# Filling hairline cracks on Pine plywood



## Zandarkoad (Nov 18, 2012)

My wife asked for benches in our kitchen as opposed to chairs, so I threw together some old pine boards and used the tea and steel wool in vinegar to turn them a beautiful dark gray. They got even darker with the three coats of varnish, and my wife loves them more than me now. So to prove that I'm better than the benches, I figured I'd make a table to match. 

Long story short, where I am now, I have four coats of varnish on a pine plywood table that was thoroughly sanded and aged using the aforementioned method. It looks amazing, but there are hundreds of persistent hairline cracks that just won't go away. There weren't nearly as many cracks on the benches, and it didn't matter because it wasn't an eating surface. I really want a total smooth surface (sloping bumps are OK, cracks where food gets caught are not). The cracks are very thin. Any ideas on how to get rid of them short of using a two part epoxy? That stuff intimidates me. One guy recommended a non-ambering shelac by Zinsser, but does that really have enough body to fill cracks? It seems like it would just vanish like varnish...? 

Thanks guys!


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## Steve Neul (Sep 2, 2011)

I believe I would just thoroughly sand the benches with 220 stearated sandpaper and put more varnish on them. I wouldn't put shellac over varnish. It sounds like too many cracks to putty so I would fill it with varnish. It might take a couple of coats to make a difference. What is disturbing though is what is causing the cracks? Normally pine is more stable than that.


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## Zandarkoad (Nov 18, 2012)

Steve Neul said:


> I believe I would just thoroughly sand the benches with 220 stearated sandpaper and put more varnish on them. I wouldn't put shellac over varnish. It sounds like too many cracks to putty so I would fill it with varnish. It might take a couple of coats to make a difference. What is disturbing though is what is causing the cracks? Normally pine is more stable than that.


Well, since you ask... I think those cracks are the result of a number of things. I was working on the table outside due to all the dust that was being created by the orbital sander. After I sanded it thoroughly, I applied tea and let it dry. Then, I applied the vinegar / steel wool mixture, and let it dry and age for a few days. Well it rained. Twice. And dried, twice. By this time, it was the perfect color, and I figured the rain and the sun would help to age it a bit more. But I think all those wet / dry / wet / dry cycles took it's toll, and opened up the wood grain a little. I didn't want to go back to square one, and the cracks seemed so thin, I figured the varnish would fill it in. But it hasn't. At least, not after four coats.

I'm going to create the same finish on a 1' x 4' section of the same piece of plywood that was left over. I'll do what you suggest (among other things) to see what works best on removing those cracks. The more I think about it, the more I believe more coats of varnish HAVE to eventually hide them. I know the varnish is going IN the crack. So I know the inner sides of the crack are getting coated with varnish. Eventually, with enough applications, the sides of the crack MUST get built up enough that they'd touch (and close). At least, in theory.


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## Steve Neul (Sep 2, 2011)

I believe it must be the vinegar making the wood crack. The tea wouldn't. I've used vinegar on wood to neutralize paint stripping chemicals before but I've never left it on more than a few minutes before being rinsed off. 

The varnish will eventually fill the cracks if they don't open more. Some of the worst ones you might take a small artist brush and run a line of varnish just on the crack. You might put a few coats like that on it before you sand it.

On your next project you could first use a pastewood grain filler prior to finishing it. It's used to fill the open pores on woods like walnut and mahogany.


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## Rick Mosher (Feb 26, 2009)

Just get a tube of Elmers Wood Filler and fill the cracks with a color that matches your wood. (walnut maybe?) When it dries sand it flush lightly with a block and 220 sand paper and then apply your next coat. I would do a burn in myself but I doubt you will want to go to all the expense to buy the tools to do that and I believe the Elmers will work fine on your project.


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## Rick Mosher (Feb 26, 2009)

just in case you are interested.


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