On Mon, 24 Oct 2011 14:55:39 -0700 (PDT), Father Haskell
wrote:

On Oct 24, 2:56*pm, Greg Guarino wrote:
Still working on my desktop, but I was away for the weekend and didn't
get anything done (except the application of what should be the last
coat). I've now got 5 coats of *MinWax poly on it, the first one Semi
and the rest Satin.

It *looks* pretty decent; a satin finish as would be expected. But I can
still feel some little nibs. So what to do next?

Someone here suggested pumice and rottenstone. I did a little reading
and I think I may try out those abrasives on something (smaller)
sometime soon. But I read an article last night that suggested that the
nibs I'm feeling could be smoothed out with 600 grit paper and paraffin
oil. He wrote that if a Satin finish was what was desired, one could
stop there, or proceed to finer abrasives.

Satin is what I'm looking for (I think), so it sounds like a good idea.

Except...

He says that poly tends to remain as separate layers; sanding through
the top one leaves difficult-to-remove "witness marks". There are
another couple of concepts in the article that seem fuzzy to me as well.

He doesn't mention how long to wait before starting the 600 grit work.
Someone here suggested a month. The last coat went on on Saturday
morning. I have plenty more work to do on the rest of the desk, so
waiting shouldn't be too agonizing.

He says to fold a quarter sheet in thirds. I assume this means to use
that little folded piece by hand, without a block. I guess I could do
that, but it sounds like a pretty small bit to keep a grip on, and might
be difficult to do an even job with as well. Could I use a bigger piece,
or at least some sort of soft block?

He also says I'll need to remove the oil and dust periodically to see
how I'm doing, which seems logical enough, but doesn't say how to do it.
Just wipe? Use a chemical?

Naptha or mineral spirits are good wet-sanding fluids. Both
wipe off clean.

I'm thinking of giving the process a try on my test piece, which only
has three coats of poly on it, but it's had a few weeks to cure. Are
three coats too few? Any advice would be appreciated, including
different methods entirely.

Gray Scotchbrite pad is the fastest way to rub to satin. Not
sure if pumice or rottenstone will bring up a high gloss on
poly.

Yeah, if it's only poly, it doesn't matter whether or not the finish
is even. With Scotchbrite, it -never- is. Good steel wool, such as
Liberon, is the only way to ensure an even scratch pattern. I love
Scotchbrite and buy it by the box, but this is one place I never use
it. One of the mags did a test and I confirmed it myself, then
stopped using Scotchbrite for finishes, unless it's for complete
_removal_ of a finish.

--
It is characteristic of all deep human problems that they are
not to be approached without some humor and some bewilderment.
-- Freeman Dyson