Thursday 13 October 2011

Farrow and Ball Exterior Primer and Undercoat

We're going to use a Farrow and Ball Exterior Primer and Undercoat as the first stage of protecting our oak wellington-boot rack from the elements. This, as the name implies, functions as both a primer AND an undercoat, saving you the cost of buying both separately.

Farrow and Ball often get bad press for their exterior finishes but we feel this is due to mistaken application, rather than the products themselves.

The Farrow and Ball Primer and Undercoat, and the Farrow and Ball Exterior Eggshell work together as a system paint.

Wood is often not kiln-dried as thoroughly as it used to be and so is regularly sold with some moisture left in. Farrow and Ball Paints are microporous. They allow that moisture OUT but don't allow outside moisture IN. The Primer and Undercoats AND the exterior eggshell are both microporous, so the two work together extremely effectively.

Problems will arise, however, if a non-microporous primer is used, and then Farrow and Ball Exterior Eggshell applied on top. The Farrow and Ball paint is extremely flexible and grips well, which usually creates a superb finish. However, if a non-microporous primer is used, these very qualities will work against it. The ability of the Farrow and Ball to shift with movement will cause any rigid primer to pull away from the wood.

If your exterior paint is peeling, we have a good test to see whether it is your primer that has failed, or your paint. All you need to do is to check the underside of any paint chips. If the underside is the colour of the primer then the primer has failed, but the paint has done its job and clung well to the primer. If there is no primer visible on the paint chip, then it is usually the paint that has failed, and the primer has clung to the surface as intended.

Farrow and Ball Undercoat and Primer sits beautifully on untreated wood, and will also sit well on old paint, as long as the paint has been sanded back to the point where it's not peeling.

However, it WON'T work well on any kind of exterior woodstain, such as Sadolin. If you have wood that has been treated in this way, then it would be better to use a primer such as Zinsser, and use a complementary paint like Little Greene, which are also available from Relics. 

Next week, we'll be looking at Farrow and Ball Exterior Eggshells.

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