Preparation is the key to your final outcome, as Mat said all loose and flaking paint must be removes and then a light sand takes the old surfactants off and allows good adhesion for your new paint.
Markit, I think your painter is confused with being able to thin the paint down for spray painting application, this done with a viscosity cup so there is no hard and fast rule about 10%, they add water to allow it to flow through the viscosity cup within a certain time.
As you open you paint tin and use it surfactants evaporate so you can add water to bring the paint back to it's original consistency allowing for even coverage, if you thin it down too much you will have to apply more coats which makes the old saying "less is more" really true
There is a product from Dulux which you add to your paint to slow down the dry time, the base formula is change for each region so the product you buy in Indonesia will already have this quality in it. In NZ due to the extreme change from winter to summer high turnover base products are altered for each season as Indonesia is basically the same temperature all year round it's not really an issue.
Hope this helps
Markit, I think your painter is confused with being able to thin the paint down for spray painting application, this done with a viscosity cup so there is no hard and fast rule about 10%, they add water to allow it to flow through the viscosity cup within a certain time.
As you open you paint tin and use it surfactants evaporate so you can add water to bring the paint back to it's original consistency allowing for even coverage, if you thin it down too much you will have to apply more coats which makes the old saying "less is more" really true
There is a product from Dulux which you add to your paint to slow down the dry time, the base formula is change for each region so the product you buy in Indonesia will already have this quality in it. In NZ due to the extreme change from winter to summer high turnover base products are altered for each season as Indonesia is basically the same temperature all year round it's not really an issue.
Hope this helps