Alternatives for Spar Varnish on Mahogany
Spar varnish's softness and flexibility matches well with mahogany's softness, but dry times are an issue. Here, finishers discuss other choices. April 30, 2006
We do mahogany countertops occasionally, 6-8 a year usually with a dark stain (MLC ws2). I have tried: conversion varnish, catalyzed vinyl, poly, and WB poly, but spar varnish seems to be the best as far as longevity. It seems to age the nicest whereas the other products are too hard and brittle over the softer mahogany and damage more easily. The problem is the dry times that come with spar varnish - is there a better option? The grain needs to be filled, and I like the depth created by filling the grain with the finish. Would using de-waxed shellac be an option as a sealer/filler under a spar varnish?
Half of the tops are subjected to water, and the others are elsewhere in the kitchen.
From contributor A:
Have you tried an Italian 2K poly like ICA? It's the closest to spar varnish I've tried. It has tremendous build and holdout. Quick dry times and no recoat windows.
From contributor B:
I'm also a fan of ICA's stuff. Our ICA 2K poly does indicate a recoat window, but I can't remember the specs offhand. It sounds like you are looking for something a little softer than CV and 2K poly, right? Being a long-oil varnish, it doesn't harden nearly as hard as the other stuff. If you don't mind the tremendous loss in the scratch and chemical resistance department, spar varnish is about all I'd recommend. You may consider nitrocellulose lacquer, but it's much less durable than even spar - just easier and quicker, and softer than CV. However, I would be trying to wean the customers off of mahogany and onto Iroko. It looks just like mahogany to the untrained eye and it is much harder. It makes a nice top and a good candidate for 2K poly, which as far as I'm concerned is tops in the surface finish department.
From contributor C:
I agree with 2pk urethane there are many brands on the market. M.L.Campbells version is ICA re-packaged. Save your money and go direct - also ILva, Sayerlack and Sayerwood have 2 pks. You will get much better chemical resistant properties along with needed flexibility.
From contributor D:
The shellac isn't a good choice for grain filling. Solids are too low and it would take way too many coats. One WB poly I've used that seems to have a lot of flexibility is Van Aqua 480. I've taken dried sheets of finish and bent them in half without any cracking. It is meant to be sprayed thickly and it dries relatively fast, being a waterbased finish. It is very tough, once cured, though not as much as a two-part poly I'm sure. I've used it on lots of mahogany.
From the original questioner:
I think the 2k urethane is going to be too hard. I would welcome the switch to Iroko, but my designer likes the way the mahogany dents and ages with client abuse and cleaning (after a year in the home the counters look almost antique). I checked the Van Technologies site and think some of the Aqua line (Van-ex 680 appears to be a spar equivalent) may fit my requirements. Thanks all for the responses.