Ok, I realize for $10 on sale it's expected that it's not going to be a great spray gun, but the 20oz Purple HVLP Harbor Freight Gravity gun is a complete waste of $10 in my opinion. I wouldn't take another one for free if it was given to me new in box. The Walmart $25 Campbell Hausfeld gravity feed is a better investment if a cheap gun is needed.
This is the one below. Although who knows how long the link will work because they change the model number so often most likely to avoid getting a bad reputation (which some have actually been ok I should add. But not this one).
But here's my experience with it and maybe it'll save someone $10. In my case I spent $50 since I bought 5 of them for various colors after reading that they were decent guns. I didn't want to make another trip since I live far from HF, so I bought 5.
First impression... Sprays ok actually pretty decent for $10. But before I used the gun I took it apart and cleaned it. They use RTV or silicone caulk sealant in the nozzle to gun body connections and lots of it. They do this instead of a good metal to metal seal or copper crush washer like most other good guns would have. The fan adjustment knob is Chrome plated PLASTIC (yes plastic!) and if the gun body sits in thinner too long it turns into mush. A gun body should be built so it's able to be soaked in thinner for a period and the more metal parts the better. Also the plastic parts should hold up to solvents... not in this case. Also, the fan adjustment (when the knob is still there) is touchy and definitely not a fine adjustment. Another issue, the seal for the cup is a plastic ring that the cup seats into as it screws down onto the body. This ring splits after only a few uses, then the cup leaks since the ring/seal is no longer there. I fixed this using Teflon tape and it doesn't leak. Next problem, I noticed where the fan knob used to be (before the lacquer thinner melted the chromed plastic knob) now the o-ring doesn't want to stay in place and it leaks air pressure (maybe it wasn't sealing before but I just didn't notice since the knob hid where it was at).
So... the purple gun... In my opinion (for a person who makes money spraying paint) is a waste of $10 and cleaning time not to mention frustration. Maybe for someone who's not picky on how clean their work is (your work is only as clean as your environment/material/tools), or for someone who needs a one use gun for something unimportant, it might be ok. I'd still recommend a different gun. For me, this one was a piece of trash and a waste of time and money.
the gun is hard to get completely clean due to design. The gun uses caulk (makes it harder yet to get clean) in the nozzle connections, the fan knob is chromed plastic, the cup's plastic seal ring breaks shortly after first use and will need to be rigged to not leak paint, it leaks air underneath fluid knob. Really a botched together little piece and definitely not well engineered.
All that to say, it's possible to get a cheap gun that works decently. I used this HF model (says 4001 on the side of the body-binks copy I'm guessing) for several years when starting out and they worked fine:
They're easy to clean and a decent conventional siphon cup gun. I still use a few once in a while. I probably have had 20 of them over the past 6-7 years. It's still a disposable gun but better for HF cheap quality. The seals leak on these over time, but they work well for a good while and are easier to get completely clean.
In the end, a good gun is worth the price. I have an Iwata that I use for clear and it's almost enjoyable to clean. The fit of the nozzle to body is metal to metal with no plastic or rubber seals whatsoever (nozzle to body that is-the needle packing has plastic but it holds up to solvents) and they planned the threads and the metal alloy (slick and easy to brush clean) so that the gun would be easy to clean. Since I spray almost everyday, it's worth $400 new and I'd even rather clean up an old used Iwata if times were tight. I'm still all for good cheap guns since I like to use one gun dedicated to different shades of colors/metallics etc and it's hard to have 3-4 x $400 guns. But still with good cleaning, three color guns shouldn't be necessary. With the HF purple gun it is necessary because it's hard to get it spotless clean with the threads and the way they planned the nozzle to body fit as well as the RTV/Caulk. When you think about it my 20 x $15 on sale for HF guns (even the one I liked) is still almost the cost of a good gun. My guess is an Iwata would have lasted me 7 years and still sprayed like new. The HF throw aways... well, they worked good at first and as time went on, well they got thrown away. So... a good gun is cheap after all.
But that's my take on the HF Purple. Hopefully it helps someone.