Re: [MV] Painting...need help with diagnosis of residue.

From: David Cole (DavidCole@tk7.net)
Date: Sat Jun 12 2004 - 07:44:58 PDT


I'm not familiar with that gun, but 30 psi at the tip is pretty high for an
HVLP gun - does that gun actually measure tip pressure? It sounds like it
does.

If you spray paint at too high a pressure, it doesn't atomize properly and
with lacquer, it will actually almost dry the paint before it gets to the
surface of the vehicle. This makes the final paint surface weak and it
doesn't adhere well. However you aren't using lacquer. I think Gillespee
is a synthetic enamel, however I'm not certain.

Around 15 psi at the tip is pretty common for HVLP guns.

If when you shoot that paint you are getting nice wet coats on the vehicle,
then paint should really not be separating like that.

I'd probably call Gillespie directly and ask them for advice. If anyone
knows, they should.

Dave

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

On Fri, 11 Jun 2004 19:49:16 -0400, Bill <bill@welovenh.com> wrote:

> Need some help from the painting experts.
>
> I am painting my WC-54 with Gillespee 33070. Using the top of the line
> SATA HVLP gun, paint is cut 4-1 with Xylene, shooting pressure is 30psi
> (digitally measured by gun at trigger). First coat. Temperature was 84
> degrees with humidity about 65%. Air line is well dried for moisture
> prior to the gun.
>
> The paint went on great (not much pilot error...runs). However after the
> paint began to set, about 6 hours, the horizontal surfaces began to
> develope a chalky residue, almost like soot, It was green but very dark
> green in color. It was only on the roof and hood and not on the tops of
> the front fenders. I did not fool with it at the time. I figured I would
> let it set
>
> After letting it sit for 3 days I went out and if you rub it with your
> hand you remove the "soot" and it leaves a chalky residue on the paint
> base which looks fine. I then took out my carwash broom dry and rubbed
> it all over the effected areas. The soft brissles of the broom removed
> all the "soot". I then washed the truck with car wash soap and rinsed
> and the paint job looks great.
>
> Any idea what this chalky substance is. Am I shooting a too high or low a
> pressure. Is the cut wrong. This has never happened to me before and I am
> hoping it will not effect the life of the paint.
>
> Any insight would be greatly appreciated.
>
> Bill Wolf
>
>
>
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-- 
Dave


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