Stupid Newb fairing question

Discussion in 'Boatbuilding' started by OrcaSea, Jan 2, 2015.

  1. OrcaSea
    Joined: Oct 2014
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    OrcaSea Senior Member

    I am getting to a point on my boat where I am ready to start addressing the exterior of my 16' wood/glass-skinned restoration.

    I am stripping off the old glass and intend on re-glassing the entire exterior. My thoughts regarding process, thus far, are to:

    • Plug or repair old fastener/deck fitting holes
    • Repair scrapes/gouges/repairs in the ply
    • Fair the above accordingly
    • Apply thinnned, non-wax laminating coat of resin to bind to the wood (would like to epoxy, but it's not in my budget).
    • Apply glass/resin
    • Fill and long board sand
    • Primer/sand/fill/primer/sand ad nauseum...

    In the blogosphere/YouTube-sphere I am getting some conflicting messages about the processes above. Mainly, as to when to concern oneself with much of the fairing. Some seem to suggest that all the fairing should be done before the glass is applied, which seems to be more work than you might need to do, as the glass/resin will address small imperfections.

    I realize that, prior to painting, I will need to do some weave fill and fairing to ensure a smooth surface, I guess I would like some feedback as to what extent I need to address the ply decking before I actually apply the glass.

    Thoughts & feedback will be appreciated!

    Curtis
     
  2. gdavis
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    gdavis Junior Member

    Hello OrcaSea,you will need to fill any of the large holes and gaps before you start to glass. If you don't the resin will drain out of the cloth and leave dry spots. Screw holes, hardware holes, splits and cracks can be filled with a good grade of bondo, 3m makes some good stuff. Fill anything that looks like the resin can flow into or thru. Then glass, fill the weave, then fair. Poly Fair is pretty good for fairing, almost easy to sand. There are fairing putties made by Awlgrip or Alexseal but these aren't cheap and the hull would need to be primed first, more money! If you apply the poly fair when the last coat of resin is still a bit tacky you'll get the best bond. Then small imperfections can be filled with the bondo. Also, after applying the first coat to the bare wood look for dry spots and put more resin on them until the surface all looks the same. Good luck, have fun.....................g
     
  3. PAR
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    PAR Yacht Designer/Builder

    If you apply fabric to a fair surface, you'll have less work to do after sheathing is on. Anytime you skin a boat, you have to fair twice. It's cheaper and easier to get the bulk of the fairing done before hand, plus has the added benefit of bulking up the surface to help with waterproofing. If you're pretty good about it, after filling the weave, you'll be mostly smoothing, not fairing.
     
  4. gdavis
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    gdavis Junior Member

    ah yes but, since he is not using epoxy and the deck is plywood any filler used for fairing that isn't epoxy based will not bond very well especially in thin fairing coats. You could do a sealing coat of resin first and then fair but that would be a sticky mess to sand.........over n out................g
     
  5. OrcaSea
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    OrcaSea Senior Member

    Thanks, guys, I truly appreciate your taking your time to respond.

    So, I think I am good to go, information wise: Plug, repair, smooth surface transitions, then glass and fair with a low-density, poly-friendly fairing compound to fine-tune.

    I have a qt. of Duraglass putty for use before skinning, but everything I am reading about Duraglass says it is very temp sensitive and really likes it about 70*. With the current temps, even with my kero heater going full blast I think I'm a good 15-degrees below that, so I might look into alternatives if I want to get some work done before spring.

    I was looking at Fibre Glast's 4116 lightweight poly filler for on-top, but thanks for the tip, George, it looks like Poly Fair is, essentially, the same thing at half the price.

    Would it be correct to assume that a dedicated lightweight fairing compound would be easier to sand than resin with microballoons, or are they, essentially, the same thing?

