Repairing small patches of delaminating varnish in interior?

Discussion in 'Wooden Boat Building and Restoration' started by DennisRB, Aug 30, 2010.

  1. DennisRB
    Joined: Sep 2004
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    DennisRB Senior Member

    My partners boat is of ceder strip construction and what looks like satin or matt varnish on the inside. Can any expert tell me what the finsh might be from the pics? The small side hatches have screw knobs that when open rub on the varnish and have cause delamination in those areas along with wet rot/or soft wood as water got the the ceder. Some don't have the rot just the blemished varnish. The areas of soft wood rare no bigger than a fingernail and probably not too deep and the delamination extends a little further. She has some putty with the boat which appears to be the right colour and looks like it has been used to fix something similar before.

    How do I go about fixing this without making a the patches even larger and more unsightly? I am worried about sanding too much as even a sanding block will cover a area much larger than the affected areas.

    See pics (sorry for bad pics) this is the worst one. As you see its no big deal but I was hoping to get this before it gets bad.

    [​IMG]

    [​IMG]
     
  2. Petros
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    Petros Senior Member

    I have a book I can look up this kind of repair, but I seem to remember for this kind of damage you first scrap off all the peeling finish and lightly sand the area right around it. Dab on the repair finish, apply several coats just to the affected area. Than wet sand after it is fully cured with fine sand paper. Than you can cover the whole part with another layer of finish. It will not look perfect, but it will be a large improvement in appearance, but mostly it will protect the wood until a more complete stripping and refinishing can be accomplished at a future date when it becomes necessary.

    An quality exterior grade wood finish will work, I like oil based polyurethane. It appears you have "satin finish" (about half way between gloss and mat) but if you do a complete recoat that is off little importance. You can spend a lot of money on marine grade finish from a marine supply shop, but I am not convinced it is any better than what you can buy in major brands from a large hardware store.
     
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  3. DennisRB
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    DennisRB Senior Member

    Thanks. Petros. To do the whole lot would mean the whole interior of the boat! I do not want to take a month of work to do that massive job and the rest is in pretty good condition. I made this thread as I really don't want to botch it up requiring a massive amount of work instead. What ever I try i will give it a go under a bunk or something first to check the results.
     
  4. alan white
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    alan white Senior Member

    My suggestion would be to do what I often do with my own boat. When I see a wear area or spot developing, I think up an attractive and efficient wear plate (or leather patch, etc.) to cover and protect the spot.
    In your case, cut a brass/bronze plate to an oval or similar shape and screw the plate over the wear spot.
    This is how it's been done for centuries. Not every situation has been figured out. Be inventive in solving these little problems.
    Nothing will look worse that a poor job of matching the interior finish. It's almost impossible to do unless you do ALL of the inside doghouse, etc..
     
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  5. DennisRB
    Joined: Sep 2004
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    DennisRB Senior Member

    Thanks Alan. There are about 6 of those hatches so 12 ware points. These hatches are in the hull of the boat, so that is a lot of internal area to redo if it goes wrong. I was going to put a 1.5" circle of clear 3M protection vinyl over the repaired area. Maybe I would be best just using a blow-drier to dry the wood out and sticking the patches right on top rather than trying to fix it first? This would stop further ware and possibly look better than an amateur repair?
     
  6. alan white
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    alan white Senior Member

    Yeah, but maybe use an opaque sticker. Did you know there's a copper sheet product that has a sticky back? Boy am I sorry I didn't buy that roll at the salvage store! Also think about a hardwood veneer glued on. Something like rosewood in a diamond shape--- stack them and do all eight at the same time. Cheap but attractive.
     

  7. Petros
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    Petros Senior Member

    Here is the most authoritative recommendations from "The Brightwork Companion" by Rebbecca Wittman (she has a company that specializes in refinishing wood boats).

    Her recommendations in the book are to keep a wood boat in "like new" condition, and are pretty rigorous. BTW the term "brightwork" refers to varnished wood, in case you did not know.

    From page 102 varnish repairs "scratch and patch":
    • "Varnish dings and cracks can be "bandaged" between-or in preparation for-refresher coats, to extend the life of an otherwise honorable finish. This is what we call Scratch and Patch work. IF you perform this work throughout the year, especially as a periodic ritual during cruises, herculean labors are avoided later, when you return to port or at refresher coat time.
    • "The minute you notice a broken varnish seal at an otherwise healthy joint, or if a brightwork trim suffers a sudden scrape, mask precisely along that joint or abrade the area [with sandpaper] and reseal with varnish.
    • "If the finish has lifted at a joint-evidenced by a yellowish "blister"-scrape the blister away carefully up to where it meets the adhered finish, using a very sharp scraper. Try to scrape off no more than the lifted varnish itself.
    • "If the wood appears darkened once the blistered varnish is removed, bleach the area carefully using Teak Wonder (a wood bleach) and a soft nylon scrubber or soft toothbrush, resiting the the temptation to scrub out the pith of the grain. Rinse thoroughly and allow the wood to dry completely.
    • "if there is a chance the joint is holding water, extract all water with a wet-dry vacuum, than allow the area to air out for at least one warm day until absolutely dry. Do not re-varnish until you are certain all moisture is eliminated from the joint.
    • "Once the wood is dry, sand just enough to remove the raised fuzz from the wood (120, than 220 grit).
    • "Stain and/or seal the area as you did for the original finish.
    • "Make a "jet speed" version of your varnish, diluting it 25 percent with its companion fast drying solvent (the one recommended by the manufacturer for spraying the varnish). Apply this varnish and allow 4 hours to dry.
    • "Without sanding between coats, apply a second coat of varnish, thinned 15 percent with the same solvent.
    • "Build up the patch with subsequent full-strength coats, a day apart, sanding between each to fair the patch.
    • "When the patch is level with the good finish, lightly sand (320 grit) the whole piece to fair the patch, than apply a full coat of varnish."

    The idea is to always keep the finish water tight, to stop moisture from penetrating the finish, which will shorten its life and allow it peel too soon. You would not need to refinish the whole interior of the cabin, just to the edges of the piece that has the damage. You can mask off the adjoining panels that are in good condition.

    BTW, she recommends two-coat refreshers for all exterior varnish twice a year! And once a year for interior varnish.

    To apply a refresher coats:
    • wash down the whole boat with soap and water, than wipe all the brightwork with alcohol.
    • Than remove "easy fittings", sand all the brightwork moderately (320 grit).
    • vacuum and wipe down with mineral spirits moistens rag.
    • Mask with tape, apply the varnish, allow to dry 24 hours,
    • than sand and wipe down again with mineral spirits, and apply final coat.

    She claims that the varnish shrinks back as it ages so this will not result in a large build-up of layers of varnish. Though refinishing twice a years seems a bit excessive to me.

    Her favorite varnish for the exterior wood work is Interlux #96 Shcooner, and Interlux #60 Goldspar satin for interior use.

    She also says the following brands are also good: Epifanes, Woolsey/Z-spar captain's and flagship, Rivale Classic, McCloskey's Bote-Kote, and Man O' War.

    I have used Epifanes, Mcloskey's, and Man O' War, all work well, these are available in most hardware stores as well as marine supply stores.
     
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