# Finishing oak plywood



## LMHmedchem (Dec 16, 2010)

I am just completing a desktop that is made with 2x 3/4" plywood glued and screwed and toped with 1/4" oak plywood. The sides are veneered with 1/4" red oak hardwood glued on. The plywood is quite smooth from the factory finish. In the past, I have had issues with raised grain when I finish red oak. I always sand with 120, 180, and 220 on the palm sander, and then with 320 and 400 by hand block to finish. I am not sure what else I can do to avoid raised grain.

Should I sand off the first two coats of stain, since the solvent may raise grain? Should I use a sealant or blond shellac first and then sand if off? Should I just stain away and deal with any raised grain when I do the top coat?

I will use a combination of red oak and red mahogany oil base stain (minwax) followed by about 10 thinned coats of oil base satin poly. I will probably tint the first 2-4 coats of poly to darken and reden the final color.

Any suggestions or things to really avoid.

LMHmedchem


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## MastersHand (Nov 28, 2010)

The sanding you described is that before stain. If so this is to much you want the veneer to accept the stain. 150 is more then sufficient before stain. Grain raise is normal and is nothing to worry about. A quick sanding between coats with 220 will knock this right down and be very smooth to the touch. Wipe with a tack cloth between coats as well


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## cabinetman (Jul 5, 2007)

I would lightly sand the bare plywood with 150x-180x. Then stain. I wouldn't sand the stain. I would sand with 320x after the first coat of topcoat, and in between coats thereafter.

I would not use an ordinary tack cloth as it can leave a resinous residue. A dry tack cloth like this would be better.












 









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## LMHmedchem (Dec 16, 2010)

cabinetman said:


> I would lightly sand the bare plywood with 150x-180x. Then stain. I wouldn't sand the stain. I would sand with 320x after the first coat of topcoat, and in between coats thereafter.
> 
> I would not use an ordinary tack cloth as it can leave a resinous residue. A dry tack cloth like this would be better.


I have more or less done just that before and ended up with a surface that was not that smooth. Not rough like sandpaper, but where the lighter and darker part of the grain have different elevations. This has mostly been with oak that was new. I have not had this issue with maple, or older oak that I am re-finishing. Do I need to thin the poly more so that is settles down in the low features of the wood? About what ratio of poly to thinner do you recommend?

I have one of those dry tack microfiber cloths. Generally I use the blower from my air compressor and a soft brush to dust the work in the room where I sand. Then I wipe off with the tack cloth. Finally, I move to the room where I apply finish and wipe the wood off with a paper towel dampened with a little mineral spirits.

Am I doing anything particularly wrong there?

LMHmedchem


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## MastersHand (Nov 28, 2010)

MastersHand said:


> The sanding you described is that before stain. If so this is to much you want the veneer to accept the stain. 150 is more then sufficient before stain. Grain raise is normal and is nothing to worry about. A quick sanding between coats with 220 will knock this right down and be very smooth to the touch. Wipe with a tack cloth between coats as well


I did mean the 220 between top coats like cman said definitely don't sand stain this would Just about ruin your top if not completely


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## MastersHand (Nov 28, 2010)

The dry tack cloth is a good point and I would stay away from using the blower because your not only blowing air but dreaded H2O. You may not see it but it is there


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## LMHmedchem (Dec 16, 2010)

MastersHand said:


> I did mean the 220 between top coats like cman said definitely don't sand stain this would Just about ruin your top if not completely


How do I sand enough to remove the raised grain, but not so much that I sand off the stain? Some of the ripples between light and dark grain are quite large. I usually do 320, 400, 0000 steel wool, between top coats. Will the 220 help to get me a flatter surface?

LMHmedchem


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## cabinetman (Jul 5, 2007)

LMHmedchem said:


> How do I sand enough to remove the raised grain, but not so much that I sand off the stain? Some of the ripples between light and dark grain are quite large. I usually do 320, 400, 0000 steel wool, between top coats. Will the 220 help to get me a flatter surface?
> 
> LMHmedchem


The only way you will get a flat smooth surface is to use a grain filler, AKA paste wood filler like this (not a wood putty). You could try thinning up to 25% and see if it levels out better. I would recommend it being wiped on. You would only need to use 320x between coats. The last coat, may not need any sanding. The grain differential can be quite obvious. Actually, there are some that like the natural orientation of the species.










 









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## MastersHand (Nov 28, 2010)

yes 220 being a little coarser will help knock them down. But keep this in mind lay your hand on top of your piece with your paper let the weight of your hand do the work. There's a big difference between sanding a raw piece of wood or plywood and sanding between top coats. All you want to do is scuff it for the next coat.you want to see the white dust and get a nice uniform haze if you will. The grain raise during finish is Just the fibers of the grain raising . If your having problems with high and low spots You can feel with your hand this is from before stain. When your prepping a flat surface for stain you want to use a block or electric pad sander. You don't want to use an orbital or even your hand until you get a little more experience because you will create high and low areas


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## LMHmedchem (Dec 16, 2010)

I have the first couple of coats of stain on, and it looks pretty nice. There are some lighter areas that I tried to darken by applying stain there, but not on the rest. That doesn't seem to be working. Is there anything else I can do to help even out the color?

