Len, I want to be careful here, and not step on anyone's toes. The written word is easily misinterpreted so don't take any of this the wrong way.
First, in my time finishing and working on projects for myself and others, I haven't ever seen anyone use a dye on walnut. A colored finish, yes. A toner in finish, yes. A gel stain glaze, (me!) yes. Yellow dye, no.
There may be a crossed wire here. If it is an older finish you are probably quite right that it is just a run of the mill lacquer. If it came off fairly easily with lacquer thinner, then you know it was. If your color came off with he lacquer, it was a toner/colorant of some sort added to the finish.
If it was dyed or toned "golden oak" or any of that family, it most likely wasn't walnut. Whether by a factory or a craftsman, a traditional finish for walnut is something clear. As newer growth came along, as we lost so many of the beautiful California walnut trees, black walnut became a substitute for "walnut". However, that stuff goes from gray to black so it presents a different challenge when looking for a uniform finish over many different boards. Still, no one adds yellow.
I am inclined to agree with Steve's comment above that it may not be walnut at all. I have seen boards of hickory, walnut, chestnut, butternut, etc., that came from different stands of trees from around the country that you couldn't tell much of a difference between them. Older, tighter grains on old pieces of furniture can fool the best of us. I have seen hickory so fine it looked like CA walnut. I have seen black walnut grain so coarse it looked like a colored red oak.
That being said, during the "Colonial" or "Early American" rage that swept the manufactured furniture world, they used colorants to give the hardwoods used (almost all of these were nutwoods for their grain) an off brownish green color. In my personal experience, these pieces were everything BUT walnut.
The tops of certain pieces received special treatment. They were sanded, then filled with a colored pore filler (sometimes almost black to accent the tubules), then sanded smooth. A finish with toner/ colorant was sprayed on them after that. These were air dried finishes, and were almost without exception (think 40's, 50's 60's without doubt and into the 70's and 80's off and on) built up with multiple coats.
The multiple coats of built up finish allowed the manufacturer to come back with to wet sand and finish with a large compound loaded buffer to cut down the finish to glass smooth.
Again, NOT with walnut. Walnut has dark tubules, and will suck in any finish and show the as dark. A yellow family dye like Golden Oak turns walnut a greenish color, which has never been popular.
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Without reiterating my earlier post, I will say this to punch up the highlights I feel may be sabotaging your finish.
Lacquer thinner is just that. A thinner. A stripper works differently. Rather than to dissolve the finish as a thinner will, a stripper will degrade and destroy it. This allows for removal. When you strip with a thinner, you WILL leave residue behind. You will simply be taking off as much finish as your rag can hold, and to the point where you will be dissolving the finish further into the wood.
When you strip, you degrade the finish to the point where it can no longer adhere. You break down the resins (at least with the good stuff!) where they no longer have the ability to bind to themselves.
Use a stripper, not a thinner to remove finish. You can't strip off half the finish anyway, so there is no point in trying to save some of it. Take it off, start fresh when refinishing.
In your case, you need to strip and start again. After stripping, clean off all residue with lacquer thinner. Use a lot of thinner and a lot of towels to clean it. When I am removing a finish that has a pore filler my experience has been that half stays in, and half comes out. So that means it all has to come out. That means scrub it off; remaining finish trapped in the filled pores may be contaminating your new finish.
Advice: don't screw with it anymore, strip it.
I use stripper, then throw on a heavy coat of coarse sawdust as my cutting medium and scrub the finish off with a stiff brush. It cleans deep and fast, and the sawdust will pick up a lot of the old finish and residue.
Advice: scrub off ALL the finish.
I let the project dry, then wash it off with lacquer thinner. For me, I only use mineral spirits to clean my brushes and guns and it has no place for me in refinishing. It isn't hot enough for me, and I actually only use it on occasion to thin paint.
NEXT to final cleaning: lacquer thinner.
Sand your project now, and inspect. There will be small amounts of finish left, no matter how careful you are, and sanding should pick up the last bits of that. Clean one more time with lacquer thinner.
If you want to pore fill, do it now. Follow the instructions exactly. Pore-o-pac is good stuff if you don't have one picked out. They make colored fillers, so you can get a black or brown to mimic the old filled finishes.
When I finish something expensive, I will sometimes flip over the piece and strip/sand/stain/color/finish a small area to test. This determines whether or not I need to apply a conditioner before staining, if I need to spray a dye, and how well I can color match. If you have this opportunity, I highly suggest it.
As far as the use of shellac goes, it has its place. Guys here are nuts about it. However, nothing sticks to a finish like itself. When I strip a door, counter top, table, etc., they are naked as a jaybird when I get finished. I only use shellac if I am unable to completely pull off the old finish, or it is contaminated.
An example of a contaminated finish would be a set of double mahogany doors I did a couple of years ago that were at a club. The maintenance man applied liberal shots of lube to the hinges and locks. This made the finish degrade to gum, and the oil penetrated the wood. After stripping, I applied my finish and it had more fisheyes than a school of herring.
So you guessed it; I stripped off my new finish and started over. Applied the shellac and I was on my way.
If you have any finish on your table now, take it all off. Do yourself a favor and start completely over as it will give much better results. Don't try to put any kind of stains or dyes over your coat of varnish. Dried varnish is simply cure resin, or a type of plastic. It will never look right because your colorant will simply sit on the plastic resins. Since it won't bite into the varnish, your stain will just make a bigger mess on top of everything, and will most likely lift when you put on your top coat.
The CLEAREST, most natural color you will get will be to do the following:
- strip
- fill pores if needed
- finish all surface prep
- spray dye
- spray shellac if needed
- spray top coats
Poor brush work can easily lift stains and some dyes, so that's why I spray.
Hey... how about some pictures when finished?
Robert