Brushing or Rollering the traditional way
The objective of good quality coach painting is to apply an even coverage of paint. Apply with relatively fast brush strokes horizontally first, covering a small area of about 30” square each time. Once the brush is empty immediately refill it and then repeat the process, brushing into the area you’ve just covered. As soon as a section is covered lay the paint off top to bottom by gently stroking it to smooth it out and remove blemishes. This is done at approximately 90 degrees to the first coat. Do this from start to finish very quickly and then keep on going in the same fashion until the area to be painted is complete. Always brushing back into the section you’ve just covered.
If you find a run or sag when the paint is initially dry/drying don’t rub it down. It is likely to still be wet underneath. Instead slice the top off it with a sharp blade and leave it to dry again. The next day you will be able to rub it down successfully. Then, re-coat either the immediate area or if required the whole panel. Always use the biggest brush you can handle for the job. A 2 or 3 inch if a very large panel is more than sufficient for most panel work. If you are using masking tape make sure you remove it as soon as you finish the panels associated with it.
Coach Enamels are not generally intended to be thinned unless you are spraying. If you find the paint is too thick or is difficult to work then add a small amount of the appropriate coach enamel thinner or etch primer thinner. This lubricates the paint molecules making them flow easier. Start by adding 2-3% and work upwards to a maximum of 10%. Remember you can always add a little more but you can’t take any out!