I've gathered that the step immediately before staining a table is to sand it. However, I wonder how to tell when the table is smooth enough? Can I skip the sanding step?
In my case I bought an unfinished pine table (new, not antique) which, to my touch, is rather smooth. Running my finger across the tabletop, I can only feel the largest grains. I even see some sawdust around the drawers, which makes me think it was already sanded.
A nice trick (learned as a wood turner) is to spritz some mineral spirits on the wood. I usually use rubbing alcohol, as I keep that around. (Not mineral oil, as that will not evaporate.) Anything that will "wet" the wood, but evaporate quickly without leaving a residue, and without raising the grain as water would do. Water is bad of course in this context, since it causes the cells in the wood to expand, raising the grain. The idea is to see what the wood looks like when wet. It will often bring out scratches that remain from sanding, or other tool marks.
I'd give it a once-over with 180 or 220 grit. I've made the mistake of assuming surfaces were smooth enough to paint/stain and found rough spots while in the process of finishing. Nothing will make you want to kick yourself more than realizing that first coat of paint/stain you just applied needs to be sanded back off so you can properly prep the surface.
Alternatively, you could call the furniture store you got the table from and ask if they recommend sanding it before finishing. They should know how (if at all) the table was prepared for the finishing process.
Well, this has a lot to do with personal taste. I'm assuming you don't want a rustic feel or anything of that nature. To see if you want to sand more, take some 600-800 grit sandpaper and sand a test spot. If the wood seems appreciably smoother then sand the entire table. The amount of sanding required for a good looking finish you put on any wood depends on the type of finish. A heavy urethane or latex based finish will fill in more imperfections than a stain will. So if you feel the table is smooth enough, then stain it. Had the table been finished, you would have had to sand it down to the wood and go from there.
