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.
--
Bill Pounds
http://www.billpounds.com/woodshop
"Putterer1" <[email protected]> wrote in message
news:[email protected]...
> 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
--
Bill Pounds
http://www.billpounds.com/woodshop
"Mike G" <[email protected]> wrote in message
news:[email protected]...
> 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.
Awe shucks. Go ahead and comment. I don't expect it to work either.
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.
True, however in my experience drying a surface in the sun has a more
dramatic affect than the opposing affect of laying the piece on the lawn.
Thus, leaving the piece overnight to absorb water in the convex side will
possibly only slightly increase the warp. However when placed out to dry I
have seen pieces move rather dramatically. No idea why.
>
> 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.
On the other hand, if one method makes it worse, just flip it and try the
other way. I guess the worst that could happen is the moisture would cause
the glue joints to fail. That might be a blessing since you won't need a
saw kerf to move to option 2.
>
> 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
> reaches equilibrium.
Since it is an existing piece, I assume with some age, it has been
experiencing good ventilation and stable humidity for some time. I don't
see that letting it sit around with stickers is going to change anything.
I think I was pretty clear that this was a long shot. But I don't think
there is anything to lose by trying it.
>
>
> --
> Mike G.
> [email protected]
> Heirloom Woods
> www.heirloom-woods.net
> "Pounds on Wood" <[email protected]> wrote in message
> news:[email protected]...
> > 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.
> >
> > --
> > Bill Pounds
> > http://www.billpounds.com/woodshop
> >
> >
> > "Putterer1" <[email protected]> wrote in message
> > news:[email protected]...
> > > 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
> >
> >
>
>
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
reaches equilibrium.
--
Mike G.
[email protected]
Heirloom Woods
www.heirloom-woods.net
"Pounds on Wood" <[email protected]> wrote in message
news:[email protected]...
> 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.
>
> --
> Bill Pounds
> http://www.billpounds.com/woodshop
>
>
> "Putterer1" <[email protected]> wrote in message
> news:[email protected]...
> > 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
>
>
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.
Take care
--
Mike G.
[email protected]
Heirloom Woods
www.heirloom-woods.net
"Pounds on Wood" <[email protected]> wrote in message
news:[email protected]...
>
>
> --
> Bill Pounds
> http://www.billpounds.com/woodshop
>
>
> "Mike G" <[email protected]> wrote in message
> news:[email protected]...
> > 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.
>
> Awe shucks. Go ahead and comment. I don't expect it to work either.
>
> 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.
>
> True, however in my experience drying a surface in the sun has a more
> dramatic affect than the opposing affect of laying the piece on the lawn.
> Thus, leaving the piece overnight to absorb water in the convex side will
> possibly only slightly increase the warp. However when placed out to dry
I
> have seen pieces move rather dramatically. No idea why.
>
> >
> > 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.
>
> On the other hand, if one method makes it worse, just flip it and try the
> other way. I guess the worst that could happen is the moisture would
cause
> the glue joints to fail. That might be a blessing since you won't need a
> saw kerf to move to option 2.
>
> >
> > 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
> > reaches equilibrium.
>
> Since it is an existing piece, I assume with some age, it has been
> experiencing good ventilation and stable humidity for some time. I don't
> see that letting it sit around with stickers is going to change anything.
>
> I think I was pretty clear that this was a long shot. But I don't think
> there is anything to lose by trying it.
>
> >
> >
> > --
> > Mike G.
> > [email protected]
> > Heirloom Woods
> > www.heirloom-woods.net
> > "Pounds on Wood" <[email protected]> wrote in message
> > news:[email protected]...
> > > 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.
> > >
> > > --
> > > Bill Pounds
> > > http://www.billpounds.com/woodshop
> > >
> > >
> > > "Putterer1" <[email protected]> wrote in message
> > > news:[email protected]...
> > > > 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
> > >
> > >
> >
> >
>
>