Urban Luthier

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Inspired by many of you and your various approaches to varnish making, I cooked up some of my own oil varnish. Why? as a visualization exercise. it is important for me to visualize end result I'm trying to achieve and I need stuff to experiment with as I learn. 

 

Rather than going crazy the first time around and cook resins for days on end to capture the mystical colour of the old masters, I set out to make the the 'boring type' of varnish Roger refers to in his Bass Blog. Linseed oil and colophony cooked together at low temperature until they blend. It is a safer place to start. I did my homework on safety -- and encourage any other newcomers to do the same. 

 

Here's the recipe:

  • 140g Cold-pressed Linseed oil from Sweden. Kremer 73020 (Washed thrice + sun thickened) You should have seen the coagulated white goo that was left over from the washing process one litre yieled 400ml of oil. Must have done something wrong
  • 200g Burgundy Resin (Colophony of European Pine). Kremer 60320. Uncooked 
  • 10g Mastic (from Chios Greece). Kremer 60050. Uncooked
  • 1 teaspoon of Pit Lime. Kremer 31800
  • 350g total. 60% resin 40% linseed oil by weight
  • Added crushed resin to warmed oil and cooked at 130-160 degrees C for 1-1/2 hrs while stirring regularly. filtered while warm
  • No turps added

The varnish is as thick as honey when cooled, it is opaque as molasses in the jar but very pale and very transparent amber orange on wood surfaces. Although pale in colour, it is naturally dichromatic (right word?) see the photo. How something that appears so opaque in the jar can appear so transparent on wood is beyond me.

 

Now I finally get what folks are talking about with the 'padding' or ' finger printing' method. It goes on thin with the printing method and levels off quickly. See the knife handle.  

 

I plan to experiment with my own madder colours -- the image of the scroll neck shows the varnish over a glaze of my madder lake. Whether this stuff is good enough to use remains to be seen -- I don't have enough info on how it dries yet

 

I'm at the beginning of a very long journey, so any feedback is welcome
 
Chris

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I've finally mustered up enough courage to start my own bench thread -- given the caliber of makers hanging out here (amateur and professional alike), showing one's stuff can be rather daunting for a newcomer.

 

Inspired by many of you and your various approaches to varnish making, I cooked up some of my own oil varnish. Why? as a visualization exercise. it is important for me to visualize end result I'm trying to achieve and I need stuff to experiment with as I learn. 

 

Rather than going crazy the first time around and cook resins for days on end to capture the mystical colour of the old masters, I set out to make the the 'boring type' of varnish Roger refers to in his Bass Blog. Linseed oil and colophony cooked together at low temperature until they blend. It is a safer place to start. I did my homework on safety -- and encourage any other newcomers to do the same. 

 

Here's the recipe:

  • 140g Cold-pressed Linseed oil from Sweden. Kremer 73020 (Washed thrice + sun thickened) You should have seen the coagulated white goo that was left over from the washing process one litre yieled 400ml of oil. Must have done something wrong
  • 200g Burgundy Resin (Colophony of European Pine). Kremer 60320. Uncooked 
  • 10g Mastic (from Chios Greece). Kremer 60050. Uncooked
  • 1 teaspoon of Pit Lime. Kremer 31800
  • 350g total. 60% resin 40% linseed oil by weight
  • Added crushed resin to warmed oil and cooked at 130-160 degrees C for 1-1/2 hrs while stirring regularly. filtered while warm
  • No turps added

The varnish is as thick as honey when cooled, it is opaque as molasses in the jar but very pale and very transparent amber orange on wood surfaces. Although pale in colour, it is naturally dichromatic (right word?) see the photo. How something that appears so opaque in the jar can appear so transparent on wood is beyond me.

 

Now I finally get what folks are talking about with the 'padding' or ' finger printing' method. It goes on thin with the printing method and levels off quickly. See the knife handle.  

 

I plan to experiment with my own madder colours -- the image of the scroll neck shows the varnish over a glaze of my madder lake. Whether this stuff is good enough to use remains to be seen -- I don't have enough info on how it dries yet

 

I'm at the beginning of a very long journey, so any feedback is welcome
 
Chris

 

 

 

I share your experience, I have added turps in the cooking 

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Test samples are drying very slowly... i don't have a UV cabinet yet -- just a UV bulb in my workbench lamp to test drying of small samples. 16hrs and the sample is still tacky -- i'm going to try natural sunlight today. 

 

Nothing ventured nothing gained -- even if this stuff doesn't work out it is no big deal!

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Test samples are drying very slowly... i don't have a UV cabinet yet -- just a UV bulb in my workbench lamp to test drying of small samples. 16hrs and the sample is still tacky -- i'm going to try natural sunlight today. 

 

Nothing ventured nothing gained -- even if this stuff doesn't work out it is no big deal!

 

You need an UV cabinet with UV tubes! I have 6 Philips actinic 18 W. After ~8 h in the cabinet the hardening process continues by it self. Without that it will take a very long time for this varnish to dry

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Good questions Ernie

 

I washed the oil with sand, salt and water -- similar to what you described in your bench thread. I did have to heat the oil slightly to get rid of the residual cloudiness. I left the oil in a jar by the window for over a month. I did NOT however pre heat the oil to 200 degrees nor did I pre cook the resins

 

As for the firm pill, i simply couldn't tell. The stuff is quite thick -- a drop simply smeared when i tried to drag it

 

As an aside, a yellow foam formed on the mixture fairly quickly while cooking -- say a half hr in at a very low temperature -- 130 degrees -- an indication, as i understand it, that the varnish is forming.

