A Bilge Painting Guide – The Floating Boatyard
Bilge painting is one of those less attractive jobs you will have to take care of as a boat owner. A well maintained bilge is important factor in function and safety of your boat. Serious problems can be caused by neglecting your bilge. We have seen bilges which had not been painted in long time. We have come across: leaking rudder stems, leaking diesel tanks, holes in gas lockers and dangerously corroded hull plates.
Bilge Painting – Before You Start
The first thing we do when we starting a bilge painting job is to professionally clean and degrease all of the areas we will work on. Please see our post on bilge cleaning for more information in this. It is important to completely remove any dirt, oil, diesel and other contaminants. Special care must be taken in corners and hard to reach areas. (We remove any fittings like calorifiers, diesel tanks, batteries, etc., before we begin work.) All this is needed to make sure that the new bilge paint properly adheres to the steel.
A very dirty bilge. This is the worst case of neglect we have come across so far.
Bilge Painting – The Prep Work
The amount of prep work needed will depend on the condition of the existing bilge paint. In many cases we have come across, the paint needs stripping back to steel. In some cases is is sufficient to prepare the existing paint. This is possible when the bilge is well maintained and kept free of water, oil and dirt. We remove any loose or flaking paint. A scraper, sharp wood chisel, wire brush or sandpaper can be used for this. All of the surface will need to be well keyed with sandpaper before any new coatings are applied.
The same bilge after a thorough clean. We can now begin the prep work.
Bilge Painting – Priming and Undercoats
Whether we have opted for a full strip back or preparation of the existing bilge paint, we will need to prime and undercoat before painting. A marine grade primer such a Teamac Zinc Phosphate Primer is a good choice for this. The first coat can be mixed with Owatrol Oil to condition it. This will improve paint flow tricky areas and rough surfaces and will improve anti rust properties of the paint. We then apply a second coat of primer before painting two coats of undercoat. Bilge painting or otherwise, be sure to properly work the paint into rough and pitted surfaces to achieve full coverage. deep pitting should be filled before painting.
A bilge with primer applied.
Bilge painting – The Top Coats
Bilge painting the top coats must be done with the right materials. Teamac Bilge Paint or International Danboline are the ones we use most often. The paint used for bilge painting needs to be strong and resistant to oil, fuel and water. Standard marine top coats or household paint will deteriorate fast in a bilge environment. This will lead to exposed steel, which will get damaged and corrode. Boat repairs of that nature are going to be expensive. We usually recommend to have three coats of bilge paint applied. This will help insure that we achieve an even coverage and the minimum recommended thickness of bilge paint.