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terryc Member
Joined: 31 Dec 2013 Posts: 27 Location: Falmouth, MA. USA
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Posted: Sat Jul 12, 2014 5:13 pm Post subject: Mixing tube oil paint to color varnish |
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Hello all,
Having a problem with a fair amount of color pigment that does not seem to completely mix with either artist linseed oil or alkyd based varnish. Once the color has been mixed thoroughly, I have to let it settle for several hours, then pour off the upper level leaving a good deal of pigment on the bottom. Anyone else have this problem?
Also any recommendations of keeping a good "fat over lean" ratio on subsequent coats? The rate I am going, it will take many, many coats while trying to increase the "fatness" each time. Help!
And thanks for any advice.
Terryc |
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L P Reedy Super Member
Joined: 02 Apr 2009 Posts: 276 Location: Brevard, NC
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Posted: Sat Jul 12, 2014 6:10 pm Post subject: |
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It's not surprising that the pigment settles. Most tube paints have rather coarsely ground pigments, intended to make a fairly opaque layer on canvas. Some are more transparent than others, probably finer particles. I use a little permanent alizarin crimson (that I thought said transparent, but it doesn't) but I mix well just before each coat. Not much use putting it in if you aren't going to use it. I also add a little tar, which dissolves with some difficulty. My varnish is pretty transparent.
As for fat over lean, you don't need to change that for each coat, just if you change the type of coating. In other words, don't use spirit varnish over oil. I have put on as many as 24 very thin coats of varnish without changing anything except maybe a little of the color. |
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DonLeister Moderator
Joined: 29 Mar 2007 Posts: 383 Location: Richmond, VA
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Posted: Sat Jul 12, 2014 10:39 pm Post subject: |
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T, are you mixing powdered or artists tube pigment?
Also, why do you have to let it settle? |
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Michael Darnton Moderator
Joined: 23 Mar 2007 Posts: 1286 Location: Chicago
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Posted: Sat Jul 12, 2014 11:47 pm Post subject: |
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If you're going to let it settle, you might as well leave it out. :-) That's why they tell you to shake the paint can before you use it.
One thing that might help is putting the color as close to the wood as you can get it, which means just sufficient, not excessive, sealer. Compare it to reading a newspaper through waxed paper--if the less-than-transparent wax paper is sitting directly in contact with the news, you can read what's in the paper. Lift it a bit, and you can't. It's the same with wood and varnish. _________________ new blog at my site! http://darntonviolins.com/blog
my work sites: http://darntonviolins.com and http://darntonhersh.com |
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terryc Member
Joined: 31 Dec 2013 Posts: 27 Location: Falmouth, MA. USA
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Posted: Sun Jul 13, 2014 7:20 am Post subject: Mixing tube oil paint to color varnish |
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Thanks guys,
My premise for letting things settle was that on my first coat of varnish, I could see small specs of what looked like, undissolved pigment. Let it dry, sanded the area with 1200 grit and water and tried again after letting the heavier pigment settle out. On the second try, did not have the problem but as you mention, quite a bit of pigment left behind. Because my varnish was not the classic oil based type, thought it might be incompatibility in the mix.
Will try again without let it settle out.
terryc |
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Michael Darnton Moderator
Joined: 23 Mar 2007 Posts: 1286 Location: Chicago
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Posted: Sun Jul 13, 2014 8:34 am Post subject: |
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What kind of varnish are you using? If it isn't an oil varnish, the specks are probably because the pigment is not mixing properly with a varnish which isn't able to accept it. In this case, what you need to do is find a coloring agent which is compatible, not try to force the two together when they refuse. _________________ new blog at my site! http://darntonviolins.com/blog
my work sites: http://darntonviolins.com and http://darntonhersh.com |
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terryc Member
Joined: 31 Dec 2013 Posts: 27 Location: Falmouth, MA. USA
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Posted: Sun Jul 13, 2014 12:58 pm Post subject: Mixing tube oil paint to color varnish |
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I am using Pratt & Lambert 38 Satin, alkyd varnish. Just this morning I mixed another small batch of color using just turps to delute the color but that reacted similiar to the varnish and linseed oil. In other words slow to desolve the pigment completely and leaving heavy sediment. Not having a lot of experience with this combination of ingredients I sincerely appreciate your help. For all I know, this is what should be expected. Put a little on a section of the ribs and wound up immediately wiping it off.
