Polyurethane finish

[O. Rob Anderson]

I've read that after proper curing for a polyurethane finish, one should rub out the finish using paste wax. What does this do and what is the benefit of doing so?

[Prashun Patel]

Rubbing out smooths and adjusts the sheen of the surface. After you feel a rubbed surface compared to a non-rubbed surface that you thought was smooth, you'll see why people do it. To work effectively, it requires a hard, brittle surface, which is why rubbing poly is not that great. However, it can be done, just gotta work a tad harder than with other types of varnishes or shellacs or lacquers.

The paste wax is a lubricant. The critical thing for rubbing is the abrasive you use - either fine sandpaper, steel wool, or synthetic abrasive pads. You can use water, soap, mineral spirits, wax, or some combo to lube the abrasive and stymie clogging.

Beware that rubbing will dull your nice glossy sheen down to a scratchy satin. To get it even, you gotta work at it. To get it back to glossy, you gotta polish using finer abrasives. There's ways to shortcut this with automatic buffers or even random orbit sanders.

I have been working for a couple years on mastering the rub out, and I'm still pretty bad at it.

[Howard Acheson]

In general, poly varnish will never be any more glossy than it is right off the brush. "Rubbing it out" is not necessary unless you want to turn a gloss sheen into a satin sheen. Because polyurethane is add to varnrish to make is more scratch and heat resistant, it does not rub out well. To get the best results, let the finish fully cure for at least four weeks at room temperature.

[Jim Becker]

"What Howie said".

Further, there's really no reason to use polyurethane on furniture. There are no real benefits most of the time and a number of undesirable characteristics, including typically less clarity than a non-poly alkyd or phenolic resin varnish and adhesion challenges even with additional coats of the same product. Unfortunately the 'borg's marketing and shelf stocking will lead you to believe that poly is "the" finish for all occasions. Go to a real paint store (Sherwin Williams, etc) and consider using better alternatives. One favorite of many woodworkers, for example, is Pratt and Lambert #38. Lighter in color due to the use of soya oil, rather than linseed oil in the ingredients and a very nice quality finish.

[O. Rob Anderson]

Jim, thanks for chiming in my on going threads.

So I've only done 2 drawers using poly. For my kitchen cabinets, where I'm using MW oil based Dark Walnut, which finish should I use found at a Shermin Williams? I have a Nova 390 electric airless sprayer with access to an 10, 11, 12 tip for finer spraying, so I'm hoping a spray on finish should not be a problem with this rig.

I'm not hell bent on using any product right now, so some guidance on this project would be helpful. Like I said, I've only stained a few drawers and finished 2 drawers and have many more unfinished ready for stain. On my other thread you cautioned me about using an oil based stain on kitchen cabinets. I would really like some guidance as to how to finish these cabinets. SW is down the street from me and I'm not worried about cost. Which stain and finish shoud I use and what process should I proceed with? If I can still use the MW oil base stain I have and seal it with a spray on water based finish, I would be okay with that. Or, changing my direction and using a compatible stain with a spray on finish.... I'm okay with that too. I just need some direction. As mentioned before, can I use the Nova 390 on this project for doing my finish.

[Chris Padilla]

There are some good reasons for using a tough finish like poly/varnish. I don't have my finishing bible by Bob Flexner in front of me (Understanding Wood Finishing...I HIGHLY recommend every woodworker have this valuable resource) but very few things hurt this finish.

One example for me: I have a surface that a reed basket will rub on. Shellac lasted about a week before needing repaired. So I fixed the shellac and then put the poly/varnish on top...this finish will last much much longer.

Another example: I have a fish tank stand with a maple butcher block top. I just laid down a second coat last night.

Varnish is a joy to brush and it levels out beautifully...but that is because it takes a long time to dry...which means it can pick up all kinds of dust nibs from the air...so use it in a clean environment.

In general, I don't like to use poly/varnish but it has its place in your cabinet of finishes.

Oh, get that book...that is the single best advice I can provide.

[Jim Becker]

Chris, you don't need the poly in the varnish to get the benefits on furniture. And non-poly varnish is generally a little harder, too.

[bob frost]

Ditto, on" Bob Flexner in front of me (Understanding Wood Finishing...I HIGHLY recommend every woodworker have this valuable resource)"

.I just got the book and it reads very well and lots of info and pictures.