"Phil" wrote in message roups.com...
Precisely why all sides need to be sealed - especially with cheap
kiln-dried pine, you will get differential drying causing warping.
That's why the manufacturer's tell you to do it.

They are wrong. If sealed all round the wood will still continue to
dry out but slightly more slowly, so it's a waste of time and primer.
You should never seal the unseen parts of trad joinery.

cheers

Jacob