Durable Clear Finish for Deck Furniture

Suggestions for a sunlight-tolerant finish for outdoor furniture. October 19, 2014

Question (WOODWEB Member) :
I am posing this question in hopes of confirming if there are any UV resistant clears out there that somebody can recommend for outdoor deck furnishing. I need to add that I do not want any water white products but want the amber look of good quality spar varnish.

I should also note that this product will not be subjected to long term overhead direct sunlight but under a roofed deck most of the time so though these pieces will not get hammered directly they will nevertheless be exposed to UV's. I am looking for somebody who has found a product that they have used and has been in the field for at least two years or more and can assure me that the stuff is holding up. No need to recommend spar varnishes as I was in the big yacht finishing business for way too many years and need to see if there is something out there that handles easier with faster recoat and hopefully builds to 20 mils or more. Not looking for promotional info from suppliers as my mind sort of filters that stuff out after years in the business. Iím using Kremlin pumps and guns with a backdraft booth.

Forum Responses
(Finishing Forum)
From contributor C:
All UV clears have an additive that make them so. It doesn't last forever so make sure you use a quality exterior product - MLC isn't one of them.

From contributor R:
I know you don't want to hear it, but I make Adirondack chairs (I also come to this from marine brightwork) and after many years of trial and error, I have settled on 100% tung oil/100% phenolic resin marine varnish with one-two coats of CPES under the varnish. I'm getting three-four years of life out of this finish on my chairs (outdoors 24/7/365) and then re-coat with mild prep and varnish.

From the original questioner:
Thanks for the advice RRM. So we both come from the same background so you certainly understand why I am looking for a faster easer solution. When I was paid by the hour on yachts this was not a problem but trying to manufacture and control labor costs is a whole new game for me. Iíve never used CPS as a foundation but I am all ears. I have done a bit of experimenting and used acrylic sealers and similar then started the varnish build up but we both know this is slow and tough to justify for production work. But just maybe this is unfortunately the truth.

What varnish are you using and spraying? Three to four years is excellent results so it would appear you have a formula that works. I am not sure about your application schedule or steps needed with your products so I can estimate the hours necessary. Can you share any of this? Are you scuffing up the CPS or can you get a secondary bond without this?

RE: the product Euro X. I may be wrong but my understanding is that this product is water white or near so. I could tint of course but that adds another control element that must be watched closely for uniformity and frankly I have heard from somebody I know in the business who has used MLC's clears that they will haze and yellow out a bit in harsh UV exposure. Neither is a problem I want to deal with.

From contributor R:
I'm not sure what your production goals are; mine are not demanding, so I brush the varnish. I have friends that have a furniture mfg and dip both parts and whole pieces. The varnish I use is sold only in 55gal. quantities. As I mentioned, it is a tung oil, phenolic resin varnish sold by US Polymers (wholesale only) and isn't cheap. Actually it is an old formula originally developed for sailing ships and other marine applications.

Regarding the CPES, clear penetrating epoxy sealer, it penetrates fairly deep into the wood and hardens fairly quickly. We used it extensively on brightwork repairs and rebuilt nearly an entire transom using CPES and "sawdust". I love the stuff. After the final coat just hit with 150 and you're reading to topcoat. I always dilute the varnish 10-20% for application. I recently did a large walnut trestle table with three coats of varnish (first coat cut 50%) and rubbed it out through 1200 - gorgeous and bulletproof. It's the only thing I brush since I'm addicted to the odor. Shooting varnish is a nightmare; sticky mess forever.