How to stain a mandolin

[TonyF-4]

I am considering doing a build and want to make a sunburst stain on both sides.
I have looked around and it seems that there is a base stain applied, then a sealer before continuing with the different shades. What can be used for a sealer If I am using the Stew-Mac water based stains?
I plan on using the Stew-Mac spray lacquer. Would the sanding sealer be the right thing to use for the staining?

[Marty Jacobson]

There are a few ways to do stained finishes. The traditional way, which requires the most skill, is to do the staining on unsealed wood. Dyes are applied and blended by hand, using water or alcohol as the solvent. Then sealers and finishes are applied.
An alternate way is to apply a base color coat which establishes the lightest shade, and then sealing the wood. Then dyed finish is applied over that, which looks more like what you would see on 60's Gibsons or the traditional 3-color Strat sunburst. You lose some 3-dimensionality to the wood texture and appearance, but the dye is more easily applied in a clean manner. If the color isn't too dark, you can get a even, uniform color fairly readily this way, but if it's a dark color, it approaches being like paint and losing the shimmer of the wood.
Either way requires a fair amount of skill. The latter method requires more equipment, but is more suited to a production environment.
So there are trade-offs either way.
Did I mention that neither of the approaches are easy? :-)

Fortunately, we have some Cafe regulars who are true masters of the art of stained finishes, who will probably add their thoughts soon. I am not a master of this aspect of the craft, but have spent a fair amount of time (hundreds of hours over the past five years or so) working on it. So I have an appreciation for those who have done the work to get good at this.

[crooksj]

Let me just say, I know almost nothing about this topic, other than what I experienced during my first scratch build. Hand rubbed the sunburst with aniline dye powder/alcohol on bare wood. The maple back turned out pretty well, but the red spruce top was blotchy, even after trying some of the tips from this forum to selectively darken . Sealing the bare spruce before dying should help that. Areas that seemed pretty dark around the edges got lighter/grayish after the lacquer was applied. Defects in the wood were magnified. I purposely didn't seal the spruce before applying dye, as I was afraid of not being able to get a dark enough color around the edges. On my next build I plan to seal, dye,vinyl seal, then air brush with tinted lacquer to "even out" the colors, hopefully avoiding a painted look. At least that's what my forum research suggests...also, check out Preval sprayers...I think might work better than the aerosol cans without the cost of a compressor and spray gun.

John

[sunburst]

I'll try to make this fairly brief, but cover the basics.
There are several ways to produce a sunburst mandolin, and there can be combinations of the various ways.
The old Gibson mandolins had the dyes (and perhaps some pigment stains?) rubbed directly on the wood by hand using rags. That gives a distinctive look, when well done, that can't be accomplished in other ways. There is highlighting of figure in figured wood (like curly maple) because the rubbing process repeatedly rubs on and rubs off color so that it darkens the portions of the wood that run out to the surface and expose an end grain component, while less color is absorbed by the parts where there is less or no grain run out. There is also a "grain reversal" in spruce (or other soft wood top), where the denser grain lines take less color than the less dense wood in between, so what was dark becomes lighter and what was light becomes darker. That is the easiest way to tell how dyes were applied to spruce because it is less pronounced or absent when the colors are sprayed.

Often, the 'burst is done mostly by rubbing by hand but some places are touched up with some sprayed color to even things out and for more color coverage near the edge if that is desired.

Another method is to spray color directly on the wood. That gives a somewhat smoother look with less grain enhancement and without the grin reversal in the spruce, but otherwise looks rather similar to a rubbed 'burst.

Sprayed color can be applied over a sealer. That gives us the least grain enhancement and the smoothest color shading, when well done. It can give us a "painted" look when not done judiciously, or if the painted look is desired.

I've heard of people rubbing 'bursts over a sealer, so I assume it can be done, but I can't do it, so I won't go into that.

In nearly all cases, the base color is amber or yellow, and the other colors are blended into the base color from the edges in. The other colors are commonly reds or browns, but they can be anything... blue, green, whatever one's imagination desires. We'll stick with reds or browns for this post.

You must first decide what type of 'burst you want. If you want the look of a rubbed burst, you must rub it (obviously). If you want the look of a sprayed 'burst, do that. As I said, more than one method can be combined. You must also decide what color you want' a red burst like an old, teens Gibson or a brown burst ("tobacco") like later Gibsons.

