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View Full Version : Problem with raised grain following water-based finish on quartersawn red oak.



Clayton Jones
03-29-2011, 6:53 PM
Hello. I'm new here, but am not new to woodworking (got back into it after a long hiatus).

I am finishing a coffee table that I built from quatersawn red oak. I have always used either linseed oil or french polish shellac, but wanted a bit more protection for this tabletop so I got some brush on water-based polyurethane/acrylic (flat/matte). Testing the finish on a scrap of rift sawn red oak went fine, so I proceeded with the tabletop (which is sanded evenly to 220grit). However, as I was finishing it was apparent that tiny pieces of grain were lifting up all over the piece, something I haven't had happen before. Now the previously smooth surface feels "fuzzy".

Thoughts? Will things end up OK with some light sanding between coats? Should I sand this off and just go back to BLO? Should I have wet-sanded the oak first? Does it need a filler?

Thanks!
Clayton

Conrad Fiore
03-29-2011, 7:19 PM
You will always get some grain raise with WB products, but not to worry. Your first coat should act as a sealer and you can cut back the tiny hairs with a light scuff sanding with 320 before your second coat.

Jim Rimmer
03-29-2011, 8:49 PM
Check out the video on Wood Whisperer. But a quick summary, spritz the wood with water to pre-raise the grain, sand it smooth again but not too deeply. Just a few strokes with 220 or whatever your last grit was. Then use the water based dyes. The water or water dyes will lift the grain but if you pre-raise it, sand the fuzz off it and will not do it again when you apply the dye.

Kent A Bathurst
03-30-2011, 5:23 AM
.....spritz the wood with water to pre-raise the grain........

I apply the water liberally. Also - if you live in an area with a lot of minerals in the water [or, even if you don't] you might want to use distilled water. I don't know for sure what the difference in teh end result is, but I always feel better, so I do it.

John Gregory
03-30-2011, 11:40 AM
It is my understanding, no experience here, that depending on the species of wood, the minerals in hard water can react with the wood. So most likely, you would be safer with distilled water.

Jim Rimmer
03-30-2011, 12:56 PM
I apply the water liberally. Also - if you live in an area with a lot of minerals in the water [or, even if you don't] you might want to use distilled water. I don't know for sure what the difference in teh end result is, but I always feel better, so I do it.
Yep, left out that important detail. :o Definitely use distilled water.

Howard Acheson
03-30-2011, 1:29 PM
Here is some info on "grain raising" the may be of interest.

Let's first understand what raised grain is; raised grain is created by sanding and to a lesser extent planning or scraping. As you smooth the wood with any of these operations you cut wood fibers such that they are free to flap about (they are no continuous). When you apply ANY liquid the loosened fibers absorb the liquid, swell, and protrude upward from the surface of the wood. When the liquid evaporates the fibers remain in their upright position. It is a bit (though not exactly) like your hair behaves when you get it cut short—it doesn't lay flat, but wants to stick up.

To a certain extent this problem (if it even is a problem) can be alleviated by pre-raising the grain. This is done by sanding to your final grit and then lightly wetting the surface with water to intentionally raise the grain. When the water evaporates you can then very lightly sand to remove the raised wood fibers. The theory is that once raised (and removed) the fibers won't raise again under finish. The problem is that the theory is correct; but, it is the execution that is flawed. It is true that the fibers that rose before won't rise again. But, when you cut them away with the light sanding you expose new fibers that were previously held in place by the ones you just removed. These will rise when you apply your finish.

In short, the whole issue of pre-raising the grain, and raised grain following the application of a water-soluble dye or a waterbonre finish is (in my never to be humble opinion) a big so-what. It (pre-raising the grain) is a finishing step to be executed by folks with entirely too much time on their hands. Why? Simple! Here are a couple of clues. What happens to the raised grain when you apply your first coat of finish? Some folks like to refer to this coat as the "sealer" coat because it seals the grain. Many of us, when using oil-based finishes prefer to thin the first coat more than succeeding coats so that it will better penetrate the grain. Any thoughts yet..?

The first coat locks the raised fibers in place so that when you sand prior to applying the next coat of finish you remove them and level the surface. You didn't need to go to all the effort of either preventing them or removing them. They don't cause a problem (other than to those among us that believe the wood should be baby butt smooth at the end of all finishing steps). They are no more an issue than any of the other causes of roughness in your first finish coat.

For what little it may be worth, I sand to 180g or 220g, or scrape, depending on the wood; apply my dye, and then apply the finish. I never engage in pre-raising the grain and I emphatically emphasize that the color coat, however applied, should not be sanded. The bottom line, Mike; don't spend a lot of time agonizing over the first step in your finishing schedule. The color coat requires only a visual inspection—did you get the color you wanted and is it consistent and evenly applied. How it feels is irrelevant. Get on with your topcoat making sure that it is properly thinned and applied so as to minimize air bubbles, dust, brush or wiping marks, etc. and let the finish level itself by attending to proper technique.

Joe Chritz
03-30-2011, 3:56 PM
What he said....

When I use water dye I just get it on, spray the first coat and move on with business. Generally I spray a dewaxed shellac but any first coat does the same thing.

Joe

Chris Padilla
03-30-2011, 4:07 PM
So the bottom line is to sand the topcoat until it is of a smoothness you like? I tend to use a lot of dewaxed shellac as my final coat and I like to rub it out to a sheen I like with steel wool and mineral spirits lubricant or sometimes I omit the lubricant. I haven't yet tried to rub out EM6000. Is it possible, recommended?

Jack Clark
03-30-2011, 10:03 PM
Here is some info on "grain raising" the may be of interest...

Ummmmm, Mr. Moderator, could you make Mr. Acheson's grain raising thesis a Sticky?

Excellent information!

:)

Kent A Bathurst
03-31-2011, 5:14 AM
Jeeez, Howie........

There you go again, applying actual "science" to a mystery.

What's next? You about to tell us there is no Easter Bunny? :D

Howard Acheson
03-31-2011, 12:37 PM
Ummmmm, Mr. Moderator, could you make Mr. Acheson's grain raising thesis a Sticky?

Excellent information!

:)

I can't accept the accolades. The data came from a top-notch finisher and I just distilled it. You can see the complete article at http://www.hardwoodlumberandmore.com/Articles/ArticleViewPage/tabid/75/ArticleId/28/Pre-Raising-The-Grain.aspx. There is lots of other good fiishing info at the same site.

Jack Clark
03-31-2011, 1:58 PM
There is lots of other good fiishing info at the same site.

That would be an understatement. I've bookmarked the site. Thanks for the reference.

Jim Rimmer
03-31-2011, 4:16 PM
I can't accept the accolades. The data came from a top-notch finisher and I just distilled it. You can see the complete article at http://www.hardwoodlumberandmore.com/Articles/ArticleViewPage/tabid/75/ArticleId/28/Pre-Raising-The-Grain.aspx. There is lots of other good fiishing info at the same site.

Thanks for posting the link. Killed my lunch hour reading articles there.

Scott Holmes
03-31-2011, 11:08 PM
Steve M. is the Finishing GURU.