My Varnish


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A few recent test samples. It's always so hard to get accurate pictures. I think part of the problem is the transparency of it. How do you take a good photo of something that is transparent? visual appearance depends on angle of view and lighting conditions, sunlight vs. room light and I would say it's kind of a copper color.

I tried to get some closeups here by putting a magnifier lens in front of my camera lens. The brighter orange look is in sunlight the darker one is in room light.

on the closeup there looks like a glowing yellow line between the varnish and the wood. That is actually sunlight shining through the translucent upper layers of the wood. Low angle to show the thickness or thinness of the layer, maybe 2 tenths mm? after it hardens more I'll remove some and measure it with a micrometer.

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Don't have a my bench thread and not building a violin but just playing with scraps so I'll just use this old thread to post odds n ends.  So an attempt at antiquing the iphone cover.   I was able to scratch away the thin varnish layer with some effort with a finger nail.  It comes away from the smoother grain preferentially and adheres to the more porous areas which makes sense.   The ground is part of the wood so doesn't flake off.  I wanted it to look like it had worn off exposing bare wood which darkens with age so scraped with a sharp knife edge and a bit of sanding on the bottom corners then darkened with dirt and grime after working on a lawnmower engine.  The wood still seems to have some protection and doesn't pick up the grime as much as I had hoped.   It sure is hard to photograph this stuff, started out with about 30 photos and narrowed it down to the three better ones. 

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Thought some of you varnish makers might like to see this.   I was at the Georgia state fair last night and was surprised to see Diamond G rosin and turpentine for sale.    Also recently saw this NanKee turpentine in a local flea market.  Top was rusted shut so I couldn't open it,  felt like it was about a quarter full.   I was tempted to buy it but didn't.  

 

 

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They are both the same sample of course. Just a different viewing angle. The one on the right has the light reflecting off the wood underneath. On the left it's reflecting more off the varnish.

These pictures came out better:

In the jar it looks like burn motor oil LOL

It certainly does look dichroic or di-chromatic.  Is the red and yellow so differentiated to the eye.  Or is this an artifact of the way the camera accentuates red ?

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It certainly does look dichroic or di-chromatic.  Is the red and yellow so differentiated to the eye.  Or is this an artifact of the way the camera accentuates red ?

Hi John,  early samples definitely show a lot of 'camera effect'.  Post number 51 shows a much more accurate image but there you can see that it can look brown or orange depending on lighting.  Accurate color photography of varnish is really difficult.   That batch was used up in various samples,  I'm itching to try a new batch, maybe adding some pigment next time.    

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Thanks, I like the color, just wish it had better drying characteristics. I'm just impatient! biggrin.gif

You mentioned lime to neutralize the acid.  But what you get is actually a rosinate of calcium.  And perhaps some combination with oil. 

 

You could also add lead oxide or zinc oxide.  The former would really help the drying,  and the latter would allow it to take on alizarin for more red.

 

I found out these things when making fulton varnish.

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How did you do the ground on the iPhone?

   I didn't tan or darken the wood.  First an application of rosin dissolved in turpentine... as I recall there may have been more than one application with a full day of sun to dry each time.  That stuff won't dry in the shade, it needs full sun.  I then got some yellow color into it by applying thinned down amber shellac.  I'm trying to remember now if I put something on it after that to fully seal the wood.   I should have kept notes since it turned out nice, next time I will.    My goal is to impregnate the ground into the wood and not leave a surface film.  That way when the varnish surface layer begins to wear off,  the ground still remains.   The only way to remove the ground then, is to wear away the wood.
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hey FredN  Here is my old varnish thread.   Post pictures of your varnish making setup and instructions here and I'll gather some materials and make a batch.  I may try to incorporate that red iron pigment but I like to get color just from the rosin too. 

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Hi Mke- ran into a problem. The temperature probe I was using the sensor had moved up the glass tube so that it was not immersed in the varnish mix. while it was being heated. This happened  I guess in the last couple of weeks when I was trying various methods, so  I've got some repeating to do. I still can post the picture of my set up (didn't realize how messy until I looked at the photo- sorry).

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Hi emviolins- yeah, really looks bad. But I only use around 15 gms of resin and 15 gms of oil, so the chance of any major event is minimal. Thinning with turp is done elsewhere.  I've used the same set up for making Congo copal varnish, which needs much higher temperatures than rosin varnish and never a problem (better stop crowing).  fred

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burnin down the house  LOL , good one.   Well Fred that looks a lot more sophisticated than my coffe can in a charcoal grill.  I have to make some effort to get a hotplate and some supplies.   I see tube paints, do you put those in your varnish?  I know you mentioned using burn umber

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hi guys 

 

I cooked a light burgundy resin with white sulphate (SO4 Zn) and iron oxide and lime  -----  100gms resin 2 g lime, 2 g  Zn SO4, 2 grams iron oxide, and it was dark brown. 

 

 

I would like to cook red varnish, but still I'm getting a brown or golden brown

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Hi Mike- The calcium and zinc are standard additions to rosin to  harden and raise the melting point. Zinc is the preferred because it is not affected by moisture as much as calcium. When used to make an oil based varnish it is called GLOSS OIL varnish.

 

You can use ordinary light rosin, but it is hard to get it dark enough when compared to dark rosin. There is even a darker rosin called Tech Rosin, when you see a pitcher reach for that bag of rosin it is tech rosin, much darker then FF dark rosin. If you have a sporting goods store available maybe they sell the stuff, and mixing light and tech rosin would probably give you the color of FF rosin. What you can try is squeezing out about an inch of pigment  out of a tube of Burnt Umber  into light rosin, let it cook in around 15 gms of rosin for about 10 minutes, just above melting point which is some foam on the surface, bubbles coming through, some smoke, about half the density of cigarette smoke. You can use more Umber if you like, and in fact it might make it a better drier for the oil you'll add afterwards in your method. I cook mine at a little higher temperature after I add oil to speed up the making, for it still takes over an hour this way. When I get a 6-8 inch string from the mix I know the cook is done and ready for thinning. A lot easier to write then do. fred

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what is the purpose of the zinc sulfate in that recipe ?

and what tree does burgundy resin come from? Is it spruce?

hi

 

http://www.kremer-pigmente.com/en/mediums--binders-und-glues/solvent-soluble-binders/natural-resins/burgundy-resin-60320.html

 

burgundy resin  (from   european  pine    -- france

 

 

About Zn an Ca   spoke FredN

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