Completely clueless

Discussion in 'Materials' started by Qbonez, Jul 6, 2018.

  1. Qbonez
    Joined: Jun 2018
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    Location: Montana

    Qbonez Junior Member

    Currently I have the boat pulled backwards so I could cut the transom apart. I could lift it up and put it on something I guess. So you're saying to put weigh in the boat to see if it goes back down?
     
  2. SamSam
    Joined: Feb 2005
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    Location: Coastal Georgia

    SamSam Senior Member

    Does that keel protrusion go all the way to the transom or does it taper to nothing from the last roller? If it tapers that's ok, if it disappears into a belly in the hull, that's not ok. It's hard to see the depression on the hull proper but it can be seen in that keel protrusion.

    So you want everything flat fore and aft from the transom up to wherever you determine it starts curving up for the front of the boat. Here's a boat term for you "fair- without irregularity or unevenness" You want the bottom to be fair, flat where it looks like it should be flat and evenly sweeping up and blending in to the curvatures in front. As few ripples and bellies or humps and bumps as possible. Well, more like 'as practical', you can get it like a mirror but it takes a lot of work and perfection isn't needed on that boat.

    The trailer looks to be an OK support for the boat, you can adjust the relevant rollers so you have a straight level of support where it's supposed to be straight.

    A long straight edge would be a help. A long, straight stick or plywood edge or something to help see how deep the hollows are or how high the bumps.

    To straighten things, you can put crosspieces under the gunnels and then posts down to the top of the new stringers, using wedges or spacers to fine tune it all. Work around the posts to glass in the stringers and then patch in those small areas after the posts are removed.

    If needed, you can also hang a couple frames from the top of the gunnels to hold a board or two you can work from without having to put your weight on the hull. It's hard to tell by yourself if it moves when you walk on it, so have someone else watch the bottom while you move around in the hull. You don't want it to move at all because if you glass a few feet and then it moves even a little while you re-position, it will mess up what you just did.

    Another possibility is to screw up through the bottom into the stringers to pull the hull into shape, glassing in the stringers, pulling the screws (and their backing plates) and then patching the holes.

    The glass that is still there where the stringers were/are is probably supplying some support, if you took all that out the bottom might become real lumpy and wavy, so you might want to do the stringers one at a time, probably starting with the middle one, then the two on each side of that and then the outer two.

    You might want to take a lot of pictures as reference. Getting the stringers right so in the end the floor is flat and at the same level as it was gets a little picky. How handy are you with tools?

    When it comes to removing the old glass, whirly things like saws and grinders raise a lot of dust. I always rigged up fans to keep the general mass of air going away from me and a shop vac hose laying right close to the action to catch the majority of the dust. Whenever it was feasible I kept it wet with light spray from the garden hose, spraying while grinding. It doesn't hurt most things and the water drys away overnite enough to glass the next day or so. Fiberglass, like that besides those stringers, can be chiseled away with a wood chisel to where very little grinding is needed and chiseling raises hardly any fine dust.
     
  3. Qbonez
    Joined: Jun 2018
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    Qbonez Junior Member

    It tapers to nothing about 3 feet from transom. Just from the weight of new wood the hump is mostly gone.

    Just from my weight alone I can tell the hull moves when stepped on. The keel stringer "tilts" towards any difference in weight. I'm assuming most the strength of holding hull together falls on the sole.

    I'm pretty good with my hands and might be able to get help in dire circumstances. I was going to run a hose down the path I will be grinding. Although the chisel sounds like a good plan.
     
  4. fallguy
    Joined: Dec 2016
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    Location: usa

    fallguy Senior Member

    You really need to get the boat to a fixed position before you glass anything.

    I would make a plan to glue in the stringers one day and glass after the stringers are in n cured up a day. Two days better yet.

    Then you can sand or grind any cured poly for a secondary bond. Fill in the ridges with thickened epoxy and glass to a solid and fair boat.

    Mixing poly needs adjustment for weather. Not my thing.

    But you'll be greasing up the stringers with cabosil and mixed resin at about 2:1 by volume. Batches should be limited to about 3 ounces of resin to start. I never mix any thickened batches with over 12 ounces of resin. 12 ounces of resin makes a LOT of thickened glue. More than rookie can get applied before it cures on you... then push the greased stringers down into their locations. The heights of the stringers must all be the same for the floor to sit flat. Some guys install a board across the top of the boat and determine or use boards from above to reference the proper stringer heights when gluing them.

    Don't modify the stringers to the unfair boat, but to a fair boat, if that makes any sense.
     
  5. Qbonez
    Joined: Jun 2018
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    Qbonez Junior Member

    Planned on using old stringers as jig. Making sure they are lined up where they will be true to the boat original shape. I have an idea how to get them all level with themselves and guess I'll start with middle stringer.
     
