Urethane vs Varnish

[MarcD]

Sorry for the beginner question, but my hardware store insists that Marine Spar Urethane is the same as Spar Varnish. Are they interchangeable terms? I am preserving an old Edwin Monk kit runabout, and would prefer the "fixablity" of varnish in the future on the mahogany deck. Thanks for any advice.

[brian eiland]

My experience long ago with 'urethane varnish', specifically clear Algrip was far less than satisfactory. Primarily it did not bond to the wood as good as diluted first coats of regular varnish, and seemed to be less flexible. When struck by some object, a whole patch area would lift from the wood substrate.

I later tried a varnish I was much happier with by the name of Bristol Fashion, which was a mixture of tradition varnish with some urethane mixed in for durability. This was exception I thought. But I don't think they manufacture it any more. This was 30 some years go, just as Algrip was coming on the market.

[MarcD]

Thanks Brian. I really want to be able to fix any minor "incidents" with more ease in the future. That's why I want to use varnish, vs. polyurethanes. My problem is that in a small town, there are not a lot of choices, and I am just not buying that the because it has the word "urethane" doesn't mean that it has the negative qualities of polyurethane products, even though it is "marine urethane". I like the quality of varnish that allows for an easier fix of a blemish.

Since most of this boat is the same as it was in 1957 when it was built, I am trying real hard to be as authentic as possible in this preservation, and at the same time trying to maintain domestic bliss by not spending more time working on the boat than other "high priority" house projects.

By the way, I am failing miserably in that aforementioned altruistic goal. That's OK. It turns out that working on this old wooden boat has done more for my sanity and peace of mind than I ever could have imagined. But I am probably not alone in that sentiment.

[Poida]

Marc

I was doing some marketing for a timber coatings company that had developed an exterior finish for timber.

We had it tested at the Materials Testing Laboratory where they use a weatherometer. This subjects the finish to humidity, dry heat, water sprays and cold over a period that is supposed to similate about ten years of weathering.

We tested the coating against about ten other coatings and the thing that surprised me was all the coatings that were labelled marine finishes came out on the bottom and in fact blistered quite badly.

It seemed to me that one should not take much notice as to what is written on the can.

[MarcD]

Thanks, Poida. Interesting scientific results, and probably will generate some discussion! What appeals to me about using true varnish is that scratches or dings can be lightly sanded out and touched up. But, as I said in the first post, this is all new to me, so most of my marine varnish vs. polyurethane knowledge has been gained by reading old posts here and researching on the internet.

[artemis]

I've been working on boats (my own and other people's) since the 1970s. Early on I used something called Doc Callahan's "Chilled Varnish" and always had good results (spendy at $ 15/quart back then). In August of 1975 I had "wooded down" the mahogany cabin on a 30' pleasure boat and was ready to start applying varnish. But no one in Seattle, Washington had any (run on varnish due to nice varnishing weather) and I didn't want to leave the cabin that way for the week minimum until some store got an order in. So I went to a lumber yard a few blocks down the road from Doc Freeman's to see if I couldn't come up with something. Came across a product called McClusky's "Man-o-War" spar varnish. Asked the guy at the sales counter if he would open a small can and let me feel/smell it. Felt good; smelled like the real stuff (and a lot cheaper at $ 3/quart back then). I've used it ever since with consistently good results. As long as it is applied as one should apply varnish it lasts well. One "renewal" coat a year is generally OK (lots of heatr/direct sun may require two). Most lumber yards in North America carry it and the price is reasonable. Have never tried the UV version - the regular has worked just fine.

Ron Fossum

[longliner45]

whats the point, Im going to use polyurethane because ,,,,,you re do every few years anyway

[MarcD]

Thanks for the feedback. Now that you brought it up, I remember using man o' war spar varnish on a wood project many years ago, and it was almost bulletproof. So, I have a plan. (Always good for a laugh)

I will invest in a good custom canvas cover, practice careful trailering, and have already arranged indoor storage for "my other wife" over the lovely Wisconsin winters. By doing this, I hope to put more time between the strip-to-the-wood-and-start-it-all-over-again process. But that's part of the "wooden boats need more maintenance" that I know I've gotten myself into--willingly and enthusiastically.

I just think that if there is an accidental ding here or there, true varnish would outperform polyurethane in terms of being able to patch over it.

Meanwhile, I am down to bare wood on the deck, and am about to give it a little naptha spongebath to see what I missed. Then, it's on to the start of the staining.

Again, thanks for all the advice. You don't know how much it is appreciated.

[longliner45]

polyuethane is harder than varnishand in most cases more durable,,,time are a changing, the key for boats is UV portection,,just puchased 1 gallon of VARATHANE brand spar urathane for47 bucks ,outdoor with UV and weather protection oilbased clear gloss,in 3 to 5 years I will reapplie,longliner