STRIPPING THE HULL FOR PAINTING
Author |
Peter Aston |
Date |
Jul 2004 |
Map
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Summary |
A haulout experience in Townsville leaves
us disillusioned with the paint Rep there. |
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Ready to launch - Looks OK from a distance! |
WHAT WE EXPECTED DURING THE HAULOUT
It has been 14 years since illywhacker
hit the water for the first time. The hull was
well prepared then with a very fair surface and at the time
we wished for many subsequent years of trouble-free haulouts.
This we achieved until the May 2004 haulout, a 22 day nightmare
in Townsville. Initially out for a quick anti-foul, normally
3 or 4 day job for me, the yacht was spotted by the local
paint representative who seized upon some loose paint on the
hull as an opportunity to recommend a complete surface strip
and recoat. Always a sucker for a high gloss finish and a
smooth underbody, we accepted a quote from his recommended
strip and application contractor.
illywhacker
is a well-built ferro-cement hull, glassed with epoxy resin
below the waterline and epoxy faired above. Inside, much of
the hull surface has been saturated with vinyl ester resin
and glassed to form a bonding surface for the plywood fitout,
allowing the bulkheads and structures to be attached with
glass fillets. Even the best ferro hulls have minute pockets
of air within the hull which form during the plastering process
and it is common to see small damp patches on ferro hulls a day
or two after haulout as the water trapped in such voids slowly
seeps to the surface. illywhacker
is no exception and due to the epoxy glass coating below the waterline, this can take a few days longer to dry out.
The base surface for the paint system is therefore epoxy and as the hull is perfectly fair, the result should be equally as good as any production fibreglass boat. The finish obtained in Japan at the previous topsides respray proved this, as can be seen in the end photo.
WHAT WE RECEIVED FOR OUR MONEY
The contractor arrived with an impressive array of equipment ready to strip the hull, above and below the waterline and quickly erected the protective barrier required by the EPA to prevent dust dissemination. The plan was to use a bicarbonate waterblast technique which allows a fine control over the paint removal process. Unfortunately the contractor was unable to produce an EPA license but he and his team cheerfully set about hand sanding. Removal of the underbody paint was achieved over a period of several days producing a good finish back to the epoxy coating (see photo). As the above waterline finish exhibited an area in which the polyurethane paint had peeled from the epoxy hi-build below, it was decided to attempt to encourage this through the use of masking tape to peel away all of the old paint - an idea that worked very well after we left it for a few days before peeling it away. This method ensured the original hull fairing was retained, something we felt sanding would have been unable to achieve.
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Epoxy sheathing intact after removal of underbody
paint and before blasting removed the sheathing |
Peeling away the masking tape
AND paint above the waterline - this was a great idea
as it maintained the original fairing |
Several damp patches were visible through the epoxy sheathing so the Paint rep recommended a water blast to ensure that only fresh water remained. The contractor unfortunately used a high pressure blast and a large section of the sheathing came away at the first squeeze of the trigger. I had no option but to agree to all of the material being removed - back to a ferro surface. The paint rep used this opportunity to recommend application of a glassfibre-impregnated epoxy coating of 600 microns. This was applied after the above waterline finish was completed to allow maximum time for the hull to dry out. The contractor had the equipment to spray such a thick paint and laid up layer after layer wet on wet until it suddenly became too heavy and sagged, dripping to the ground - what a mess! After a difficult sanding the finish below waterline was worse than before with an indeterminate thickness. A binder then antifoul were applied over this surface.
While we had been waiting for the hull to dry, the contractor sanded and sprayed the topsides with a polyurethane which I now believe was an industrial coating, not suitable for the quality finish that a yacht demands. This he did 3 times, trying to achieve the gloss finish he knew we wanted. Whether it was the paint type, the thinners or the application I don't know. The climate was perfect - dry with little wind, but the finish was a consistent orange peel effect. The Paint rep amazed me by saying that was the best finish achievable and I should be happy with the result. As the marina is full of boats sprayed on the same hardstand with a far more acceptable finish I remain unconvinced. To add to my disappointment with this person he announced there would be no warranty as he claimed the hull had not been dry enough.
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Epoxy hi-build all over, ready to spray finish coats |
Disappointing orange-peel finish, top and botom |
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The photo on the left is the
finish obtained previously on an outside hardstand during
a wet winter in Japan - for about the same price. I expected
this result in Townsville. |
The marina at Townsville is wonderful and the haulout facilities and staff are the best you'll find. Sadly there is always someone wanting to sell a sub-standard product to the unwary. Next time I'll be more discerning.
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