Kurt Hughes Daycharter 36

Discussion in 'Boatbuilding' started by Charly, Mar 10, 2010.

  1. Charly
    Joined: Dec 2009
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    Location: st simons island ga

    Charly Senior Member

    Well, Hellfire.:eek: There are just landmines everywhere, aren't there?

    Thanks for that Cat. My ekg is still on the chart, but I am wiping off some sweat;)

    I remembered that Kurt said that wood fillers absorbed water, but the fact about white fillers absorbing water somehow slipped past me. He has a bog recepie for the keel pour, that includes a good portion of microballoons, and when I poured my first hull's keel, i was too green to know the difference between glass bubblues (white) and phenolic microballoons. I thought they were just different versions of the same animal. AND, I remembered that somewhere i read that colloidal silica (aerosil) was stronger than balloons. So, also being paranoid, and unsure of my building skill, I opted for strength in the keel and went heavy on the aerosil!

    So I guess it is not too late :)rolleyes:) for me to be asking some questions:

    How much water is "some" water absorption? will weight increase significantly in the keel? Is there a sure method to block water out, of the keel cove if it is mainly aerosil, and would the weight gain from the addition of any material on top offset the benefit?

    Also, I remember someone on here noting that aerosil does not increase volume, only thickness and weight of the resin. What about phenolic microballoons? Does it increase the volume?

    I may have to end up putting all my batteries in hull #2:D
     
  2. CatBuilder

    CatBuilder Previous Member

    Yeah, there are a lot of land mines. Remember my wood/epoxy hulls? Now THAT's a landmine. Hell, that was a hydrogen bomb.

    I'm not sure how much water they will absorb, but I do recall him saying somewhere else that graphite was really bad and absorbed a lot.

    My thinking (and you probably need to ask Kurt about all this) is that you should be just fine if you cover it with some brown microballoon bog, sealing it.

    I remember reading in Kurt's material that 100% colloidal silica was the strongest, but could be broken (cracked) by impact. Heavy on colloidal silica is fine, I think, so long as you have the microspheres in there as well, at more than 50% of the filler.

    I think you could very easily seal the entire keel up with about half a gallon of epoxy and microballoons (with a tiny bit of colloidal silica to make it more thixotropic).

    I believe you are correct. Colloidal silica does not increase volume or bulk it up. Phenolic microballoons do bulk it up. They are just tiny bubbles that the epoxy sets up around and does not penetrate. This leaves it as a microscopic foam and reduces the weight of the filler a lot compared to straight epoxy.

    You're probably not in bad shape. I hate to be the messenger, but when I saw the white, I figured I'd speak up just in case there was an issue.
     
  3. Charly
    Joined: Dec 2009
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    Location: st simons island ga

    Charly Senior Member

    Well thanks for speaking up. I will order some microballons next week to go into the next keel pour, along with the aerosil and chopped glass. It should be lighter, even though I did use some glass bubbles on the first pour.

    My goal on the next keel is to use less filler anyway. I hope to do a better job of fashioning the keel timber to fit, and I have some nice clear WR cedar on hand for that. I have no idea what that first hull weighs, so far. I know I used about eleven gallons of resin in the keel. That seemed like a lot at the time, but I have never been too sure. I used aerosil and fibers for the fillets too. Cutting it with balloons would have to save some weight.

    Bottom line is that hopefully the learning curve will work in my favor and I will produce a lighter hull in round two.
     
  4. eladio
    Joined: Sep 2010
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    Location: ARGENTINA

    eladio trimaran...

    Hello Charly!
    This year was very dificult, but in a few mounts I`ll buy the plans and make slowly my boat.... the model is a 40´ trimaran "mad dog" , seems simple and no very expensive.... You well recibe a few cuestions when I begening the buid.....
     
  5. fg1inc

    fg1inc Guest

    No matter what type of fairing material is used, all below waterline surfaces should routinely be final coated with some type of epoxy barrier coat, i.e. Interprotect, Tuff Stuff, etc. Makes for a better surface, it's truly osmosis resistant and it helps the bottom paint stay on.
     
  6. Charly
    Joined: Dec 2009
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    Charly Senior Member

    Thanks fg. What about the interior? the bilge on this boat is just a long wide glassed over cove connecting the two hull halves. There is already a coat of neat epoxy rolled over that, from when I coated the inside of the hull. Now, I am more concerned about adding even more weight...
     
  7. AndrewK
    Joined: Mar 2007
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    AndrewK Senior Member

    The most waterproof coating is neat epoxy resin.
     
