Missing In Action update - heading down the home stretch..

Discussion in 'Wooden Boat Building and Restoration' started by missinginaction, Jul 8, 2009.

  1. missinginaction
    Joined: Aug 2007
    Posts: 1,054
    Likes: 225, Points: 63, Legacy Rep: 512
    Location: New York

    missinginaction Senior Member

    It's been a while since I posted regarding the restoration of my 1973 Silverton Sedan.

    All below the sole work is completed and all new engine stringers and mounts are installed. The foredeck is installed and I'm working my way down the side decks to the transom. The cabin parts are prefabed to the extent they can be and the deckhouse will be going up over the next few weeks. Most of the interior joinery has been installed.

    I'll post some photos when I get the time to take a few. I bring the camera sometimes but get so caught up in my work that I forget to take the pictures.

    Before I install my decks I have one question for some of you epoxy experts out there. I understand how to sheath the exterior with a couple of layers of 4 oz. or one layer of 8 oz. cloth. I'm wondering about the undersides of the decks however.

    I installed the foredeck last summer and simply coated the interior (bottomside) of the deck with three coats of epoxy. I layered the resin on over a thirty six hour period so that I'd get a good chemical bond between the coats. It came out beautiful, the golden color of the coated douglas fir looks great with the dark mahagany support beams. Since the interior of the v-berth gets no direct sunlight I decided that leaving the wood bright was best and I'm glad I did. That wood has been installed for almost a year and there are no signs of any checking. I'm wondering about the bottom of my side decks and the deck in the transom area. My inclination is to just coat the bottoms as I did in the v-berth and and leave it at that. I'm wondering weather those decks will be more likely to deteriorate over time though as in some areas the deck is "outside" the cabin and thus more exposed to the weather.

    To sheath those deck bottoms or not? That is the question. If I sheath them I'd just use a single layer of 4 oz since no one will ever see them let alone step on them.

    Thanks in advance for thoughts on this one and many thanks to you many prolific posters for sharing your knowledge of building techniques. I wonder if you realize how many people silently read these many posts and benefit from the knowledge that you take the time to share.


    Regards,

    MIA
     
  2. apex1

    apex1 Guest

    No, skimp on that. As long as there is no daylight, there is no deterioration by UV rays. But if there is daylight (must not be direct exposure to the sun) you should apply a UV protecting varnish (any). It´s not worth to varnish the bottom sides of the sidedecks though.
    Sheathing overhead is a real PITA and I assume you do´nt need the additional abrasion resistance until the junk flips over and you decide to leave it that way.
    Additional strength you will not gain in a noticeable amount with a single layer of 4 oz.
    And you have been right to make the layup in one go! Finally one who was listening to the advice.

    Regards
    Richard
     
  3. missinginaction
    Joined: Aug 2007
    Posts: 1,054
    Likes: 225, Points: 63, Legacy Rep: 512
    Location: New York

    missinginaction Senior Member

    This is a 25 foot boat Apex. The foredeck was built up in the shop from three sheets of douglas fir , I coated the inside (bottom) in the workshop, flipped the panels over and did the final assembly after it was all cured. Much better to let gravity work for you! I'll laminate the cabin top from two 1/2 inch sheets of Okume plywood. Prior to laminating the sheets together I'll coat the bottom of the lower sheet, flip it over and install it. Again I'll have a finished overhead without raising a roller or brush over my head.

    WIth regard to the sheathing issue, I wasn't worried about strength, my concern was with the epoxy coating failing after a number of years. Based on what you wrote the issue is UV degradation.

    Thank you for the reply,

    MIA
     
  4. apex1

    apex1 Guest

    Did not know the size of boat.
    Well, UV protection is your only probable issue here. (But a serious one). The past 4 decades have proven that a well applied and protected EP layup does´nt degrade by water ingress. Though EP is not completely impermeable. We routinely paint (or varnish) EVERY Ep surface, no matter visible or not! A deteriorating paint surface is a good indicator for possible problems, a "naked" Epoxy surface might hide.
    And I should have added, UV degradation starts when the coat is cured! We do´nt have (unfiltered) daylight in our larger production bays where some boats sit for a year with exposed EP surfaces.

    Regards
    Richard
     

  5. PAR
    Joined: Nov 2003
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    Likes: 485, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Hi MIA, good to see you back. Yes, a light sheathing is necessary on your fore deck. Yea, I know it sucks, but the Douglas fir will check in time and permit moisture to get inside the plywood. I'd use 6 ounce if you can.

    You can get UV damage from reflected light too, so if light is going to bounce around in there, then you need something. I'd recommend paint as the least maintenance product.
     
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