[Rhodes22-list] Progress on keel repair and sanding the slot

[The Rhodes 22 Email List]

As some of you will remember I was working on the keel and in particular
wondering how I might fill voids that I found within it. I have just
completed filling the keel, as best I could with polyester resin. I did this
by drilling holes along the top of the keel from the outside and anywhere I
thought there might be a void. I searched for voids by tapping the surface
with a wooden handle of a large screwdriver. This is not a fool-proof method
in that after drilling some holes I found no indication of a void. On the
other hand I also found some large voids. I also drilled about 6 holes down
into the keel through the cabin sole. I injected the resin, thinned slightly
with acetone, into the holes in the side of the keel until the void would
take no more. I would then cover the hole with masking tape and move up
higher and inject the resin there. Once I had injected as much resin as I
could through the side holes, I covered them with masking tape and injected
more resin down through the holes in the cabin sole. In total I injected 3
gallons and am still not certain I have filled all of the voids. Still,
three gallons represents  a lot of space particularly if it becomes filled
with water and then freezes. 

If you are anything like me, you have spent countless hours thinking about
how to sand the inside slot of the keel. The slot is about 1' deep and
varies in width from about .5" at the stern to about 2" in the middle. The
best that I could come up with was to attach a round sanding pad with a 20
grit disk to an aluminium strip, reinforced with .5" strip of aluminium
angel stock that was in turn attached to a scraper attachment for a
reciprocating saw  - see attached picture. This works to a point. The
problem is that the inside of the slot is not smooth. There are many dips
and valleys that the sander cannot reach short of excessive sanding of the
surrounding area. The other problem is that it is very difficult to see what
is happening and you are unable to feel more than a few inches into the slot
with your fingers. For the ends of the slot where the sander it to thick to
reach I taped a strip of coarse sandpaper to a length of .5" metal conduit
and sanded it manually- see picture attached.

If anyone has developed a better way to thoroughly sand or otherwise remove
antifouling paint from the slot I would appreciate hearing about it. Since I
will be coating the hull with epoxy I would like to so the same with the
slot but I worry that remaining antifouling paint in the slot will not allow
the epoxy to bond.

Finally, I have completed the osmosis and hull repair in that I have dug out
any blisters or cracked gelcoat and filled with epoxy and filler. I have
attached two photos that show the extent of the repair in some areas. Where
the front of the trailer bunk pressed in on the hull I found that the cracks
extended through the gelcoat and into the substrate - although not through
the substrate as best I could tell. This required grinding out the area and
patching it with several layers of cloth before using the filler to fair the
area. Later I will reinforce the hull on the inside. In some areas the
gelcoat blistering was extensive and did not become visible until the
surface was sanded at which point small openings that looked like a rash
became visible. By rights I should have removed the gelcoat completely and I
worry that the repair will be inadequate. But the prospect of that much
grinding and fairing was more than I could contemplate. Given that the boat
is 40 years old, I figure that if my repair lasts as long as the original
gel coat, I will be happy. I will be 107 by then an probably past my active
sailing stage anyway.


Graham 
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