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Polycarbonate Urethane vs Pettit ZSpar Varnish

Discussion in 'Wood and Canvas' started by pipeandscarf, Sep 27, 2016.

  1. pipeandscarf

    pipeandscarf Curious about Wooden Canoes


    I'm working on my Chestnut Prospector Fawn from the 70s. I'm still sanding and scraping off the old varnish but I've been researching varnishes (likely/possibly spray on at a local shop). I'm applying to clean, freshly sanded cedar.

    Has anyone used either of these two products? I don't know much about urethane or z-spar? I'm looking for a durable, long lasting, UV protection finish, I'd rather not reapply each year.

    EMTECH EM9300 WB Exterior Polycarbonate Urethane


    Pettit Z-Spar Flagship Varnish

    Also, should I give a coat of urethane/varnish to the out side of the planks? Do the planks under the canvas get any special treatment before canvassing?

    Thanks in advance for your advice/stories,

    Last edited: Sep 27, 2016
  2. David Satter

    David Satter LOVES Wooden Canoes

    Dave, your going to get all sorts of responses. Don't over think it a good traditional spar varnish will be fine. I've used everything and I always go back to Pettit Z spar 1015 captains varnish, looks better than the more expensive ones. I brush it on by hand. thinning the first coat or two. doesn't take that long , sand in between coats. Never had a problem with it. should last for years with normal use. If your after satin low gloss finish the best look is Epifanes woodfinish matte. good luck. Dave cranford canoe,sagi canoe 015.jpg
  3. Dave Osborn

    Dave Osborn LIFE MEMBER

    I agree with Dave Satter.....Pettit, Interlux, Epifanes, and other varnishes designated as marine varnish have been successfully coating watercraft for a log, long, time.
    Unless you have experience with the MTECH in other marine applications, I would say don't try it.. IF it didn't work, it may be difficult to remedy or remove.
    I say stick with what has worked.....
  4. Jerry Fruetel

    Jerry Fruetel A well built wooden canoe is a work of art

    Yes, you should seal coat the exterior hull before canvassing. Traditionally, the sealcoat was 'boiled' linseed oil thinned with mineral spirits or turpentine. But, because linseed oil is a mildew magnet, a better sealcoat choice is a 50/50 blend of marine varnish and mineral spirits.
  5. Abenakirgn

    Abenakirgn Curious about Wooden Canoes

    I agree with both Capt's varnish and using same under the canvasing. I usually use 4 to 5 coats on the inside of the canoe and it will last a very long time. I have found if you want the satin finish, use the gloss for the first few coats and finish with the satin. In my opinion the gloss is more durable.
  6. OP

    pipeandscarf Curious about Wooden Canoes

    wow, thanks for all the responses. Much appreciated, sounds like varnish is the way to go. I'll post photos once it's done.
  7. Howie

    Howie Wooden Canoe Maniac

    For what it's worth I use Minwax's Helmsman Spar Varnish. Works fine for me. I had an 'extra' canoe unside-down under my deck for about 25 years. When I finally decided to do something with it I found the interior varnish to be in perfect shape. This is after going through the extreme weather we get in upstate NY. I do think Epifanes can give a nicer appearance, but it's extremely expensive.
  8. Paul Scheuer

    Paul Scheuer LOVES Wooden Canoes

    This is a timely topic for me. I'll be canvasing in the Spring, and plan to do all of the final prep this Winter.

    Most of the picture I've seen of canvasing projects show bare wood on the outside of planking, almost convincing me to not apply anything. The original construction of my Morris has no coating outside. I'd be interested in comments regarding the merits of no coating. At this point I plan to apply thinned spar varnish.

    On the Urethane vs Spar Varnish, I have found that urethane is very difficult to remove.

