[Rhodes22-list] Re: CB trunk delam update

[Roger Pihlaja]

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.

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.

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!

Does this make sense?

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.

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.

Hang in there, Lou!

Roger Pihlaja
S/V Dynamic Equilibrium


----- Original Message -----
From: "Lou Rosenberg" <lsr3 at MAIL.nyu.edu>
To: "The Rhodes 22 mail list" <rhodes22-list at rhodes22.org>
Sent: Monday, December 13, 2004 11:22 AM
Subject: Re: [Rhodes22-list] Re: CB trunk delam update


> >Lou,
>   ROGER:  This is going to be a Non std reply format!
>
> So, the small circular saw blade in the Dremel Multitool worked OK for
you?
>
>
>    Yes, basically its a very narrow fit even with a 1" OD diamond
> cutter blade not sure how well I will be able to cut the aft end of
> the well if I have to.  Can you recommend another tool that might
> work to remove the bulge in aft end of the trunk where the clearance
> dissipates into less than an inch of  work space??  I bet NASA has a
> laser cutting tool that would burn right through that old
> fibreglass...  Hey i could wait ten yrs and maybe it'll be sold on
> eBaY!
> ***
> >
> >If the cement is damp; then, you will probably have problems in the
future
> >with delamination.  Is there any way you can leave the exposed cement
open
> >to the atmosphere for a while so it can dry out?  Even better, is there
any
> >way to put an electric space heater blowing on it to dry it out more
> >thoroughly?
>
>   TOTALLY, has been open since Thanksgiving weekend and is exposed to
> air now, however I did cover my trunk top with wood to keep cold air
> inside to a minimum.  Will be using a hair dryer set to max temp next
> week.  Also purchasing a  MOISTURE METER SOON!!
>   Surveyor on board as soon as weather gets warm for a test of my hull
> and ballast.
> ***
>
> >
> >1. I  know you said I needed to bridge the gap btw the garolite and the
wall
> >with tape and I think I can do it .. will try to buy  medical forceps for
> >this job, but don't you think a few layers of thickened epoxy would also
do
> >if I keep the gap to a minimal space?
> >
> >Hey, if you absolutely can't get in there to laminate a piece of
fiberglass
> >tape across the crack between the G-10 patch and the centerboard well;
then,
> >troweling some thickened epoxy into the crack would be better than
nothing.
> >The trouble is, the shear strength of these polymers isn't their
strongest
> >MOC property.  You will have to worry about long term creep and sheer
> >failure.
>
>    The issue of fibreglass tape insertion is going to depend upon how
> long a set of forcepts I can buy!   Not being as experienced with lay
> up as most guys, doing this with forcepts and gloves in a space of
> 1.75" is the obvious hard part!  I think the widest section aft of
> the pivot can get the glass.
> ***
> >
> >Consider making a cardboard mockup of the G-10 patch that you can trim to
> >exactly fit the hole in the centerboard well.  Then, you can use the
> >cardboard mockup as a template for the G-10.  Once you have cut & trimmed
> >the G-10 patch such that it dry fits the hole, consider laminating half
the
> >width of the fiberglass tape onto the perimeter of the G-10 patch before
you
> >install the patch into the centerboard well.  Let the epoxy on the
> >fiberglass tape only cure to the green state & then quickly install the
> >patch with thickened epoxy bonding the patch to the concrete, thickened
> >epoxy in the crack between the G-10 patch and the centerboard well, &
> >thickened epoxy on the fiberglass tape.  This technique has the advantage
> >that the fiberglass tape will be automatically held in perfect alignment
&
> >prevents the G-10 patch from being inserted too deeply.
>
>   Thanks for that reminder re: template.  Dont think the glass tape on
> the perimeter is going to work BEFORE the G10 is laid in. What would
> keep the fibreglass tape stiff enough after being wetted?
> I was planning on inserting a filler piece of wood behind the G10 to
> fill the space once made by cement, being ultra carefull not to allow
> too much since the entire operation is to remove the bulging area not
> to increase it.  There is only about  a space of  .250" deep x  10"L
> in there of missing cement so far.  Poked around NO large voids found
> (yet).  Once the G10 is in place I was  planning on inserting a
> plastic sheet btw the laminating G10 & a straight pc of wood that
> fits the trunk space firmly.  I would hope this pressure might help
> in keeping the trunk wall as flat as possible.. suggestionss??
> ***
>
> >
> >2. Would I need to bevel the trunk wall even though its been sanded down?
> >
> >I'm not certain I understand the question.   If you are wondering about
> >sanding a relief into the centerboard well all around the edge of the
hole
> >so there is room to laminate the fiberglass tape across the crack & not
have
> >it stick up above the surface - The answer is yes, you should do that.
If
> >that's not the question; then, you will have to clarify.
>
>    Yes, sanding a relief bevel around the hole allowing room for the
> glass tape across the crack.
>   sorry about my confusing question.
>   ***
> >
> >3. Is it common on most older Rhodes for the pendant to be run right
through
> >the hole in the board or do some boats have a U-shaped SS fitting which
> >attaches through the hole?  Mine had no fitting but I machined one from
3/32