  6. Qbonez
    Joined: Jun 2018
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    Qbonez Junior Member

    Now I gotta build a carport and put my tarp on it
     
  7. Mr Efficiency
    Joined: Oct 2010
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    Mr Efficiency Senior Member

    What Sam Sam says about the need to preserve the shape, is pertinent. You really need to have a good cradle made, to accept the hull, and keep it more or less in shape, while you rip out, and replace the innards. The advisability of restoring old glass boats is doubtful in very many cases, it requires a careful assessment of the state of the boat, and that is made difficult by a lot of "sins" being hidden out of sight, and unable to be accurately gauged, without major surgery. Sometimes it is obvious that the bottom has gone out of plumb, through some combination of disintegrated structural members, and/or a trailer that offered insufficient support. I always get back to the idea that the boat hull better be a good one, a classic even, or it really is not worth it.
     
  8. Qbonez
    Joined: Jun 2018
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    Qbonez Junior Member

    Just realized I didn't order any chopped glass... is it logical to buy a repair kit and just cut the glass up to make the PB?
     
  9. Blueknarr
    Joined: Aug 2017
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    Location: Colorado

    Blueknarr Senior Member


    Please remind me what "PB" stands for.

    If you are thinking of thickening the resin to a "peanut butter" consistency, NO it won't work.

    Cutting up the glass cloth creates "kitty hair". Useful to strengthen resin putty. Kitty hair mostly forms splinter blobs which are difficult to grind off.

    Cab+o-sil makes pastes that don't sag and are hard to sand.

    Micro- balloons make pastes that will usually sag, but sand easy.

    They are often mixed together to make non-saggy easier sanding pastes.
    -fillets: more cabo. Less balloons
    +fairing compond: less cabo more balloons
     
  10. Qbonez
    Joined: Jun 2018
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    Qbonez Junior Member

    So I need to order some- that's what you are saying? I guess I'm not sure of the difference between b using chopped glass and chopping my own.
     
  11. Blueknarr
    Joined: Aug 2017
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    Blueknarr Senior Member

    I'm not saying to order anything.
    I'm saying that I don't understand the point of your question.
    I have already once jumped to conclusions based on incomplete info from you. I don't want a repeat.

    Now ten pages on this thread. I know you're getting ready to install stringers and repair transom. What resin and glass weave did you choose.
     
  12. Qbonez
    Joined: Jun 2018
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    Qbonez Junior Member

    I got poly resin and 1708 cloth. It was my assumption that when making the fillet resin mixture that it needed to be the resin, hardener, cabosil and 1/4 inch chopped strand. I did not order any strand and was wondering if I could make my own with scissors
     
  13. ondarvr
    Joined: Dec 2005
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    ondarvr Senior Member

    You can cut it yourself or buy it, the stuff you buy is a little easier to use, but it's not really an issue. The longer the strands the harder it will be to work with, so most putties are made with milled fibers, these are very short, but the putty will be far easier to shape and get smooth when applying it.
     
  14. Blueknarr
    Joined: Aug 2017
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    Blueknarr Senior Member


    You won't be using enough to warrant ordering/buying. By all means chop your own. Most fillits don't require kitty hair, but it rarely hurts to add a small amount if it is on hand. A pinch goes a long way.

    Most textbooks say to catalize resin before adding powders. Great with epoxy's finicky presision mix ratios. Polyester cooks off faster than I can mix to a smooth consistency. I thicken before catalizing.

    Warnings only good if using POLYESTER. DO NOT TRY WITH EPOXY
    +Measure off known quantity of poly (one quart).
    -stir in cabo until desired consistency
    -cover an let sit for a day so the lumps self dissolve
    -divide into user friendly amounts
    -If half batches then catalize for 1/2 quart or 1/4 for 1/4, etc


     
    Last edited: Jul 22, 2018

  15. Blueknarr
    Joined: Aug 2017
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    Blueknarr Senior Member

    I sence that you are preparing to reinstall the stringers. I didn't want to information overload before so I waited. You stated early on that the stringers did not touch the hull. It is critical that you remember if they 1- rotted away from hull, or 2- never touched the hull to begin with.
    153229208009464130499.jpg

    My partial history of FG boat construction:

    In the beginning hulls were very thick chopped matt with plywood stringers and bulkhead tabled directly to hull. Just as done in all plywood hulls.
    All was well until builders started saving weight and materials by reducing the thickness of hull and cracks developed at the red xxxx

    Fillets were added. All was well again. Until hull thickness was reduced. The cracking returned

    Instead of thickening hulls, some engineer thought;
    Put an air gap between hull and plywood. No more hard hinge and the tabbing will act as shock absorbing springs.

    And all was well again.
    Until some fool discovered foam and it was never well again.

    As illustrated:
    - the thickness of pink tabbing at joint should equal the thickness of hull
    -full tabbing thickness should extend 12 times thickness onto hull and or bulkhead
    -tabbing should then taper at 12-1 slope
    -total tabbing width of 48 times hull thickness
    -several methods of tapering tabbing are shown
    -If air gapped, it is equal to hull thickness.

    In either arrangement:
    -pre seal plywood on both faces and all edges with 2 coats of resin
    -CSM against plywood or hull
    -CSM between bi-axial cloth
    -CSM fills irregularity of wood grain, cloth weave or hull
    -glass cloth goes not like to change direction abruptly
    -sand/grind away ridges and fill troughs with fillit as needed

    How to air gap
    -dowels, stacks of popsicle sticks placed in gaps of first layer of tabbing
    -removed before 2nd layer
    -many layers of double stick foam on edge of stringers. May safely be left in place
     
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