Application of Varnish on Two Sides

[Kovar]

I'm refinishing the mahogany on my 1988 SPORT 13. I've sanded the original parts to bare wood. I've applied the [first of eight] thinned coat of Epifanes clear gloss.

Q1 : should I apply all eight coats on one side then flip?

Q2: or should I apply varnish to both sides with each coat?

Fig. 1. Wooden parts to be varnished.

wood.jpg (38.03 KiB) Viewed 609 times

[jimh]

There is another option: apply one coat to one side, let that coat thoroughly dry, apply one coat to the other side, let that coat thoroughly dry, sand both sides, remove dust, repeat seven more times.

[Palomino]

I was always told not to [apply] varnish [to] both sides [of teak wood parts used on Boston Whaler boats because that] would be encapsulating the wood, and if [the varnish were] ever nicked moisture [would] get into [the wood] and cause [the varnish] to blister.

I've varnished a fair amount of teak on Boston Whaler boats.

I use West System epoxy and then apply three coats of Epifanes. I have never had a problem [with moisture getting into the wood].

I don't leave the wood exposed, I always wash the boat down and put on a cover if the boat will be sitting for more than three days.

[jimh]

I was always told not to [apply] varnish to both sides...

Who gave you this advice?

If you leave one side of the wood unfinished, certainly moisture will be able to get into the wood.

[Palomino]

Yes.

But think of it differently, if you do not varnish the backside moisture has a way of evaporating.

It's counterintuitive, but it also makes sense. I think it has to do with maintenance and that there will be less if you leave the back unfinished so moisture can evaporate vs. being encapsulated in the wood when there is a blemish/knick in the varnish.

I have done it both ways. On My 1983 Montauk when I did a full restoration the bow teak hatch top was varnished but the back was not. That was a paid job by a highly reputable person in the sailing and wooden boat world, and when I asked about it he said something to that effect.
The rest I had already done myself and I stripped everything, 3 coats of West epoxy & then 4 of Epifanes.

My finish was a tad darker because of the epoxy. Both held up equally as well, only mine did get water at the bimini connections and would have needed to be refinished at some point.

So, both ways seem to have their places. Maybe it's only with something like an anchor hatch that gets varnished on the top but not the back.