Official Luthiers Forum!

I'm beginning to experiment with my first sunburst for the OM I am currently building. The look I am aiming for is the hand-rubbed tobacco finish that is found on vintage Gibson mandolins (see below). I have the alcohol & water soluble ColorTone liquid stains from StewMac (Vintage Amber and Tobacco Brown). My usual finishing schedule involves wiping on dewaxed blonde shellac, followed by an oil varnish applied with a brush. As you have probably guessed, I don't have any spray equipment.

My initial tests (with the stains dissolved in water and applied directly to the spruce) weren't completely horrible, but they were far from perfect. They tend to be splotchy, and the fade from the light center to the darker perimeter isn't very smooth or subtle. I'd appreciate any tips or hints you might have.

Chris

well I don't have any experience trying to do a hand rubbed burst, but I can say that transtint type dye stain on raw spruce is definitely going to splotch. I think you are going to have to look at some other kind of stain to pull this off, or putting down some kind of wood conditioner or chemical barrier first. Generally dye stains tend to penetrate wood a little deeper and pull the finer particles that make up the color, in with the solvent, than oily, wiping stains do. To what degree depends on what kind of wood you have, what the formula of the stain is in terms of amount and kind of oil, and ratio and type of solvent. Most wiping stains have some kind of binder, or oil, and a reducer or solvent as well as the pigments. An ideal stain would allow you to keep the stain wet long enough to manipulate it on the surface and wipe off excess before it all dries. With a dye stain in water alone on raw wood, you will not have this opportunity. Basically the wood will absorb the water, pull the color in, and then it will be in the wood.

I'm wondering if you could go ahead and put your base coats of shellac down on top of the bare wood and then tint your varnish. I would actually start with the dark color first, working it in towards the center from the edges a little at a time trying to end up with a real soft edge. After that first color layer hardens, then go back over the whole thing including the dark border with the amber colored varnish. You might even be able to work the region where the dark color blends in with a little extra elbow grease, but I would push so hard that you smear the finish.

I'm not sure how the dye stains would dilute in varnish, so an alternative, if you don't have access to industrial pigments would be to buy some oil paints from an art supply store, (for oil based varnish) or acrylic for water based. I'd probably thin down the oil paint with mineral spirits a bit before I added it to the varnish, and would be careful with the amount added to the varnish overall. Usually 5-10% is a good rule of thumb for overall pigment to binder/reducer.

This is just a guess though, maybe something to play around with on scraps. I do have some finishing experience but I've never tried this so just relying a bit on some of my chemical knowledge. Based on that this should be possible, but I can't say if it's the best or easiest way to do it!

First off, unless that mandolin dates from prior to about 1925, I doubt the burst is hand rubbed. By the mid 20's all the major manufacturers were spraying nitro. The hand rubbed bursts were usually very black around the edges with a more abrupt color transition. Here is s link to some good pics of a mandolin with a hand rubbed burst
http://mandoweb.com/Instruments/Gibson- ... -1977/3855
Achieving what you want with dye directly on the top will be difficult. Some things to try would be to make the dye with alcohol rather than water. Use a more dilute color and apply the dye in several sessions gradually building up the color as you go.

_________________
Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/

That vintage "Cremona brown" Gibson type sunburst was done by rubbing dyes by directly onto the bare wood, by hand. You can use Transtint / Stewmac Colortone dyes with alcohol, I would advice against stains (with pigments) as they tend to obscure the nice, deep look on figured maple. Sealing prior to applying the colors is usually done if you plan to spray the 'burst. Some folks feel this is a 'safer' method, as it makes it somewhat easier to fix mistakes, but the look is very different. A sprayed sunburst generally looks more even and smooth looking, but it has its own set of problems too. One of the challenges with the hand applied method is to make the colors and their transitions reasonably even and smooth; part of the attraction here is that there will always be some variation, but it should not be blotchy, and the color transitions should not be abrupt. It is also possible to mix hand applied and sprayed, I usually rub the lighter colors and spray the darker ones around the perimeter on my mandolins. Since guitars are lager, they are somewhat harder to rub to a nice, even color than mandolins.

There are some good tutorials on youtube, and over on Mandlin Café. Siminoff's 'Bluegrass Mandolin' book has pretty good instuctions as well.

_________________
Rian Gitar og Mandolin

Thanks for all the comments, guys.

Brian, I downloaded the mandolin photo from mandolinarchive.com. It was signed by Lloyd Loar on Feb 26, 1923, so it probably was a hand applied finished.

The video suggested by Arnt is very useful, albeit without any sound. The stains in the video are "Alcohol soluble dyes (Transtint) applied to bare wood, sealed after staining with sprayed blonde shellac". The technique itself is pretty much what I've been trying, but the person in the video is just a lot better at it than I am! He or she occasionally uses an unstained rag to blend the colors together, and I assume the rag was soaked in alcohol. One problem I see is that wiping a shellac sealer coat over the sunburst will tend to smear it. Would a thinned coat of varnish be a better sealer, or does turpentine also dissolve Transtint stains?

I'll keep practicing with the stains I have and let you know how it turns out.

Thanks again,
Chris

The person who did the mando in the youtube clip I linked to is John Hamlett, ace mandolin/guitar builder/repairman, he goes by the name "Sunburst" over on Mandolin Cafe...

