If you’re a detail kinda person, and you want to really finish up your wood projects perfectly, here are some tips.
A lot of us are happy to simply countersink finish nails in trim, so they’re not noticeable. But to really finish it properly, you should fill the holes. Now, the problem is, much of the time, the filler’s just as noticeable as the holes themselves — sometimes moreso. So try and match the filler to the surrounding wood.
You can mix wood filler, sawdust from your trim, and the stain you’ve used on the wood, though this will likely come up a little darker than the remainder. You can get tintable putties, but beware: don’t try and match the wood color before staining or urethaning the wood. The putty won’t change color the same way the wood will. The trick? Stain or urethane the wood first, then match the color and fill the holes.
The endgrain of wood will soak up stain more than the surface grain, and, especially in soft woods like pine, will become darker. Before staining, use a sealer on the wood, so the stain takes more evenly.
Before painting, seal any knotholes with shellac.
If the wood is scratched, the scratch will take more stain and show up, so carefully sand any scratches before staining.
A final trick. If you need to repair outdoor trim that’s going to be painted over, here’s a little cheat. Use auto body filler. It’s pretty easy to work with, it’ll stand up to the elements, and you can shape it to replace edges or pieces which have rotted or fallen off.