Paint spray technique?

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Final outcome of lessons learned, for the archives.
1.5mm nozzle Gravity feed gun on sale at Aldi for $20, less than the cost of the paint - seemed worth a try.
Much easier to blend the passes but the thinners ratio recommended by the paint manufacturer was a bit too thin, after it had been too thick for the smaller gun.
Or I was too heavy handed because I was used to the smaller gun.
So a few paint runs but otherwise pretty nice.
Probably I should have sprayed the paint a little thicker, then added some thinners for the final pass.
I suspended the parts from wires to do both sides in one paint batch rather than wait until they dried and flip them.
So I saved a second set-up and paint mix but the parts were mostly vertical, which made runs more likely.
The cheap gun is not bad at all, top feed is not as versatile as the side feed Iwata/Anest style but unbeatable at the price.

Now to rub down the runs, see if I need one more coat - for proof that I have mastered the job rather than because the equipment needs it.
Speakers with nice flat surfaces should be easy, the extra projections, tabs and holes of my machine parts cause a disproportionate amount of trouble.

David
 
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Dave - we use an array of air powered syphon and gravity feed guns for spraying lacquer, stain and paints. The syphon (pot) guns are 1 quart, the gravity feeds approx half that. Standard tip size is 1.8mm - by dialing the air pressure to around 40 psi, and adjusting material volume and spray fan width, we can get pretty decent coverage.
For large horizontal surfaces, we also use airless.
Dave, We are also using this type. I think you should try it
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nick: longhb
 
I think you should try it...

He mentions gravity feed, syphon and airless, which one do you think I should try?
I do have an airless gun, the top-of-the-line carbide pump Wagner, it's terrible for fine work.
Since my last post I did a final coat with the cheap 1.4 mm nozzle gravity gun.
This time I positioned the surfaces mostly horizontal and the paint was less thinned.
No runs at all, a little texture but perfect for machinery parts.
It's a balance between runs if the paint is too thinned or texture if the paint is too thick - and the window is quite narrow.
With just a bit more thinners I think I could do a gloss finish off the gun that was "piano" after a fine sand and polish.

But I would like to avoid spray if possible, wasteful and a health risk.
For flat panels I plan to try a roller, should work because a horizontal position allows very thinned paint.
DIY boat painters roll on and then immediately smooth with a follow-up brush, but they don't have a horizontal surface so their paint is thicker.
Anyone have hints on this?

David
 
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Spray technique requires a combination of experience and quality equipment. What you are currently seeing is called, "orange peel", caused by the paint not flowing out to a level surface. When I spray lacquer, I must match the thinner to the temperature of the air around the surface I am spraying. Slow thinner for hot days, fast thinner for cooler days.



Yes, it is a very fine line between orange peel and runs, and it can take years of experience to get it right. Horizontal surfaces are easier, because the paint can't run, and you can spray it on heavier, so it gets a better chance to flow out. Yes, sanding and polishing is an option, depending on the paint you are using.
 
Spray technique requires a combination of experience and quality equipment...

Yes, I understand why painters can be so committed to some particular combination of paint, equipment and technique, it's painfully won experience.
I am pretty happy with my results after just a few set-ups, not really "peel", that's why I used the word texture.
Like a satin finish house paint rather than a gloss.
There was a extensive thread here about "piano" finishes.
I didn't read it all but the consensus seemed to be that a DIY painter had better expect to sand and polish, it's so difficult to produce perfect gloss off the gun.

Best wishes
David
 
I will argue that it is needed to commit to a particular paint, I have successfully gotten quite good glossy finishes with several different paints, including old-style lacquer, acrylic paint, catalyzed automotive finish.... but then, I have been using the same spray gun for 30 years...


It's a pressurized siphon sprayer, Binks 52. Just keeps on laying down what I'm looking for.
 
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