Expert: Jamie Yocono - 11/9/2005

Question
Dear Jamie,
    I am a rank amateur and have built (nearly finished) a Harvest Table for my daughter.  I used some 2" K.D. Western Maple and lammed a solid top and 3 insert leaves.
    However, I live on Harrison Lake in coastal British Columbia and here it rains every day in November and the humidity in my unheaated open air shop is about 100%.  I have a warm room where I can spray the table and have been intending to lacquer the bottom and legs as a sealer and to spray polyurethane on the top.  If it warms inside will it warp? Do I take it inside and spray it while still cold? (50F) Or?
Fred

Answer
Hey Fred,

I can sort of relate to your woodworking question, as I live in a climate that's the exact opposite of what you experience. I live in the desert, where it's like 2% moisture outside, and more like 20% moisture inside, thanks to the humidifier.

The best advice I can give you is-acclimate, acclimate, acclimate. You want to finish your harvest table when it's at the same moisture content as where it will eventually be housed. If you finish it outside, you risk a failed finish, with results that might include cracking, splitting, fogging and more.

Now it could take a little time, but what I recommend is that you take the table inside and let it acclimate to it's final resting place. If it's going to be sitting in a room near a heater vent, that makes a difference than if it's sitting in a cooler mud room or a screened in patio. So let the table sit in the room where it's going to be permanently, if possible. Since you mentioned such an extreme moisture content in your shop (100%) I would think that that table has a good deal of acclimation to do. So it's possible that you might want that table to sit there (unfinished) for a month or so.

Just for curiosity, you could do a few things to check the moisture. Obviously, if you have a moisture meter, you could test the wood at the beginning of this period, and then again, a month later to see what the difference is. Without a moisture meter, there are a few other ways to determine if the wood is losing moisture. You could weigh the table (which might be tough, depending on it's size) or you could measure it. Across it's widest span, let's say it's 40." Measure ACROSS grain, not parallel to grain, as wood will shrink or swell across the grain much more than end to end. So let's say you start out at 40," and a month later, it's down to 39 1/2". Then you would know there is some shrinkage going on, which would be evident in the size fluctuation. But obviously, a moisture meter would be best.

Anyway- let it acclimate - and who knows how long that might be, but you want it to lose it's moisture slowly, or it will crack. If it loses it too quickly, it SURELY will crack and split. So allow it to do this slowly. And then- once it's stabilized in the house, you can apply the finish.

And although I tend to not use lacquer or polyurethane, it's my opinion that you want to keep the treatment of the table the same all over it, both top and bottom. So if you're going to lacquer the bottom and legs, I would at least give the top a coat too. Then- if you still want to add some poly for protection, you can let the lacquer cure and do it later. But generally, applying different finishes to each side of wood is sometimes a disaster waiting to happen. Wood needs to be treated the same, so that it's pores are sealed the same and will hence, lose or gain moisture the same on both sides.

I hope I didn't get too technical for you, but it's all about moisture and losing it slowly. If you do it too fast- well, you're not going to be happy with what happens. So bring that table inside and let it acclimate slowly.

Good luck, I hope this helps. Feel free to write back with any other questions you might have after reading this.

Jamie Yocono
Wood It Is! Custom Cabinetry
www.wooditis.com
Las Vegas, NV