Paasche H giving me fits with primer and clear

[Juicegoose]

Recently had a Paasche H passed over to me. It came with all the tips 1,3,5. I was looking for a good alternative to apply a medium build primer then my badger 105 with standard tip and I had read that this little single action was the ticket.
for reference the HOK KD3000 series primer I'm spraying is reduced to a medium build surfacer and the recommendations on the tech sheet state a 1.4-1.8 tip on a conventional gun.

Now the problem
It seems like the paasche H sprays the primer and clear well at first. It lays down a good wet coat. Problem is about halfway through a spray session it seems like the gun quits spraying a thick coat and i have to open up the tip more and more. I can dump the primer or liquid right back into my badger 105 and it'll finish the job for me(especially the clear).
i thought at first maybe is was material drying but i've gone as far as taking the paasche H completely apart and soaking the tips between coats and running lacquer thinner through the pickup tube and i get the same results.

Obviously i'm doing something wrong with this simple airbrush.
I'm using my small HF airbrush compressor and have the regulator set to 20-30. Normally 30 with a drop to around 20 if i hold down the nozzle to long.

 

[basepaint]

You might not have the cfm needed for the clear/primer long enough with the compressor falling behind as you spray

 

[Juicegoose]

Its possible. While running the paasche mine drops yo 20psi. I ordered a detail gun today with 1.2 tip. We'll see if that helps.

 

[Nessus]

The fact that the drop in pressure doesn't happen the instant you press the trigger does mean your compressor is lagging behind the what the brush is using. An instant drop of a few PSI is normal and just the difference between static and working pressures, but a 10psi drop coupled with the delay before it drops is more telling.

Test and see if the drop in spraying efficiency correlates to the drop in pressure.

Another possibility is paint adhering and drying inside the nozzle cone. Not in clumps, but in layers on the inside wall, effectively reducing the nozzle diameter. When you took it apart to clean it, did you examine the inside before cleaning, or did you just stick it directly in the soak? I'll admit, this seems less likely than the CFM thing, though.

If it's a CFM issue, then unfortunately the solution is to get a new compressor. Might be cheaper to buy a 155 (Anthem) needle/nozzle set for your 105. That would let you spray heavier stuff with the 105 using the compressor you have.

 

[Juicegoose]

Well last night i mixed up a bigger batch of primer in a medium build thickness. HOK recommends a 1.7 tip minimum from there tech sheet.
First I sprayed it with the H and using the size 5 tip. I adjusted my compressor to 30 psi and began spraying opening the nozzle from full close. I had to rotate out roughly 4-6 turns before I got a decent coat working that wasn't immediately dry. Obviously the pressure dropped to 20 while this was happening but stayed steady at 20. If I don't hold the trigger down for a long time it'll keep up with the airbrush at 30 but typically there is a drop. I also noticed the spray seemed to be pulsing some. I switched over to my badger and lowered the pressure down to 20 psi and it sprayed better then the paasche did for sure. Is the paasche H size 5 head equivalent to a .5mm tip that is on the badger?
I've got a large 30gal 2hp shop compressor that I can use with the paasche if need be but I went ahead and ordered a 1.2tip detail gun to try and spray the primer with as well.
What I'm wanting to ultimately do is spray my parts with little to no sanding before basecoat but I need the primer to stay thin(mil wise).

 

[Nessus]

I wish I knew. Best thing I could say would be to try it on your shop compressor, and see if the higher airflow improves things. Unfortunately I was never able to get my own H to spray to my satisfaction. No matter what, it always had chunky atomization, and didn't really spray any higher volume than my double-action brushes.

Eventually I said "sod this" and went looking for an alternative. Ended up with an Iwata HP-TH. A lot more expensive, but it did the H's job miles better right away, and cleans easier as well.

I know there's folks out there who make it work well, but I'm not one of them. Either it takes a lot more special skill to use than a good double action (sort of negating the "simplicity" angle), or the build quality is inconsistent enough between individual brushes/parts to effectively randomize the experience between owners. I more suspect the latter.

 

[Juicegoose]

Well over the weekend a ran the Paasche H on my big compressor with a steady 20 and 30 psi. I tried HOK KD300 primer mixed as a sealer and also some House of kolor USC01 2k clear. Both times I got about halfway through the session and kept having to open up the fluid adjustment because the material kept getting smaller and smaller. Finally gave up and went to the trusty badger 105 on the airbrush compressor and shot them both.

When the paasche is first spraying it sprays great but it's like the material is drying up in the tip or something.

 

[Nessus]

What are the downsides of priming with the 105 that made you want to seek an alternative? Just wondering, since you keep going back to the 105 and saying it works well where the H doesn't.

I mean, If the 105 is doing a better job, why bother with the H?

 

[Juicegoose]

I had false hopes that the H would lay down a smoother coat of the primer. I have been getting a somewhat rough(grainy) surface when I apply the primer and I was thinking the H with its larger size tip would help that.

 

[Nessus]

From what you've described of your issue (paint flow steadily reducing despite all other factors being nominal), I'd also suspect paint is building up inside the nozzle during spraying. That's something that shouldn't happen at all, and it suggests either the plating is bad, or there's some kind of chemical residue inside that's causing paint to coagulate on contact.

What solvent/cleaner are you using to clean the nozzle/needle? Is it something recommended by HOK for their primer? (My apologies if this comes across as a "have you tried turning it off and on again" type question.)

If it's a plating issue, then the solution would be to buy a new needle and nozzle. If it comes to that, then I recommend getting an Anthem needle and nozzle set for your Patriot instead. The Patriot and the Anthem are just different feed-type variants of the same brush, but their default needle and nozzle sets are different (though still interchangeable). The Anthem needle/nozzle has a larger nozzle aperture and a much more aggressive double taper on the needle, so having a set of those you can swap in and out of your Patriot will get you the larger spray volume you're after without having to deal with the H-related issues/uncertainties/adjustments.

 

[Juicegoose]

Thanks for the anthem heads up. I cleanup everything with lacquer thinner.