Wine and fruit industry coatings

Now that the harvest time is over, maintenance starts on wine cellars and in fruit packaging warehouses. We have an impressive portfolio of customers in these industries and offer a full package of advice, training and products approved for use. Large amounts of money can be saved by good planning and routine coating maintenance. We service the entire Western Cape and have references from top clients. As an additional service we keep full records of all products used for HACCP, GLOBAL GAP and ISO inspections. We are listed as a supplier in the Wineland Directory 2014 edition due to go into circulation 1 July.

Joint Sealer

This product was developed during 2013 at the request of a mass housing developer constructing panelled houses in the Western Cape. It is used to seal the joint between panels, and the main requirements are good adhesion to the substrate, flexibility and high film build. Essentially, it is a high solids acrylic formulated on a blend of binders to provide the required properties. As with all products of this type, there is a degree of shrinkage on drying, necessitating two "coats" to be spackled into the joint. Since the successful introduction of the product, contractors have used it to fill plaster cracks with equally good results. Its toughness and flexibility would make it a good option to seal between timber panels used to construct timber homes, in addition to the above applications.

Coating of cement floors

After inspecting a floor for an applicator to determine its suitability for coating, I feel that putting down a couple of essential pointers would be appropriate. Previously uncoated cement screed floors need to be fully cured, dry, free of oil or dirt, and of a sufficiently rough profile before coating. Often calls come in from applicators or home owners after the coating has been applied asking why problems have occurred - all of which could have been prevented had these guidelines been followed.  Cement slab driveways and verandas (stoeps) are often thrown without a damp proof course below them - here the rule is simple - do not coat them.
Allow at least 28 days for the cement topping to cure, then check the moisture level with an appropriate moisture meter. The moisture level should ideally be below 12% as measured by  a Protimeter. Ensure that the profile of the surface resembles 100 grit sand-paper, if not mechanically abrade the floor using a floor grinder. This step will often remove surface dirt and oil at the same time. All dust should then be removed by sweeping or vacuuming the surface clean.
The first coat can now be applied - preferably thinned 10% by addition of the relevant solvent. Generally, a 24 hour drying time should be allowed before application of the first unthinned top-coat. After another 24 hours, the second top-coat can be applied. Depending on the coating type, there will be a specific time that needs to be allowed before the coating is subjected to heavy traffic.
Coating types vary from Water-based Acrylics to single pack Alkyd and Polyurethane-Alkyd enamels, then on to the Twin Pack Epoxy and Polyurethanes. There are cost and performance advantages related to each of the above options - check with your supplier as to which one best suits your requirements.

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Premature fading of roof coatings

Many failures have been seen over recent years of roof coatings, particularly where dark colours are concerned. Temperatures of metal roof sheets have been measured as high as 110 degrees centigrade in the Western Cape area in South Africa. Recent work suggests that the acrylic binders used in roof coatings simply cannot withstand such high temperatures and degrade after as little as a year. The introduction of so called 'cool roof' technology - which simply involves the replacement of the iron oxide pigment with an infra-red reflecting variant, seems to be sorting this problem out. Costs are considerably higher, but the benefit of a lower internal temperature saves costs and provides a more comfortable indoor environment.

Chosing colours for exterior paints

For the past month I have been unexpectedly involved in the matching of colours in our production plant. The amount of orders received for colours that are essentially unsuitable for exterior coatings has been alarming. Several of these colours have been selected and specified by architects, making the chance of advising the client against proceeding very small. Always check with your supplier that the colour you have chosen is both u.v. and alkali resistant if it will be applied to an exterior substrate. Very often a colour very similar to an unsuitable option is able to be produced using resistant pigments. These pigments are mostly far cheaper than the problematic options, giving you added benefit.

Do it right the first time

I saw another example of poor options leading to time and money being wasted at a housing development this week. Exterior plaster was very poorly bound resulting in the addition of primers or surface densifiers being added to a very price sensitive coating budget. On questioning the site manager, we were told that there was no time or personnel available to re-wet the plaster once applied to the brickwork. This resulted in a very poorly cured substrate for painting. Even very gentle abrasion of the uncoated plaster resulted in removal of the very dry and powdery mixture. To rectify this prior to coating, bonding liquids, densifiers and primers were being tested to render the substrate suitable for painting. This apparently, the developer had personnel and time to do.
Had the plaster been re-wet two or three times, at 24hr intervals, after applied, it would have cured to the point that none of the above products would be required. Water would surely have been the cheaper option!!!