: I will be doing varnish coat #2 tonight. Is it better to wait longer than the
: minimum time to sand (24hr) between coats of varnish? I assume the longer
: it is left the harder it gets, therefore sands better?

Some varnishes do not need sanding between coats if you put the second coat on within a certain time period-- usualy a matter of hours. Best I can figure is that recoating while the underlying layer is still not completely hard allows the solvents in the second coat to partially disolve, or at least soften, the underlying varnish. Thus the additional layers fuse themselves together. But, if you let the varnish harden too much ( say a day or more) then you MUST sand in order to increase the surface area of the bond between the layers of varnish.

Best advice on recoating and sanding for any varnish is usually found on the can label, and it may vary from brand to brand.

Varnishes are "plastic" resins which are dissolved in solvents. If yo put on a thick coat of varnish it will take much loner to harden than if you put on two thin coats. As I understand it, this is because the solvents on the surface rapidly evaporate into the air, causing the varnish to "skin" over with a hardening coat of nearly solid resin. Trapped underneath that skin may be a soft, gelled, mix of solvents and resins which will stay soft until the solvents can somehow get past the surface layer of hardend resin (that skin) which traps them.

With very thin layers of varnish the skin itself is thin and there is little or nothing trapped under it. The extreme case of a thick layer of varnish can be found inside the can a day or two after you use some. You'll see the liquid sealed over by a skin on the surface of the varnish inside the can.

PGJ