Ol Danl

I have a small compressor (8 gal.) that I mostly use for nail guns and airing car tires. Awhile back, I bought a small touch up spraygun, thinking I might paint a bike. I've currently talked myself out of painting the bike, but was discussing the need for drying the air with a fellow customer the other day at HF. Do any of you use a similar small compressor, and what external traps or whatever do you use to get the air dry enough?

OldsCOOL

Put a watertrap at the *** and paint when temps are in the 70's, and fairly low humidity. If you paint in a garage be sure you are not in the breeze of the heat outlet. And lastly, if the air is too dry or hot, be sure to maintain a closer shoot distance with the *** and watch for "flash drying" where the paint begins to dry while it is between the *** and the subject. Just a few tips for ya.

ETA: the stupid word filtering.....that was supposed to be "GEE-YOU-EN"

Grand Bois

MINI WATER FILTER DISPOSABLE FOR DEVILBISS, SATA, IWATA,ETC

Ol Danl

Okay, so the other guy at HF said that little disposable filter at the spraygun was all you need -- and I'm tending to think you should probably have a better water trap, and then use the little disposable filter. Are you guys saying the disposable filter by itself is adequate? Can the air be too dry?

rootboy 

I personally have, and would use, is an inline moisture trap with pressure gauge/regulator attached.

OldsCOOL

It is quite adequate if it isnt 80/90% humidity. First, be sure your little air tank is purged of water. There should be a petcock on the bottom of the tank to drain it by blowing the compressed air out. Then put the filter on and spray! I shot the paint on my restored '55 chev doing this. No water drops anywhere. Your project is a bit smaller in scope and size.

rootboy 

Also, which Horror Freight gune did you buy? If it is a conventional spray gune, you should be OK. If you bought a HVLP gune, your 8 gallon portable compressor will probably not put out enough volume to run it. Just FYI.

crank_addict

For spray gin, definitely a filter. For the moment disregard whatever ambient temperature or moisture is in the air. You're going to have condensation from heat and cool down cycling from the compressor operation. I'm guessing you have an oil less compressor, but if not, you need an oil separator as well. Also, if spray environment has higher humidity, you can adjust by using the appropriate drier additive to the mix.

+1 on the HVLP mentioned above. They need big CFM to use. However there are 'hybrid' versions (gravity feed / HVLP) that can operate off lower CFM.

Ol Danl

The little touch up spraygun I have is conventional. But my compressor is not an oil-less one (there is an oil resevoir) so I guess I need an oil separator -- hadn't thought about that. Again, I mostly use this for nailers, so I usually put oil in the nailer and don't worry about the water. I think HF has a combination oil and water separator, maybe?

rootboy 

Oh, OK. I can say spraygun here. Raygun. Stungun? Potaoto ***?
Nah....

rootboy 

They should. I got one on ebay for cheap. Pretty good unit too.

Bikedued

Shouldn't that be the opposite? HVLP means high volume low pressure. A conventional suction type *** takes loads more pressure, and wastes more paint through overspray. Am I not understanding your post, or?,,,,BD


I've mostly used gravity feed HVLP, to the point of not even knowing there was another type. I have three sprayguns at the moment. Two are harbor freightish, one large, and one touchup type(both gravity feed). The third is an Accuspray Isaac, that I totally lucked out on. It was ordered for someone that never picked it up from the auto parts store I worked for. It sat around for a few years, and wasn't in inventory. One day a week or so before yearly inventory the manager took it down off the wall, and handed it to me, knowing that would have a use for it. I said "What's this?". He says "Exactly". I got the idea pretty quick, and carried it out to my truck.

Grand Bois

Here's an inline filter that has a Presta valve drain. I've only used the inline filters on my small portable when using an airbrush to paint models. They work just fine and the air gets pretty damp here by the Bay. I don't think that compressor could keep up with even my HVLP detail spraygun.

1/4" INLINE MINI AIR FILTER

I also have a large compressor mounted in a cabinet outside the garage with a wall mounted filter/air regulator/lubricator and separate hoses for tool lubrication and spraying. Having the wall mounted filter means that you have to drag hose to wherever you need air, so it's nice to also have a portable.

I've never tried a HF or other inexpensive spraygun, but I'm curious. Is it really necessary to spend $200 for a name brand spraygun for small projects?

rootboy 

A conventional spraygun, like used prior to the introduction of HVLP sprayguns, do indeed, or can, use loads of pressure. Hence the loads of over-spray. HVLP sprayguns use a lot lower pressure, but as the name suggests, use HIGH volume. Most HVLP sprayguns require something like 8+ cubic feet per minute. CFM. Small compressors don't put out nearly that kind of volume. Most put out somewhere around 3 to 4 CFM, or so they claim. Often much less. A small compressor can be used to run an HVLP spraygun, but you have to stop frequently for the tank to catch up. If that makes sense.

A good compromise is a LVLP spraygun. Low Volume Low Pressure. But there aren't a lot of those out there and they can be expensive.

rootboy 

I'm thinking about getting one of these
https://www.youtube.com/watch?v=4pfejpvr3nw

crank_addict

Sort of drifting off the topic of bikes but since its about painting one....
A quality gravity feed 'gin' with super fine machined nozzle, and a lower CFM compressor can get the job done just as nice but less efficient, meaning more atomized paint is wasted into the air.

Spraying with an HVLP 'gin' or even having is overblown (pun). But if one has the luxury of having and a sufficient compressor, by all means, its the way to go. It was invented as an alternative means of applying more atomized material coming out of the 'gin' to the surface being sprayed. In other words, less material wasted instead of blown into the environment. The EPA caught onto the idea and enforcement in many states followed.

As mentioned above for true HVLP, one needs a compressor with high CFM. You're not going to get it with a small compressor. However, it is possible to use a portable like a engine driven, high CFM, twin tank (for construction trades) to keep up and run multiple air nailers. Of course, with all the vibration, a remote oil and water separator is needed.

If you're still sold on the entire HVLP set-up, don't forget to using larger feed air line AND couplers! When using the conventional 1/4 quick couplers, you're restricting the air volume. Spend for larger i.d. quality non leak couplers.

Lastly- HIT ME NOW.... recently did a rattle can jobbie using Rust-O-leum 2X.
Sprayed outside as well during a pleasant dry and 70 temp afternoon. On sale for $3 a can. (Usually at the auto paint supplier, its $50 in material alone for such small projects as a bike. Two part urethane.) After I'm done with the embellishments, will top with rattle can clear. For those holding a tight budget paint on a lowly frame, its great stuff. The can sprays inverted and for a cheapo plastic nozzle, the mix comes out OK. Cured hard.

(FYI: Not of the same quality but Devilbiss 'gin's are made by the same makers of HF)