[Rhodes22-list] Re: CB trunk delam update

[Lou Rosenberg]

  Roger,
  Although I just did cut out a 10x5swath of  cb wall, there was a 
hole from the previous weekend where I was trying  to sand down the 
bulging area and cracked through the laminate.
  Which made me aware that the laminate is of varing thicknesses 
throughout the trunk.  Actually I mis spoke as it has only been a 
week since that piece cracked not two wks.



>Lou,
>
>Right off the top of my head, the only other cutting tool that comes to mind
>would be a small end mill that would be chucked up into the Dremel Multitool
>using the flex drive.  These cutters resemble the small burrs the dentist
>uses on your teeth when you have a cavity.



    I know what you are referring to and will investigate.  The flex 
drive unit itself is almost the width of  the narrow aft section ,  I 
ve mounted the flex drive on a strong pc of wood but will have to go 
to a steel rod next so I can  manipulate the blade into the tight 
corners.



>If you just cut the bad FRP laminate out this past weekend, how can the damp
>cement behind it have been exposed to the atmosphere & drying out since
>Thanksgiving?
>
>I'm not sure you understood my suggestion re the fiberglass tape.  Let me
>take another run at explaining it.  Imagine you are going to build a
>"flange" on the centerboard well side of the G-10 patch.  Up on the
>workbench, where everything is easy to get at & nice to work with, you
>laminate half the width of some fiberglass tape all around the perimeter of
>the G-10 patch.  In effect, you will have built a flange of fiberglass tape
>that extends beyond the edge of the G-10 patch.  You let the epoxy cure to
>the green state so the fiberglass tape is good & stuck down & starting to
>get fairly stiff.  With half the width of the fiberglass tape stuck down to
>the G-10 patch, the fiberglass tape should behave nicely when you laminate
>it into position in the centerboard well.


  GOT IT NOW!! thanks for the more descriptive picture.

>
>After putting an epoxy tie layer on the cement, I would fill in the rest of
>the void space between the G-10 patch and the cement with thickened epoxy.
>Press the XS epoxy out around the sides of the G-10 patch as you push the
>G-10 patch home.  The epoxy squeezing out around the sides of the G-10 patch
>will provide the adhesive you will need for laminating the fiberglass tape
>down to the centerboard well.  As long as you can get in there with some
>sort of small tool, like say a tongue depresser, to wet out the fiberglass
>tape as the epoxy squeezes out underneath it; then, this technique should
>work slick as a whistle!



NEW QUESTION!!*************

  Roger,
   DOES the tie layer of epoxy has to be cured before I proceed with 
the G10 patch?
   That part of epoxy/glass work is a bit confusing to me..
  I will most likely be working in 40 - 45F temps under my tarp here 
so I am guessing it may take a while for that tie layer to even begin 
to  kick.   And I assume I need to place plastic under the glass tape 
so it will not adhere to the worktable wood under it?
  sorry to be stating the obvious but you can see we are writing a 
book here on  "FIBRE GLASS LAY UP FOR DUMMIES!"


   I think I might just sand down the other narrow aft bulges with my 
small grinding tool if I cannot cut it out as that will just take 
care of the bevel at the same time.

>
>Your idea of a piece of plastic & a board to hold the G-10 patch in
>alignment while the epoxy cures will probably work OK.

  Thanks!

>
>I like the idea of the fiberglass tape around the edge of the trunk vs. a
>simple fillet of thickened epoxy.  With the fiberglass tape, there will be
>no concerns over strength & it will be absolutely waterproof.


   Yeah thats gonna be  an easier job than the trunk but getting the 
bad FRP our from around the edge is still a big job!  I might see the 
voids come into play there and will be pokin around to see how deep 
my driver goes before I hit the hull... yipes7^$#@!!

  thanks again Roger!
  Lou