Michael, you mentioned a coloring agent compatible, any suggestions?
Thanks
terryc |
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Michael Darnton Moderator
Joined: 23 Mar 2007 Posts: 1286 Location: Chicago
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Posted: Sun Jul 13, 2014 1:11 pm Post subject: |
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For a start, nothing will dissolve pigment, nor keep it suspended. That's like asking rocks to dissolve in the ocean or stay mixed in, off the bottom. Pigments are insoluble solids, not stains. They will not dissolve, and they will not fail to settle out.
What you need to do is to disperse it completely so that it doesn't show as clumps. The best way to do that is on a piece of glass with a spatula, mixing it in the appropriate solvent for the varnish until it's completely dispersed (not dissolved). Then mix it all up again just before brushing. What's happening to you sounds like simply a failure to mix in sufficiently, which will happen if you just try to stir the pigment into the varnish directly. _________________ new blog at my site! http://darntonviolins.com/blog
my work sites: http://darntonviolins.com and http://darntonhersh.com |
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terryc Member
Joined: 31 Dec 2013 Posts: 27 Location: Falmouth, MA. USA
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Posted: Sun Jul 13, 2014 7:39 pm Post subject: Mixing tube oil paint to color varnish |
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Michael,
I will give the spatula a try on the next batch. I previously mixed the pigment into a little turps but will do as you suggest using the glass and spatula for a more consistent mix.
As an aside, should I expect an absolutely glass surface after the application? And if not, will some be able to be rubbed out later. I think I am looking for absolute perfection in the finish.
Thanks
terryc |
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Michael Darnton Moderator
Joined: 23 Mar 2007 Posts: 1286 Location: Chicago
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Posted: Sun Jul 13, 2014 7:49 pm Post subject: |
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The key to getting a perfect final finish is good preparation. Any zits that are there when you start with the color varnish will attract a gathering of color, by capillary action. So make sure everything is perfect before you start with color. You will still need to do some polishing after, and it's usual to lay on two coats of clear after the color so that you aren't cutting away color when you polish, which would lead to a spotty job. _________________ new blog at my site! http://darntonviolins.com/blog
my work sites: http://darntonviolins.com and http://darntonhersh.com |
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terryc Member
Joined: 31 Dec 2013 Posts: 27 Location: Falmouth, MA. USA
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Posted: Sun Jul 13, 2014 8:17 pm Post subject: Mixing tube oil paint to color varnish |
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Tying to keep everything from brushes to mixing containers under cover in order to protect from dust; not to mention tacking off the fiddle itself. I understand clearly what you mean about dust particles and capillary action. You can see it build up around the spec.
Always a challenge! Will move on and test "the water".
Thanks again, I sincerely appreciate your help!
Terry |
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Michael Darnton Moderator
Joined: 23 Mar 2007 Posts: 1286 Location: Chicago
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Posted: Sun Jul 13, 2014 8:21 pm Post subject: |
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Just when the varnish is dry and tacky, and you can touch it without moving it around, take a fingertip and rub those little zit spots down flat. If you pick the right moment, you can rub the whole violin with your hand and flatten all the little bits of problems all at once, but you shouldn't do it while there's still a risk of pushing varnish around on the surface. Then once they're gone they won't come back in subsequent layers, if you've really pushed them down flat. _________________ new blog at my site! http://darntonviolins.com/blog
my work sites: http://darntonviolins.com and http://darntonhersh.com |
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terryc Member
Joined: 31 Dec 2013 Posts: 27 Location: Falmouth, MA. USA
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Posted: Sun Jul 13, 2014 8:33 pm Post subject: Mixing tube oil paint to color varnish |
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Michael,
Thanks this is great info.
I so appreciate your advice! Will try this tomorrow. The fiddle is in the drying cabinet, should be ready for another coat tomorrow.
terryc |
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Michael Darnton Moderator
Joined: 23 Mar 2007 Posts: 1286 Location: Chicago
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terryc Member
Joined: 31 Dec 2013 Posts: 27 Location: Falmouth, MA. USA
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Posted: Sun Jul 13, 2014 8:43 pm Post subject: : Mixing tube oil paint to color varnish |
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I hear you. It's all about the timing with varnish!
terryc |
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