> >thick SS,  and now am wondering if there will be clearance for the bolt.
> >This part of the board has to move through the trunk the most so I
realize
> >its clearances are crucial.
> >
> >My centerboard pennant is attached with a simple hole thru the
centerboard.
> >I can't speak for other boats.  Perhaps Stan has better data.  If you
have a
> >centerboard width clearance problem associated with the diameter of the
rope
> >loop thru the hole; then, a U-shaped SS shackle could be used to reduce
the
> >width.  You can reduce the width of the thru bolt on the shackle by using
a
> >round head machine screw with a chrome plated barrel nut.  One possible
> >downside of this strategy is the extra vertical clearance required
between
> >the aft edge of the centerboard and the top of the centerboard well
because
> >of the shackle.
>
>
>    AHH now i get to use one of those BECKSON Barrel nuts i paid so
> much for on my portlights!
>    Did a carefull measurment on the vertical side as my cap is in my
> basement now along with the board. This clearance is OK so far.
>
>     Thanks for pointing out that the  rudder seems like the exact
> shape of my CB!
> ***
> >
> >Once you've done the best repair job you can with the centerboard well;
> >then, any remaining interference will have to be removed from the
> >centerboard.
> >
> >Certainly, if there are any leaks between the centerboard well & the
bilge;
> >then, these are going to have to taken care of.  At least these leaks
should
> >be relatively easy to get at!
>
>     Would you "fillet" in this space ( btw the bilge and the trunk,
> under the bolt flange) or  put glass tape around the edge of the
> trunk?
>    I could go either way but glass obviously is going to be more
> structurally sound.
>    Thanks again so much for your help!!!
>   Lou
>
>
> >Roger Pihlaja
> >S/V Dynamic Equilibrium
> >
> >
> >----- Original Message -----
> >From: "Lou Rosenberg" <steadilsr at verizon.net>
> >To: "The Rhodes 22 mail list" <rhodes22-list at rhodes22.org>
> >Sent: Sunday, December 12, 2004 5:06 PM
> >Subject: Re: [Rhodes22-list] Re: CB trunk delam update
> >
> >
> >>  Roger,
> >>
> >>    Ok got down to cutting a 10"x5" swath of the CB trunk out with the
> >>  dremel tool today.   The garolite should arrive tomorrow, and I dont
> >>  think i can remove the narrowest section of the bulging by the rear of
> >>  the board where its at the narrowest opening in the trunk.   So I have
> >>  to make the tough call and just leave it alone and not pull the board
> >>  all the way up.
> >>    Using a mirror on a sharpie pen, I was able to see the small void
> >>  where the cement had become loose and expanded,  It did feel somewhat
> >>  moist but not wet.  Getting the lower part of the bulge out is the
most
> >>  difficult and I will have to come back and work from below on  my back
> >>  , mask and goggles all the way.  Hopefully we will not get blitzed
with
> >>  as much snow as Michigan probably has already!
> >>
> >>    NEW QUESTIONS:
> >>
> >>  1. I  know you said i needed to bridge the gap btw the garolite and
the
> >>  wall with tape and I think I can do it .. will try to buy  medical
> >>  forcepts for this job, but dont you think a few layers of thickened
> >>  epoxy would also do if i keep the gap to a minimal space?
> >>
> >>    2.Would i need to bevel the trunk wall even though  its been sanded
> >>  down?
> >>
> >>  I took my cam today but didnt really have time since I am my marina is
> >>  having issues with power.
> >>  If we dont get blasted with sub zero temps in late Dec, i get a week
> >>  off from Christmas to New Years and plan to do as much as I can that
> >  > week to fix the trunk.
> >>
> >>    I did find the source of the water  intrusion to the ballast.  Where
> >>  the cap bolt flange meets the bilge there is a space where the rain
> >>  water must have found its way down into the cement.  It looks like
just
> >>  poor workmanship or a combo of water damage and not enough epoxy
there.
> >>     I will have to clean out the ENTIRE length of the CB trunk joint to
> >>  the bilge and re epoxy.  I  might glass the entire gap if I find its
> >>  been compromised through out.. That is a fun job compared to what i
> >>  have got to do  with the trunk.
> >>  BTW:   I think I actually ran my hand around that space when i
examined
> >>  the boat for the first time , cringing at how damp it was back in
> >>  August, but would have had to get my fingers behind the bolts to feel
> >>  the crack and space opened by years of neglect and too little epoxy or
> >>  glass.
> >>    I plan to bring the cleaned up board next time and see how it fits.
> >>
> >>    ONE LAST questions whenever you get a chance:
> >>
> >>  3, Is it common on most older Rhodes for the pendant to be run right
> >>  through the hole in the board or do some boats have a U shaped SS
> >>  fitting which attaches through the hole?  Mine had no fitting but I
> >>  machined one from 3/32 thick SS,  and now am wondering if there will
be
> >>  clearance for the bolt.  This part of the board has to move through
the
> >>  trunk the most so I realize its clearances are crucial.
> >>    Thanks Roger,
> >>     Lou
> >>
> >>
> >>  __________________________________________________
> >>  Use Rhodes22-list at rhodes22.org, Help? www.rhodes22.org/list
> >>
> >>
> >
> >
> >
> >__________________________________________________
> >Use Rhodes22-list at rhodes22.org, Help? www.rhodes22.org/list
>
> __________________________________________________
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>
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