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Burst and French Polish?

PostPosted: Fri Jun 08, 2018 11:46 am
by Randolph Rhett
Is it possible to do a burst AND French Polish a guitar?

I tried (on scrap, of course) by first bodying up with shellac and then spraying the die in just alcohol. It made a runny mess. Then I tried wiping on the die, again a mess. Finally I sprayed the die in very diluted shellac. The pattern was fine and it looked great until... I came back with a rubber to actually polish it. Of course the die got pushed around making a mess.

I’m sure I’m missing something obvious, so what’s the trick?

Thanks.

Re: Burst and French Polish?

PostPosted: Fri Jun 08, 2018 12:09 pm
by Christ Kacoyannakis
Tom Bills talked about this in one of his recently monthly webinars for The Luthier's Edge. Tom switched to French polish many years ago. He said he can get a sort of very subtle burst effect by using a darker shellac in the French polish bodying process over several coats, all around the edge. However, it is subtle, and never going to be that burst you think about when we say "sunburst finish" that is achieved with a spray gun. You might try contacting him. He is very open and sharing with his knowledge.

Re: Burst and French Polish?

PostPosted: Fri Jun 08, 2018 12:16 pm
by Brian Evans
Can you spray several coats of 1# shellac over the burst layer, when you get that to your liking, and then polish the outer layer? Or does french polishing necessarily involve all layers? If so, you might do a burst stain directly on the wood before you start to polish or apply any shellac. The question in my mind is the alcohol in the shellac reactivating the stain, even after drying.

Re: Burst and French Polish?

PostPosted: Fri Jun 08, 2018 1:04 pm
by Joshua Levin-Epstein
There was an article in Guitar Player in the '80s about a mandolin maker doing a hand rubbed sunburst. As I recall, he did it backwards, doing the dark first and then the center. I also recall they had a picture the size of a postage stamp showing the work...

Looking for that article just now, I came upon this: http://fraulini.blogspot.com/2012/07/ha ... burst.html

There is a video that makes it look easy. Just like laying a floor in 1/2 hour on "This Old House".

Re: Burst and French Polish?

PostPosted: Fri Jun 08, 2018 3:46 pm
by Bob Francis
Joshua Levin-Epstein wrote:There was an article in Guitar Player in the '80s about a mandolin maker doing a hand rubbed sunburst. As I recall, he did it backwards, doing the dark first and then the center. I also recall they had a picture the size of a postage stamp showing the work...

Looking for that article just now, I came upon this: http://fraulini.blogspot.com/2012/07/ha ... burst.html

There is a video that makes it look easy. Just like laying a floor in 1/2 hour on "This Old House".

It was also in Fine Woodworking.
The guy was James Condino a luthier in NC. He posts a lot in the Upright section of talk bass.

Re: Burst and French Polish?

PostPosted: Fri Jun 08, 2018 3:52 pm
by Steve Sawyer
Randolph - Just pulled out an issue of American Lutherie (Number 125/Spring 2016) and re-read the write-up of James Condino's demonstration of doing a hand-rubbed sunburst using water-based dyes on raw wood. Toward the end of the article, it becomes clear that he's French-polishing after applying the color:

One of the nice things about padding a water-based color is if you get a chip in your finish later, the shellac may chip but the color's still going to stay there and the touchup is pretty easy...My experience has been that whenever I use an dalcohol-based color and then use an alcohol-based French polish over it, as soon as I start to swirl around it's going to grab and pull out some color...The water-based color never runs under shellac

Re: Burst and French Polish?

PostPosted: Sat Jun 09, 2018 6:06 am
by Joshua Levin-Epstein
James Condino is a wizard.

Re: Burst and French Polish?

PostPosted: Sun Jun 10, 2018 12:46 am
by Randolph Rhett
Thanks to all. The answer seems to be to dye the raw wood, not tint the finish. A shame, as I’ve had only mediocre results with dyeing the wood. I’ve never tried spraying shellac, although I assume it would effectively seal a sprayed tint. I’ll experiment, and in the meantime this next one on my bench gets a sprayed lacquer finish.

Re: Burst and French Polish?

PostPosted: Sun Jun 10, 2018 6:06 pm
by Alan Carruth
When working by hand you can also wipe finish back to make a burst. Paint it on with a brush, and then some solvent on a rag and wipe back the edge to soften it. You have to use lots of thin coats to get a reasonably deep color, and it takes time, but it can work. I will say I've only used this with oil varnish, not shellac.

Re: Burst and French Polish?

PostPosted: Tue Jun 12, 2018 12:43 pm
by Rodger Knox
The key to French polish over a sunburst is using a water based stain/dye/tint on bare wood. Mr. Condino hand rubs the colors to make the burst, but you can also spray the colors. I've done it both ways, spraying the colors with an airbrush was easier for me. James IS a wizard, and he's very open to sharing his magic. He's frequently published in both GAL and ASIA.

Re: Burst and French Polish?

PostPosted: Fri Jun 15, 2018 3:42 pm
by Alan Carruth
I'm of the school that doesn't like the look you get with dye on bare wood. The curl pops because the end grain absorbs so much color, but that 'nails' the pattern: its as if it was just painted on. With a clear coat under the color to seal the wood you see the real chatoyance of the grain; the reflective areas move as the wood moves. The color contrast is not as intense, but it's far more beautiful IMO.

