Painting with an Underpowered Air Compressor

[FMC1]

I'm no artist. On my best day I can do a passable stick figure, but lately I've been thinking of some paint schemes requiring more than matte black rattle can. Flake, pearls, maybe a little striping and leaf, so I went through the rattle can selections at my local big box and sprayed some test panels with very disappointing results. Their "flake" is just glitter, no pearls could be found, the whole experiment was a disaster.

I've already made the switch to battery tools so I don't have an 80-gallon 2-stage air compressor (my "shop" is my garage) and really only kept my old HF 21-gallon compressor for inflating tires, footballs, and my "girl friend". I think the CFM stats on this compressor are: 5.8 CFM @ 40 PSI, 4.7 CFM @ 90 PSI

I've seen Paint Huffer advertisements on CC and that's the kind of chunky flake I want and I want the pearls to be high quality as well. I know my compressor is anemic, but was thinking of riding to HF, getting a cheap paint gun and trying these paints with the gun. After all, I'm not painting a 1980 Eldorado, I have a gas tank and a fender, I can put a coat on in a minute or two and rest if needed while the compressor builds pressure again.

Anyhow, I'll definitely try this, but was just wondering if anyone has past experiences to share about using an underpowered compressor to paint. Maybe tips or tricks picked up that might save me some headaches.

[ExplodingCoffinEmporium]

It’s very doable with a smaller compressor on motorcycle tins. I’ve painted sets with my Ingersol Rand shopmate 20g, 5.2 cfm with no problems. Would I paint a full car with it, likely not as I wouldn’t want to sit around letting it build to shoot, but even then it could be done if push came to shove. A lot of people reccomend 10-14 cfm for paint and with good reason, but a 2 stage, 5+Hp, 60g plus isn’t in everyone’s budget. Not all HVLP’s are created equally as well, some will require more cfm’s then others and that’s something to keep in mind. With that being said technique will help balance a wimpy compressor. Your spray may not atomize as well and your effective fan spread will likely be lessened with a low CFM demand gun. The spread is important to note as your coverage must overlap properly if you want to avoid tiger stripes.

At the end of the day we’re working with motorcycle paint which is a lot less demanding than painting a car and you can get away with a lot more. I’d reccomend getting a cheap throwaway gastank and practicing to get a feel for your rig. Get comfortable with reducer, activator, and the paint your using and mostly enjoy yourself. Painting is fun and gives an excellent outlet for creativity. I’ve been spraying metal for quite awhile now and always enjoy the process. Good prep is 75% of the battle. Of note, water in lines, get at least an in-line filter and a separate hose to use for paint that will be used with nothing else but paint. Oil, water, or anything else but dry air running through that gun will cause havoc on the other end. I will update with more tips and personal fuck up learning experiences as they come to me but it’s early and I’m having coffee still.

[FMC1]

..I’d recommend getting a cheap throwaway gas tank ...

Thanks for the feedback. As luck would have it, I'm the proud owner of several cheap throwaway gas tanks 😁

[1954bmw]

Years back while doing body work I had a reconditioned Sears 3 horse, 20 gallon tank, I also had an airboard to try and get panels flat. While using the board you could run for 5 plus minutes and compressor would kick on to build more air, take a breather, let compressor catch up and go back at it. Compressor reeds took a shit, so replaced reeds and air filter while there. Fired the compressor back up and ran great, plugged in the airboard and started sanding, compressor kicked on, ran a little and kicked off, ran a little and kicked off, compressor could now keep ahead of the airboard. Short story long, check your air filters on the compressor to give yourself best chance. Good luck.

[farmall]

I collect compressors and air tanks, the bigger the air tank the better. While hunting a deal on a 10 or 15 HP head (big compressors can be quite inexpensive in pieces) I gang the small compressors to feed the main tank.

5HP is sufficient for painting cars. The wife used one with two dryer/filters (one near the gun of course) and we placed a surge tank (any air tank with a T-fitting etc) with the dryer so the gun wouldn't quickly deplete line pressure.

Dead compressors are usually easy to fix so I collect them. It's rare for motor/tank/pressure switch/head to die at once (I've never seen it).

Any size compressor can be put on wheels or a cart for convenience. Vertical tanks can be laid horizontal if a condensate drain at lowest point is available or added.

Large ID hose is a very good idea. If I painted I'd go much larger on those hoses and will eventually add larger fittings off my main tank to include at least one glad hand high flow coupling for future blasting.

[flatman]

just an fyi paint society had a youtube video where he paints a car fender and door with a 5 gallon pancake compressor. also on you tube speedokote has a video of him priming a car with a harbor freight electric sprayer (think wagner electric house sprayer) He is going to paint the car also with this set up this friday also spraying pearl clearcoat?

[crankyformer]

Embarking on a painting project with an underpowered air compressor can present its own set of challenges, but with the right approach and some tips, you can still achieve satisfactory results. Here's a guide on navigating the process of painting with an underpowered air compressor:

Choose the Right Tools:
Opt for a spray gun that is compatible with lower air pressure. High-volume, low-pressure (HVLP) spray guns are often more forgiving and can work well with compressors that may have limitations in terms of air output.

Thin Paint Appropriately:
Thinning your paint to the right consistency is crucial when working with an underpowered compressor. Thicker paints can cause clogs and uneven spraying. Follow the paint manufacturer's recommendations for thinning ratios.

Proper Ventilation:
Regardless of the air compressor's power, always ensure proper ventilation in your workspace. Work in a well-ventilated area or use additional ventilation equipment to minimize the impact of paint fumes.

Remember that while an underpowered air compressor may pose challenges, with thoughtful adjustments and careful planning, you can still achieve satisfactory results in your painting projects.

Thank you.