How to do a black top finish

[MANDOLINMYSTER]

Hey gang
I am refinishing an old ugly duckling garage sale find. It's a 1920s bz Rosewood back and sides Spruce top mandolin that's worthy of restoration. Unfortunately someone in the past did a horrible job repairing some top cracks and refinished the top with some awful product.

I was able to remove the Finish from the top and make the necessary repairs to the cracks unfortunately the old repairs left staining which makes the cracks stand out.
My thoughts are to Re color the top in a black finish and was wondering if anyone could recommend the materials/products and steps to get a good Blacktop finish.
I plan to use shellac as a top coat when everything is done. Currently the spruce top is free of any finish and is just bare wood.

Thanks,
Mike

[multidon]

You could go cheap and just use Krylon spray paint, which is available everywhere. Mask it off, spray several coats of black outside, scuff sand between coats, and finish off with a couple of coats of clear. Make sure you stuff some newspaper into the holes so the spray doesn't get to the inside. Krylon is acrylic lacquer, and is very durable. If you want to go more traditional get some rattle cans, black and clear, of nitrocellulose lacquer from a place like Stew Mac or Re-Ranch.

[Urthona]

I haven't done this exactly but if you can get hold of a black wood dye and dissolve it in water rather than alcohol and then French polish (fear not) you should produce a very attractive dark finish; if it isn't opaque enough you can redye the wood and add dye to the shellac. If there are bindings or inlays you need to think about them strategically, but if they are impervious to stain you can wipe, sand,scrape them. See the recent posts about the flaky Gibson A that I reluctantly restored when I couldn't find anyone who wanted to do it. My finish is brown but it could have been black. I dissolved the dye in alcohol and the stain washed up a bit in the sealing coat of shellac; that's why i recommend staining with a water stain. French polishing is actually a pleasure if you study up and do as you are told. Post some pictures so the collective wisdom can see potential problems. The furniture genius John Dunnigan gave me some ebony powdered dye which I can specify.

[sunburst]

I've done black finishes (pegheads, mandolin top) using lamp black powdered pigment in blond shellac, then spraying lacquer over that, or finishing over with blonde shellac.
Pictures of the black top mandolin can be seen here.

[Tavy]

I've used black wood dye (probably labelled as "ebony" coloured in the store), then finished over with shellac or endurovar. You can get a deeper black if your dye is mixable with your finish and you put the first couple of coats on with the dye in the finish as well as on the top, but it's not required by any means. Basically whatever you do, you need to pay attention to the coverage and really make sure there are no thin spots where the wood colour shows through, so slap the dye on more liberally than normal, and if it's of the wipe on/wipe off kind, don't do the wipe off part Just be careful there are no runs or other leakages of dye in places you didn't want it - the black is very hard to get rid of!

[ProfChris]

This is clear shellac with black alcohol-soluble dye added. Brushed on, wet sanded to level and then hand buffed.

It would have made my life easier if I'd dyed the wood black first, as this finish is translucent so any thinned spots when wet sanding stood out. Fortunately for a reso the thickness of the finish film doesn't matter!

[MANDOLINMYSTER]

I have always read that the bare wood should be sealed first before applying any stains as to prevent a blotchy finish. I like the idea of using a Dye mixed with alcohol since my top finish will be shellac.
On the other hand I am a bit intrigued about spraying the color from a rattle can which seems very non-traditional tho.
I suspect a more opaque finish can be achieved by using a spray type method where the layers can be built up.

Thanks to everyone who has replied I will continue to ponder my next steps.
Mike

[fscotte]

StewMac sells black spray as well. Krylon or equivalent is a good choice too.

[Mark Marino]

I've done black finishes (pegheads, mandolin top) using lamp black powdered pigment in blond shellac, then spraying lacquer over that, or finishing over with blonde shellac.
Pictures of the black top mandolin can be seen here.

A second vote for this. Don't use black wood dye as it has a tendency to look purple. If you have the ability to spray, use the lamp black. It's cheap and really fine powder so easy to mix a small batch of shellac and spray on.

[fscotte]

Since black doesnt need to show the wood grain, a nice little trick for sharp binding edges, is to first spray a few clear coats. Sand somewhat smooth. Then spray your black coat. Then scrape the binding. Since the undercoat is lacquer, the edge will be super sharp and you avoid the black bleeding into the binding.

