Ray wrote:
We have a rather nice mahogany dining room table that is beginning to
need refinishing after 30 years of reasonably careful use.

I'm thinkng of doing this job myself. I have a hand sander.

A few questions:

1. Do I need to remove the old high-gloss varnish before saning?

2. Is sanding likely to significantly change the color of the wood?

3. If it does, can I get a stain that will restore it?

4. After staining, should I apply several coats of high gloss polyurethane?

5. How do I prevent, bubbles, which I've gotten in the past when I used
polyurethant?

Any guidance appreciated.

If there are deep scratches that go through to the wood, you need to at
least stain those a close color before doing anything else. If there
are a lot of them, refinishing is probably the best choice. If there
are only fine scratches in the finish, then deglossing and putting on
another clear coat would probably be fine. If you sand enough to remove
the stained wood, it will be difficult to match; best in that case to
strip and refinish. I would not use a power sander, and use very fine
sandpaper or steel wool to degloss and put on a gloss top coat. Gloss
finishes tend to be more difficult to brush and often require thinning,
in my experience. Semi is nice.

I don't like poly for good furniture. I prefer varnish, oil-based, good
brush, several coats. Careful stirring (NO SHAKING) and a good brush
should give a good, smoothe finish. If you get bubbles or brush marks,
thin it a tad. Poly is great for table tops that get heavy use, but it
looks plastic to me. Three coats and you can slop KoolAid and PlaDoh
all over it without damage.