painting/paint gun technique advice ?

[fairchild]

So I was painting some lift struts today. Using acrylic enamel with a gloss hardener additive. Using a top tank HVLP gun. I was able to get it to go one fairly well--- except I was getting runs along the leading and trailing edge areas. What I THINK was happening is that the air pressure was kind of flowing (blowing?) the paint over to and kind of off the edge making it pile up there and
accumulate a run. Another mechanism might be that the edges of the part are kind on in the edges of the paint fan and may be getting more paint than the in the center of the fan-- (since
the edges are kind of more tangent to the fan....)

Any ideas on how to prevent this problem ? Maybe slowly and continuously rotate the part with each pass ?
May try to water sand out the runs and polish--- but rather have a better job !!!!

Tim

[quadra]

if the air pressure is pushing paint around I am going to say you are either too close and/or putting on too heavy of a coat.Try building up several thin coats, vs runs and sags because of a single too heavy application.

[S Lathrop]

When I paint, I have a pressure regulator that is close to hand so I can get the paint to flow as I want.

In general I start with 30 psi and adjust around that number.

I also work with getting the paint thinned for the equipment I am using. I tend to like the paint on the thin side and spray at a reduced pressure. But that changes with every type of paint.

I put down a thin "tack" coat and as I am doing this, I can make a good guess what I will change for the finish coat.

The thin paint tends to flow out better and will smooth the surface left from the tack coat. The tack coat helps reduce the tendency to run.

[fairchild]

Yes Lath----- I do all of that exactly as you said---
I have been using an HVLP but I kind of miss the fine atomization of the old fashioned guns like the binks 7. I havnt used mine in about 15 yrs...… it may have air leaks.

Quad--- when doing acrylic enamel--- you cant really sneak it on in thin coats like you might 2 part poly U. After a tack coat you have to be bold---heavy and cover the part fast
before the solvent evaporates and prevents it from self leveling and flowing out flat. WAY easy to get texture or orange peel or sandpapery texture. Plus-- white seems to be the hardest
to spray because you cant see reflections well in the wet paint. I don't have to paint too many strut shaped items I guess...…
Maybe a smaller sized gun might help since it was a narrow part.
T