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Frequently asked questions for Double Coat

Below please find a summary of frequently asked questions for Double Coat.

 

Please contact us by e-mail in case your question is not in the list.

 

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How do I remove a one component paintsystem from an GRP anti-slip profile?

Put some Double Coat Spraythinner or Double Coat Degreaser on a piece of cloth and leave on the surface for 30 minutes. The old paint can easily be removed by brush or pad.

 

How do I apply Double Coat over an existing anti-slip profile?

Clean the surface thoroughly with a Scotch Brite pad. Clean with Double Coat Degreaser and allow to dry. Applying a coat of Double Coat to the surface will make the surface slippery. By adding Double Coat Anti-slip powder to Double Coat prior to application, it is possible to restore the profile again.

Can I cure Double Coat at elevated temperatures?

This is possible after a flash-off time of approx. 3o minutes. After this period it is possible to force cure at 40 to 50oC. At higher temperatures it is possible that airbubbles in GRP may break and cause damages in the surface.

Can I repaint previous coatings with Double Coat?

Double Coat can be applied on top of old layers of two component paints after proper surface preparation such as sanding. Always check the quality of the previous layer. When this layer does not dissolve or softens when exposed to Double Coat Degreaser, then you can repaint with Double Coat.

 

Can I repaint GRP with Double Coat?

Double Coat gives an excellent adhesion to GRP, provided the GRP is dry, clean and free from contamination and loose particles. For best adhesion the GRP should be grit sanded and cleaned with Double Coat Degreaser.

 

Can I apply several layers of Double Coat without sanding?

This is possible provided the next layer is applied after 24 hours but within 48 hours. If not, sandind with grit paper is recommended.

 

Can I apply Double Coat to a non-slip surface?

This is possible, clean the existing non-slip surface with a scotch brite sanding pad and clean with Double Coat Degreaser. When an existing non-slip surface is coated with Double Coat it will result in a slippery surface when wet. Add to the last layer of Double Coat Double Coat Anti-slip Powder to restore the non-slip properties.

Why do blisters appear in fresh Double Coat?

Blisters may occur due to several reasons, a.o.: a too high air or surface temperature, a microporous polyester surface, a too high relative humidity, wrong rollers or a too high filmthickness. The problem may be solved by applying a new coat under more favourable conditions or applying a lower filmthickness with more suitable equipment.

 

Why is the gloss so low?

Probably the gloss of a fresh painted surface is low due to early exposure to moisture. This happens particularly when is painted close to the waterfront. At the end of the day the temperature may drop and condensation may occur on the fresh painted surface. This may result in loss of gloss and/or a white discolouration. Loss of gloss may also occur when the paint is directly applied to coarse fillers or to a surface sanded with a coarse gritpaper. Correct the problem by: applying a new coat of Double Coat under more favourable conditions, or sanding the surface with fine grit paper (P320) or by applying a barrier coat (IJmopox ZF primer).

 

Why do yellow stains appear in fresh Double Coat?

When after a short time yellow stains appear in Double Coat, this may be caused by previous layers of filler. When epoxy or polyester fillers are recoated too soon, residue of the hardener or peroxide might migrate through the fresh Double Coat, resulting in a yellow stain (discolouration by UV exposure). The problem may be solved by applying a barrier coat first, e.g. IJmopox ZF primer.

 

Why do craters appear in fresh Double Coat?

Craters may appear when the surface is contaminated with silicones or when the surface is microporous. The problem may be solved by sanding the surface and clean thoroughly with Double Coat Degreaser followed by a coat of IJmopox ZF primer.

 

How can I remove dust from fresh Double Coat?

Dust which settled into a curing layer of Double Coat may be removed by sandpapering followed by a new coat of Double Coat or by sanding with very fine grit paper followed by polishing to high gloss. Polishing is possible after Double Coat is fully cured.

How much Double Coat should I prepare?

Do not prepare more material as can be applied in one to two hours time. Larger volumes of prepared paint will reduce the potlife as temperature will increase due to the reaction between base and hardener. Also, at higher temperatures potlife will be shorter.

 

Should I apply a clear varnish on top of Double Coat?

It is not necessary to apply a clear (two component) varnish on top of Double Coat. Double Coat has a high gloss, a good colour retention and is scratch resistant.

 

How can I clean brushes and rollers used for Double Coat?

You may use Double Coat Brush Thinner or Double Spray Thinner for cleaning tools used for Double Coat. Rollers are in general used only once and are not cleaned.

 

What is the correct mixing ratio of Double Coat?

The mixing ratio of Double Coat is always 2 parts (by weight) base component and 1 part (by weight) hardener. Double Coat Dubbel UV and Double Coat Karaat have a mixing ratio of 3 parts (by weight or volume) with 1 part (by weight or volume) hardener.

 

What is the correct procedure when various colours Double Coat are applied?

When different colours of Double Coat are applied, it is important to use a good quality of masking tape, such as Scotch Fine Line Tape or Kleen Edge tape. Apply the tape, paint the surface and remove the tape. Wait for 24 hours before applying masking tape to fresh layers of Double Coat.

 

What solvent to use for Double Coat?

Use only Double Coat Brush thinner or Spray thinner. Do not use mineral spirits, thinner or solvents for other suppliers. Other solvent may not be compatible with Double Coat.

Should I apply a wax or polish Double Coat?

It is not required to apply a wax or polish to a surface painted with Double Coat, but a wax or polish may increase the durability. When a wax or polish is used, please make sure the material is free from silicones. Silicones may cause problems when the boat has to be repainted.

Can I use Double Coat for areas below the waterline?

We do not recommend Double Coat below the waterline, especially when the boat is permanently immersed in water. When the boat is taken out of the water after a day sailing and put on a trolley, Double Coat may be applied also on areas below the waterline.

How soon can Double Coat be applied over an epoxy laminate?

An epoxy laminate should be fully cured before Double Coat is applied, especially when recoating with Double Coat Dubbel UV. Most epoxies are fully cured after 14 days. Always sand the epoxy laminate before applying Double Coat.

 

How soon can Double Coat be applied over a polyester laminate?

A polyester laminate may be recoated with Double Coat after 24 hours. Make sure mould release agents or paraffin wax deposits are fully removed prior to painting.

 

How soon can Double Coat be applied over IJmopox products?

IJmopox ZF primer may be recoated after 16 hours with Double Coat. IJmopox HB coating may be recoated after 8 hours.

At what temperature should I apply Double Coat?

A temperature between 15 and 25°C is required for good levelling. At higher temperatures curing will be too quick and levelling will be poor so brushmarks will remain visible. At lower temperatures curing will be too slow with risk of gloss reduction due to exposure to moisture.

What is best: dry or wet sanding?

The best choice is dry sanding. Wet sanding will give the risk of moisture entrapment in the surface , especially when fillers or porous gelcoat is sanded.

 

What gritpaper should be used for sanding Double Coat?

Use between each layer of Double Coat a finer grain of gritpaper, e.g. 280-320-400. Never use a too coarse gritpaper at the scratches will remain visible after the final coat.