Problem with air gun

[JoeKan]

I bought a Harbor Freight's HVLP Spray Gun and I was figuring out how it works today (I've never painted a car with an air sprayer) so when I hooked it up to the air compressor, the air control knob continually leaked air. It didn't matter if I turned it clockwise or counter-clockwise, it was leaking. Is the gun flawed?
Another problem I am having is that there was very little air being shot through the nozzle. So, I'm not sure why the control knob was leaking, but is the reason why there was very little air passing through is because I have a 30 gallon air compressor?

[JoeKan]

Here's the info on the gun and my air compressor. I mis-spoke on the gallon capacity, it's a 25 not a 30 gallon. Thanks for any help.

[72c20customcamper]

Sounds like the gun is defective . If you plan on painting the whole truck at one time your compressor is woefully inadequate. You may have problems with even panel painting . In any case you will need a air cooler and dryer as the compressor will be running nonstop and moisture will be a big problem . I have a 60 gallon Dewalt and I wish I had bought a bigger compressor . I’m going to replace this one with a bigger unit in the future and give this one to my son .

[JoeKan]

Thanks for the response! I took the gun(s) back to HF and they allowed me to exchange it for a new one (same model). I took it home and shot some air through it and didn't have any leaks. I think with the set-up I have, I can do the chassis. I'll be looking for a new/used Air compressor for future use...and a better gun too.

[franken]

Glad you were able to swap the guns. I've had good results painting things like inner fenders with one.
Yes, you'll have to take a lot of breaks with a 25 gallon compressor. I currently have a good 80 gallon compressor that sells for ~$4k these days and still want more. You can never have enough air.
You might want to look at a video or two about the purple gun.
https://www.youtube.com/watch?v=VxswuUgMwVQ

[Dead Parrot]

Storage tank size has nothing to do with compressor capacity. Think of the tank as a battery and the pump as the charger. Also, most compressor mfg's overstate the output of the pump. I think you will find that your compressor won't keep up with the needs of the detail gun even though the numbers indicate it might. Unless HF is overstating the air needs of their paint guns.

Another problem might be your regulator. If you are using the common 1/4" pipe regulator often included, it could limit the air output to your paint gun.

If your chassis painting involves a bit of painting and some down time while you move, you might be ok. It will show you where any issues are with your current setup.

[franken]

Right. Think of the tank as a battery. The alternator won't provide the current needed to start the car. Yes, compressor makers lie. That's why you buy from a reputable seller and not Lowes or Home Depot.
Any 25 gallon compressor pretty much has minimal capacity to do anything but make someone newly married blow some crap out of the garage and impress the husband or wife.
If the pump has the capacity (which they never do) to provide the needed pressure and CFM, all is well.
HVLP means high volume low pressure. A 25 gallon compressor can't provide the volume needed to paint much without rest to refill the volume of air in the tank.
Yes, good Milton fittings throughout will help.
As I said, you can never have enough air...

[72c20customcamper]

I went with all 1/2 inch flex lines on my system . Haven’t hard plumbed it yet but there is no air pressure drop anymore like I had with 3/8 lines . Tank size does play a major roll in the system if the tank is to small even with the best lungs you will run constantly which causes heat which in turn cause excessive moisture . Good lungs and a large tank is the best situation .


Wish I could have taken the compressor from my uncles shop . Very old if I remember a Hayward unit. 250 gallon tank and it ran very low rpm’s . But the buyer wanted it left as part of the sale . My next one I’m leaning towards the Polar by Eaton .

[Accelo]

Why are CFM ratings BS?
https://www.youtube.com/watch?v=cfjSm_ieRkE&t=12s
I love the AvE channel. Entertaining and I learn stuff.
Cheers