trying to get silky smooth finish from poly...

[chris fox]

I am finishing up a bath vanity project where I ended up toping BLO with 50/50 mix of MS and poly(semi gloss). So far so good, but on my last coat(3) I am trying to get smooth finish. The thinned poly helps for smoother finish but still not happy as is. Typiclaly I use 0000 steel wool over satin finishes but with semi gloss this will just dull it.

Couple of ideas:
- work up to 600+ grit light sanding - concerned that I will still get a dull white haze and a waste of time.
- just add a coat of brie wax and buff

Another concern I have, on some other pieces I finished up coating with BLO and curently its drying out before I topcoat with poly/ms mix.
I noticed when buffing out/removing the oil there were a few areas of the piece where the rag snagged a little - so I overlooked some rough areas. Should I thicken up the poly mix for a fill or add zinzer shellac (Seal Coat) to fill in these areas. I have a feeling adding shellac will change the appearance between the pieces.
Another lesson learned - finish all pieces at the same time :o

Chris

[Casey Gooding]

What grit did you sand to?? A smooth finish is dependent upon smooth preparation. Are you sanding between coats?? With the thinned mixture, I would apply several coats without sanding. You want to start building a finish. If you start sanding too soon, you will sand off the finish rather than just leveling it. After the finish has started to build, sand with 320 or 400 grit between coats. I like a 320 sanding sponge. They can be rinsed out and re-used.

[Joe Chritz]

For best results skip the poly and get some Waterlox or rockard table top varnish, it levels better and more importantly rubs out nicer if you want to polish to a true gloss.

I assume you are wiping the poly on which just leaves technique to improve the final finish. Best bet is to wipe it on and hit it all with one smooth motion then let it dry. Scuff very lightly between coats and a bit harder on the third or so.

Seal coat can be used as a grain filler if you want to sand for months on red oak so adding a coat likely won't hurt anything. I expect the roughness will even out after a few coats.

I don't have good enough hands to wipe on a finish that is perfectly smooth from the can, I nearly always have to do a little rubbing, usually with a sanding sponge.

Joe

[Tom Veatch]

Finishing is far from being my strong suit, but aybe something in this article will help:

http://www.woodworkersjournal.com/articles/192_MOW_Skill_Builder.htm

[Steve Schoene]

First, what kind of wood are you using.

But even with a diffuse porous hardwood like maple or cherry you are trying to achieve a smooth finish much too early in the process. You have applied about the equivalent of one coat of brushed on varnishsince it takes about three wiped on coats to achieve the same dry thickness as one brushed on coat. You need about 6 more wiped on coats to be able to rub out to a smooth and even sheen.

Further, I would switch away from polyurethane varnish, which doesn't rub out nearly as well as a tradtional resin varnish, either phenolic or alkyd.

With wiping varnish I would apply it in "sets" of 3 coats on a day, space just far enough apart in time for the coat to loose it's tacky ness, but not be fully dry. This would not be hard enough to sand. In reasonable temperatures around 70° this would space them about 3-4 hours apart. Then let it cure over night to where you can sand. Sand with 320 grit paper to remove defects and level the surface. Then apply another set of three, and let it cure for several weeks. Sand with 600 grit to remove defects, this would be a pretty dull hazy surface, then sand with 1000 or 1200 grit (CAMI) or P2000 or so. This would be pretty close to satin. Then you can move tot he final sheen you want. For satin use a rubbing compound, or fine pumice, or for gloss use polishing compound or rottenstone.

[chris fox]

I sanded the piece to 220 grit then applied BLO. I have 3 coats and lightly sanded 320 grit after the second. I have been using a foam brush for applying.
The varnish is not a bad idea...