    Also - some of the pics I've seen show rough rasp marks on the planking where final fairing was done. How smooth is smooth ehough ?
  9. Howie

    Howie Wooden Canoe Maniac

    Don't worry too much about how the outside of the canoe looks - the canvas will cover all valleys and divots unless they are very large. If however the outside was fiberglassed then you need to pay special attention to get rid (by sanding or scraping) all the tall spots because these will be visible on he canvas. And pay special attention to the stem areas. You need enough wood there to hold the tacks or staples used to secure the canvas flaps. And the flare of the wood at the stems ought to come to no less than 3/8" and little more than 3/8" where the stem bands attach. If necessary use ring nails & glue to hold a thin strip of wood over this area and shave it down to 3/8" width to make a nice sharp transition from sides to stem.
  10. Jerry Fruetel

    Jerry Fruetel A well built wooden canoe is a work of art

    I can think of no good reason to leave the wood bare. When paddling, water will inevitably get into the canoe from rain, entering/exiting, splashing etc. Some of that water will seep between the planking seams onto the hull exterior next to the canvas. A seal coat will minimize the amount of water soaking into the hull exterior and potentially causing planks to expand and crack. A seal coat should also help preserve the wood over the decades. You may be lucky and avoid problems with an uncoated hull, but "an ounce of prevention...." applies here.
  11. Abenakirgn

    Abenakirgn Curious about Wooden Canoes

    While I agree with Howie, I saw an older canoe at the Common Ground Fair this last weekend that had one of the nicest planking and fairing jobs I have ever seen. It had been stripped of its old canvas and the planking was as fair and unblemished as a fine piece of furniture. I'm sure the old formula of wood preservative and linseed oil worked fine in conjunction with the old fillers that contained white lead, but now, I believe, a coating of thinned varnish is a safer bet than leaving the wood untreated or coated with boiled linseed oil.
  12. Cliff Ober

    Cliff Ober Enthusiastic about Wooden Canoes

    The Minwax Helmsman product is urethane, not a traditional resin based varnish. I like it a lot for interior projects when I want the golden amber tone it imparts. I never, ever use it for projects that are subject to sun exposure. I've had it fail too many times (clouding and peeling) as it has almost no UV inhibitor. In my opinion (and many other's) its marketing is badly flawed in claiming protection from the sun. I'll accept the extra cost of the high priced marine finishes for anything that will see repeated or prolonged sun exposure. My time is worth more than the few dollars savings on a cheap product.
  13. Howie

    Howie Wooden Canoe Maniac

    Interesting... Thanks! Though... do any of us keep our canoes 'face up' for any length of time? I store mine upside down on saw horses with a tarp covering them - they see the sun rarely.
    At least for me Epifanes is an expensive item. Can anyone recommend an easily obtained 'cheap' varnish/urethane that is better than Helmsman that has UV protection?
  14. MGC

    MGC Scrapmaker

    I line up with Epifanes on my boats but I consider Z-Spar to be a good alternative...It's super easy to use, quite bright if that makes any sense, very clear.
    I have it on one boat and it looks great.
    I used Helmsman once many many years was all that I could find at the did cloud in a few places. I have since stripped it. Urethane is a product that I use on indoor furniture.
    If you time it right you can buy the Epifanes on sale..that will save a few dollars. One can will do a 16 foot boat with some left over. Wit Z-Spar you can do an 18 foot boat and have some goes on thinner than Epifanes if that makes any sense.
    Last edited: Sep 29, 2016
  15. OP

    pipeandscarf Curious about Wooden Canoes

    I think I'm going to give the outside a coat of z-spar or what ever brand of spar varnish I settle on. The planking on the Chestnut I'm working on is in rough shape after years of neglect. I'd like to avoid that in the future.

    From what someone told me it is likely my 70s era Chestnut had urethane. I didn't connect the dot, so to speak, until this thread. I've been struggling to remove the old finish. spar varnish makes a lot of sense. Lots to learn:)
  16. Gary Willoughby

    Gary Willoughby Boat Builder

    Interlux $17 a quart
  17. Dan Lindberg

    Dan Lindberg Ex Wood Hoarder

    Thanks for posting Gary,

    Interlux regular is my favorite, didn't know it was still offered with all the fancier stuff now days.
    It goes on nice and predictable and smells great.
    Did I remember to say it smells great? Combined with the smell of white cedar, Hmmmmmmmmmmm.

    I've tried some of the others, but don't like them, they are clearer and turn to pudding if left in the can too long.


    btw, I've used Helmsman, don't like it, too thin

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