Beware of Altex coating paint: it fails then you're on your own

[charliehows]

well ive been using their ablative antifoul paint for a decade, never had a problem but cosmetics aren't a high consideration below the waterline.

[JPA Cate]

Originally Posted by Sebinnz

Thank you wotname. After a search it seems Accuweather.com would provide the dew point for cities in New Zealand. Good think to look at then! Although on that day I painted from 2 to 3pm with temp of 16°. I'm a little puzzled that dew point would have been reached so quickly. Anyway, good tip.

Hello, Sebinnz,

Yes, you had a dew point problem. That's really disappointing, but it will be fixed, and you don't have to sand it all off, just prepare the surface for a new coat, and the paint that blushed will be covered. However, you're going to need to wait for a warm enough MORNING, so that you're finished before noon, to give it enough time to meet a 1600 dew point, which is very common. It's a hard time of year to get your needed conditions.

Think of it like you do your towels. After 4 in the afternoon, they don't get any dryer very fast, and you bring them in, right? Can't expect the paint to cure properly, either.

Ann

[RyanT.]

I've been applying polyurethane and epoxy lining systems full time since Feb 2012. I would say its almost entirely a weather issue.
We use 'distance to due point' to judge if we will start our application process.
Our general rule of thumb is more than 5 degrees from due point, and below 70% humidity. Due point is easy enough to calculate but its a lot easier/safer if you lash out and buy a hygrometer with a surface temp reader. This will tell you exactly how far your substrate is from reaching dew point. (well worth it if you do a lot of painting)
But Ray is 100% correct, and its the same thing I tell my customers, paints come in systems and have to be applied correctly.
Sales persons are just that and they may be very helpful, but at the end of the day, they are not the technical specialists. The best thing you can do before you choose your paint is download the TDS and read it. The technical data sheet will explain to you the recommended system and exact application parameters. If the company has a lousy TDS, try another paint.
But is still sucks when it goes wrong!

[MarkSF]

I'm not being funny but I wouldn't put any more paint on until you figure out how to get a decent result with the brushwork. Maybe practice on a sheet of cardboard or something. That paint looks way too thick, which can also contribute to problems with drying. Did you follow the manufacturer's advice on thinning? Most paint these days is supplied far too thick to apply neat, due to VOC regulations.

Thinning allows it to flow, reducing visibility of brush strokes, and also keeps the applied thickness down, allowing it to dry more quickly.

Have you considered trying "roll and tip"? Many people say it gives the best result short of a spray gun.

[MarkSF]

Originally Posted by RyanT.

I've been applying polyurethane and epoxy lining systems full time since Feb 2012. I would say its almost entirely a weather issue.
We use 'distance to due point' to judge if we will start our application process.
Our general rule of thumb is more than 5 degrees from due point, and below 70% humidity. Due point is easy enough to calculate but its a lot easier/safer if you lash out and buy a hygrometer with a surface temp reader. This will tell you exactly how far your substrate is from reaching dew point. (well worth it if you do a lot of painting)
But Ray is 100% correct, and its the same thing I tell my customers, paints come in systems and have to be applied correctly.
Sales persons are just that and they may be very helpful, but at the end of the day, they are not the technical specialists. The best thing you can do before you choose your paint is download the TDS and read it. The technical data sheet will explain to you the recommended system and exact application parameters. If the company has a lousy TDS, try another paint.
But is still sucks when it goes wrong!

Dew point?

[RyanT.]

Originally Posted by MarkSF

Dew point?

'the atmospheric temperature (varying according to pressure and humidity) below which water droplets begin to condense and dew can form.'

if your at the dew point or close, its likely there is a small amount of water on your substrate which is a recipe for disaster.
Again, this is something you can google. Painting is the easy part of painting….

[Davo1404]

Originally Posted by Sebinnz

Thank you wotname. After a search it seems Accuweather.com would provide the dew point for cities in New Zealand. Good think to look at then! Although on that day I painted from 2 to 3pm with temp of 16°. I'm a little puzzled that dew point would have been reached so quickly. Anyway, good tip.

I would be using the NZ Met Service for a accurate dew point. Also I am sorry to say that 2 to 3pm is to late in the day to be applying paint in the winter months. 11 to 12 midday would be more like it.
Hope you have got it sorted.