[Rhodes22-list] A Special Full Moon

[Graham Stewart]

Jesse:
I redid the bottom of my boat a few years back and, so far as I can tell it
was the first complete strip and repair in its 40 year life. It can be a big
and unpleasant task if you have osmotic blistering. I did. I used MANY
layers of paint stripper for boats and a scraper to remove the old paint. I
really didn't want to sand the old antifouling paint because the dust is so
toxic. Even so, you want to protect the ground and you so that you can clean
the site thoroughly afterwards. 

Once the paint is mostly removed any osmotic blistering will become very
obvious as the tops of the bumps will come clean before the valleys between
them. I then used a dremmel with an abrasive drum to grind out all of the
disks down through the gel coat to the substrate - all 100 million of them.
Ok, that is an exaggeration but if the bottom is too bad it might be worth
having a professional soda blast the bottom to completely remove the gel
coat and then have the surface rebuilt by a professional - preferably in
epoxy. Once the bottom is stripped it needs to dry out thoroughly and that
can take months. It is best to strip it in the fall and let it dry all
winter. Once dry all of the blister holes need to be filled with epoxy
paste. There are a tone of YouTube videos and online instructions about this
part of the process and you would be well advised to take the time to become
familiar with the process.

Once the bottom is ready it is essential to give it a very thick epoxy
barrier coat. This is far more than a "sealer" coat. The two major options
are epoxy from a supplier like West system or use Interlux 2000E. Although I
have a lot of experience with West System epoxy I chose to go with the
Interlux 200E and I am glad I did. It is also an epoxy but also contains
tiny metal disks. It looks and goes on like paint easily with a roller. It
comes in white and grey. Get both and alternate the colors. Otherwise you
will miss areas very easily. I bought a gallon of each and used it all. I
think they recommend 5 coats but I applied 6 because I had the paint. As
soon as the coating tacks up you can apply another so over a day you can
apply at least three coats. No sanding is required between coats so long as
you apply each coat before the previous one cures. Applying the coating is
trivial compared to the work involved in preparing the bottom so I think it
would be insane to skip the barrier coat.

If your bottom has no osmosis consider yourself blessed. Even so I would
definitely adding an epoxy barrier coat. 

I have attached a few photos of the process.


Graham Stewart
Agile 1976 Rhodes 22
Kingston Ontario



-----Original Message-----
From: Rhodes22-list [mailto:rhodes22-list-bounces at rhodes22.org] On Behalf Of
Jesse Shumaker
Sent: Friday, December 13, 2019 12:11 PM
To: rhodes22-list at rhodes22.org
Subject: Re: [Rhodes22-list] A Special Full Moon

Since you mentioned bottom job, I'm curious if you (or anyone on the list)
have had to sand down the original bottom paint from before and apply a
sealer before reapplying bottom paint.  

I was able to secure a slip next year so bottom paint has become a
consideration for me.  Fortunately my boat already has the bottom paint from
GB (it's the orange ablative) in fair condition since it hasn't ever sat in
the water for an extended period: it has always been on a trailer or on a
lift.

The owner of the local sailboat shop took a look at my boat and he mentioned
that it did not appear there was sealer under the bottom paint.  He
mentioned that if blisters show up when I haul it out next year, then it
would be best to sand off the bottom paint and apply sealer and then bottom
paint on top of that.  Just curious if any one else has had to go back and
apply sealer before applying more bottom paint.  Thanks for any insight on
this.



--
Sent from: http://rhodes-22.1065344.n5.nabble.com/
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