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LMHmedchem
19th December 2010, 01:10 PM
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

ubeaut
23rd December 2010, 08:03 AM
Sand to a higher grit, at least 6000 then apply a coat of Sanding Sealer (http://www.ubeaut.com.au/sandseal.htm) this will raise the grain torn by sanding and will make it stand up hard ready for removal. This is best done with a wipe over with 800 grit abrasive a few hours after application, even better next day.. Don't rub hard just a very light wipe to smooth the surface and cut off the nibs of raised grain.

You can apply another coat of sealer as a base for your finish if you wish.

You can also do this with warm water but it takes a lot longer and may need to be done more than once which could be detrimental to the ply.

Cheers - Neil :U

AnselmFraser
10th January 2011, 10:48 AM
Sand to a high grit spray on some methalated spirits/alcohol this will raise the grain,fold a piece of sandpaper using the smooth side and push the raised grain flat then apply your shellac/finish .You will get a high quality finish much quicker.The alcohol raises the grain quickly with out damaging the wood.
Good luck.
Anselm.