Welcome to the Hatteras Owners Forum & Gallery. Sign Up or Login

Enter partial or full part description to search the Hatteras/Cabo parts catalog (for example: breaker or gauge)
+ Reply to Thread
Page 1 of 4 1 2 3 ... LastLast
Results 1 to 10 of 39
  1. #1

    Aft Deck Balsa Core Repair - How To / Not To

    Since I am now reporting and recording what I am doing rather than asking for advice I thought I would start a new thread with a more descriptive title. This is a continuation of the thread:

    http://www.samsmarine.com/forums/sho...ck-Sag-Problem

    The bad balsa coring extends into areas I did not expect and as I followed the rotten balsa I decided to use a 2.5" hole saw and have since learned that the multi-tool works well in removing bad coring surrounding the hole and I can go out about 1.25 inches out from the perimeter of the hole with the blade. I will post pictures later as I came to the house for lunch and left the camera on the boat.

    My plan is to track down the rot, remove it and clean the area with a shop vac. Once it is clean and reasonably dry, I will flood the area with ethylene glycol (anti-freeze) to kill the rot,
    see:
    http://www.angelfire.com/nc3/davecarnell/rot.html

    then vacuum the area and let it air dry. I will fill the voids with plywood and filled epoxy. Areas under the hole saw opening will not be accessible to plywood. I have ordered 6 gallons of RAKA epoxy and several pounds of filler.

    Although I have decided on a plan, any suggestions will still be welcome.

    To be continued
    Regards,
    Vincent Castigliola
    Lilly Marie - 43 DC 1983
    Pascagoula, Mississippi

    Rather than history as a peaceful continuum interrupted by war, “For the first time in the nation's history men in authority are talking about an "emergency" without a foreseeable end" _ C. Wright Mills 1956

  2. #2

    Re: Aft Deck Balsa Core Repair - How To / Not To

    I followed the rot with the hole saw and it took me aft to the port cleat and midships to the escape hatch.



    The core was rotten all around the aft port cleat and I drilled a couple of holes next to the cleat to get that area dried out. The underside fg is very thin and I wonder how secure that cleat is with rotten core between the cleat and the backing plate.

    I followed the wet balsa forward along the port side deck, but it did not go up to the cabin windows as I suspected.



    I am at a loss to determine the source of the water into the core. I wonder about the helm window frames. I have never removed them. Possibly water is leaking from the window slider trough into the cabin side below.

    The state of core deterioration ranged from black crud to balsa skeletons.



    The multi-tool narrow wood cutting blade handled the bad balsa just fine. I put the 5 gallon shop vac aside and brought down a 16 gallon one with a 2" hose and it sucked out the balsa debris without hesitation.

    If it does not rain tonight, the core should be dry enough for a treatment with ethylene glycol.
    Regards,
    Vincent Castigliola
    Lilly Marie - 43 DC 1983
    Pascagoula, Mississippi

    Rather than history as a peaceful continuum interrupted by war, “For the first time in the nation's history men in authority are talking about an "emergency" without a foreseeable end" _ C. Wright Mills 1956

  3. #3

    Re: Aft Deck Balsa Core Repair - How To / Not To

    I have to ask why you are going to put ethylene glycol in the cavity. Yes, it is toxic, but it will not evaporate easily, if at all from the confined spaces. That might compromise adhesion of the epoxy to remaining balsa and the fiberglass skins.

    A suggestion on cleaning out the rot. The pro that did my hardtop bored smaller holes and spaced them further apart, then used a sharpened, bent hack saw blade to root out the bad wood. He was able to reach in 5-6 inches. One end of the blade was attached to a solid wooden handle like a file handle.

    The repair was made with some sort of a high density foam that he gunned into the holes working from the lowest to the highest areas. The foam would knit together and rise just a little bit from the holes. I had the whole area glassed over after sanding off the high foam spots, then faired and painted.

    snip:<<I am at a loss to determine the source of the water into the core. I wonder about the helm window frames. I have never removed them. Possibly water is leaking from the window slider trough into the cabin side below.>>

    You can try to follow the moisture in the core using a moisture meter. I found wet cabin sides at the corner with the windshield in several of the 48's that I looked at and suspected frame leaks. These led to wet areas in the side decks.

    Does RAKA epoxy produce much exotherm? I'm not familiar with it. Worth testing off the boat first?


    Good luck. It looks like a big job. Keep the progress reports coming.

    Bobk

  4. #4

    Re: Aft Deck Balsa Core Repair - How To / Not To

    I don't know that I would use glycol to kill the rot. That material seems awful slick to me. I would also step away from the edge a little more to give you enough material to taper the repair to . It may be easier to cut a large panel out then bond a foam or plywood core to the inner layer then layup over the top, fair and finish. Resin can create a large amount of heat when poured in a thick application. It can cause the repair to warp all to hell. I would carefully use a het gun to dry out the old core and kill the rot.

