help with final finishing/polishing of varnish

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help with final finishing/polishing of varnish

Postby Justin Tugaoen » Tue Oct 09, 2012 6:51 pm

I'm in the middle of varnishing a violin I made, so far the color coats are on, and 2 coats of clear varnish and planning 2 or 3 more. My problem has always been levelling the varnish to get rid of all shiny spots. I can never seem to level it well enough without cutting through in places, down to the yellow base stain/ground. I've been using wet 400 silicon carbide, then tried 600 but with the same issue. So then I'm having to touch up those areas with more colored varnish which of course doesn't end up being very even. This is especially problematic for me with the front plate, where I left it somewhat rough, with prominent grain corduroy. Is it even possible to completely level this? I'm thinking maybe I should just go straight to rottenstone/oil to lower the varnish gloss and be done with it? I'm sure part of the problem is the my initial sanding/scraping of the plates isn't completely level to begin with (difficult for me with all the wild maple grain, and of course the spruce grain too). So what's your approach, short of putting on 10 or more coats of varnish just to get it thick enough to avoid cutting through? Thanks. BTW I've successfully leveled my guitars sprayed with 6 or so coats of KTM9 without cutting through. These violins are giving me a fit! Thanks for any advice offered!
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Re: help with final finishing/polishing of varnish

Postby John E Giarrizzo » Wed Oct 10, 2012 9:23 am

Justin,

I can't really answer your question, as I am still trying to learn to varnish myself, and have had the same problems as you are having. Getting an even flat color coat. Most of my finishes have been clear natural color of wood. The best color I did was very thin even coats of oil varnish. And then like you said, just rub out with fine pumice. Although, sanding flat is the way some books teach.

Michael Darnton has some online instructions at http://www.darntonviolins.com/violinmag ... ishing.pdf

And there have been many threads and thousands of pages written on varnishing. I've read and read and read, and still trying for a finish and color that looks as good as the pro's do.
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Re: help with final finishing/polishing of varnish

Postby Barry Daniels » Wed Oct 10, 2012 9:37 am

Justin, what do you use to back your sandpaper with?
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Re: help with final finishing/polishing of varnish

Postby Craig Bumgarner » Wed Oct 10, 2012 1:55 pm

Sounds like your suspicion the surface was not really ready for varnish when you started is correct and you're trying to compensate with the varnish and two coats over the surface you don't want to get into (color coats in your case) is pretty light. At a minimum, you need more build coats.

Consider stripping the varnish and starting over. Get the wood really smooth, fair and defect free. Try to always use the largest, stiffest sanding blocks the surface will accept, never hand sand. Once the surface is as good as it can be, then build up varnish. Try to find the varnish, thinner, brush and technique that minimize brush strokes. Otherwise, build up higher and cut back down.

I use a varnish system on my guitars and apply five coats by brush before polishing out. I sand fairly aggressively between coats, but not enough to break through. I'm not trying to get the surface perfectly level until the fourth or fifth coat. By sanding fairly hard between coats, the overall buildup of varnish is not too thick.
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Re: help with final finishing/polishing of varnish

Postby Cliff Green » Wed Oct 10, 2012 8:12 pm

It depends on the type of final finish you're shooting for. If you want a smooth surface then leveling clear varnish before you put on your color coats will give you better results. If you want a textured surface such as corduroy on the top then leveling has to be an absolute minimum. When leveling I like to use felt (available from McMaster Carr) cut in small squares to back wet dry 400 or 600 or pumice and mineral oil, kerosene, water whatever you like. The felt pads work especially well on textured surfaces. You can also shape the felt to fit in difficult areas. For final polish I use felt and rottenstone. I think I bought a 12X12" square of each of 1/2" hard and medium felt that will last me a lifetime.
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Re: help with final finishing/polishing of varnish

Postby Justin Tugaoen » Thu Oct 11, 2012 5:55 am

I'm actually ok with the surface not being completely level since I prefer the handmade look. I'll try using felt to cut back the sheen on the low spots with pumice as suggested. Barry, I've usually used a small eraser as a backer, and my fingers for the channels and the scroll. I actually just stumbled on somebody's blog where it sounds like they go straight from varnishing to pumice or Meguiar's cleaner/polisher, using a toothbrush on the front corduroy...something I'll also have to consider. Next violin I'll try to put on clear coats first to level out before the color coats as suggested. Thanks for the tips.
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Re: help with final finishing/polishing of varnish

Postby John E Giarrizzo » Thu Oct 11, 2012 9:18 am

Justin tugaoen wrote:they go straight from varnishing to pumice or Meguiar's cleaner/polisher

From an email in response to a question I asked Meguiar's: "the A1216 Deep Crystal Wax does contain silicone in it as do all of our current waxes"

It is generally recommended to not use silicon waxes on Violins, as that could interfer with future repair. Glue does not adhere to silicon.
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Re: help with final finishing/polishing of varnish

Postby Craig Tucker » Thu Oct 11, 2012 12:00 pm

John E Giarrizzo wrote:
Justin tugaoen wrote:they go straight from varnishing to pumice or Meguiar's cleaner/polisher

It is generally recommended to not use silicon waxes on Violins, as that could interfer with future repair. Glue does not adhere to silicon.


Absolutely correct.
At least, I find that this is true also.
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Re: help with final finishing/polishing of varnish

Postby Justin Tugaoen » Thu Oct 11, 2012 4:34 pm

hmmmm. Thanks for the Meguiars warning. I guess I'll just do the pumice/oil rub-down and maybe followed with rottenstone, after careful use of wet 600 or 1000 paper. Maybe violin #4 will be better!
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Re: help with final finishing/polishing of varnish

Postby John E Giarrizzo » Thu Oct 11, 2012 5:13 pm

Justin tugaoen wrote:Maybe violin #4 will be better!

Each one does get better, but I'm warning you, they are never as good as you want. <g>
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Re: help with final finishing/polishing of varnish

Postby Cliff Green » Thu Oct 11, 2012 7:27 pm

John E Giarrizzo wrote:
Justin tugaoen wrote:Maybe violin #4 will be better!

Each one does get better, but I'm warning you, they are never as good as you want. <g>


You're so right. But after you play one for a while and nurse it to it's best potential it gets to be like a good significant other. Full of flaws but better than you deserve.
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Re: help with final finishing/polishing of varnish

Postby John E Giarrizzo » Thu Oct 11, 2012 7:47 pm

Cliff Green wrote:You're so right. But after you play one for a while and nurse it to it's best potential it gets to be like a good significant other. Full of flaws but better than you deserve.

I know what you mean --- unconditional Love. And my significant other? Poor woman --- has to put up with an artist/musician --- and now I guess violin maker. <GG>
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