  8. CatBuilder

    CatBuilder Previous Member

    Oh, you already have neat epoxy over the bilge? You're all set, then, as Andrew says.
     
  9. fg1inc

    fg1inc Guest

    For the wet sections of the bilge a barrier coat (epoxy) works fine. And neat epoxy above that. The only problem with using neat epoxy as a waterproof coating is the inherent imperfections - outgas bubbles, runs, sags, etc.
     
  10. Charly
    Joined: Dec 2009
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    Location: st simons island ga

    Charly Senior Member

    second hull update

    Hey guys, the second hull foldup is going much smoother than the first. I did a few things a little differently this time, and I think it made a difference.

    This time, I thoroughly checked for voids and fixed them all before folding. I thought I had done that before, but missed a few. You just can't be too casual about voids. Tap every square inch and mark every one. At the foldup, I cranked the hulls together slowly... over a period of days... with barclamps. I did cause one small split at the transom when I ran a line around the hull and horsed it a little too much, fortunately it was minor and was easy to patch.

    The hull panels were braced off to the overhead beams more securely this time- it made it easier to keep things on track, and the deck clamp was more maneageable because it was hung from the overheads with 1/4 inch lines that I could adjust as the hull came together. MUCH better arrangement than trying to stand the thing up on temp legs.

    The lace-up was easier also. I laced my hulls up in the inverted postion--keel up. I dawned on me the second time that there is MUCH less resistance when twisting the wires if the beam of the boat is kept narrower,ie, sheer timbers on the floor much closer together, which makes the hull higher, but the curvature of the cutout in the panels is at a different angle in relation to each other, making it easier to pull the panels together at the keel seam. It is hard to describe on paper.


    The rollover stage too, was kept more simple. No giant osb wheels this time, just brace off the sheers and interior section midships with some stout two bys, put a few wires in the stem to hold it in place, and lever the bugger over. I used some of those two liter plastic bottles and a couple of studs braced against the wall to cushion the fall.

    I bought one of those bosh elecric hand planers. As you can see, I have been making a happy mess everywhere with it.:)
     

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  11. eladio
    Joined: Sep 2010
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    Location: ARGENTINA

    eladio trimaran...

    Congratulatios Charly!!!
    Your work is very interesting!! may be you must, when you finish, write a little "book" whit tips of tre building process, like the union of the panells in a diferent possicion.....
    I´follow your work....closelly

    Eladio
     
  12. hoytedow
    Joined: Sep 2009
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    hoytedow Carbon Based Life Form

    It looks great, Charly. Good going!
     
  13. CatBuilder

    CatBuilder Previous Member

    Glad to see the update, Charly. It's amazing how much better the second hull goes, isn't it??

    Just doing halves, my second half went up in about 1/2 to 3/4 of the time it took the first half to go up.

    Now, I'm hoping when I get on to the second hull, the pattern will continue.

    Looks like you are really getting somewhere and will be lining up beams in no time! Nice!
     
  14. Charly
    Joined: Dec 2009
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    Location: st simons island ga

    Charly Senior Member

    Now this is the kind of stuff that can strain a marriage:!:The good side is that now the garage is back at her disposal:D. Fortunately I have some very understanding neighbors and most of this boatyard stuff is all hidden from the street.


    The more I shuffle these hulls around the easier it gets. A good come-along, some used tires and a mess of soda bottles all are indispensable. I use a 4x4 for a lever, and some scraps for supports. This last session I did today in an hour or so. You have to be careful though. And try not to bugger up the topsides:rolleyes: And that last one when I used my truck as anchor for the come along... it dragged it sideways across the gravel. You need a better anchor than an S-10.:D

    Keels are now semi-fair. I am about done with the plane, and am ready to start using some fairing bog, here and there, followed by the belt sander and the longboard. the centerboard trunk areas at the keel and the stems still need some shaping and reinforcement. Much work is to be done yet, before the cloth goes on the hulls exteriors, and flipping them back over for the crossbeams. So far, it seems the best method for me, working alone, is to do the bulk of the planing while the hulls are on their sides, blocked up a bit for easy access, then fully inverting them for the most accurate sighting and fairing with the fairing batten.

    The oldest hull (about 5 months) has a little bit of mildew on the bare okume on it in a few places. If I clean it with bleach will that compromise the bond when I epoxy up the topsides?
     

    Attached Files:


  15. CatBuilder

    CatBuilder Previous Member

    Thanks for posting, Charly!

    You really developed a nice, accurate shape on those hulls. Looks just like the plans! That's some remarkable fold up ability you have.

    I highly doubt a light bleach solution (once dry) would cause an issue with bonding.

    Excellent work.
     
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