I am a newbie in woodworking and have some questions regarding the repair of a
3 foot square oak coffee table that the top has warped/bowed over time. The top
is made up of strips of 3/4" oak ranging in width from 2-4". A glue joint
failed in one spot so I have taken the top off of the table frame, cleaned the
mating surfaces and have them ready to glue back together. Now the major
problem: The larger of the two parts has a definate upward bow to it. Is it
possible to straighten/flatten this bow out without somehow seperating the
strips in the bowed area? Could I brush on a bit of water to the underside
(unfinished) in hopes of making that side "expand" to straighten it? Any
guidance to my thinking would be appreciated. Thanks in advance... Bill
Your observation of the bottom being unfinished explains why the top is
bowed. Uneven exposure to changes in humidity. Once you get it flat you
will want to finish both sides evenly.
As for straightening it, I have not found anything that works all the time.
I don't think spraying water will help. I would try scraping all the finish
off the top, then leave it out overnight on your lawn, convex side down, to
absorb some moisture. Bright and early next morning, lay it in the sun on a
bench or sawhorses with the concave side down, convex side up. You should
see some movement during the day. Watch it and flip it over if it gets near
to flat to even out the drying. It might take a few cycles to get where you
want to be.
Now after that fails, and I'm guessing it will but it's worth a shot and
won't hurt anything, you can rip down the glue joint on every strip. Let
the strips sit for a week to acclimate, then joint the edges to get them
square again. Then glue the piece backup and finish both sides. You will
end up with a top smaller than before in one direction, so hopefully the
table is designed with overhang and the difference won't be noticeable. You
could add another strip of Oak if you can find stock with matching color.
Lastly, you could just make a new top.
Without any comment on the merits of the methods suggested I would point
out that when wood absorbs moisture it causes the cells to swell. If the
absorption of moisture is uneven the side taking in the most moisture would
expand causing the stock to bow away from that side.
In other words the convex side would be the side with excessive moisture and
if you were to try the "laying it on the lawn method" one would want the
concave side down so it has a chance to equalize (take in more moisture) and
have it's cells swell forcing the stock, hopefully, flat again.
I would opine that if one wanted to flatten out such a board/panel, putting
it somewhere that has good ventilation and stable humidity then stickering
for good circulation and waiting to see if it flattens naturally would be
better then force feeding it and not knowing what it will do when it again
You're right of course, up or down it's a shot in the dark.
Again your correct but actually I took into consideration that it was an
existing piece with good circulation and don't hold much hope it will cure
itself either. However it's the least possible destructive chicken soup
method and I was kind of counting on the possibility that the poster had
maybe taken the piece apart at some earlier time and left the top laying
around, say in the cellar on the concrete.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.