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What is the best way to finish a plywood board that is going to be used as a desk top? Answered

So far I have tried sanding it down and applying a poly based stain.  But I still feel like it could be much smoother. 




Best Answer 7 years ago

Sand the top lightly with 220 grit sandpaper after staining, apply a good quality filler and sand again with 220 grit.
Use a high quality polyurethane floor finish and apply light coats with a foam brush sanding between each coat. When you have achieved a nice smooth surface. Sand again with a 400 grit wet or dry sandpaper and then with 600 grit wet or dry.
Buff it several times with a good carnuba paste floor wax. You should end up with a near furniture grade finish when done and the surface will be hard enough to resist shadow dents caused by writing on paper placed directly on the desktop.

Hi Burf, I am sort of a novice here. How do you apply wood filler? Do you want to spread it out all over the top or do you only want to apply it in scratches and dents?

If you use a paste filler, you will need to thin it with the appropriate thinner (check the label) and apply it with a brush. First brush on a coat with the grain, working it into any of the low spots and cracks in the grain.
Let it dry, sand and then apply a second coat with a brush, perpendicular to the grain and sand again. You can repeat if necessary, until all the surface imperfections are filled.
Just remember that all that sanding in every step serves a purpose and the better you do it, the better the final product.


Answer 7 years ago

I should have added the product you want to use is actually called a "Sanding sealer/filler" (I generally just call it a filler) and is usually in a liquid form, though it is available as a paste also.

Another possibility would be one of the pourable "bar top" finishes -- somewhere between a poly and an epoxy, if I remember correctly. That produces huge "build" the first time. Then sand with progressively finer grades, then polish through still finer grades, then buff. Getting a real mirror finish takes time and patience and a lot of elbow grease, but the results may be worth it. Then again, if I was going to do that I would want to at least put a good-looking layer of veneer on the plywood first, so you aren't looking at awful ply through that nice finish.

Envirotex is a name I remember from the "make your old slab of growth tree trunk into a really mod table" ('70s) days. The local bars used it to cover their turn of the century bar surfaces too. I have no idea if they're still around (the makers of Envirotex that is). I had several slabs, one of which was ~5 feet wide) from a trio of giant Sassafras trees that came down in a summer storm in our side yard when I was in my teens. I soooo wanted to have a groovy table, but alas, 'twas far too expensive. the larger slabs have long since split and been burned, but I still have one of the smaller slabs right here in my office...See? like gvoovy babee. toe-ally gvoovy!

Sand it again, wipe it throughly to remove any generated dust, and carefully apply more poly, followed by more sanding...etc etc. Poly is very susceptible to surface variation and dust. Keep the area well protected against dust intrusion while applying the poly and while it cures. Regarding the plywood itself, unless you purchased cabinet grade plywood, there's only so much you can do to make it perfectly flat, since lower grades have a pretty large surface variance, and even if only measured in mm or smaller, those differences show up when a gloss has been applied.

Many coats of clear finish sanding between each coat with a flat sanding board. If you use a soft sanding pad or your hand to back the paper you will just dig out the low spots more each time.

Pine is a real bear to get really smooth  cause it's got alternating layers of hard and soft wood so the soft wood gets removed more than the hard wood.

Second idea is to get it looking really pretty then have a piece of glass cut as a desk top.  Makes a nice really hard and flat top.

Third suggestion is to cover the top in formica.  This could add some color to the top.

A final thought:  As I type this I'm at my "custom" made corner computer desk that I built using pine plywood.  I had no trouble getting the top flat enough for my taste.  But I notice that in the area that I use for a writing desk my pen has created many many little grooves in the soft wood even though I used 4-5 coats of poly.

You might need to sand it again with a finer grit sand paper and re-stain, then again with even finer paper or steel wool to help remove fine burrs that still appear. Keep doing light sanding between coats and you should see it improve each time.

.  You probably are working with pine, which is really a pain to get smooth ... but it can be done. Google "finishing pine" for details.