On Fri, 26 Nov 2010 08:29:37 -0800 (PST), Robatoy
wrote:

On Nov 26, 10:28*am, "Max" wrote:
"cm" wrote in message

...





blueman wrote:
As a newbie to HVLP, I have encountered the following problem...
I am spraying Minwax (water-based) Polycrylic semi-gloss polyurethane.

Although the spray seems to atomize well, it seems that unless I put
on
a fairly heavy coat that it deposits in discrete though very small
droplets resulting in a somewhat rough surface.
i.e. - the spray doesn't seem to coalesce into a uniform coat unless I
spray it on pretty thick. It's almost if some type of surface tension
is
causing the spray to coalesce together rather than completely and
uniformly wetting the surface.

When I move the gun slower to let more finish deposit, I do get a
uniform sheen that completely 'wets' the surface (however this only
works when the surface is horizontal because otherwise it would run).

- Is this normal or am I doing something wrong?
- If so what are the likely causes and corrections?

Note: I am using the low cost but surprisingly well reviewed Harbor
Freight #66222 (purple) gun. My 8 gallon compressor seems to have
enough
reserve to power the gun since it is able to cycle. on and off and the
pressure never drops below about 70psi.

The surface I am spraying is clean, well-sanded Birch plywood.

I have the inlet pressure set at about 30PSI.

I have made some (non-exhaustive) attempts to:
- Adjust the inlet pressure in the range of 20-40PSI
- Adjust the fluid volume
- Adjust the spray pattern (more round vs. more oval)
- Adjust the distance to the object (from maybe 8 to 16 inches)
- Adjust the speed at which I sweep across the object

While Minwax claims it hasn't tested and hence can't recommend
polycrylic for spraying, others have had good results with it. Also,
it
seems to be of fairly high viscosity and hence seems to spray well.

Thanks
I have had better luck spraying Fuhr water based products. I sprayed
polycrylic and it never leveled out as nicely as Fuhr.

Cm

Especially if you're after that fuhrry look. *:-)

Max

Ahw, fuhr crying out loud!!

Poly-shades/crylic are a fuhr cry from decent finishes.

--
Education should provide the tools for a widening and deepening
of life, for increased appreciation of all one sees or experiences.
It should equip a person to live life well, to understand what is
happening around him, for to live life well one must live life with
awareness. -- Louis L'Amour