[barry k]

Krylon rattle can Flat Black first, then nitro clear over it.......

[amowry]

That's how I've done it too (Krylon flat acrylic lacquer with Sealcoat sealer), but as far as I can tell the hardware store Krylon has been enamel rather than acrylic lacquer for around the past ten years. You can still order the acrylic lacquer on Amazon and elsewhere under the Krylon "Industrial" brand. I've been told that it's difficult to get other finishes to adhere to enamel.

[sunburst]

At "the factory", we sprayed clear finish over Dutch Boy flat black rattle can paint. They had a test piece with the clear finish (catalyzed varnish) sprayed over a bunch of different hardware store black rattle can paints, and the Dutch boy had the best adhesion. It's probably just as difficult to find now as Krylon lacquer, but it is a possibility if it's available.

The thing about adding black pigment to our own shellac or lacquer is; we get to make out own paint, and we know it's characteristics and compatibility. It is not difficult.

[Marty Jacobson]

Rust-Oleum makes black lacquer rattle cans. Cheap and effective.

[MANDOLINMYSTER]

Well it seems like the general consensus is flat black lacquer in a spray can or lamp black mixed in shellac.

I do not have any spray equipment but was wondering if I could spray shellac and lamp black mixture in a Preval sprayer if it were thin enough?? I have one of those little buggers in my shop.
Thanks again for all the info.
Mike

[Paul Busman]

I built a kit Les Paul clone years ago and painted it with automotive paints. Several coats of color, then quite a few coats of clearcoat, allowing it to outgas in between. I wet sanded it to knock down some orange peel with the finest wet/dry paper I could find (2000?) then polished it with automotive rubbing compound. The finish was, if I say so myself, outstanding and very tough.

[Urthona]

The advantage to French polish over spraying shellac is that it produces a beautiful finish when very thin, which makes the top responsive, but if you rely entirely on the shellac to provide color and thin it for spraying you'll end up with a lot of shellac before you get it opaque. The top willl be swaddled in shellac and will sound dull. I am not sure what wood dyes look purple, but I recommend using dark dyes like the StewMac black dye as well as lampblack mixed with alcohol or water to stain at first, then add more dye to the shellac that you use to French polish if you need to make it more opaque. French polishing is not so hard that you can't get good results the first time.

[sunburst]

...if you rely entirely on the shellac to provide color and thin it for spraying you'll end up with a lot of shellac before you get it opaque. The top willl be swaddled in shellac and will sound dull...

Not true.

[Urthona]

Ok, straighten me out. Which part do you dispute? If the first sealing coat is mixed with a very high proportion of a concentrated black dye and/or lampblack I guess it could get opaque with one or two subsequent sprayed coats of similarly darkened shellac, but I had trouble getting the shellac to behave when there was too much lampblack in it when French polishing. Thick shellac on the top definitely dulls the sound.

[sunburst]

Paint is pigment in a varnish of some sort. It can be an oil varnish, a lacquer, a spirit varnish... and that brings us to black pigment in shellac. We've basically made paint. It's not that much different from a black spray lacquer, and there's no reason it would "swaddle" the mandolin any more than black spray paint or spray lacquer.
I've had success spraying shellac/lamp black and brushing shellac/lamp black. A couple of coats have been enough for a fully opaque black finish, and the thickness of the film was not excessive.
I've also used white pigment in shellac for a white top mandola. Neither black topped mandolin nor white topped mandola have exhibited any dullness of sound.

[sunburst]

Here's a picture of the black top (shellac/lamp black) before the clear top coats. This is simply the sprayed black shellac. As you can see, it is fully opaque and thin enough that the "fluting" of the spruce grain shows.

[amowry]

Looks great ro me!

[sunburst]

Just for fun, here's the same mandolin right after buffing the lacquer top coats.

[Urthona]

Can't argue with that!

[fscotte]

Ugh black.

Don't use paper towels to fill the f-holes.
Don't use two different shades or strengths of black dye.
Don't spray if any small bugs are flying around.
Don't spray if there's a hint of humidity.
Don't wear long sleeve shirts that may leave traces of lint on the surface when swept up by the sprayer.
Don't casually wet sand the surface.. Really sand it flat and level leaving no traces or swirls around.

Do look at the surface in direct reflected sunlight to find mistakes.