HVLP painting - help needed

[Frederick Smith]

Mike, Since Imron is a polyurethane paint you might have better luck 
with a #4 Air Cap and a 1.4mm needle (medium output set-up). The #3 is 
ok for the catalyzed primer but the dry/rough areas in the top coat are 
probably from a lack of material being deposited or the material drying 
too soon.(larger cap, larger needle)

Since the turbine produces HOT air, distance from the surface (vertical 
pattern, horizontal movement) is critical. Longer hoses can help cool 
the air but depending on how many stages the turbine has there are 
limits to the length of hose that you can use.

You can spray two coats in the same day without any problems and there 
is a three day window for recoating. Imron is NASTY stuff and it can 
make you sick if you don't use the proper breather type mask. Thre are 
NO acceptable felt type masks that are adequate. If you get it in your 
lungs................ it's there FOR-EVER, so be cautious.

Even though the stuff is expensive, you need to do some test panels 
until you get the correct results. Air pressure at the gun is important 
too, some turbines produce 8-10 psi @ 70-80 cfm, others 5-6 psi at 50-60 
cfm. Most turbine guns have pressure limits of 6 psi, so a 
regulator/gauge, at the gun, is essential on some 3 and 4 stage turbines.

Turbine HVLP systems work great. Excellent yeald from material, no 
overspray, no air dryers needed etc. but like everything else they take 
practice to produce the result. (you chose a difficult product to learn 
with. A simple nitrocellulose or waterborne material would have been 
easier, then step-up to the catalyzed.)Mike Arman wrote:
> 
> I'm having a bad time using a Fuji Q3 HVLP spray system, and I need some 
> guidance.
> 
> Using a #3 tip, I find I am able to do a reasonably good job with Corlar 
> (epoxy) primer. I don't get many runs, but sometimes I do get some orange 
> peel, which I understand is from putting too much paint on and/or being too 
> close. I can sand the Corlar down smooth, and come back to it - I'm by no 
> means good at it, but with enough cussing and sufficient tries, it works OK.
> 
> The problem is when I try to spray the Imron top coat - this stuff is too 
> expensive to screw up, and I am screwing it up royally. I have gotten the 
> correct finish, deep, smooth, shiny "wet look", ONE time - and everything 
> else has been an unmitigated disaster - orange peel, rough surfaces, no 
> shine, thin spots, runs, occasional drips, 
> 
> I'm following the instructions on mixing the Corlar (mix per ratio on can, 
> thin to 20 seconds in drip cup, wait three hours, then spray) and on the 
> Imron (mix per ratio on can, spray any time), and I think I have the 
> correct nozzle size (#3). The end of the needle is flush with the nozzle 
> with the trigger in the off position. The air supply from the turbine isn't 
> adjustable.
> 
> Can someone in this group send me some words of wisdom on this? 
>  
> Help Help Help -I confess to rapidly discovering that I am clueless here, 
> and I need some advice.
> 
> Mike Arman
> 90 V8, not just a car, an ADVENTURE!
> 
> 
>