I have refinished an Armoire from the 1950's. It is made of red cedar. I used Minwax products. I am happy with the color. The problem is the brush marks that are left. I used the quick dry polyuretane. I used 0000 steel wool between coats. I have about 4 coats applied with some brush marks showing. I have even diluted the poly with paint thinner. I have heard to just use the steel wool and then apply a wax. I am confused as to how to get a smooth finish.
The key to no brush marks, is to avoid them during the application. A high quality brush, and good technique is the surest way, (besides spraying).Steel wool(especially 0000), won't remove brush marks, but if they're really bad, you can wet sand with some 400-600 silicon carbide sandpaper (black wet/dry), and a little water with a few drops of liquid dishwashing detergent in it. The 'Quick Drying' product is also more prone to brush marks, because it sets up too fast and doesn't flow out as the slower drying product does. You could buy the same stuff in an aerosol for the last coat, and that would give you a very smooth final layer.On future projects, I would strongly consider spraying, as you can use fewer coats, and those cans with their blue spray nozzles, are capable of a very high quality, smooth finish with the proper technique, eliminating the possibility of brush marks altogether. The one negative thing about polyurethanes and varnishes, is that each successive coat is a single, separate layer of finish film, unlike lacquer, shellacs, etc., which chemically 'burn' into each previous layer, creating a single film of finish, so when sanding down the poly/varnish finish, you can fairly easily sand through the top layer exposing 'witness' lines that are visible on the finished surface. Therefore the final coat should really remain as untouched as possible to allow for the thickest film layer when completed.After several days to a week or so, you can then rub it out with the 0000 steel wool and wax it if you want, but know that wax and poly don't always work so well, and an oil polish like Guardsmen, Old English or similar are usually a better choice on larger surfaces like table tops, armoire sides and other large areas....unless you're trying to create an"older" look by using a dark paste wax.Just remember that waxes will have solvents in them that will attack a fresh polyurethane finish, so make sure to give it those few days to a week or so to cure, before waxing The other suggestion is the excellent General Gel Satin urethane topcoat product, which is a wipe on product, the consistency of pudding, that is a light straw color, (almost like solvent lacquer),has almost no odor, nearly goof proof,glides on without being overly 'sticky', and levels out and dries beautifully every time.I apply it with a pad of cloth folded into about 6 layers, the size of a cigarette pack or so... No sanding between coats, and it's a fantastic "secret weapon" to know about. Once you use these products, you may never use Minwax again.The Gel stains are also excellent, WAY better than the Minwax stains,(although Minwax does make Gel stains, they are harder to work with than the General and set up too fast), excellent color depth and strength, and in a polyurethane base so they dry predictably and seal in a single operation. .