FAQ- Exterior
Frequently Asked Questions about painting Outside
What do I use to paint ZINCALUME® steel?
Scenario: Brand-new ZINCALUME® steel guttering and downpipes that have not been coated or weathered at all.
Answer: ZINCALUME® steel usually has a coating of 'grease' that protects it during transport, so therefore it needs to be degreased thoroughly with mineral turpentine (and then wiped with a dry cloth to remove any residue), and then a general degreaser or warm soapy water before any coating can be applied. A coat of an etch primer or acrylic gal iron primer is usually recommended with two coats of either an exterior acrylic or an enamel as a topcoat.
STEPS:
1. Degrease
2. Etch Prime
3. Top Coat
Can an interior acrylic be used under the eaves?
Answer: Generally speaking yes, providing it is not exposed to any weather.
The exterior of my house has been painted many years ago with an enamel. I now want to use a water based on top. Is that OK?
Answer: The most important first step of preparation in this situation is to ensure that the existing paint is stable by doing a cross adhesion test. This is done by using a sharp blade to cut a deep, close together 'naughts and crosses' pattern in the existing paintwork. Press a piece of masking tape over the cut area and press down firmly. If any paint comes off when the masking tape is ripped off quickly, the old paint is not stable and therefore must be completely removed. If the paint does not come off at all with the masking tape, and as long as the surface is washed with warm soapy water, (to remove any contaminates) and sanded thoroughly (to remove any gloss), an exterior grade acrylic designed to be applied to a surface without an undercoat, can be applied. Two coats of this acrylic is always necessary for protection.
I have a metal balustrading on my house that has rust spots coming through and some flaking paint. How do I fix it?
Answer: Remove all lose or flaking paint with a wire brush and sandpaper. Sand any remaining existing paint. With a rust converter, coat rusted areas and allow to dry (as recommended on can). Follow by spot priming areas treated with the rust converter with a metal primer and finish off with two coats of either an enamel or an epoxy coating.
STEPS:
1. Remove flaking paint
2. Sand remaining paint
3. Use a rust converter on rust (optional depending on severity of rust)
4. Metal primer
5. Top coat
Is an oil based or water based paint better for outside?
Answer: It depends on what is being painted. For the majority of surfaces, an acrylic is going to last longer. Acrylics are softer, more flexible, and more resistant to chalking. This is because the acrylics have a much higher elasticity rate, so that when the surface, such as timber, expands and contracts with the weather, the paint moves without cracking. Haymes Acrylic Trim Gloss Paint is suitable for areas such as sash windows or any other situation where two surfaces are touching. This is because the general Exterior acrylics, being softer, have the tendency to stick to themselves in hot weather, so using this Haymes product will avoid sticking. Oil based primers etc. are necessary for any ferrous metal, such as steel.
Can an exterior 'no primer' acrylic go straight onto a steel balustrading?
Answer: No. A water-based paint will cause the steel to rust almost immediately. It also does not offer any long-term rust protection. An oil based metal primer must always be applied first and allowed to dry for at least 72 hours before a 'no primer' acrylic can be used as a top coat.
It is strongly recommended that 2 coats of primer are applied wherever a water-based topcoat is being used.
Can brand new Colorbond be painted with a 'no primer' exterior acrylic?
Answer: It is almost impossible to get paint to stick to new Colorbond as it was designed to be a product that never needs painting. It is usually recommended that the Colorbond be weathered for several years so the surface has a chance to chalk before even attempting to coat it. It is then advisable to use an etch primer before applying two coats of either acrylic or enamel.
If however it is deemed necessary (eg because colour change is required), then the most effective treatment is probably as follows.
Wash with solvent (Min Turps or White Spirit) to remove surface grease/oil etc. Abrade surface with fine grit to roughen surface.
Apply Acrylic undercoat and allow to dry through (it may take as long as a fortnight before adhesion is developed), prior to top coating with either acrylic or enamel. This is no guarantee given with this procedure, and it may be regarded as impractical in some circumstances, however it is offered as advice only in answer to the question.
What is the proceedure of Acid Etching concrete
Answer: Remove all dust and dirt from the surface and apply a solution of 10% Hydrochloric Acid and water using a brush or broom. Allow the acid to remain on the surface until all the fizzing has ceased, then thoroughly rinse the treated areas with liberal amounts of clean water. Allow to dry for at least a week before dusting and coating.
Which climatic conditions are ideal for exterior painting?
Answer: Between 10-35 degree Celsius and not when there is very high humidity (above 85%) or windy conditions. Avoid painting directly in the hot sun, since the surface can often be up to 10 degree Celsius hotter. When painting outside in hot weather (i.e. porous surfaces using water based paint) dampening the surface slightly with clean water will help with the application.
I live along a harsh seashore environment, where there is high humidity, wind-driven rain, and salt. Which is the best product to use, an acrylic or oil based paint?
Answer: Acrylic paints have demonstrated outstanding durability in the most rugged of environments, including direct sunlight, moisture from rain and snow, and at the seashore. Due to the superior adhesion of acrylic paints, they don't tend to blister, crack or flake when exposed to rain or high humidity, compared to oil based paints. Note: Prior to painting, wash away any salt deposits found on the surface, along with any chalking.
Is it best to paint the exterior of my house with a PVA or 100% acrylic paint?
Answer: Acrylics are much more durable, as vinyl based paints tend to be moisture sensitive and could lead to premature breakdown. Most exterior paints are formulated with acrylics, and are preferred for exposed areas. Paints made with other polymers may be used in sheltered areas i.e.. under eaves etc.
Can I use a 'no primer' exterior acrylic on my unglazed cement tile roof and collect drinking water from it?
Answer: Refer to label or ring the manufacturer. If the product is suitable to be used to collect drinking water, it is always recommended to disconnect the tank pipes after painting and allow a couple of heavy rainfalls before reconnecting and using the water.
We have compressed sheet boards acting as window shades on our exterior windows as a part of our renovation. Just wondering what paint appication we should use to the exterior surfaces of the compresed sheet?
Answer: Ensure the surface is nice and clean. The best product to use would be Haymes Solashield in either Gloss or Lowsheen, applied 2 coats straight on. Tip: best drying conditions for paint are 25 degrees & 50% relative humidity.
Do Haymes manufacture any products suitable for a marine environment?
Answers: Haymes do not manufacture any Marine coatings, only architectural paint.
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