Spraying bursts

[thistle3585]

I normally use Fiebings dye mixed with lacquer to spray my bursts. I don't use much lacquer but just enough to act as a carrier. After spraying my burst then I just transition directly to pure lacquer. I now want to try my hand at a varnish finish. Can I spray the burst using nitro lacquer followed by a varnish over top of it? Should I mix the dye with a shellac instead? I was thinking of using Epiphanes varnish. I also have read where some have "french polished" tru oil over the Epiphanes. Am I going in the right direction here or way off base?

[sunburst]

Varnish over lacquer is generally not a good idea, but if you are using a minimal amount of lacquer in your dye mixture you might get away with it with no problems, but I think it is a chance I would not want to take. I normally apply my 'bursts, either rubbed or sprayed, directly on the wood and follow with a light sealer coat of sprayed blonde shellac. After scraping the bindings, I can lightly scuff sand the shellac and apply lacquer, spirit varnish, or oil varnish. There are some modern catalyzed finishes that don't adhere well to shellac, but most of the older types of finishes will. You could try mixing the dye with shellac instead of lacquer to check for compatibility, and if it mixes/dissolves and sprays well, it should work.
I've used TruOil over oil varnish, not the Epiphanes specifically, but similar stuff, and the results can be very attractive and it seems to be very durable in use.

[Joe Mendel]

I have been using Epiphanes for a few years, when I do a sunburst I mix the color with shellac and spray that until I get the colors & shading I want, then spray the Epiphanes over that. No problems so far and I've been happy with the few bursts I've done.

[thistle3585]

Joe, would you be willing to share the brand of colorant that you are using? I have heard that you can add a hardener, or catalyst, to the Epiphanes to help with drying time and hardness. Have you done that before?

Thanks John, I figured the nitro wouldn't be the best solution but thought I'd see if anyone had any experience there.

[Big Joe]

We have used water based colors applied directly to bare wood for some instruments. It will give nice fading for bursts and avoid the hard color line often seen in bursts. The downside is that the color is in the wood, and it will not come out readily if you make a mistake. You could practice on a piece of wood before applying to the instrument to see you are getting the burst you want. Then when the color dries you can put your varnish on top.

You can also put a thin sealer layer on the wood and then apply your color on top of that. If you use a poly sanding sealer as a base coat it should not be affected by the Epiphanes. It would allow you to strip the color if you were not satisfied with the results.

A very thin coat of nitro under the color would also work. Just be sure it is sufficiently dry before adding the color. If you use a thin coat you should be ok. If the finish is dry completely before applying the varnish it should be fine. You can use a French Polish on top with tru oil as well.

The color will work differently on the wood depending upon whether you apply it directly to the wood or on top of a base coat of finish. A good example is the original Loar mandolins. The burst seems to blend from shade to shade very nice. On some mandolins where they use an undercoat you will often see a more dramatic change in colors. Neither is wrong or necessarily bad, just different.

[thistle3585]

Normally, I use a base coat of yellow followed by a coat of amber shellac to seal it then I spray the burst. The combination of yellow and amber shellac tends to soak in to the figure which results in the figure being darker to "pop" it. I was planning on doing the same thing here but I will try using the Epiphanes as a carrier.

[Joe Mendel]

I use the Trans-Tint that Stew Mac sells. I do spray a couple of seal coats of un-tinted shellac on before starting with the color. I have not used the accelerator, I don't know how well it works. I think this is the stuff that you are referring too: http://www.jamestowndistributors.com...nt+and+Varnish
For oil varnish it dries quickly, I haven't felt the need to speed it up.
I haven't tried tinting the varnish, so I'm no help there.

[Dale Ludewig]

I wipe on a base coat of diluted dye, usually yellow or blue (depending on the final burst color). I use the Transtint stuff with alcohol for yellow, metal acid dye from LMI with MEK as a thinner if doing blue. Other colors as the occasion demands. Then wipe off with solvent, trying to leave the color depth in the grain figure. Careful on the top- spruce is a whole 'nother animal compared to maple. Then I'll spray the burst with just diluted color and no finish in it, different colors to get the burst about where I want it. Then a very dilute coat of finish, usually vinyl sealer or shellac, because if you don't do that, as the dyes dry off quite quickly, you don't really know what color you've got.
As hard as this is to imagine, it's almost impossible to not find a little spot here or there next to the binding where there isn't a tiny bit of evidence of some glue stuck down in the pores of the wood. Because of this and because of what I feel are more controllable conditions, the last little bit of bursting is done with a little more sealer in the dye mixture. At this point it actually becomes a "toner", because it isn't soaking into the wood very much. It's laying on top of it. It's more opaque. The more finish type product in the solution, the more opaque its tendencies are. It hides those little flaws, is more uniform in color, but at the same time it hides the grain as well so it should be used sparingly.
After the burst is done, a light coat of sealer. Binding scraping. More touchup. Smooth with very fine sandpaper or a paper bag. Then top coats.
I typically topcoat with nitro and have good results with either shellac or vinyl sealer underneath. I would think that the varnish would bond well with shellac, but most varnish to my knowledge a mechanical bond not biting into the finish underneath. So there has to be a little "tooth" under there. MHO.