    Thanks, again, I always appreciate the input :)
     
  6. gdavis
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    gdavis Junior Member

    orca, the temp in your shop isn't much of a concern, the duraglass putty is kicked off with a bpo hardener, this is a chemical reaction so at worst it may just take a bit longer. Hit with a heat gun if your still worried. The duraglass is going to sand harder than the surrounding wood so you'll have to watch that. Try putting it in flush this will eliminate the sanding, it will be buried under the glass. As for the fairing putty phenolic microspheres are what to add to the resin. You might save a few bucks by buying 6oz of it and making your own, you already have the resin. Try a test batch and see how it is. And by the way orca your question is not stupid. None of us knew this stuff before we learned it and asking questions is a good way to learn. Know what I mean? What kind of boat are you fixing up? I'm just curious. Hope this info helps ya some........peace out....g
     
  7. OrcaSea
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    OrcaSea Senior Member

    Hey George,

    Thanks, again and thank you for the encouragement :) Depending on the forum one is in there, evidently, are stupid newb questions, but I have been fortunate and some folks like yourself, PAR and others have been very kind, tolerant & helpful here.

    The Readers Digest Short Story is that I found this boat on CL for $225, and that included a trailer and running 2-hp Honda kicker, soooo...basically, it was a way for this guy to get rid of the boat without having to chop it up and haul it off himself. It is a 15'6" 'Crescent', a plan-built boat published by 'Boat Builder's Handbook' (I believe it was a magazine) and looks to be late 50's/early 60's (I cannot find any copyright info, but I have found a copy of the article and plans).

    Though I have wanted to sail for a very long time, this is the first boat I have ever owned (other than a triple sea kayak). I'll include some pics below, but, while the essential frame and ply skin is in good shape, the chain plates had leaked, the forestay fitting leaked and cracks around the bow FG leaked and rotted the ends of the deck and hull ply as well as the upper park of the knee and entire cutwater. Also, the drain holes in the ribs had extensive rot and the boat had been allowed to bounce on the trailer and several of the ribs had separated from the lower skin.

    I had/have my work cut out for me, but it's been fun, has kept me off the streets and has gotten me back in touch with hand woodworking and - being as old as I am - it is a symbolic statement that, by gawd, this old boat's gonna get back in the water ;)

    Some before & after shots, thus far:
    [​IMG]
    When I bought it.

    [​IMG]
    Rot from leaking chain plate - everything had to be replaced.

    [​IMG]
    After repair to ply and replacement of rib and upper chain plate, less lower chain plate.

    [​IMG]
    Lower chain plate before install.

    [​IMG]
    More Ughknown...

    [​IMG]
    Ugh...

    [​IMG]
    After some new oak. That was a bear as I have only hand tools and nothing to cut compound angles accurately.

    [​IMG]
    With some new skin and oak cutwater. Looking a lot better!

    Most recently I have fabbed a new hatch for the forward floatation compartment and am starting to primer the interior.
    [​IMG]

    I made a dolly so I can roll it in and out of the garage. The cradles are removable for when I flip it. It has had the upper FG stripped as well as the fiber-glassed, ugly-assed hardboard combing. I can't afford exotics for the combing, but I am thinking Alaskan Cedar or clear Fir, epoxied and varnished, with a laminated buildup for the semicircular section at the front of the cockpit. It also needs a rub rail, which PAR has been kind enough to advise on.
    [​IMG]

    [​IMG]
     
  8. LP
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    LP Flying Boatman

    Nice bit of work OrcaSea!
     
  9. gdavis
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    gdavis Junior Member

    Holy smokes orca you dove right in there didn't you! Looks real good. Have you done this sort of work before? Maybe you missed your calling. After all these years I still enjoy the work and most of the time I can say I love my job. It's kinda fun, don't you think? It used to annoy one of my bosses when I would tell him i was having fun and getting paid for it. Oh well..Any how think how satisfying it will be when you sail her for the first time after all the fine work you've put in to bring her back. Arrrrr, she'll be a fine vessel arrrrrrr..................................peace....g
     
    Last edited: Jan 4, 2015
  10. ondarvr
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    ondarvr Senior Member

    It's best to not thin the resin, it degrades it significantly. Buy some infusion resin (VE if possible) and use that, it is formulated for a very low viscosity to begin with. Also don't use just cloth as a finish, it will peel of easily, CSM needs to be used as the first layer under it.

    Epoxy wouldn't cost much more, if any.
     
  11. OrcaSea
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    OrcaSea Senior Member

    Thanks, guys, for the kind words :)

    George, I built tail sections for 747's and 777's for fifteen years, as well as having built models and such all my life, so I have some aptitude and enjoy the challenges of mechanical problem solving. Thank goodness for the Internet and YouTube, as well as forums like this where people are willing to freely share their knowledge! Not so certain I could have pulled this off as well in the pre-Internet age without an on-site mentor.