Here are some examples.
First, a rubbed 'burst, applied directly to the wood.

The curly maple grain is enhanced and the spruce shows the grain reversal in the dark colored portions.

This one is a sprayed 'burst, sprayed directly on the un-sealed wood.

The curly maple grain is less enhanced and the grain reversal in the spruce is not present. This one also has a "satin" finish, so that contributes to the difference in the look.

This is the only example I have of a 'burst sprayed over a sealer (shellac), and it is only the spruce top (and not a very good picture), but the grain is mostly obscured by the sprayed dyes, and it is approaching a "painted" look.

[mirwa]

The old Gibson mandolins had the dyes (and perhaps some pigment stains?) rubbed directly on the wood by hand using rags. That gives a distinctive look, when well done, that can't be accomplished in other ways.

Just so happens I was redoing a vintage 335 gibson this morning, this is far from finished, but it shows the gibson dyes being used

1st application via a rub on and then follow up sand to remove any raised fibres
2nd applyed again
3rd Final rub in coat

The beauty with the dyes, is that when you put the coats of gloss on, there is not many other stains or paints that shows such a strong colour

Steve

[Mark Gunter]

John, that is a great post with good info, thanks for that. I'm new to the forum and the mandolin (relatively speaking), but have over 40 years experience with film finishes, beginning with automotive paint and custom finishes, and for the past 30 years, wood finishing. I would like to add that combinations of techniques are often the most desirable, especially when dealing with woods like spruce. Certain species of wood have a big tendency to absorb stains in a splotchy manner. Some degree of sealing is often desirable, after which a person still has many choices as to how to proceed: French polishing using powdered pigments rubbed in offers a great deal of control. Spraying toners can have a very nice result without muddying the grain if done properly with the correct materials.

When you're going to use toners, there is no need to use pigmented toners. You can mix alcohol penetrating stains (aniline based) directly into your clear lacquers. Also, aerosol toners are available with strictly dye-based lacquer colors containing no pigments. These dyes allow a translucent coloring, whereas pigments will build up and block light, obscuring grain.

One good resource for finishes, including both pigment-based and dye based aeosol toners for professional wood finishers, is Mohawk Finishing Products, http://mohawk-finishing.com/ Look under Products > Browse Catalog

And back to John - what gorgeous photos, your finishing is top rate! Beautiful instruments.

[Marty Jacobson]

Hi Mark, I see where you're coming from. When we're finishing trim, doors, cabinets, etc. it makes sense to put a base coat of something to even out the wood, or it's possible to end up with dramatic differences in how the dye was absorbed by the wood.
With a mandolin-sized object, we have two things going for us.

First, it's small enough that we can work far harder in the careful blending of the dyes to avoid blotchiness than we could on a cabinet, without it becoming a year-long project. Usually it takes an afternoon or two, at most. The way you avoid blotchiness is by pre-saturating the wood with water, or a lightly dyed solution of your lightest color, so the wood is primed with dye and is still wet when you apply your darkest stains. That way, it doesn't slurp up too quickly and irrevocably into the wood, it just blends on nicely, more like using watercolor paper which already has some medium on it. Also, if you work with a rag of a dark color and keep burnishing the surface of the wood with it until the rag dries out a bit and the wood dries out, you get an increasingly subtle control over the process, allowing you to smooth out finer and finer graduations in the color with less and less effect (and therefore likelihood of making a big error).

Secondly, we actually want some level of blotchiness in our finishes. What would be "blotchy" on a piece of maple crown molding is only "blotchy" because it has inconsistent figuring. If the figuring is very nice and consistent, as we are used to seeing in musical instrument woods, then the very thing which is undesireable for cabinet work serves to enhance the grain on our instruments, making it more three-dimensional and dramatic.
Spruce is generally very well selected for musical instrument tops, and has minimal run-out and wiggle in the grain, so splotchiness in the spruce top is rare, but when it is encountered, it can be dealt with in the normal priming and application of dyes process.

[Mark Gunter]

This is all very interesting to me, going back to read more posts about finishing on here. I hit the plateau years ago on learning new things about finishing; it is refreshing to see the great results here and read of differing processes. I am really humbled and happy to discover so much great musical talent and building talent in this one place.