Rub on poly after brush on poly?
#4
I'm refinishing my dining room table. It's been stripped, sanded, stained and has 3 layers of oil-based polyurethane that I applied with a brush (after sanding lightly with 600 grit between layers).

No matter how slowly I go, no matter what quality of brush I'm using, I still have brush marks when the poly dries (see attached photo).

It doesn't look too terrible, especially since I'm not a professional, but I'd just like to smooth out the finish more.

I've seen people get great results with rub on poly (half poly / half mineral sprits) and am just wondering if I should try that instead of brushing.


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#5
Wiping varnish is widely described as a "fool proof" method of application. I like it a lot and often use it. You can  make yours by simply diluting the regular varnish by about 50% with MS. As for the finish you now have, it might have flowed out better if you had thinned it a little more. Even so, my normal routine when brushing varnish is to sand it smooth after I get "X" number of coats on. Then the last coat is usually a wiped on coat. Small disclaimer here: I don't use urethane varnish preferring the alkyd resin formulas...but I have to think it will work with a urethane type.  So, to answer your question: Yes, I think you should try it and see what you think. Just remember the finish build is a lot less when wiping it on, the most common rule of thumb is that 3 coats of wiping is roughly equal to one brushed coat.
I started with absolutely nothing. Now, thanks to years of hard work, careful planning, and perseverance, I find I still have most of it left.
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#6
If you get a perfect finish with a brush it will be the first one ever.  Seriously, you can't expect a dead flat, defect free result with a brush.  Thinning will help, an expensive brush will help, or a cheap foam brush, but when it's all done the only way to get a factory type finish is to rub it out with abrasives.  It looks like maybe you used satin or semi gloss, yes?  If so, you could switch to gloss and apply another coat or two, ROS that with 600 grit until it's flat, then apply another one or two coats.  Let that cure at least a week, preferably two, then rub it out with your choice of abrasives.  I usually ROS with 600, 800, 1200 and 1500 or 2000, then switch to automotive polishing compounds to get whatever sheen you want.  But if you go through 1200 grit then rub it with the grain with 0000 steel wool and wax or wool lube using a rubber block you will get a lovely silky smooth satin finish.

If you don't want to rub it out, then just ROS it flat with 600 grit then wipe on a coat or two of your finish thinned with about 25 - 30% MS. Let that cure a week or two, and then use the 0000 steel wool and wax to get rid of any nibs and create a uniform, satin finish.

John

All of this is predicated on the finish you now having being thick enough to ROS w/o cutting through into your stain. Only you can judge if it is. Three full strength, brushed on coats should be.
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