If you want to seal alcohol soluble dyes with shellac, it is best to use a spray gun, and go very 'dry' and light. Rubbing shellac can quickly turn your beautifully hand applied 'burst into an awful mess. You can also just spray nitro, it is safer anyways.

_________________
Rian Gitar og Mandolin

You can apply the sunburst by hand and then spray several coats of shellac to seal the dyes. You could use one of these http://www.harborfreight.com/airbrush-kit-47791.html and a can of this http://www.amazon.com/Testors-Ozone-Saf ... B0032U7MGK

I used that method to spray a water based aniline dyed sunburst, then brushed oil varnish.

The picture is of the last sunburst I did which is hand rubbed with shellac sprayed to seal the burst then french polished. You will get blotches as the spruce absorbs the dye at different rates, but that's what the customer wanted for this guitar. I used an air compressor to spray the shellac the last time. A small portable $69 compressor was used.

The biggest challenge with spraying anything is the appropriate space to do it, shellac and nitro are VERY flammable. The testor air brush propellant is extremely flammable too, so don't try to put a candle out with it! I tried that once

Really? I know nothing about this, but stains into bare softwoods? Maybe stain in the back and sides? That's a look that still has its fans. Staining the top before sealing would be pretty crude in this neighborhood. Maybe I don't get around.

Eric, in the mandolin world, sure; applying colors to the bare wood on top as well as back, sides and neck is pretty much the norm. Avoiding the dreaded blotches etc takes practice and skill, but in the hands of the best makers, it is not only possible, it is a unique and sought after look that is quite different than a sprayed burst, especially ones that are applied over a sealer. You want the colors to soak somewhat into the wood, but in a controlled manner. You can do this by several diluted applications of dye, blending with plenty of alcohol, but not too much etc. I have found that spruce needs a lot more alcohol than maple, for example; I wet the top with some before even putting any colors on, maple on the other hand can go fairly 'dry', but you can sometimes use more alcohol after the colors, to blend things, and so on. It takes practice, that is for sure!

Since I already mentioned John Hamlett, here is another example of his fine work; the colors are applied directly to the bare wood, by hand. There might be some spraying involved with the darker shades around the perimeter, I'm not sure, but getting the lighter colors to blend like that in the middle would be very difficult any other way.

Take a look in the 'Mandolin archive' for several examples of the vintage stuff, http://www.mandolinarchive.com/perl/list_mandolins.pl?all

_________________
Rian Gitar og Mandolin

Thanks, Arnt. That mandolin from John Hamlett is perfect IMO. One way to tell if the stains were applied directly to the wood is to examine the fade between the dark and light sections of the sunburst. The late wood takes the stains very differently than the early, and the grain is enhanced in that area. I think it looks really nice, especially if it's done as well as that mandolin.

Logan, that's a nice looking guitar. It reminds me of some very old Gibsons that I've seen.

This morning I soaked a rag in mineral spirits and rubbed it over a test piece I'd prepared earlier. Little or none of the stain came off, so maybe using a thinned version of my oil varnish will work as a sealer.

I know a professional who does this and he was very generous in walking me through my first hand done sunburst - just delivered at Thanksgiving:

http://www.flickr.com/photos/ruby1638/s ... 130471994/

The stewmac dyes I used can be dissolved in either water or alcohol, but I chose water because I heard it was easier for beginners - pretty simple once you get the hang of it. The result is dependent on your technique, which is easy to learn, but mostly your eye for what the end looks like. I used some spruce framing lumber and did about 6 samples before I tackled the top and by then I was fairly fluent in the medium. I see where I could improve the result with a little more transition at the center. I chose not to make mine black at the edges, so I did not use the Tobacco stain, but used the medium brown as my darkest color. I used amber, red, and medium brown.

Remember to blend from the middle out - it is hard (but not impossible) to lighten it once you have gone dark. Also, just a small wash of the brown over the amber at the end takes the neon out of it.

Remember (DAMHIKT) that the dyes are soluble in both water and alcohol, so whichever you use to apply it, you are still in danger of making it all run if you brush on shellac or a water based sealer/finish. So be sure you spray (lightly, as has been noted) at first to get everything stable.

I intentionally built up a little extra finish so I would not break through - I do NOT have the skills to fix that!

If you use water as a solvent, you can lightly wet the surface of the wood before you start and the blotching will not be as bad - look at the comparison between my first try on the top and my second try - blotches in the first one and almost none in the second one. For some reason, the framing lumber never blotched!!

Good luck

Ed Minch

Thanks, Ed. That looks really good, and very similar to the look I'm after. I need to get some more scrap spruce and start practicing again.

I notice that you masked off the bridge before staining. Were you worried that the bridge would not glue as well to the stained wood?

Chris

Probably not necessary, and the stain got under in a few places anyway. Just thought it would be "better".

By the way, I recommend using the hair dryer trick to keep the water from soaking in too far and to allow y9u to keep moving quicker. I was chicken to use the full-fledged heat gun and found the hair dryer to be just abut right.

Ed Minch

The hair drier trick: does that mean you warm the top before applying the water-based stains? Or do you evaporate the water shortly after applying the stain?

After each 3-4 minute application session I dry the surface with the hair dryer, then start again right away. It only took about 4 passes with the darker color to get the darkness that I wanted around the edges. It is a little deceiving in that the color you get is not what will come out with the finish on it, so be sure to put some finish on your test pieces to see how dark you should go.

Ed Minch