    It's good this is just a little day sailer, as well, and I don't have to worry about imperfect technique quite as much as a blue water boat that might actually see some serious forces. Still, I have tried to error on the side of over-engineering much of what I have done just to make up for any mistakes I might have made. It's been fun and I have enjoyed it (except for squeezing into spaces the size of underneath a coffee table - which I had hoped were over with my Boeing days!). I will have so much blood, sweat & tears in this little boat by time it's done the idea of eventually trading up to something I can weekend in will be difficult (though living on Puget Sound, it will always be tempting!).

    Ondarvr, thanks for the tips! I have read that poly resin can be thinnd up to 10%, and I have fiberglassite resin, which is pretty low viscosity to begin with, but I will look into some infusion resin, as you have advised. I am a little concerned about proper adhesion, as when I stripped the old FG off the deck I was a little shocked at how easily it came off in large spaces with little (or no) evidence of resin on the ply at all(!) I wonder if there are special issues in fiberglassing what may very well be 50-year old ply? The ply is in good shape, and I do plan on roughing it up a bit in the direction of the grain with 60-80 grit before laying down any resin and CFM to try and create a better mechanical bond.

    I have found that even unwaxed laminating resin will hard cure eventually, but I am assuming that for the best bond the resin applied to the ply, CFM AND glass should all be done while it is still tacky for the best chemical bond, as well as mechanical bond?

    George, I am more and more leaning towards the lightweight poly filler, if it does, in fact, allow easier sanding, initially, but hardens more completely given proper cure. I'm finding sanding cured poly resin - containing 'sandable' filler, or not - is not as fun as it sounds and I'd probably save enough in pads to make it worth it ;) BUT is it okay below the waterline on a trailer boat that won't live in the water?

    Thanks, again, guys. I heartily appreciate all your input; I don't have anyone around me to talk boats with and learn from, so your advice, suggestions and support a dearly appreciated :)

    Curtis
     
  12. ondarvr
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    ondarvr Senior Member

    Thinning at 10% will significantly reduce the physical properties of the resin, this includes water resistance and crack resistance, just because a resin gets hard after its been thinned doesn't mean its still a good product.

    Using epoxy doesn't end up costing much more, if any all, in the final build. If you go with polyester you need to add the cost of CSM and the resin to wet it out (this will about double the amount of resin needed), plus the time involved to do the extra work. And then in the end the final product isn't as good.

    While polyester over wood doesn't work nearly as well as epoxy, it's made even worse when common mistakes are made, like thinning it, or using the wrong resin.

    Depending on the exact resin you have right now the window of time for bonding to it can vary a great deal, from as little as 24 hours to a couple of weeks or more.
     
  13. Tungsten
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    Tungsten Senior Member

    Consider the smell of the poly resin,your shop is attached to the house?You'll have to leave the boat outside for a week as any fumes entering the house will be sure to fast track you to divorce court.
     
  14. SukiSolo
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    SukiSolo Senior Member

    I would second ondarvr's comments on the resin type. As long as the wood is dry, epoxy is far superior for adhesion to the ply/solid substrate. Ideally coat the wood first then lay on a layer of 'cloth' - I prefer woven roving to CSM and this will wet out properly. These two 'layers' can be done in one go, and a third sealing layer of resin added perhaps a few hours later or after curing for a day and light sanding. Remove any amine bloom to ensure adhesion.

    BTW epoxy has far better cohesive strength as an adhesive, as well as being a more versatile resin than polyester. Oh and yes, it does smell less....;)
     

  15. OrcaSea
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    OrcaSea Senior Member

    Thanks, all, for your advice!

    I am aware of all the numerous advantages of epoxy (I've used epoxy for all the structural repairs), but, honestly, It's a money-thing right now. I do have a gallon of poly and a quart of epoxy as of now. The bottom and deck covering will be a bit down the road, so we'll just have to see how the financial situation is when I get there (I work freelance, so it's as variable as the wind).

    I'm pretty certain I have a keelson to replace once the boat gets flipped, so I do have time to consider the options.

    Thanks, again! :)
     
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