  5. #5

    Re: Aft Deck Balsa Core Repair - How To / Not To

    Thanks for the comments.

    Probably a good suggestion regarding glycol evaporation and slickness; however I filled the space with antifreeze before reading your post. I have vacuumed the area and it still has a film on the lower fiberglass skin. That might be something not to do the next time.

    I have wiped the fiberglass area with paper towels. Any thoughts on a solvent or cleaner?

    Exotherm is a good point and will watch for it. I have used filled Raka epoxy for the forward deck core around the pulpit without problems and over the years I have had several pails of epoxy kick off before I could use them all and they were an inch or so thick in a quart plastic pail. Did not generate a lot of heat or expansion.

    Cure time will be an issue as it is 90+ degrees. I will keep the epoxy in a cool place before mixing.

    I plan on gluing down sections of 6mm meranti, plywood , 3 layers, in accessible areas and then pouring the the epoxy in the other areas, in 2 layer pours, 3/8" thick.
    Regards,
    Vincent Castigliola
    Lilly Marie - 43 DC 1983
    Pascagoula, Mississippi

    Rather than history as a peaceful continuum interrupted by war, “For the first time in the nation's history men in authority are talking about an "emergency" without a foreseeable end" _ C. Wright Mills 1956

  6. #6

    Re: Aft Deck Balsa Core Repair - How To / Not To

    Vincent,

    Ethylene glycol is water soluble so a good water flush will get rid of it. You may want to do it several times. It is also alcohol soluble, but if you use alcohol, you need to take care regarding it's flammability. Don't vacuum the residual out etc.

    Bobk

  7. #7

    Re: Aft Deck Balsa Core Repair - How To / Not To

    Thank Bob,
    Good advice regarding vacuuming flammables. I met a man who vacuumed acetone in an enclosed space. He lived to tell about it, but could not speak very well due to burns to his throat.

    This is how it looked with 5 gallons of antifreeze.



    The islands in the pond were my nemesis in removing the fg skin. The fact 5 gallons pretty much filled the area, tells me 6 gallons of epoxy will be more than enough, especially since about 1/2 of the area will be filled with plywood.

    I ran 3 string lines thwartship and compared the camber port and stbd. The yellow tape indicates where I measured from deck to string line at 30 cm intervals.



    I have good camber perhaps due to the support from the 2x4 stud walls running fwd and aft in the aft cabin, one just to port of the centerline, I did not want to remove the light fixture frame. The other stud wall runs just port of the queen bed. I wish I had measured the camber before I started rather than just placing a batten to find the depression and then deciding I knew the solution.

    Before I started cutting up my deck, a batten indicated that the lowest point of the sag was just to port of the fb ladder. The cut line shows that point. However the balsa there was very sound and it does not appear that the bad coring goes nearly that far. I used a 1/16" metal rod as a probe poking it out from the holes I drilled in the deck.

    If there is a moisture meter that will detect moisture under a 1/4" of fg available at a reasonable cost, please let me know the name and source as I would love to check this further before I close up the patient.

    Thunder storms have been an issue and I cover the area fwd of the aft deck enclosure with visqueen and built a dam which hopefully will direct the water to the port side scupper and away from my cut area. OTOH, a little rain water might wash away the antifreeze.

    Regards,
    Vincent Castigliola
    Lilly Marie - 43 DC 1983
    Pascagoula, Mississippi

    Rather than history as a peaceful continuum interrupted by war, “For the first time in the nation's history men in authority are talking about an "emergency" without a foreseeable end" _ C. Wright Mills 1956

  8. #8

    Re: Aft Deck Balsa Core Repair - How To / Not To

    holy sh@##$%%^ttttttt. you'll never make the rendezvous unless you work day and night on that project. hope to see lilly marie there. keep up the good work and the great documentation.

  9. #9

    Re: Aft Deck Balsa Core Repair - How To / Not To

    Bill,
    You don't think the worst is over?
    Unless the weather gets me, i should have structural repairs this weekend. Cosmetics will probably come post rondesvous.
    Regards,
    Vincent Castigliola
    Lilly Marie - 43 DC 1983
    Pascagoula, Mississippi

    Rather than history as a peaceful continuum interrupted by war, “For the first time in the nation's history men in authority are talking about an "emergency" without a foreseeable end" _ C. Wright Mills 1956

  10. #10

    Re: Aft Deck Balsa Core Repair - How To / Not To

    I've tackled alot of boat projects, but I get scared just looking at that!
    Sky Cheney
    1985 53EDMY, Hull #CN759, "Rebecca"
    ELYC on White Lake--Montague, MI

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts