Airbrush pressure with Lacquer paints..!!

[mickbench]

Does anyone know or can tell me what the recommended spraying pressure is for Lacquer using a suction feed airbrush?

I was using 25 PSI, then knocked this down to 20 PSI, but many might have read that when I used these pressures the lacquer paint has gone on thick, and created some bad cracking, lines etc… I’m trying to work out what I’ve done wrong with a recent paintjob and I’ve never used lacquer paint though an airbrush before. I’m wondering if I’ve used the wrong pressure.

Or perhaps the paint was too thick, and this created the weird ripples, cracking etc…. I would post a picture, but its REALLY hard for me to get a good upclose picture with my crappy camera.

I use 25 PSI with Acrylics, as any lower and I can’t get a wet coat etc… But I’ve noted with some testing that Lacquer paint seems to shoot out really fast at 25 PSI, so obviously too high. I’m almost certain, that I’ve applied the paint at too high a pressure, and this has in turn melted the coats underneath, and created a very strange crazing affect…


BTW - It's modelcolourworx one stage gloss auto paints I'm using... and I'm having troubles adjusting from using only arcylics or Alclad II with my aribrush to this type of lacquer paint as well. Seems each paint has a preferred pressure I think and I need to find the balance..

I know Alclad II is 12 - 15 PSI and Acrylics are 20 - 25 PSI when ising a suction fed airbrush..

Thanks all..

[Cobra Colors]

20 to 25 PSI should be right, so if it's going on thick try adding more thinner. What's the current thinner-to-paint ratio you're spraying? Unlike conventional hobby paints that may work well thinned 1:1, automotive paint needs to be thinned considerably more than that for airbrushing.

[MPWR]

What Leon sed.

25 psi does seem a bit high, but in my experince it's much more importaint to get laquers thinned properly than to get the pressure precisely controlled. Thin it back, and apply it in light coats. Hobby paints can be thinned to 'milk consistancy', but auto laquers can be thinned well beyond that, and they work better that way.

[nugundam93]

i'm spraying with the sprayworks AB with compressor with no pressure modifications (i think stock psi is about 29?i forgot) and i thin the laquer to a ratio of about 1:1.5 and works fine with me.

[mickbench]

Really... That thin..!! The paint I got was pre thinned for me, but its not like water.. In fact, it's thicker then acrylic. I think my thinner evoporated away, as I left the lid off, by mistake for a few hours..

I did re-thin with lacquer thinner, but not this thin.. I "think" i've worked out what I've done wrong. I'm being a plank.

Hmmm... Think I'll grab that datsun out the box again, sand the paint, and try it Much thinner...

I'll let you know the results.

[nugundam93]

mick, yup, i go that thin with paint. and i don't slide the trigger llimiter to fully open, so i'm spraying only like i'd say 30% of maximum or so.

[patoffspyder]

Lacquer should be spray at 20-25 PSI? Damn, I always use 30-35 PSI when I use Cobra Colors paint, I will try with a lower pressure next time.

Can you tell me what the pressure change?

[Cobra Colors]

Originally Posted by patoffspyder

Lacquer should be spray at 20-25 PSI? Damn, I always use 30-35 PSI when I use Cobra Colors paint, I will try with a lower pressure next time.

Can you tell me what the pressure change?

If 30-35 is working for you and that's how you're accustomed to working with your airbrush, stick with it. I only mentioned 20-25 PSI because that's about what the minimum should be to avoid problems with paint sputtering.

[MPWR]

Originally Posted by mickbench

Really... That thin..!! The paint I got was pre thinned for me, but its not like water.. In fact, it's thicker then acrylic. I think my thinner evoporated away, as I left the lid off, by mistake for a few hours..

Yeah, you need to add some thinner!!

When spraying laquers, forget about milk. Think water. When spraying laquers, I almost always use more thinner than paint. 1 to 1.5 paint to thinner is a good guess, but it of course varies with each application.

"Thinned for airbrushing" almost always means "this paint is thin enough that it can be pushed through and airbrush". It does not mean "this paint is perfectly thinned for optimum airbrushing performance".

For learning how to spray auto laquers, I couldn't steer you better than to Leon's tutorials on his site. Read them all, it will help. Nearly all of the info there will apply to any type of auto laquer you're using- and alot of it goes for hobby paints, too.

[mickbench]

Originally Posted by MPWR

Yeah, you need to add some thinner!!

When spraying laquers, forget about milk. Think water. When spraying laquers, I almost always use more thinner than paint. 1 to 1.5 paint to thinner is a good guess, but it of course varies with each application.

"Thinned for airbrushing" almost always means "this paint is thin enough that it can be pushed through and airbrush". It does not mean "this paint is perfectly thinned for optimum airbrushing performance".

For learning how to spray auto laquers, I couldn't steer you better than to Leon's tutorials on his site. Read them all, it will help. Nearly all of the info there will apply to any type of auto laquer you're using- and alot of it goes for hobby paints, too.

Thanks.. I’ve emailed the supplier of the paint to find out the recommended thinner for his paints, but out of frustration, boredom, sod it and try attitude, I ued some Tamiya thinner, and it was so thin, water is thicker… It was almost a red dye…

Shot some on a test plastic body I’ve got, WOW… What a difference.. 22 PSI, and it was smooth, wrinkle free and dried much faster, smoother, and virtually orange peel free… It was too thick. The bottle offers no instructions on how to thin, or what to look out for. I was like a virgin and I jumped in head first, went in like James Bond, and came out feeling like Frank Spencer..!!

Lesson learnt, and the paint is REALLY good…. It just needed a lot more thinning…. Thanks for all the help. I’ll perhaps now pull the tail from between my legs, start wagging it and get that datsun back on track again..

Much to the applaud of MPWR I think…

[WasteGas]

I usually spray lacquer at 20 sometimes just a tad lower. When I go higher, I get too much mist that just ends up all over the place. LOL.

[cyberkid]

20-25 psi, 1:1.5 ratio!!!
I use around 15 psi and my laquers are thinned to around 1:0.5..
Might be the humidity here above 60% all year round ..
I guess the main thing is that you gotta try all the possibilities and go with what works for you.