Plywood sealants and wood glues and PVA

[bordercollie]

Hi

I have some birch ply that I intend to construct my baseboards and frames. I have seen it suggested that plywood should be protected in some way to reduce warping from moisture. I was wondering if sealing with paint, varnish or some other way would effect how PVA adheres when ballasting and  joining of the plywood.

Regards

[Nearholmer]

If the baseboard design and construction are good, plywood baseboards will resist warping even if they take-up a bit of moisture from the air (I left a set of not-sealed boards in an un-heated and freely ventilated shed for c20 years, and they remained perfectly square), but it is better to seal, and I’ve found that both  polyurethane varnish or primer/undercoat do a good job. I think some people use very dilute PVA.

The time to seal is after assembly of each board, before adding track and scenery, and its worth paying particular attention to the exposed edges of cut plywood.
 

PVA will hold ballast to either of the above finishes.

 

If the boards are going to live in the house, all this sealing is a bit OTT from a moisture-resistance viewpoint, but it does at least keep things up to ‘furniture standard’, preventing grubby marks on the timber from handling.

 

 

Edited October 22, 2022 by Nearholmer