Hull repainting??????

[Bejasus]

Just purchased first boat. Interior immaculate, however requires some repairs to the bow.(bad docking) At present hull is light blue with a couple of darker blue stripes each side. At present out of water. Needs antifouling & repairs to bow and would like to repaint the hull white.
Question: What preparation do I need to do prior to repainting. Ie rubbing down. What to use? Power tools etc?
Any advice appreciated. I beleive current paint original although now some 26 years old.

"I am the master of my fate: I am the captain of my soul."..........I think????

 

[salamicollie]

Hi, repainted our hull last winter. You need to rub down then fill (probably polyester filler) undercoat, fill again under coat and then two top coats.

We had mooring damage and in the end we used an air sander with 120 grit all over to get a flat surface plus a bit of filling. If the damage is not too bad you can manage with an electric sander and a finer grade but its slow... Use a fine grade P600 or better still a Scotch brite pad between the final undercoat and then two topcoat. depending on the top coat you use you may need to significantly thin the topcoat for painting in the summer- and if its the first time you have painted a surface like this be prepared have to rub down heavily again do an extra top coat to get rid of the flaws from the first attempt.

Note Spraying gives the best result but careful use of brush and roller can give a result that looks damn good on the water but is easy to touch up when you get some damage.

 

[Gaffer]

There are so many options available to you as far as paint systems go...here are a few.......assuming that you are going to do the work yourself........and any filler you use will have to be compatible with the paint which goes over it.......the initial preparation will be the same for all systems.......

Epoxy :- Good hard finish - poor colour retetion - difficult to do well - requires controlled environment for best results - should last about five years before repainting.


2 pack Poly :- Good hard finish - good colour retention - difficult to do well - requires controlled environment for best results - should last about three to four years before repainting.


1 pack Poly :- Good hard finish - good colour retention - not quite so difficult to do well - best results in controlled environment, but not absolutely necessary - should last about three years before repainting.

Alkyd :- Not such a hard finish - reasonable colour retention - easily applied - can be applied in a greater range of humidity and temperature - requires repainting almost every year.

Good luck.............

 

[vyv_cox]

Your options may be severely limited by what was applied 26 years ago. This was almost certainly a conventional paint, as two-packs, polyurethanes, etc were probably not available then. You cannot put a two-pack on top of a conventional paint and some modern single packs may contain solvents that will react with the original paint. Verify with the paint manufacturer that what you choose is compatible, and try a small area first before painting the whole boat.

I have had very good results with Toplac, a single pack that contains some strong solvent but does not appear to react with old paint films. Its gloss and colour retention are virtually as good as a sprayed two-pack.

As with painting in every type of application, its the preparation that makes or breaks it.

 

[dickh]

I have also used Toplac, but spent a long time in the preparation. Again check compatibility. It came up really well with two coats, I was well pleased.

 

[PuffTheMagicDragon]

Did it three years ago (Spring 1999). Original gelcoat was very dark blue and this had been hand-painted over, in a similar colour - previous owner was a Scot! I was tempted to use Toplac but I think that you need two persons working as a team, one with roller and the other with brush. Local weather would probably be too warm for successful levelling / smoothing with a brush without leaving marks. (Today it is 28 Celsius and it's only the middle of June)
I opted for a two-pack acrylic, i.e. paint, activator and thinner, of a kind that is used for automobiles. The local paint manufacturer persuaded me to spray it, explaining each stage as work progressed. Previous experience was limited to one metre class R/C boats!
ALL traces of the existing paint were removed with an orbital (?) sander of the type that takes half a sheet of 'wet-and-dry' abrasive. Locally we call them 'vibrators' but I don't think that that is what you'd call them over there. This is the tiring part because good machines of this type are quite heavy and you need to press while moving it along.
Make good any damage that you find - scratches, gouges, patches, etc. - and apply primer / filler, rubbing down wet between coats. Mixing about half a teaspoon of dishwashing liquid in a bucket of water helps to prevent the paper from getting gummed up too soon. Conscientious attention at this stage will determine the final finish. You cannot skimp; you're employing yourself and, if you try to cheat the employer, you'd be cheating yourself!
It can be done; if you do decide to go along this route remember:
(1) Make sure that the place is well ventilated.
(2) Use a good type of face mask (absorbent) because of the fumes. Ideally you should be using a type where clean, fresh air is fed directly to the mask but, since this is a one-off job and you do not work in confined spaces, you should not get into trouble.
(3) When you rub rown between coats avoid the temptation of running your hand over the surface to "feel how smooth" as this leaves finger marks that could affect inter-coat adhesion.
(4) In any case, use the 'pre-cleaner' that is supplied by the manufacturer just before each coat.
(5) MOST IMPORTANT! IF YOU HAVE ANY FORM OF CARDIAC CONDITION OR HAVE RESPIRATORY PROBLEMS, DISREGARD ALL OF THE ABOVE AND GET SOMEONE ELSE TO DO IT FOR YOU.
I am pretty sure that there will be people who will strongly disagree with this (two for sure!) but I feel that, if you are a sensible person and use common sense to guide you, you can do like I did.
Incidentally, my 'new' colour is White and it is still brilliant after three years in the Mediterranean. You should do even better with your climate. Note that I only haul out once a year (for antifouling) at the start of the season, 2 to 3 weeks maximum.
Good luck!


Wally

 

[Gaffer]

Pretty well all the acrylic two packs used in the automotive industry use isocyanate activators so choose your respirator filter with great care to be absolutely certain that it is the correct one should you decide to go for this option.

One big advantage of using the automotive acrylics is that any small scratches can be compounded out. The one major disadvantage is that the only way to get a decent finish is to spray.

 

[Bejasus]

Thanks all

I think I am swaying towards an epoxy undercoat, rub down & second coat if necessary followed by 2 coats Blakes 2 pack poly topcoat. Gave go ahead to yard to repair bow damage today as I won't be home until beginning of July. That way I should be able to devote my time to filling the small nicks etc and rubbing down & repainting hull white. Hopefully I acn have her back in the water again before I have to leave again at the end of the month. Thanks for the advice.

"I am the master of my fate: I am the captain of my soul."..........I think????