steel boat painting

[Idlerboat]

greetings from oz.
l am building a roberts offshore 38 in steel and would love to get any information on painting systems (manuals etc) email to martin@tecsol.com.au

also problems that you have had.
regards.

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[Ships_Cat]

I would expect that all the major paint manufacturers (International, Jotun, etc) will all give you a detailed painting specification for your boat which they will stand by as long as compliance with it is proven. International, for example, also have free information booklets which their distributors normally hold in stock. The best specification will be based upon an epoxy primer/undercoat all over and a linear polyurethane topcoat above the waterline and, in my opinion, that is the only sensible choice.

The interior of the boat should be coated with the same specification except that the topcoat is omitted. You will find that many will now advise against zinc rich primers, at least for the underwater surfaces and in my view that is the best current advice (you then need to be careful about what is on your plates if they were delivered primed).

Ensure that the coatings are sprayed, not brushed or rolled, so that the correct thicknesses are obtained.

If the boat is to be faired, the paint manufacturer should be advised and he will include that in his specification. When sanding the fairing take care that one does not sand through to the metal and take the sand blasting "bite" off the steel, especially underwater - if you do you will likely end up with an area of poor paint adhesion during the life of the boat. Regardless of any amateur advice that you get, have the boat blasted to the paint manufacturer's specification and do not compromise that in any way whatsoever - so do not sand or grind any part of the steel as an alternative, it will likely lead to problems later.

John

<hr width=100% size=1>I am the cat but I am only 6.

 

[AndrewB]

Also own a Roberts 38, now 15 years old. I'd agree completely with Ships_cat's advice. The International Paints recommendations on yacht paint systems can be found <A target="_blank" HREF=http://www.yachtpaint.com/UK/boat_painting_guide/default.asp>HERE</A>, but there is tons of stuff on the internet, often based on project boats. However, it is important not just to follow received advice but to consult the paint manufacturer specifically regarding your project. The major companies will offer detailed advice. That way if anything goes wrong with the paint job - a not uncommon event, which can cost a mint to fix - you will have a proper come-back.

Incidentally the old general rule on preparatory grit blasting for a steel hull was to specify SA 2½ standard (ISO 8501) with the first epoxy primer coat applied within 3 hours of blasting.

Regarding problems - in fitting out try to think 15 years down the line when the original paint coating starts to fail, and how you can provide access to every nook and cranny to enable the yacht to be maintained. Minimise the number of small holes in the steel by welding rather than through-bolting, and avoid direct contact between wood and steel, in all places that might tend to get damp.