Good day all. After a long break from posting on this site there is some great news to share. Paint Consultant (Pty) Ltd is up and running. Owned by my wife - Joanne - and I, we will be servicing the paint market in the Western Cape, concentrating on the fruit and wine industry's requirements, as well as the domestic housing market.
All advice, backed by nearly 45 year's experience, is given at no cost. The products that we recommend are tried and tested.

Colour choices - performance versus aesthetics

Very often we get requests from customers to tint colours that we know could be problematic. Despite the warnings we give, most times our advice is ignored - often with the predicted consequences. There are two cases that we saw recently, the first involving our paint, and the second involving a competitor's product.
The first case involves product supplied to an entry level housing development in Cape Town. The 'accent colours' specified for the project raised concerns. Blues and greens on the exterior of buildings in a high rainfall area are going to be subject to alkali attack should there be any moisture ingress. Sure enough the original window sill design was cost-driven, allowing moisture ingress. The end result is shown below.

For the remainder of the phases of the project, the window sill design was changed - moisture ingress eliminated and the coatings have survived the first winter without a problem.

The second example of alkali attack we saw this week involves a competitor's product. The house was painted 6 months ago - just before winter. The effects of alkali attack are alarming - indicative of a high degree of moisture ingress.

Hopefully these images will encourage people to check with the manufacturer before colour selection is finalised. Organic colours (bright greens, blues, oranges, reds and yellows) are subject to alkali attack in addition to being less light-fast than oxide shades. They cost a lot more too......

Consequences of incorrect product selection

Some applications, that are less demanding than others, will have minimal consequences if product selection is incorrect. The more technical the application, however, the greater the consequence. A couple of years ago a client was given advice by a paint retail outlet that seemed logical to the advisor, but had disastrous consequences.
The client asked for advice with regard to over-coating a bituminous water-proofing membrane that had been applied to a flat roof below a second storey window. The membrane had weathered considerably, leaving it looking unsightly, and in obvious need of protection from the elements. The client did not want to use Bituminous Aluminium, leaving the sales person in a quandary. We have a product designed for application directly to bituminous membranes (Super Acrylic ST)  but the sales person did not remember that. Logically - according to the sales person - Road Marking Paint is used on bituminous substrates, making it the ideal product to recommend. Unfortunately, bituminous water-proofing membranes become far softer in hot conditions than tar roads do, causing the Road Marking Paint to crack and peel off the surface. Before coating the membrane with the correct product, all of the Road Marking Paint had to be removed from the substrate. This proved to be such a messy operation that it was decided to allow the Road Marking Paint to continue to crack and peel off the substrate on its own - a process that took over a year to complete.
Below is a photo of the roof at a point where most of the Road Marking Paint had peeled of the bituminous membrane. Fortunately it was only visible from the second storey, and that the neighbours were spared the sight!

How to coat swimming pools

As spring has arrived in the Western Cape, and end of year holidays are getting closer, we have the usual increase in requests for information with regard to the coating of swimming pools. This is a far more technical application than most, and it is advisable to get professionals in to do the job. For paint manufacturer's, a sale of generally 10 - 20 litres of paint can result in such dissatisfaction and months of problems that very few companies have swimming pool paints on their ranges. We are the same - we have a product that will work very well if applied by a professional, with due regard to surface preparation and correct application. We are reluctant to give out advice to home-owners or contractors without previous experience in this line.
The short answer then, to the question "how to coat swimming pools", is don't. Get a professional to do the job, pay the price and hopefully have a great summer in your pool!
Not all advice is what home-owner's want to hear - but honesty remains the best policy, even if it sounds a bit abrupt!

Metal Protection at the coast

Last week we were called to give a specification at a coastal installation - literally at the water's edge. Salt spray, wind and high humidity all challenging the integrity of metal gantries and equipment. Design of structures seems not to include the ease of maintaining metal components, and as it often happens we are asked "what now". Good stainless steel would surely have saved the day - but mild steel had been used to construct large moulds for concrete ramps and a series of beams forming an overhead delivery system some 100 metres long, down to the high water mark.
Priming had already been done, after in-house sand-blasting, using two coats of a high build epoxy-ester based anti-corrosive primer. The beams and moulds have to be coated in-situ, limiting application methods, as well as product types. Fortunately, the business has a full-time painter, dedicated to the maintenance of the installation. His days will be filled with removal of dried salt from the metal, sanding, spot priming with the epoxy ester primer and over-coating with Chlorinated Rubber Enamel for the next three years. While this should be music to a paint manufacturer's ears, use of a better material at the outset would have saved a lot costs down the line.

Some weeks are more intersting than others

This week has proved to be far busier and more interesting than most. In the Western Cape, winters are cold and wet, and painting slows down considerably. Spring is in the air now and it seems that business in this industry is set to begin the end of year rush earlier than in previous years.
Buildings visited this week for specifications and advice included an old multi-storey block in the centre of Cape Town (we had to reach the roof of this building through the top floor which proved to be a brothel), a 200 year old manor house in Stellenbosch, an 1800 square metre new luxury home in the farmlands outside Robertson and a fruit pack-shed re-furbishment on a well known estate in Somerset West.
Each of the above sites has its own set of requirements, budgets, and customer expectations. Giving the best advice to each individual owner is our goal, irrespective of the gain to our business. Not all we do as paint technologists is watch paint dry.

What are "snail-trails"

Snail trails can simply be described as shiny vertical run-marks seen on dry paint films. They are often seen soon after water-based paints have been applied, particularly if it has rained or after a heavy dew-fall.
Dry paint films are made up of pigment and binder, but to present the paint in a usable form, many additives are used in the formulation. These additives are mostly water-soluble and remain in the dry paint film until they are effectively washed out by water - be it via rain, dew or by irrigation sprinklers. If the amount of water falling on the surface is low, then only part of the water-solubles are washed out, and they can dry on the surface. This leaves what we call "snail-trails". They tend to be sticky, and can act as a dirt trap as seen in the photo below. Generally these additives are washed out of the paint after the dry film has been wet a couple of times.
Matt paints tend to show snail-trails more readily than sheen paints due to the fact that there is less binder in the dry film. Snail trails can also be seen in kitchens and bath-rooms due to the high humidity. Wiping with a damp cloth often can remove these snail trails.