Waterlox vs. spar varnish?

[Ken Cohen]

I need to choose a finish for a mahogany/okoume tack trunk. It will live in an unheated barn environment, suggesting priorities are (1) hardness/durability, (2) ability to handle seasonal temperature changes, (3) dampness (+ very occasional wetness). Sunlight not an issue.

I have no experience with either finish. Based on prior posts, Waterlox seems the preferred choice (for its hardness), but I am concerned how it will handle the outdoor-like temperature variation.

I'd appreciate any advice.

Thanks.

Ken

[Jim Becker]

The waterlox is just fine. Spar varnish is a very soft (long oil) product and was designed to be very flexible...as spars on boats tend to bend a lot. Besides "good" spar varnish (not the 'borg stuff) will cost you an arm an a leg, too. That said, the finish on the tack trunk (http://www.sawmillcreek.org/showthread.php?t=97948&highlight=Tack) I recently built is shellac and Target Coatings USL water borne. I have no aprehension about it handling the variable "climate" at the barn nor the abuse that it takes from folks "accidentally" putting things on it that they shouldn't...

[Ken Cohen]

Thanks for your advice.

Good to know that Waterlox will work. I'm not much of a finishing pro -- and would welcome any thoughts on your lacquer approach (I don't have a sprayer, however) vs, Waterlox.

Most importantly, I checked out your tack design post. Really nice design and execution. Like you, I tried to reduce weight with using post and rail frame (using sliding dovetails) and 3/8 and 1/2 plywood for the panels. I'll post when done.

Thanks again.

[Jim Becker]

If you're going to hand apply, Waterlox is a wonderful finish to use.

On the construction of our trunk, that's fax frame and panel...it's a 1/2" cherry plywood box with 1/4" solid cherry applied to simulate rails and stiles. :) The 1/4" stock was mitered on the router table with a 45º chamfer cutter so the corner pieces came together like a post, hiding the butt joints on the plywood. Those were glued and nailed with 1 1/4" brads and then clamped until the glue dried. The internals were built using pocket screws and provide a lot of support for the plywood box. It's solid!

[Prashun Patel]

Jim's the expert, and I've used Waterlox to great effect on a bench (interior). But it IS hard, so I wonder how it will handle the expansion and contraction of the wood that will likely happen with temp/humidity fluctuations.

I used Spar varnish on an exterior bench that got rain, sun and all the elements. It lasted about 3 years but ultimately split in places.