 

The varnish is indeed drying -- although slowly. My chief concern is whether the stuff will be too soft once cured given I neither heat treated the oil or pre cooked the resin

 

Got to say i've always had a healthy respect for the pro varnish makers -- even more so now. It must be immensely difficult create a good product, manage consistency and quality control

 

Here is a photo of the stuff on glass. Nothing special -- it is essentially clear -- but again by goal was to create the 'boring' type of Varnish Roger referenced in the Bass thread through conversations with Professor white.

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As an aside, a yellow foam formed on the mixture fairly quickly while cooking -- say a half hr in at a very low temperature -- 130 degrees -- an indication, as i understand it, that the varnish is forming.

 

 

 

The yellow foaming is linseed oil and happens when you cook linseed oil. I didn't mix colophony and linseed oil before the foaming had happened. My varnish was a lot more red, what's the color of the colophony?

 

 

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Thanks for the extra info...my washed raw linseed oil takes a long time to dry in thick coats, but I cooked a small batch of varnish with the albies alba and colophony resin at a 1:1 ratio and cooked for about two hours not reaching the firm pill stage but rather blending. The varnish was much slower to dry than other varnishes that have been cooked to a firm pill but it dried nevertheless.

I think I will prehat the oil in the next small batch and see if that makes a difference.

The film has been curing for about 3 weeks in the sun but still has cold flow properties. It will leave a slight fingerprint but the imprint will disappear in a day. It is also soft and flexible, not chippy so I think I will adjust the resin ratio next time.

I remember Joe saying something about not cooking to firm pill stage is not really a varnish...it is a blended oil.

So that is why I have been inquiring about cooking time and preheating the oil.

I also cooked at a higher temperature than you slowly reaching near 200 degrees Celsius.

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Good points guys.

 

Rather than having the conversation here again about what is and isn't varnish i'll point folks back to the thread Jacob started  -- there is a lot of ground covered there. I intentionally set out to cook up the kind of stuff that Melvin, Neil and Roger reference in various posts. But without the pre cooking of the resin.

 

no idea whether it is any good or even varnish! but it is fun having a bit of a go.

 

the stuff is drying by the way... i'll see how things go over the next few days

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 Hi Urban Luthier

 

  Joe just beat me to the punch. I have the same set up as he does, a shiny galvanized trach can with 4 black lights I bought on ebay. I have been happy with it so far and my third fiddle is out in it right now.

 

  I also just (two weekends ago)made my first simple varnish with colphony from kremer and artist grade linseed and no turp. I am loving it but need to find the ideal tranparent color to add to it. It has been the most challenging aspect of fiddle making by far but I'm gaining on it and would encourage anyone to cook some stuff and experiment. It comes off easily with denatured so dont be scared.

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awesome thx David and Joe

 

David

as for the colour -- I'm dealing with the same thing. But I'm getting to a state where I can draw most of the colour I want from my home made madder lakes without mixing with anything  else. My first few attempts were dismal -- I've found however if I let the madder root and potassium carbonate sit for a month or so -- i get a mellower colour extraction (I do the extraction cold) -- more brick read, less purple.

 

lots of fun!

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 Yes , I tried madder lake and it came out purple. I think I will try transparent iron oxide from kremer next as well as trying to cook resin down to the color we all want.

 

  I do feal I am getting closer to figuring out a real varnish somehow but I have learned the hard way that you cannot make a violin look like a violin with varnish. The ground layer or the preparation of the wood has to look lovely and interesting before any varnish touches it.

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I do feal I am getting closer to figuring out a real varnish somehow but I have learned the hard way that you cannot make a violin look like a violin with varnish. The ground layer or the preparation of the wood has to look lovely and interesting before any varnish touches it.

I agree...it is the most important step.

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Thanks for all your comments!

 

I've been putting the stuff on tool handles to test it out! Few observations

  • The varnish on its own dries to the touch in 24 hrs. with UV and sun exposure
  • BUT it is really soft even after 2 weeks of curing - on knife handles my hand will stick to the varnish after a few minutes the varnish become very soft and looks cloudy -- If I leave it over night and buff it with a cloth and it goes back to normal
  • As soon as i add some of my madder lakes to the varnish it becomes gummy (dry to the touch but clearly wet under the surface) -- it imprints with minimal pressure. Doesnt matter if i mull the pigment dry into the varnish or if i mull it into linseed oil and mix with the varnish. The oil i use in my lakes dries well on its own

I took a detour from making to do this for fun and to learn so I had low expectations -- in the end when it comes to finishing my next instrument -- I'll be using a commercial solution.

 

it would be nice however to understand what's causing the softness and if there is a way to correct it. Is the varnish simply not cured yet? Would driers help?

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The yellow foaming is linseed oil and happens when you cook linseed oil. I didn't mix colophony and linseed oil before the foaming had happened. My varnish was a lot more red, what's the color of the colophony?

I've never, ever, seen foaming when heating linseed oil.

Mastic foams like crazy, though.

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Chris, I think the problem might be that the colophony wasn't precooked enough. However I am not familiar with that particular species of pine. This is just my opinion though, I am not a professional varnish maker.

I have not had drying problems when I cook it at 200-230 C for a couple hours, even using raw oil mixed in cold. I do use a drier with the oil, and a leaner mix like 3 or 4 parts resin to oil. I also have not mixed in any mastic.

I am trying some variations of spruce resin that I have collected to see what works, the higher temps give a great color, although I want it darker. It is pretty dark as a colophony though. My next batch I will cook it longer or hotter, my reservation about that has been that it tends to diminish in quantity the longer I cook it at high temps.

I enjoy everyone's comments about their experiences with making varnishes and cooking resins.

Ernie, I saw your posts, hope you have success with the slow cooked resin.

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