Shading on violins is often done using transparent 'lakes' pigments. Lakes are made by precipitating alumina in a dye solution. Some of the dye is incorporated in the colorless and transparent aluminum oxide particles, which protects the normally fugitive colors from degrading, and makes them permanent. These can either be added to the finish, or applied as a glaze. In the latter case, you'd apply a thin film of the pigment in an oil medium onto the surface and allow it to dry before putting on the next coat of varnish, either spirit or oil. Makers will often simply use artist's oil paint right out of the tube, rubbing it in with the heel of the hand. Some of the 'earth' pigments can also be acceptably transparent in an oil based varnish, but I'm not sure about shellac.

Re: Burst and French Polish?

PostPosted: Mon Jun 25, 2018 2:45 pm
by Craig Bumgarner
I tint with sprayed shellac, sometimes very dark or subtle edge bursts. I first seal well with clear shellac, then spray shellac tinted with aniline dyes. Sand very lightly with 2000g, then seal with sprayed clear. Once sealed, I finish in the conventional FP manner. Just be careful not to overwork the finish until you get some buildup. If you are getting color on the pad you know you on the edge of breaking through, just go easy until it is fully sealed.

Re: Burst and French Polish?

PostPosted: Mon Jun 25, 2018 6:04 pm
by John Clifford
Alan Carruth wrote:Shading on violins is often done using transparent 'lakes' pigments. Lakes are made by precipitating alumina in a dye solution. Some of the dye is incorporated in the colorless and transparent aluminum oxide particles, which protects the normally fugitive colors from degrading, and makes them permanent. These can either be added to the finish, or applied as a glaze. In the latter case, you'd apply a thin film of the pigment in an oil medium onto the surface and allow it to dry before putting on the next coat of varnish, either spirit or oil. Makers will often simply use artist's oil paint right out of the tube, rubbing it in with the heel of the hand. Some of the 'earth' pigments can also be acceptably transparent in an oil based varnish, but I'm not sure about shellac.


Alan, I often think how sad it is that steel-string guitar finishing went in a completely different direction than classical stringed instrument finishing. I guess this is the result of a factory-dominated process setting public expectations. I never liked the idea of making beautiful wood look like glass or plastic. Fortunately, there are signs of greater acceptance of more natural-looking finishes. Even some of Eastman's Chinese factory made archtops now come with an "antique varnish" finish.

Re: Burst and French Polish?

PostPosted: Mon Jun 25, 2018 8:38 pm
by Beate Ritzert
Alan Carruth wrote:I'm of the school that doesn't like the look you get with dye on bare wood. The curl pops because the end grain absorbs so much color,


Indeed. And that will almost inevitably look ugly, like this attempt on my basses (btw my favorite) -take these pictures as a warning:

Image

And after a lot of effort to improve that:

Image

To my experience, wiping on water based dyes might work well on surfaces lacking end grain., e.g. a guitar top with a binding. Otherwise it is just frustrating.

(i removed the stain and stained that body in red, now its pretty.)

Re: Burst and French Polish?

PostPosted: Tue Jun 26, 2018 12:51 pm
by Alan Carruth
They do use the stain on wood on arch top mandolins. They wipe the stain on, and then use a lot of solvent to wipe most of it back off. That's how they get some of it out of the end grain.

Re: Burst and French Polish?

PostPosted: Sun Jul 01, 2018 9:59 am
by Ed Minch
I tried this a few years ago based on the Condino video. I used The Stew Mac Colortone (TransTInt?) dies in water, not alcohol. I found them very easy to use, and every few minutes I would run a hair dryer over the surfaces to avoid wetting the wood too much. On samples, it became clear that it didn't matter whether you used water or alcohol as a solvent, once they were dry, if you put water or alcohol on the surface it would dissolve the dies. So I followed Mr. Condino's lead and sprayed shellac lightly over the finished surface. I used a hand applied and polished varnish finish and had to be VERY careful not to go through the varnish or the colors would have been difficult to reproduce. I imagine that doing a French Polish finish over the sprayed shellac would work as long as you built a reasonable thickness.

https://www.flickr.com/photos/ruby1638/10931985546/in/album-72157635130471994/

Ed

Re: Burst and French Polish?

PostPosted: Thu Jul 05, 2018 12:09 pm
by Alan Carruth
..or you could use an oil/lacquer based dye that the alcohol would not pick up.

Re: Burst and French Polish?

PostPosted: Wed Aug 08, 2018 7:59 am
by Beate Ritzert
Back to that topic:

There are actually four natural color graduations available, from clear to garnet.
Do You think it is possible to just wipe on a burst using differently colored types of shellack?

Which would mean a procedure analogously to the one with water dye, but ideally not penetrating into the wood:

- pore filling + closing of the end grain with a suitable clear filler, maybe oil or shellack based.
- wiping the entire surface with the lightest component, e.g. lemon shellac.
- wiping on the darker parts of the surface with the gradually darker types of shellac?

Alternatives?
- tinted oils?
- tinted NC laquer?