Can't flatten red oak desk top...my first project

This is my first woodworking project.
I made an activity desk for my kids out of some reclaimed red oak. The main activity will be drawing so I want the top to be super smooth. I know now red oak was probably the wrong choice but the desk is built.

I read quite a few posts and even a couple books about finishing and because I couldn't find any wood pore filler on the island I thought that I would just build up the coats of poly, then sand it flat.
The problem is that I've now done 6 coats and it doesn't feel remotely flat. The grain pattern still feels super indented.
Is it time to sand? Do I just keep adding more poly? I'm assuming it is too late to add wood pore filler.

The products I've used thus far are:
-Minwax wood conditioner
-Minwax wood finish ebony penetrating stain. 3 coats.
-Minwax Clear Satin Fast-Drying Polyurethane Interior Wood Protective Finish. I did a super light 320# sanding after the 1st and 2nd coat. The close up picture is after the 6th coat.

The finish has been curing for about a week so I'm ready to either start sanding or keep building up more layers of poly.
Not at all sure what to do at this point.

BTW, my plan was to sand flat, add one more coat of poly (might not be necessary), then rub out the finish with paste wax and 0000 steel wool after the finish has cured.

Attachment 372253
Attachment 372254

oh. forgot to mention that I've been applying what I think is a thin coat, and I'm doing it using a 2" foam brush. 6 coats on this ~12 sf desk has taken about 1qt of poly. I've been applying in the direction of the grain.

Let's ignore timber choice etc and work with what you have. The following is a way to fix the problem but I strongly suggest a trial on some scrap or somewhere not readily seen so you can assess whether it works for you.

First you need to sand it reasonably flat with your 320 paper. Go as flat as you can without going through the colour. This will get rid of the rolled edges around the pores.

Next you need a wood filler. Since you don't have one available, you need to make one. Use the minwax polyurethane as the base. You need a black coloured filler material to thicken it. I suggest finding or making some charcoal and grinding it to powder in a mortar and pestle or something similar. It will need to be very fine so sift it to get just the fines. Make up a slurry of charcoal powder, polyurethane and a touch of black dye stain. Apply this with a cloth pad in a circular motion. Keep rubbing until it starts to feel sticky and lightly finish it with the grain to get rid if any swirls. Let it dry overnight, give it a light sand and then proceed with clear finishing. By the way, a touch of black in your clear coats give extra depth to black stain. Cheers

Mishkin,

Wayne Lomman is right on target, except if this were my job I would use wood flour instead of charcoal and dewaxed shellac (Seal Coat). By wood flour, I mean very fine sanding dust. I don't know what tools you have, but if you have a hand held sander with an attached dust collector you can make enough by sanding a cutoff of the red oak. Maybe you already have some from when you sanded the desk before finishing. You could do it by hand sanding but it would be very tedious. Mix the wood flour with enough dewaxed shellac to make about a tablespoonful of sticky dough and apply it to the worst of the holes. Press it in with a putty knife and smooth it as smooth as possible without pulling it back out of the hole. Then repeat. You will see why you make a little at a time because it dries and thickens fast. If you can't get dewaxed shellac you can use the polyurethane or even elmer's glue. When everything has dried, sand the top again and apply your last coat of poly.

By the way, as you know now, a coat of varnish is only a few thousandths of an inch thick and some of your holes look an order of magnitude deeper than that. The filling procedure would work even better on bare wood.

Doug

How about a resin table top? They look great, are durable & there's plenty of info online.

Wow thanks guys.
I thought about the resin top but the desk has slots in it for the paper roll so it isn't as straight forward to tape off the sides, and it wasn't quite the look I had in mind.

I think I'll try one of the wood filler techniques, probably the "flour" as I have lots more red oak on hand and can make dust.
For the flattening/sanding I'm about to do with 320# can I do it with ROS or is it something you are supposed to do inline with the grain?

Quote:

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Originally Posted by Al Launier

How about a resin table top? They look great, are durable & there's plenty of info online.

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That was my thought as well, especially for a children's piece, resin will be the most durable finish you can use and it will be dead flat no matter what's underneath. I mean, you could just slap a piece of plastic on the top and call it done if you were really lazy, but resin is simple to do and can even handle the slots he has in the top.

Mishkin,

In reply to your question about sanding, I would hand sand with a sanding block. If you have much to remove and the sandpaper clogs with varnish, use 320 wet or dry with water as a lubricant. Wipe it off frequently with a clean, dry rag to watch your progress, so that you won't sand through the stain. All you want to do is level the patched places and provide "tooth" for the next coat of poly. Poly is kind of notorious for not adhering well to well-cured earlier coats, so you need fine scratches all over the top. (It's called scuff sanding.) You want to just dull the shine. If you are using water as a lubricant, you will have arrived at your goal when the water spreads smoothly and no longer beads up. Better not to go past that point. Another rule of thumb is that no part gets more than 25 strokes (back and forth). I know that this sounds anal, but I remember my frustration in trying to flatten a varnished surface without going through to the stain.

Good luck

Doug

Sanding a polished top is all about getting the finish flat without sanding through to the timber. Sanding through means you lose colour and you get dull spots where there is less finish.
If you think you can do it, use the ROS, otherwise hand sand with a cork block.
With regard to the filler, wood flour works but it isn't black. This is why I suggested charcoal instead. You can fill it and proceed with coating. The wood flour you will have to colour.
I also don't recommend using different classes of coating in the one job. Doing it all with urethane means you are not risking incompatibility between coats. Plenty of guys use shellac as a silver bullet however. The final decision is yours. Cheers