small text size medium text size large text size print this article mail this article  

Boero Defender Underwater Epoxy Primer 613

Using State of the art Epoxy Technology to deliver maximum underwater hull protection.

07 December 2010

Boero has been manufacturing high quality paints since 1831. The founder, Bartolomeo Boero, was quick to learn the pure aesthetic aspects of paint, with superior protective qualities, would be key to his success. Today, 179 years later the business is still managed by the same family with the same commitment to quality, the environment and aesthetics for the marine market. Genoa, Italy is where the company was started and offers close proximity to the sea and the growing yacht building industry in Viareggio, Italy.

• High performance underwater primer to DEFEND and PROTECT hulls
• For the prevention and repair of Gelcoat Blistering or hull osmosis
• Contains Mica Platelets to block water from getting into the hull
• Highest Solids means less coats, less cost, less time to apply
• Ideal for Fiberglass, Aluminum, Steel, Keels and Wood Hulls
• Excellent for propellers, rudders and shafts with antifouling paint


Gelcoat blistering, or osmosis as it is sometimes called is the result of damage below water caused by the migration of sea water into the fiberglass layup of GRP hulls. In some instances water can pass through antifouling or bare hulls by finding passages through the gelcoat and into the laminate of the fiberglass hull. Gelcoat is used in the construction of the hull to, not only look good, but also to protect the laminate from water absorption.

In some instances no matter how much care a boat builder takes in building the hull there could be some areas of dry fiberglass fibers within the hull which can absorb water. This water accumulation can build pressure which will want to release and equalize itself to areas of lower pressure. Osmosis is the process by which areas of high concentration of water pressure moves to areas of low water pressure through a semi-permeable membrane or gelcoat in this example.

When this water pressure begins to equalize it bumps into the gelcoat and may cause the gelcoat to expand or form a blister before the water pressure is released. These gelcoat blisters will need to be removed by grinding, filling and priming. By removing the blisters and properly sealing these areas the hull will once again be protected from water absorption. This will not only protect the hull but will also protect the value of the boat.


The best approach to avoid gelcoat blistering below water is to add additional thickness of epoxy primer to create a greater water barrier to prevent water from reaching the laminate of the fiberglass hull. By adding 12 mils of epoxy primer to the existing fiberglass gelcoat there will be a greater barrier to keep the water from being absorbed by the hull.

But are all epoxy primers the same? The answer to this question is no!

Some epoxy primers are more effective at blocking the permeation of water than other epoxy primers. Defender Underwater Epoxy Primer 613 is specifically formulated to exceed all of the important criteria for marine underwater epoxy primers.

Boero Defender Underwater Epoxy Primer 613 is a water resistant two-component epoxy primer to protect and defend hulls from water migration that can cause damage to the hull. This damage can come in the form of osmosis or gel-coat blistering on fiberglass, corrosion on aluminium or rust on steel.

Defender Underwater Primer 613 is a high build formulation with mica platelets, which form a layered barrier within the coating to block the water from reaching the hull. Unlike other products for this purpose, Defender Primer 613 contains an anti-corrosive pigment to help prevent corrosion and oxidation of aluminium and steel. It is a high solid, fast dry primer
that meets all VOC guidelines.

Due to its fast drying properties, multiple high build coats can be applied in a single day,
making it easy to complete priming and painting in one weekend. For these reasons Defender Underwater Epoxy Primer 613 is well suited to be a universal underwater primer to protect the hull under all types of antifouling paint, on all types of hulls. All of the raw materials used in Defender meet or exceed the most stringent US standards for two component epoxy primers. This product will defend the bottom of your hull against the migration of water to the hull surface.



The answer is significantly that Boero has specifically formulated Defender primer to address the shortcomings of older epoxy primers. For that reason Defender has much higher volume solids which means each application will build higher than any other primer for this purpose. Defender is a full 60% solids product. As a result of the higher solids Defender has the lowest solvent emission available on
the market.

Defender is the only Primer that meets every guideline in the US for low solvent emissions.

By using state of the art high solids technology the boat owner benefits from saving money by purchasing less gallons of paint and also saves labour because only three coats are required rather than five coats from older technology products. Saving time and money while being environmentally responsible makes Defender Underwater Epoxy Primer the best choice on the market today.

For further details, please contact:
21-23, Msida Road,
Gzira GZR 03
Tel: 2133 8253
Fax: 2134 3821
Mob: 9949 6510