> For spraying I am using a Croix CX-9 HVLP system with 40 feet of hose (to
> cool the air) and a 1.2mm orifice with a 0.7M aircap, all courtesy of the
> local EAA chapter.
>
> This spray system produces a slight "orange peel" in the finish
John --
I had the same experience with a HVLP conversion gun and Smooth Prime. A
conventional gun performed much better for me. The amount you're thinning it
is excessive, and can cause mud cracking besides the runs. When you have to
thin it too much, the problem is in the gun somewhere.
I have not used Poly Fiber's topcoat, but I didn't get good results with the
HVLP either, shooting a similar product. Maybe the waterborne polyurethane
paints just don't atomize well in a low pressure gun. It reminded me of the
old days using the straight lacquers, which evaporate very rapidly.
> If a sag or drip has dried, a sharp wood chisel parallel to the surface
will slice the > thick portion of the drops off.
Auto refinishing supply shops sell a little tool for this purpose. It's
called a "nib file," and it looks like a little 1-inch square piece of a
metal file, but cut in a special way. It does not mar even a gloss top coat.
> I was originally going to build a wing holder to allow rotating the wing so
> that the surface could be held horizontal for spraying.
I hope you'll be shooting the topcoat horizontal. Getting good results
without runs on a vertical surface is difficult, even with more forgiving
topcoat formulations than you plan using.
Regards,
Fred Fillinger
|