Problems with shellac over hand rubbed sunburst. Any Advice?

[Jackson84]

Hi there!

I have experience with lacquer finishes and and sprayed sunbursts, but i'm trying to expand my horizon and am having some issues with the hand rubbed burst when using a shellac finish. I've been practicing on a mandolin top that I'll never use so I haven't actually ruined anything.. yet.

I'm using the water based dyes from Stewmac. They seemed to be working ok, but soak in to the grain less even than what I would like. Maybe that part will just take practice.
The real issue comes when I try to apply the 1 lb cut shellac. Even when spraying a very light coat, it causes the sunburst color to run a little. I'm wondering if I have too much alcohol mixed with the shellac. Would a heavier cut help?

Any advice would be greatly appreciated!

Thanks everyone,
Tyler

[HoGo]

1lb cut is pretty thin. I'd go for at least 2lb. cut. that's roughly what I use.
What gun are you using? You want very light application almost dry when it hits the surface never apply too much in one place and let it sit for few minutes if you want to overcoat it, apply just enough to lock the color. I'm using airbrush for this, Rewell with 0.5mm nozzle (0.7mm would be better for larger area coverage). I just sealed color two days ago and 1.5 oz of shellac was enough to cover whole F-5 generously. I'll add one more coat after I scrape bindings.

[Jackson84]

Thanks Adrian! I'll try the 2 lb cut and take your advice on spraying as little as possible until there's some build up. I really appreciate you taking the time to respond!

Regards,
Tyler

[j. condino]

If it is a true water based dye then there should be no bleeding or reaction from the alcohol- that is why they come in water and solvent based formulas. If it is one of the generic type that work for ether, that is when the bleeding happens.

If the color is grabbing unevenly with the dyes, are you wetting the wood first? Applying the color direct to a dry wood will cause that nice piece of thirsty air dried wood to grab it and have streaks. Lightly wet the wood first and it will be much less of an issue. The maple is always easier than the spruce.

If everything goes on schedule, the next issue of American Lutheire will have a very detailed, long photo essay and transcription from a workshop I gave for the Guild of American Luthiers convention several years ago on handrubbing sunbursts and shellac finishing. No matter what finishing method you decide on, the answer is always the same: practice, practice, practice, and eventually you will find a method that works for you. Do you have any photos for us to look at? Good luck.

Here is a link to the video from a few years back of the process that Fine Woodworking shot at my shop and another of spray finishing a big double bass. If one of the more computer skilled folks made it pop up direct that would be great :

http://condino.com/skoolin/

On another note, I should have a new website coming soon instead of this old onel!!!!

j.
www.condino.com
www.kaybassrepair.com

[bernabe]

Thanks Adrian! I'll try the 2 lb cut and take your advice on spraying as little as possible until there's some build up. I really appreciate you taking the time to respond!

Regards,
Tyler

. To add to Adrian's statement about "almost dry when it hits the surface", its not just about spraying as little as possible, but also how it's coming out of the gun. You dont want it wide open. A fine mist thats highly atomized is what you want.

[sunburst]

I regularly spray shellac (approximately 2lb cut, I don't measure) sealer over rubbed 'bursts done with alcohol soluble dyes with no bleeding of the color. I simply spray very lightly. Just a mist coat for the first coat, followed by a very slightly heavier coat. That usually seals the dyes enough to apply a more thorough coat or two.
I don't know what size tip or nozzle I have on my cheap Harbor Freight gun. As long as I can get decent atomization, I can use just about anything that sprays, by adjusting my technique to the tool, though you may not be able to yet. We must consider that I bought my first spray gun in the 1970s, and I've used one off an on ever since.

[Jackson84]

If it is a true water based dye then there should be no bleeding or reaction from the alcohol- that is why they come in water and solvent based formulas. If it is one of the generic type that work for ether, that is when the bleeding happens.

If the color is grabbing unevenly with the dyes, are you wetting the wood first? Applying the color direct to a dry wood will cause that nice piece of thirsty air dried wood to grab it and have streaks. Lightly wet the wood first and it will be much less of an issue. The maple is always easier than the spruce.

If everything goes on schedule, the next issue of American Lutheire will have a very detailed, long photo essay and transcription from a workshop I gave for the Guild of American Luthiers convention several years ago on handrubbing sunbursts and shellac finishing. No matter what finishing method you decide on, the answer is always the same: practice, practice, practice, and eventually you will find a method that works for you. Do you have any photos for us to look at? Good luck.

Here is a link to the video from a few years back of the process that Fine Woodworking shot at my shop and another of spray finishing a big double bass. If one of the more computer skilled folks made it pop up direct that would be great :

http://condino.com/skoolin/

On another note, I should have a new website coming soon instead of this old onel!!!!

j.
www.condino.com
www.kaybassrepair.com

I used water a few times to raise the grain and then sand down, but I let it dry out before applying the dye. Lightly wetting the wood before dye application makes a lot of sense. Thanks for the help! Here is the picture that you requested. A little blotchy with the obvious running of the dye on the right side...

- - - Updated - - -

Thanks so much to everyone for taking the time to respond. I'm anxious to sand the top and give it another go. Truly grateful for all of the advice!

Tyler

[amowry]

That's a nice looking 'burst! Any irregularities just give it character, which is the reason to do a hand-rubbed burst to begin with. If you want to even it out a bit, you can lightly airbrush Transtint in alcohol after the first coat of shellac.

Yep, you want to increase the air pressure and reduce the fluid until you're just getting a light mist. After you scrape the binding (I realize that test top doesn't have any ) you want to be especially careful, because any shellac that doesn't dry immediately will cause the stain to bleed onto the binding. So, just a light mist on that coat, and then you can gradually spray wetter coats after that. I also use a 2-lb cut.