[Public-list] Bottom Job

[George Dinwiddie]

I'll second that opinion.  I've known of a couple A30's that had more 
problems after barrier coating than before.  In general, A30's don't 
blister much.  My theory is that the gelcoat is so porous that the 
hydrolyzed resin byproducts pass back out through the gelcoat without 
lifting it.  Also, keeping the bilge dry seems to correlate with lack of 
blistering problems.

In any event, for a small area, I would just grind and fill those 
blisters.  I've never known of an A30 to have blisters to the point of 
threatening the integrity of the hull.

If you do decide to barrier coat, you'll need to really dry out the 
boat, much more than just a winter on the hard.  Maybe a winter of 
vacuum drying or a year of covered storage.  Maybe more.  And I'd 
suggest that you barrier coat the bilge, too, as I think that water 
penetrates just as much from the inside if you let it accumulate in the 
bilge.

I recommend the Drip Less packing described on 
http://www.alberg30.org/maintenance/MechanicalPropulsion/StuffingBox/ so 
that you don't need to let the stuffing box drip.  Store your charts in 
the bilge.

  - George

John Irving wrote:
> I've been considering an epoxy coat "bottom job" as well because I'll
> be replacing bottom paint in the next year or so.
> 
> I got an opinion from a trusted boatbuilder who advised against epoxy
> barrier coating unless the owner is already making significant blister
> repairs. He felt that problems can be created by sealing moisture *in*
> the laminate and blocking its avenue of migration out. He was aware of
> instances where epoxy coating a hull as a preventative measure
> actually caused blistering where none existed before.
> 
> I'd appreciated hearing about the experiences listees have had with
> epoxy barrier coating.
> 
> John #284
> 
> On Thu, 20 Jan 2005 08:41:10 -0800 (PST), Michael Connolly
> <crufone at sbcglobal.net> wrote:
> 
>>Roger,
>>Gougeon Brothers, Inc. publish several booklets that detail procedures for fiberglass repairs.  One is specific to Gelcoat Blisters.  When I did a bottom job I found that the Technical folks at Interlux were superb.  Since you are doing the full Monty I would strongly recommend applying an epoxy barrier coat of your choice.  I used Interlux products exclusively and have been very pleased with the results.   Oh yeah..  be sure to visit Popeyes web site to purchase the final top coat.
>>Michael
>>
>>Roger L Kingsland <rkingsland101 at ksba.com> wrote:
>>Albergers,
>>
>>In asking about "careening ship," I forgot to ask the more important question. How do I do a bottom job? The deck and topsides are ready for paint. I have gotten down to the gel coat a few inches below the boot stripe and discovered a total of about one square foot of blisters. I don't know if this means I should expect more or the hull is in good shape. Is it customary to sand blast everything then refinish the hull or should I take less drastic measures? It was quite a chore getting the few inches of bottom paint off in the area of the waterline. I used several coats of stripper and still had to do allot of sanding. I would appreciate any suggestions, particularly "how to" reference material.
>>
>>Thanks
>>
>>Roger 148
-- 
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   When I remember bygone days                         George Dinwiddie
   I think how evening follows morn;            gdinwiddie at alberg30.org
   So many I loved were not yet dead,           http://www.Alberg30.org
   So many I love were not yet born.
                                             'The Middle' by Ogden Nash
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