Water Based Paint Problems and Solutions Pt 2 Snail Trails & Touch Ups

   

This week, we carry on with specific paint problems that are particular to the south african climate. In this article we will teach you how to remedy badly done touch up jobs, and snail trails

Touch Ups..

Description

Areas of different colour with signs of application directionality and or texture

Causes..

• A poorly colour matched paint was used.
• The touch-up coat was applied at different temperature – this can cause it to be lighter or darker than your last finish coat
• Sun exposure may have caused the applied paint to fade slightly.
• the original retained paint was used , while the existing in-situ coating has faded.
• The touch up paint was stored for a prolonged period of time and has degraded or colour developed.
• Failure to reduce the touch-up paint by up to 25%.
• Touching up marks that could be removed by washing with a sponge and liquid detergent.
• The touch-up coat was applied to a porous surface – porous surfaces give problems especially with high-sheen eggshells and higher gloss finishes because unprimed porous substrates absorb more of the paint they leave less of a sheen or gloss.
• A different type or batch of paint was used – different paint types require different amounts of time to finish. the amount of time between the application of your finish coat and touch-up can affect how well these two coats blend together.
• An application technique different to the original one was used from the e.g. Touching up with a brush when the original coat was applied by roller.

Preventions and Remedies

How to prevent touch up problems                                       

Prevention, is always better than cure as they say..

So here are 5 easy tips to prevent future touch up problems..

• Always use the same batch number when available
• Try to wash the mark off first with a sponge and liquid detergent.
• Use only enough paint to cover the mark, excess paint may cause a halo.
• Use a feathering-in technique, avoid dabbing.
• Thin paint up to 25%.

How to remedy touch up problems

Fortunately, the cure (in this case) is much simpler than the sickness. All you have to do is match your colour coating to the existing colour, and then recoat the entire area from edge to edge/ corner to corner. Priming is essential for better adhesion, sheen uniformity, mildew control and durability. Select a top quality interior paint in the color and sheen of your choice.

Description

Snail trails are shiny vertical run-marks seen on dry paint films, they are predominantly seen on matt coatings but can also be seen with some sheen coatings. Streaks generally start to emanate from flat topped walls or parapet walls. They are usually randomly spaced and follow gravitational direction. Although snail trails look like dirt streaks, they are not the same.

Causes

Snail trails happen when the water soluble paint components have been washed away by water. 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. This could have occurred within the first 2 – 24 hours depending on the  humidity and dampness experienced during the time of painting, or in rooms of high humidity eg kitchens, bathrooms and showers etc

Preventions and Remedies

• Avoid painting in adverse weather conditions. eg late afternoon if cool damp conditions are expected in the evening or overnight.
• If the problem occurs in the first day or two it can usually be rinsed off rather easily, with a damp cloth, soap and water. Problem may occur once or twice again before leachable material is completely removed. When paint is applied in a bathroom, it is helpful to have it dry thoroughly before using the shower. Remove all staining before repainting.

• Fortunately, more difficult trails weather away within the first 3-6 months or are washed from the film after 2-3 rains. Snail trailing should not affect the ultimate durability of the coating.

• If none of the above works, recoat taking care to consider touch-up batch variation, difference in application technique etc.