finish to allow for later painting if desired?

[mound]

my daughter (10yrs) and I built this quick project - plywood dresser/shelving unit for inside her closet. Birch plywood with poplar face frames and poplar drawer fronts.  The plan all along was to paint it white, thus the wood choices, but now that she sees it (and I admit those poplar drawer fronts have a cool kinda look to them) she says to keep it natural wood, "but maybe we can paint it some other time if I change my mind" 



I kinda still think it should be white but what do I know, and I really dislike the whole process of painting anyway. I was thinking then just use some wipe on poly.. But what if we later paint over it once installed?  Would poly have to be sanded away before painting over? would it better maybe to use shellac? or doesn't it really matter?

thanks!

[Cooler]

Dewaxed shellac (SealCoat) can be used as a clear finish or a primer for most other finished.  Dewaxed shellac will adhere strongly to most substrates and most finishes will adhere well to dewaxed shellac. 

It dries in 20 minutes (but you should allow good ventilation).  Foam brushes are OK for small projects but they will fall apart from the solvent in the Sealcoat, so for a larger job like this, use a good brush.

It sands easily and you can polish it to a high shine if you build up enough finish.

Shellac is not the most durable of finishes, and Poly will stand up better.  

I would note that I painted with PPG's Breakthrough!, an excellent cabinet paint and it did not want to adhere to the Sealcoat.  That is the only finish I have come across that didn't adhere to shellac.

Shellac will seal knots well, and will seal odors (smoking, cat urine, etc.).  The main drawback is the smell.

[mound]

Thanks Cooler.
Will the SealCoat give the birch plywood the same darker look that Poly (or even BLO) would? I've never used it before

[MichaelMouse]

Thanks Cooler.
Will the SealCoat give the birch plywood the same darker look that Poly (or even BLO) would? I've never used it before

Nope, you would have to use amber or tinted shellac to give ambering similar to BLO or alkyd varnishes.  Poly, especially water-based, would be pale pale as well.

[mound]

Nope, you would have to use amber or tinted shellac to give ambering similar to BLO or alkyd varnishes.  Poly, especially water-based, would be pale pale as well.

Gotcha. I know for sure when my daughter said "look like wood" she was referring to a piece of birch ply on another project that had the amber look from being finished with wipe on poly.

maybe BLO and then SealCoat, BLO for the color, SealCoat essentially as a primer for some future painting?

edit: gonna have to try it on a scrap piece of poplar too, I've never actually put anything other than paint on poplar

[jteneyck]

You can use poly now if you prefer.  If you decide to paint it some time in the future, just scuff sand it with 150 or 180 grit, then prime it with BIN pigmented shellac primer, then paint it. 


John

[Bill Wilson]

Thanks Cooler.
Will the SealCoat give the birch plywood the same darker look that Poly (or even BLO) would? I've never used it before

By itself, SealCoat will impart a slight amber tint and that will help accentuate the grain.  May not be quite as strong as oil Poly or BLO.  As was mentioned, test on some scrap.  You could wipe on the BLO first, then apply SealCoat.  Give the BLO several days to cure first.

As was also mentioned, you could always poly, then, if you decide to paint later, apply SealCoat as a barrier.  Much depends on how durable & scuff resistant the top coat needs to be.  Shellac will scratch easily, but it's also very easy to repair.  Poly would be more durable, but less repair friendly.

[MichaelMouse]

By itself, SealCoat will impart a slight amber tint and that will help accentuate the grain.  May not be quite as strong as oil Poly or BLO.  As was mentioned, test on some scrap.  You could wipe on the BLO first, then apply SealCoat.  Give the BLO several days to cure first.

The grain accentuation is a result of reducing surface scatter.  For the skeptical, wipe BLO to refusal on a piece of well-sanded wood, noting the loss of scatter as long as the surface is a continuous liquid film of BLO.  After two days, note that much of the shine is gone.  This because the surface is irregular, though saturated.  It's the bridging film in shellac or any finish which reduces scatter but makes reflections possible. It fills the irregularities, eventually becoming a mirror if enough effort and finish is expended.  
The first coat of a even a 3#cut of shellac will lose its sheen too, so be prepared for coat two, or possibly more, to produce a finish that allows more of a look into the wood.

[cputnam]

Garnet or Ruby shellac will add a very nice amber color. Test on scrap. Current problem with shellac is getting the alcohol.

[fredhargis]

I'm in the camp of do whatever you want now (the varnish would be good) and then prime with shellac based BIN when you want to paint it...if that day ever comes.