I was in a rush earlier and didn't get to explain staining in detail. Staining is much trickier than it appears. Especially in my early years, I ruined more projects in staining than I care to remember. Between formal training, books, and applying 500 gallons of stain we've figured it out and now never make mistakes.

Most commercially available stains are pigmented stains. That means they're basically thin paint. The pigment is suspended in the vehicle solvent which is just used to get it to flow around. The pigment catches in the pores of the wood, and that's what causes the color to change. The pores will only accept so much pigment. Proper stain technique involves flooding the surface and letting it soak for a minute or so. This allows the wood to absorb as much pigment as it "wants". All that's left to do is wipe off all the excess stain. When the first application of stain is applied correctly, subsequent applications or coats will not change the color detectibly because the pores are already full. Proper technique should yield even coloring with no streaks or light spots.

Some woods are a pain in the ass to stain. Maple and pine (among others) are both famous for being blotchy. They will contain areas that absorb WAY more pigment than the surrounding areas or WAY less. The bitch is that it is impossible to see these areas until you apply stain. Of course, that's always 5 seconds too late. These species can be stained successfully, but it requires some different techniques. One option is to use a wood conditioner. These are products that are designed to control stain absorption and limit blotching. I've never had much success with them. Around here, we generally use spray stains on blotchy species. Spray staining is just like using an airbrush. You can use the same pigmented wiping stains or specialized spray stains. The trick here is that you are controlling how much stain the surface receives, so super porous areas can not get over-stained. It's extremely technique sensitive. You're basically misting stain on the wood trying to keep the color even. Doing one piece is not so bad, but not fun. Doing many pieces and getting consistent color over the whole batch is very, very difficult. In all seriousness, we generally just don't work with species that blotch. If we do, we primarily just apply a clear finish.

Poly/stain combo is like the worst of both worlds to me. It's basically varnish with color in it. The thicker the final film, the more color you'll get. It's just about guaranteed to give streaks.

Once you have color down, just use your choice of clear coat. Most homeowners have good success with regular old polyurethane varnish. It's a nice product because it's slow drying so the brush marks self-level. The down side is the dry time as it just gives more time for contaminants to fall (or crawl or fly) into the finish. We use catalyzed lacquer or conversion varnish here, but those are spray-only finishes.

For those not yet sleeping, I'll add one more detail. There's a category of stains out there called dye stains. They are radically different from pigmented stains in that they actually dye the wood. There is no pigment. Dye stains get darker with every application. This is nice in one sense as it allows you to build color to whatever you want, but just like a spray stain, it's very sensitive to technique. In fact, many spray stains are dye stains. If you go to Woodcraft or whatever, you will find the occasional hybrid dye stain that claims it can be wiped on. In my experience, that is total baloney. I avoid them. Some pigmented wiping stains will have a little dye in them to achieve deeper colors, but I've found those to be easy to work.