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Rebuilding This End Up, Part II  Bottom

  • Here is the link to the 2nd video on the steps I'm taking to rebuild a 1976 NACRA 5.2.

    [https://youtu.be/gRuG9_cBEFY]

    Please tolerate/excuse the length on these videos. My intention is to show the steps and some of what I am encountering. Hopefully then others will see that older boats can have a much extended life.

    Made excellent progress today sorting out the painting of the aluminum parts and will post that information from Interlux/Awlgrip separately.

    I was also convinced by my brother a production boat builder to use the Interlux Perfection product on the hulls. While I could spray these hulls with the Perfection product, it apparently works exceptionally well using a roll and tip method or roll and roll. So since most don't have the HVLP setup it makes sense showing the simpler step and it also will make my work flow easier. The key is getting the quality high gloss finish I want and I have been reassured that if I follow the procedures carefully that is what I will get.

    I will also build an album soon with still images as soon as I sort that process out.

    But so far this project is going really well and I am confident that very soon I will have a structurally sound and very good looking beach cat with a lot of experience (40 years of it).

    --
    dg
    NACRA 5.2 #400
    This End Up
    Original owner since 1975
    --
  • [https://www.youtube.com/watch?v=gRuG9_cBEFY]

    This link looks modestly different than the one in the post above.

    --
    dg
    NACRA 5.2 #400
    This End Up
    Original owner since 1975
    --
  • I tip my hat to the rehab Zen Master....

    I have rehabbed some cats, but nothing to the extent you're doing here...

    Regarding the aluminum, can this be re-anodized

    --
    John Schwartz
    Ventura, CA
    --
  • That is probably the most in depth re-build ever done! GAMICK has an album here where he built a neglected 5.2 into a great looking boat, you're going a magnitude deeper. I have done a 5.7, & a 5.0, but not as deep as you re going.A few things to help reassembly.
    To re-attach the traveler track, easy job, those holes on the bottom are your friends. The holes will accommodate a thin wall socket/extension. Plug the socket with a bit of masking tape, leave just enough to fit the nut flush with the end of the socket. The nut will stick, & be easy to start.
    The compression sleeve inside the front beam. Push a bent stick through that sleeve right now, as a keeper, else you will have to tape the sleeve to a batten, or long stick, insert in the beam, then get a friend to push a stick, or the DS rod through. I changed a DS rod on my 5.7, this might give you some ideas.
    http://www.thebeachcats.c…pictures?g2_itemId=73301
    When you re-attach the V brace bar, do up the innermost bolt first, then the middle one, then outside bolt. If done in a different order, they get in the way of your box end wrench when trying to do up the inside one.
    To get those bolts out of the beam, double, or triple nut them. Turn 1 or 2 nuts onto the exposed end, & snug them against each other. Then turn 3rd one down, put a 6pt socket just onto top nut & turn. It will break the bolt loose. Usually you only need 2 nuts. You can also heat the aluminum with a propane torch, play it just around the perimeter. The aluminum will heat/expand faster then the SS bolt. Tapping with a hammer as you turn will help. You could also have a helper simultaneously turn the head of the bolt inside the beam.
    When replacing them, again, masking tape on one side of a box end wrench to keep the bolt pushed upwards, allowing you to tighten the nut with a socket. (Good mechanics always turn the nut vs the bolt).
    I would humbly suggest that when drilling rivets, don't use a bigger drill than the rivet shank,(7/32 for a 3/16 shank). This results in damaging the material just under the rivet head when you drill through it, as can be seen on the clam cleat you drilled. Use a drill 1 size smaller than the rivet, then use a pin punch to knock the shank through. For large rivets drill them almost through the head, then insert the other end of a same sized drill bit into the hole, & snap the head off. This comes from hanging out in our aircraft engineering shop, & seeing thousands of rivets drilled. It is a major no-no to damage the sheet aluminum surface, because the new rivet heads won't have a flush surface to mate to, compromising strength.



    Edited by Edchris177 on May 19, 2016 - 12:15 AM.

    --
    Hobie 18 Magnum
    Dart 15
    Mystere 6.0XL Sold Was a handful solo
    Nacra 5.7
    Nacra 5.0
    Bombardier Invitation (Now officially DEAD)
    Various other Dock cluttering WaterCrap
    --
  • I really think the 7/32' bit is the right size bit to use. The trick in this case is to not go beyond the bottom of the head of the rivet. The problem with using a smaller bit in the case of the Monel is that when you try to punch the remnant through the hole the Monel is strong enough to hugely resist that effort. Cutting the head off relatively cleanly allows the rest of the rivet to be driven through but still with some effort.

    Now that I have the aluminum refinishing plan sorted out I am totally OK with minor damage to the top of the hole in the aluminum. That damage to the anodizing already existed when they drilled the hole in the first place. The Monel is not the problem material in this equation, it is the stainless steel. With the refinishing plan I now have I think the holes themselves will be in a better situation than they were when new.

    Here is the aluminum refinishing plan I can live with from Ray Tucker at Interlux/Awlgrip:

    Hi Dave,

    Cool project! So the pitting does not appear to be that bad. I would feel confident with the following process.

    • Sand blast pitted areas
    • Sand the rest of aluminum with 120 grit
    • Apply one coat of Wash Primer CF within the same shift of blasting and sanding
    • Wait a minimum of 1 hour and up to 6 months, apply 3-4 coats of 545 epoxy primer (usually 2 coats of 545 is sufficient but I would recommend an extra coat or two to add extra insulation between the aluminum and stainless).
    • Sand 545 with 320-400 grit
    • Apply 2-3 coats of Awlgrip or Awlcraft 2000 topcoat
    • Wait a week before installing hardware to ensure full cure of the coating system

    I hope this helps. Please let me know if you have any further questions.

    Ray
    ________________

    So my next step is to track down some blasting media for my never before used sandblaster (very tempting to use actual sand since it is extraordinarily available in my neighborhood, but I am trying to set a good example here). This plan and finish material makes sense to me based on all the reading I've done in the last few days. It is not the Alodine material with its benefits, or really big negatives, but it seems reasonable and manageable. I am comfortable working with the epoxy and think that will give me the finish life I want to see. If the epoxy bonds as well as I would expect the next person working on this boat shouldn't have to strip the parts down as far as I am going.

    I'm starting tonight on the next video of days 3 and 4, but I'm going rafting soon and may not get real far until early June.

    I do appreciate all the information, keep it coming!

    --
    dg
    NACRA 5.2 #400
    This End Up
    Original owner since 1975
    --
  • I missed the comment about re-anodizing. It is possible with the right prep to re-anodize, IF you have somewhere that can do this kind of large work. Might not be too difficult for the beams, but the mast would be a huge problem. It is also possible to powder coat these aluminum parts and that could work for the beams and boom, but not for the mast because of its length. I wanted all of these parts to look the same, so will go through the steps to make that happen. At this point I don't think that getting the result I want will be all that difficult and that is why I'm trying to document the steps I'm taking. This process is relevant for all kinds of older sailboats.

    --
    dg
    NACRA 5.2 #400
    This End Up
    Original owner since 1975
    --

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