Fibre glass 'repairs'

Fibre glass 'repairs'

Post by R.J.Ha » Sat, 30 Jan 1993 18:38:02


I have two small holes in my boat - these are the inlet and outlet for a
sal***er pump, now removed. Obviously, I wish to plug the holes.

What is the best way to do this?

The holes are small, close to one another, and 'clean', ie: they are sharply
ccut, etc. I am reluctant to cut a larger hole in the hull with bevelled
edges, etc. to do a 'proper' repair on such small holes, because the hull is
in good shape - no osmosis etc.

What I thought was that I could clean up the area round each hole, both insid
and out, including the insides of the holes. Then, drive tapered bungs of a
suitable size, soaked in resin into the holes so that on the outside of the
boat at least, the bungs are below the surface of the hull. Fill the resultant
depressions with chopped mat and resin, dry, sand and repaint. On the inside,
I would do the same with the addition of some layers of glass fibre mat over
a larger area.

Does this sound sensible, feasible? Comments and suggestions welcome.

Thanks.

Roger Hare.

 
 
 

Fibre glass 'repairs'

Post by David Ziel » Sun, 31 Jan 1993 01:06:35

Quote:
> I have two small holes in my boat - these are the inlet and outlet for a
> sal***er pump, now removed. Obviously, I wish to plug the holes.
> What is the best way to do this?
> The holes are small, close to one another, and 'clean', ie: they are sharply
> ccut, etc. I am reluctant to cut a larger hole in the hull with bevelled
> edges, etc. to do a 'proper' repair on such small holes, because the hull is
> in good shape - no osmosis etc.

> What I thought was that I could clean up the area round each hole, both insid
> and out, including the insides of the holes. Then, drive tapered bungs of a
> suitable size, soaked in resin into the holes so that on the outside of the
> boat at least, the bungs are below the surface of the hull. Fill the resultant
> depressions with chopped mat and resin, dry, sand and repaint. On the inside,
> I would do the same with the addition of some layers of glass fibre mat over
> a larger area.
>   Does this sound sensible, feasible? Comments and suggestions welcome.
>   Thanks.
>   Roger Hare.

I would not do this.  You will create stress points from the outside to the
inside and introduce water into the layers of fiberglass, resulting in
blistering all around the area.  You should feather the outside with a slope
of 1 to 12 (i.e. 12 times as large as the depth of the feather) to half way.
On the inside do a 1 to 6 ratio.  Then use altering layers of cloth and mat
which are proper sized for the depth you are at and build up the inside and
outside to the proper thickness.  

Your solution has reasonable strength on the inside of the hull, but if the
hull flexes at all, the plug will disconnect from the surrounding fiberglass
resulting in a hairline circular fracture all the way through the hull.

David Zielke
'Botany Bay'
Cal 35 Hull 006



 
 
 

Fibre glass 'repairs'

Post by USA » Wed, 03 Feb 1993 03:23:43

Quote:

>I have two small holes in my boat - these are the inlet and outlet for a
>sal***er pump, now removed. Obviously, I wish to plug the holes.

>What is the best way to do this?

[stuff deleted]

Quote:
>Does this sound sensible, feasible? Comments and suggestions welcome.

>Thanks.

>Roger Hare.

I pulled a thru-hull off my Bristol Corsair last year and was faced with the
same problem. After some discussion on the net, I settled on a technique
recommended by (I think) Wayne Simpson. I ground down both sides into
nice cone-shapes, then I epoxied-in progressively larger disks of
heavy matting. I started on the outside, and finished on the inside.
I am very pleased with the results, and have no trouble sleeping
on-board. Any other technique would leave me nervous. NOTE: Use
West System epoxy! This will seal the existing glass from water.
Besides, the stuff is a real joy to work with. Lay it up, cover
with wax paper and let it harden up. Then mix it with one of their
fillers for the subsequent surfacing. Never again will I use standard
resin for 'glass work.
When it comes to work under the water line, take the time to do it
right the _first_ time. It's too late to consider alternatives when the
hull is resting on the bottom!!!

        tomb..

Laser #15878
Bristol Corsair #270

 
 
 

Fibre glass 'repairs'

Post by Dick Luc » Thu, 04 Feb 1993 03:04:53

West System Epoxies (I think that's their name) recently offered a set of
manuals for fiberglas repairs for about $4.00.  I ordered them and they have
a wealth of information.  They suggest that you grind the hole out to give
a very shallow taper (1 in 10 or so) as was suggested by several people on
the net.  If there is interest, I can get the ordering information and post
it.

Alternatively, rather than messing with fiberglas, resin, gelcoat etc, why not
get some blank through hull fittings and seal them in place?  Since the
holes must have had some feedthroughs installed in them when they were in
use as inlets/outlets, somebody must make blank-offs that can be bedded into
them and be at least as reliable as the original hull fittings.  This would
be clean, neat, inexpensive , with the only drawback being perhaps some
additional drag.

Dick Lucas

 
 
 

Fibre glass 'repairs'

Post by R.J.Ha » Thu, 04 Feb 1993 22:45:56

Thanks. Excuse my notanswering by mail but our stupid address tables
seem not to have heard of you, soI am forced to reply like this.

Sounds useful - I think I'll adopt this approach - or get a pro to do it
for me...

Roger Hare.