time is chemical saponification to eliminate the glycerin content, but as I was saying the final product will not be the same, more pale in color and softer, even if it will be soluble in alcohol and therefore usable to make a varnish.

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  • 4 weeks later...

Trying to choose color for violin #4.  

Bottom: violin #1

Left: violin #2

Middle: violin #3

Right: scrap violin for varnish practice - this is a candidate varnish for #4 (homemade from tree sap)

Far right... Other test samples

PXL_20240617_184011695_MP.thumb.jpg.70257e5fd504de64693ddab486170bf1.jpgPXL_20240617_184124981.thumb.jpg.e6425978043a148d23b492c7936dab86.jpg

PXL_20240617_184145663.thumb.jpg.1c1f4f574c9af6fe7af6a1b967b3ef84.jpg

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  • 2 weeks later...

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