Quote:


...thats what I thought, pratice and more pratice. So far only around 3 for my trunck, 4 for my roof, and 1 big thick layer on my hood, I mean thick, I've been using a 220 grit paper with water to take it down again and smooth it out. My hood was my first go at it and I put too thick of a layer on it, I thought you were suppose to make it so it doesn't show the bottom paint. My friend said it might show though up to 4-6 coats later.



The problem with the world is that when we are painting things... like walls, bikes, tractors and patio furniture we expect to nail it in one or two coats. And that is kewl for those types of items.

But to do a car paint job with the roller, you need to lay down coats of paint that are thinned down with mineral spirits in order to achieve self-leveling. For the paint rolling job... self leveling is our first priority and the color coverage is simply something that we acquire as we lay on our layers of leveled paint.

And that means that with the roller jobs YOU MUST EXPECT to take four or five coats of thinned paint to achieve color coverage.

The paint coverage comes from the amount of pigment in the paint you are rolling on. So simply imagine it this way... IF each coat of thinned paint is only equal to 25% pigment coverage... then the first coat that is laid down with be almost see through ( since there is only 25% of the color pigment in what has been laid down.

When you add your second coat of paint... you now have gotten 50% pigment coverage ( 25% from the first coat and 25% from the second coat ). You will still see through the paint to the original paint that you are painting over BUT it will be slightly tinted more towards the color you are trying to achieve.

When you add your third coat of paint... you now have gotten to 75% pigment coverage... fourth coat... gets you to about 100% pigment coverage... fifth coat gets you to about 125% pigment coverage etc.

But you also have been doing some wet sanding between every second coat and that DEDUCTS a percentage of the pigment coverage up to that point.

So the bottom line is that you are slowly building up your layers of percentage coverage to finally reach a true 100% or higher coverage.

NOW... with regards to the flat paint and lines. It probably is the result of the paint mixture being slightly too thick. Thin the paint mixture down a bit so that you are not getting so much pigment color coverage with each applied coating.

As well... when laying on a coat... feather the paint over the demarcation line of where your rolling is at. Basically what I am saying is that if your paint is sufficiently thinned, you should be able to overlap the last area you just had laid down. I had to do the same thing with the high gloss paint... feathering each section with the previous just rolled area.

NOW the other thing that I found important in reducing lines is how I loaded and unloaded the foam roller before applying the paint. What I tended to do is this : I would roll the roller around in the paint tray to load up the paint on to the roller. THEN I would slighly unload some of the paint off the roller in the tray. THEN I would tilt my roller and apply a little extra pressure while rolling the roller in the tray to more significantly reduce the amount of paint on the end or tip of the foam roller. THEN I would tip the foam roller the other way to reduce the amount of paint on the opposite end of the foam roller.

00000000000000 if this is the foam roller

XXX00000000XXX I would have applied more pressure while the roller was in the tray to the end tips.

The whole point to this being to reduce any excess paint at the ends of the roller and leave the greater concentration of paint in the middle of the foam roller.

SO... when I actually put the roller on the car and start spreading the fresh paint, it is the center of the roller that is primarily spreading out the paint. And as you roll it back and forth on the panels surface, the paint from the center of the roller will spread out to the tips to give you coverage.

This quirky method of loading up your roller and then unloading the tips will greatly reduce the chances of a concentration of paint at the end of the tips building up and producing those lines.

WHAT you see in your picture of your roof.. are lines that were created when the paint at the end of the tips was laid down in a higher concentration then at the center of the roller. AND when you laid down the next section of paint, the concentration of paint at where you overlapped, basically double or tripled the concentration or percentage of color pigment where the overlap occurred.

As long as the paint self leveled out, it would eventually disappear and not be as noticable when all areas of the roof hit 100% color pigment coverage. You can have areas of 100% color pigment coverage and areas with a higher color pigment coverage and yet the EYE will only visually see 100%. BUT if the actually thickness of the paint at those overlap areas is thicker then you would still see the lines - NOT because of the amount of color pigment that is laying there, but because of the way light will defract differently against the two different thicknesses of paint on that surface. A light wet sanding might be in order to cut back any 'extra thickness' that has been built up so far and to give you one level starting point from which to continue with your build up of coats of paint.


Hope this info helps.

Marq

Last edited by Marq; 04/05/08 09:14 PM.