I don't think the issue is all that bad, and it may be lighting as much as anything. I have attached a picture. You can see that there is some darkening on the right side top compared to the top center. The lighting makes the effect much more pronounced than it really is. When I pass a work light across the surface, I have a hard time picking up the darker and lighter areas. I will be adding a bit of stain to the first few coats of top coat to redden it a bit, so that will help to even things out some.

LMHmedchem


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## jack warner (Oct 15, 2010)

you cant/shouldnt use a penetrating stain to tone with, its excess is ment to be wiped off. tone with gel stain or dies.


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## MastersHand (Nov 28, 2010)

jack warner said:


> you cant/shouldnt use a penetrating stain to tone with, its excess is ment to be wiped off. tone with gel stain or dies.


Jack has very good advice for you. By using stain to try an darken an area of your top you are creating literally a"stain". I think I can almost spot the areas in the picture you tried this on. The light and dark area's created naturally with the stain and top coat and the way the light hits it is the beauty not the problem


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## LMHmedchem (Dec 16, 2010)

MastersHand said:


> Jack has very good advice for you. By using stain to try an darken an area of your top you are creating literally a"stain". I think I can almost spot the areas in the picture you tried this on. The light and dark area's created naturally with the stain and top coat and the way the light hits it is the beauty not the problem


I tried to darken the center, and it didn't really do anything, meaning it didn't look any different after than before. I guess the wood just wouldn't take more stain, at least not without drying overnight. I leave the stain for about 30min, and then wipe it off, first with a stain rag, and then with a clean rag. The color just didn't turn out super even, but it is hard to tell in the light. It is a bit darker along the top right edge. I don't know if I didn't get this part sanded quite as well, or if that is just how the wood took the stain.

Either way, it really doesn't look bad, so I will just leave it I think. Colors change with the top coat, so I shouldn't judge it just yet. I will put some red oak in the first coats of poly, and that will give it a nice rich and darker red. I have never used a gel stain, I guess I should expand my list of finishing products a bit.

LMHmedchem


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## LMHmedchem (Dec 16, 2010)

I have the first two coats of top coat on. I used 1.5oz satin poly/1.5oz mineral spirits/2 tsp red oak stain. For the next two coats, I will use 2oz poly/1oz mineral spirits/2 tsp red oak stain, but I could go to 3:1 if there is no benefit to staying thinner. What do you think? I am wiping on with a microfiber cloth. I used a circular rub followed by a finish wipe with the grain for the first two coats. I will just wipe with the grain for the rest. At the moment, I an sanding with 320 between coats, but will move up to 400.

The coats are drying pretty fast with the 50% thin. Do I need to wait a full 12 hours between coats, or can I go shorter until I get a bit less thinned?

I also have some wipe on poly (minwax product). I think it just has a bit of linseed oil in it to slow the cure time and let you work it a bit. I use it for the last few coats, especially where I need to fill some nail holes, or something like that, after the project has its finish. For some things, I do most of the finish before I put the thing together, and I use the wipe on for that as well. Right now I am just wiping on regular thinned poly. Is there any benefit to using an actual wipe on type finish. Also, does it matter if I thin with paint thinner instead of mineral spirits?

LMHmedchem


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## cabinetman (Jul 5, 2007)

LMHmedchem said:


> Also, does it matter if I thin with paint thinner instead of mineral spirits?
> 
> LMHmedchem


Paint thinner is mineral spirits. The ply you're using is a rotary cut face veneer. Your next project might be a tad easier to finish if you start with a better grade of plywood.












 









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## LMHmedchem (Dec 16, 2010)

cabinetman said:


> Paint thinner is mineral spirits. The ply you're using is a rotary cut face veneer. Your next project might be a tad easier to finish if you start with a better grade of plywood.


Mineral spirits generally has a smaller fraction of aromatic hydrocarbons (toluene) than generic paint thinner. I think this is the basis of the "orderless" tag. I have read that generic paint thinner is more for cleaning then for thinning, and impurities, lower quality control, etc, can cause issues. Other than the fact that mineral spirits costs 30% more and smells allot less, I am not sure about the other differences. If you say there is no difference, I won't worry about it.

What do you think about the dry time between coats?

Total I had about $100 for this, which was a limiting factor for the oak. I am building a desktop that will sit on two rolling 3-drawer file cabinets. I also made some 2" risers that sit between the cabinets and the desktop to give me a bit more height and also some pullouts. The file cabinets cost $100 used, so I only had another $100 or so for the rest. If I did this again, I would probably try to get some better quality 1/2" oak plywood and use a second sheet of 1/2" normal plywood for the bottom. That would be instead of the 2x sheets of 3/4" toped with 1/4" oak plywood. Part of the issue is that the surface is 58"x27". This is for an odd shaped space and it is hard to get those dimensions without buying multiple sheets of plywood and wasting allot.

LMHmedchem


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