Where to go from here? Moisture pimples

Even if it builds pressure it doesn't have enough volume. Volume is more important than pressure with an HVLP.
I dunno Chris. It seems to me if pressure is holding at the gun then volume is there. If pressure drops volume is not there. As I said if he is choking his gun then his volume requirement is decreased below the Iwata spec. That is the only logical explanation I can think of. The gun valve is after the gun regulator….

It seems this topic is similar to the “compressor making water” topic. A lot of opinions and theories that folks are adamant about.

This subject is bringing back bad memories of mind boggling nozzle calculations in my college thermodynamics class. :D

Cheers,
Don
 
What I should have said Don, was if the system isn't capable of delivering the volume needed then it doesn't matter if he had good pressure or not. Iwata LPH's need 10 cfm to operate. If his compressor is only delivering 8 or 9 then he doesn't have enough volume. I don't think any 30 gallon compressor has enough volume (CFM) to run an HVLP gun for any length of time if the rated output is less than the air consumption of the gun. Most of those 30 gallon ac's are putting out around 6 cfm at 90 psi and 7ish at 40 psi. Not enough.
 
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What I should have said Don, was if the system isn't capable of delivering the volume needed then it doesn't matter if he had good pressure or not. Iwata LPH's need 10 cfm to operate. If his compressor is only delivering 8 or 9 then he doesn't have enough volume. I don't think any 30 gallon compressor has enough volume (CFM) to run an HVLP gun for any length of time if the rated output is less than the air consumption of the gun. Most of those 30 gallon ac's are putting out around 6 cfm at 90 psi and 7ish at 40 psi. Not enough.
Hi Chris. That’s why I think he may have choked off his gun with the air valve on the gun. Iwata guns have that air valve right beside the air connection. If it’s turned in he may be choking off his gun. This would explain how he holds pressure, because his air consumption has been reduced below the specified 10 cfm by that valve. It also explains what Barry is saying.

This valve circled in red
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Anyway, I think we scared the OP off… :)

Don
 
How do mobile painters get away from this? Besides they clearly don’t drive around with 80-120 gallon 220v compressors in their work vehicles. Is it the small areas? I know most work are blow ins, touch ups etc but at times they do complete bumpers, maybe a label or 2. Keeping the clear as low solids as possible?
 
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Hi Chris. That’s why I think he may have choked off his gun with the air valve on the gun. Iwata guns have that air valve right beside the air connection. If it’s turned in he may be choking off his gun. This would explain how he holds pressure, because his air consumption has been reduced below the specified 10 cfm by that valve. It also explains what Barry is saying.

Anyway, I think we scared the OP off… :)

Don
Yes that should def be all the way open.
 
As an aforementioned mobile guy, I have a Harbor Freight, 2hp, 29 gal compressor. I use either an Iwata but mostly a Prolite. I've landed on lowering the tank pressure to the point that my gun valve can be adjusted to a few pounds over my preferred PSI. That way, my pressure gauge is practically wide open. It really changed my results. I almost always do full bumpers or often a couple panels. I use the Speed Clear with a 1.3. I might add a touch of reducer.
 
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Thanks for the tips everyone! Been busy with holidays. I really do hear you guys on my compressor, but I dont have access to 240v power in my current rental living situation, which is a really amazing location for other reasons in my life currrently. In the future I will invest in a larger compressor, but for now its not in the cards. I could add an auxiliary tank to my currrent one to increase runtime on the painting.

There seems to be a bit of magic attributed to pressure and volume, but I am going to side with you and say yes, though there will will be fluctuations due to the cycling of the pump. If you want to know if a given compressor can handle a given tool, just run the tool at the intended air consumption continuously and see if the pump can keep up once it kicks on. If the air pressure continues to decay when the pump is running and the tool is running, there is not enough pump output. It doesn't really have to be more complicated than that.
Thanks for the sanity check here, this is what I believe as well, as long as my gun doesnt outrun the wall under 100psi I should be OK
It is all very marginal, but I am definitely not getting into a situation where I lose pressure and atomization, 100psi into the gun is giving plenty of fog out of it, I had the gun reg set to just under 2 Bar and it stays there rock solid.
Wall starts off around 140psi and very slowly degrades but I am painting with ~80% duty cycle, but the air compressor runs at 100%. I paint two fenders and cowl and stop at the rocker and slowly walk around the car, during that time the compresser has caught up again.
Its more like 30ft of 1/2" air line to my wall reg, and my water traps are high flow rated for 100cfm. Final .01 micron coalescing filter is rated to 30cfm.
OP says his pressure is holding despite his setup doesn’t work on paper. I think it may be because he has choked off his gun using the valve on his Iwata gun. That would lower his air consumption and lead to his issues that Barry is attributing to low air. Just a theory….

Don
I definitely have my air knob all the way out, the car looks a lot better this time around after the flowcoating, some parts look downright good! So I think the popping is down to my technique and 70% humidity. I think I got too close with the gun at times and too heavy. I had the material at 2.5 turns but it went on too heavy first coat so i dialed back to 2 turns for next 2 coats. I am going to wait for the next 30 days to see if the dieback and popping is worse, otherwise its good for 1500 and buff.

As an aforementioned mobile guy, I have a Harbor Freight, 2hp, 29 gal compressor. I use either an Iwata but mostly a Prolite. I've landed on lowering the tank pressure to the point that my gun valve can be adjusted to a few pounds over my preferred PSI. That way, my pressure gauge is practically wide open. It really changed my results. I almost always do full bumpers or often a couple panels. I use the Speed Clear with a 1.3. I might add a touch of reducer.
Mine is similar but older, it says 8cfm, but I dont just hold my paint gun open the entire time I paint, and I will stick to just doing quarters and a few panels at a time from here on out I think!!
The Universal clear went on very thick, lots of mils on the panel for buffing and its soft and easy to buff.
I think next I am going to try the Production clear and stick to doing panelwork with this compressor.
 
when i do mobile stuff i have a small twin tank wheel barrow type gas compressor. has a small honda gx160 on it. it will just run any of my full size sata guns or a da. it will run constantly but it works. its also my backup for the shop if my main was to ever go down. its relatively small and no big electric power needed, also much cheaper. about 1/3 the cost. for someone shooting maybe 1 or 2 cars a year i can see this as being a good solution. they do make alot of water though here with the summer nj humidity so you may need to deal with that.
 
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