"sherwindu" wrote in message
...
Arnold,

I think you missed my drift. I was thinking about regular paint vs.
gelcoat. I
suppose
that gelcoat is used for repairs or when the original gelcoat has worn
through.
In my
case, the gel coat is probably still intact, but there are numerous tiny
crazing
and the
original white color has faded to a dull yellow. I guess regular paint is
the
way to go,
but can it be applied with a brush and still come out streak free? Any
special
tricks
to make this happen?

Sherwin
Hi Sherwin,
you're opening up a can of worms learning to paint! I'm guessing you know
about surface prep etc. Here's a tip when prepping - use as fine a grit
paper as you can stand. 300 plus grit will be ok but your paint will flow
better if you go higher, say 600. Custom car guys will sometimes go to 800
but we don't need to aim so high. Some people are happy with 220 grit. The
finish will be ok, just not stunning. Your prepped surface has to be near
perfect because paint will not cover up any surface imperfections; that's
what a hi-build primer is for. So any crazing, nicks etc will have to be
filled first.

Now to the painting! The most important thing you can do is to thin your
paint properly. The manufacturer will have a recommendation but I've found
that they are almost always cautious. You need to buy or make a vicosity
measuring device like a Ford cup or a Dean cup. You fill this up and time
how long it takes to empty. Write this figure down! Roughly you can expect
a Dean cup to empty in about 18 secs (very big +- ). I like the roller
brush method (lots on Google). But use the softest brush you can find and
treat it to some hair conditioner (really!).

The theory behind getting a flawless finish is like this - You need to apply
enough paint such that it almost wants to sag and /or run but doesn't. If
you have enough paint on there, the brush marks will "flow" and even out.
This is how you get a mirror finish. Too much paint and you get runs. Too
little and it won't flow out. Fun, huh? Don't forget that vertical
surfaces will flow out much easier! So how do you aid flow out? Thinning!
But that's not all, you need to know how viscous to keep your paint at
different temperatures. You need to know how much time you have before the
thinner flashes off. Once the thinner has mostly evaporated (flashed),
you're out of luck - the paint will be too tacky to flow. If using
polyurethanes, buy the slowest harderner they have. Good quality paints
flow better than cheaper ones. Matt and semi-gloss paints show fewer flaws.
Might be something on youtube to further confuse you!

Feel free to mail me directly if you have other questions.

Arnold