On 02/05/2021 09:36, The Natural Philosopher wrote:
On 02/05/2021 08:22, wrote:


The cupboard I have made and only noticed the box once I have glued
and screwed it all together!!Â* It is about 5mm out at the centre so
can't see how I didn't notice it!

It will have a back once I can get the bow out of it.Â* As suggested
above, maybe if I can clamp it somehow from the front and get the bow
out, maybe gluing and pinning the back onto it (12mm ply) will fix
it? Or will it break the glue and return once the clamps are
removed?

What I would do is roughly as follows.
Cut some struts to make a V shape going from the opposite corners to the
center of the bowed panel,. then use a car jack andÂ*Â* a bit of strut to
push the bow out long enough to fit the struts - a pair should lock into
place without fixing.

spray water all over the bent panel and leave it a day or so. Fit the
square back with the struts in place.

I was going to suggest something very similar. Another thing you could
consider is to temporarily close off the front and back e.g. by taping
or pinning polyethylene over it, then filling the inside with steam from
a wallpaper stripper for perhaps an hour. That adds heat as well as
damp. Ideally you would steam the outside at the same time. If you get
it reasonably straight when internally braced, you could put wood glue
all over the outside surface of the dodgy panel and fix it to the "good"
box with those furniture bolts, waiting until the glue has dried
properly before removing the internal braces.