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Tuesday, March 7, 2017

Bottom and Rudder


  Sides and bulkheads done, time to laminate up the bottom.  Had  a real dilemma about whether to go with titebond 3 or LPU for my laminating.  I'm sure the Titebond would have done it, but I'm really afraid of not being able to get the plywood snug enough, so I ordered some off-brand Gorilla Glue, which expands and therefore is more forgiving of what Dave Z. calls "gap-osis."


  While I waited for it to come in, I used the time to make the rudder stock. Here are the cut out pieces.



  This finishes out to 1 1/2" which felt nice and beefy.  Next I Glued up three more pieces for the rudder itself.




Rudder before shaping

I did all the shaping with various planes, except the part near the top, on which I used an old farrier's rasp I got from my dad. 


Belt Sanders???   We don't need no stinking belt sanders!!
   I followed Michalak's 7% of submerged surface area suggestion for a sink-weight cutout.

  Here you see it with a metal plate clamped to the bottom and the center rabbeted out with a router.  After I did it, I realized it would have been better to round off the outsides  instead of setting in a rabbet, but whatever.  



  It takes a LOT of tire weights to fill a cylinder 6" by  1.5"  Melted them in an old tea pot.  


  
This was my first time pouring lead into wood.   Didn't char the wood the way I thought it would.  



  Once it cooled, I lifted it and decided that 1.5" for the rudder may be TOO beefy.  Rudder, stock, and hardware are going to weigh like an outboard!  Probably that's normal for this size range of boat.  God knows the rudder and cheeks for my old boat weighed like a pig.


    With the glue in, I started lamming up the bottom.  Started with the deadflat section, bottom-side-up on the floor. 


   


Then I glued the second layer onto it and rolled out the dynel I want to sheath it in. This will provide at least a little protection against abrasion. 


  I looked up the resin coverage for 5 oz. dynel, which is hard to get a good number on.  Sounded like I could need as much as 3 gallons,  I couldn't stomach buying another 3 gallons of epoxy, so I went with good old stinky polyester.

    


  This is the cheapest resin that US composites sells.  Just fine for this purpose.   

I had never worked such a large, flat area before.  I soon found that my old had glue spreader was not going to cut it.   The paint roller I had wasn't working.  In desperation, I ran into the house and did something I'm not proud of.   I stole my wife's squeegee. The one we mop the floor with. The one we brought back with us from Uruguay in 2004. I used it to spread nasty resin on the boat.  Worked soooooo nice, though.  I would suggest this tool to anybody.

Sorry, Honey!!!




 Here it is all sheathed.  The only regret I had was not thickening some resin and puttying the holes left by the removed screws.  Thought they would just "fill up" when I put resin over them, but they ended up as divots to fill- under the dynel.  I poked holes in the dynel with a nail and my shop hand went behind me with thickened epoxy in a syringe. 

Child labor.....   so sad. 



3 comments:

  1. Looking good!

    For future reference, my tests with T3 showed me that clamping pressure isn't required to laminate plywood. As long as you got contact, it will glue so well that the wood fails always - not the glue - when you try to split it apart. Boiled samples will split at the glue line though, but they need some serious boiling, and even then a lot of wood comes away.

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  2. Alan,

    Thanks. Don't think that I was doubting your research as to the abilities of T3 in itself. What I doubt sometimes is my ability to "get contact" consistently- and I haven't even started on the curvy part!. Laminating big sheets of plywood is a style of carpentry that I have no experience with. This is my first rodeo with "big" wooden boats, so I am having to feel my way through this. I'm just glad to live in the age of "miracle and wonder" when a person with no background in a given area can reach out to knowledgeable folks like yourself for help in real time.

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    1. No, I didn't think you were doubting my research...I only repeated some stuff here because I wasn't sure if you saw it or remembered it from my blog. It's all good :-)

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