Pine resin spirit varnish

[Julian Cossmann Cooke]

I cooked in alcohol some locally collected pine resin and then created a roughly 50/50 pine resin/Siam seedlac varnish.  I say roughly because I did not measure out the dry ingredients but rather the resin-alcohol mixtures in each case.  I added the seedlac to cut down on the elasticity of the pine resin -- encourage it to harden.

I have found that the brush -- oxen hair -- starts to catch about a third of the way down the plate, leaving the application splotchy -- particularly on the top.  See pictures below.

I tried heating the varnish on a coffee warmer but that did not seem to make a difference.  Likewise with adding alcohol.  I have now added a few drops of lavender oil since that finds its way into spirit varnishes such as 1704 when it is used in mulling pigments.

I never have had problems applying 1704 made of Siam and Kusmi seedlac and elemi.

Any thoughts/suggestions greatly appreciated.

[Wood Butcher]

Oh dear! It really looks to be dragging around the soundholes 

Given how uneven the top looks, I’d wash it off and start over, it will be incredibly difficult to try and even it out.

[ScotPiper]

Hiya, Julian. 

I noticed the date of your post as January 15. But only after I’d written my reply did I recognize  that 2019 is gone.... oh, well. Here’s a belated reply; maybe it’s useful anyway?

 

I have a fair bit of experience using alcohol-spirit varnishes with a high ratio of colophony/rosin.

When applying the second coat, the first coat feels “tacky” and grabs at the brush partway through a long stroke. I think it’s a combination of two things: the first coat is easily soluble in the second coat, and the colophony is drying too quickly on the brush.

What I’ve done to mitigate the effect: reduce the relative quantity of colophony/rosin by adding seedlac; add lavender oil; keep the brush heavily loaded with varnish; dilute the alcohol with water.

I’ve also found that high-ratio colophony/rosin varnishes are not terribly durable to abrasion and can be chippy, but also have a nice sparkle a shine.

I’ve used 1:1 seedlac:colophony varnish a bit; for a while it was my go-to alcohol varnish. With practice and technique it goes on pretty alright. 
 

An interesting demonstration is to soak a big piece of colophony in alcohol for a few minutes then pick it out and see how tacky/sticky it feels, and how long it continues to feel that way.

[Dominik Tomasek]

On 2/4/2020 at 5:37 PM, ScotPiper said:

Hiya, Julian. 

I noticed the date of your post as January 15. But only after I’d written my reply did I recognize  that 2019 is gone.... oh, well. Here’s a belated reply; maybe it’s useful anyway?

 

I have a fair bit of experience using alcohol-spirit varnishes with a high ratio of colophony/rosin.

When applying the second coat, the first coat feels “tacky” and grabs at the brush partway through a long stroke. I think it’s a combination of two things: the first coat is easily soluble in the second coat, and the colophony is drying too quickly on the brush.

What I’ve done to mitigate the effect: reduce the relative quantity of colophony/rosin by adding seedlac; add lavender oil; keep the brush heavily loaded with varnish; dilute the alcohol with water.

I’ve also found that high-ratio colophony/rosin varnishes are not terribly durable to abrasion and can be chippy, but also have a nice sparkle a shine.

I’ve used 1:1 seedlac:colophony varnish a bit; for a while it was my go-to alcohol varnish. With practice and technique it goes on pretty alright. 
 

An interesting demonstration is to soak a big piece of colophony in alcohol for a few minutes then pick it out and see how tacky/sticky it feels, and how long it continues to feel that way.

Dear ScotPiper,

thanks for those rather interesting informations. Did you have to colour your varnish somehow? 

Thanks

Dominik

[ScotPiper]

Hiya, Dominik. 
 

I colored the varnish using pigments (usually) or dyes (less frequently). I make my own pigments using madder and walnut, and other stuff  

I used Siam seedlac and WW-grade colophony, which is quite colorless. I experimented with cooked colophony, and if it wasn’t over-cooked it was soluble in ethanol. Cooking didn’t add much color to the final varnish, and it still required pigment. 

Edited February 8 by ScotPiper

[joerobson]

Julian

I would drop the spike oil and add a few drops of castor oil instead.   Then a bit stiffer brush.

on we go,

Joe