Automotive Painting.

[jhelrey]

I have a Kobalt 30 gallon air compressor with a V twin pump. 240V. It's capable of 155 PSI. SCFM 5.3 at 90 PSI and SCFM 6.2 at 40 PSI.

I'm wanting to paint a front bumper, mirror caps, and the Platinum placque on the tailgate of my Ford.

The spray gun I purchased needs 11 CFM at 35 PSI. I don't have enough CFM.

Will I hate life trying to do this?

I could hook up another portable compressor that is capable of putting out 4.0 CFM at 40 PSI.

 

[GeoBruin]

Remember that your compressor tank gives you a little buffer. You will be able to do quite a bit of spraying before the pressure in the tank drops below a regulated pressure of 35 PSI, and as soon as you drop below the cut in pressure of the compressor (probably 120 psi or so) the compressor will kick in and be helping to offset the demand from the gun.

Based on the relatively small size of the items you want to paint, I think you'll probably be okay.

As for hooking up multiple compressors, that should work great. I'm actually a big fan of using a "peaker" compressor for occasional high demand needs. Just make sure the max pressures of the compressors/tanks are relatively compatible and that you're not maxing out a single circuit.

 

[Walkers]

What spray gun do you have? I have never really looked at the cfm ratings, but that seems awfully high. Regardless, you have plenty of air for painting that stuff. I have painted cars with the little 20 gallon 2-3horse compressors. Generally you tune the gun down a fair bit, so you only have 20psi at the head, then the fan is generally not at its widest point. Then you don't use air constantly when painting, you spray back and forth, stopping in between, then stop while moving to different parts. If you are worried and want to try it out, just fill the cup with water and practice painting.

 

[The Cobbler]

I bet also that you find the compressor will keep up. in spraying you don't have the trigger pulled constantly and you're dealing with relatively small parts . even assuming they are the same colour you will have a lot of time when you're not spraying for the compressor to rebuild.

 

[jhelrey]

Thank you for the responses. This is the gun I may purchase.

Premium HTE Gravity-Feed Air Spray Gun with Side Fan Control

Amazing deals on this Premium Hte Spray Gun, Fan Control at Harbor Freight. Quality tools & low prices.

www.harborfreight.com

 

[dnschmidt]

Short answer is YES you will hate your life. A full sized gun will eat this compressor for lunch and don't believe what anybody tells you about so-called low CFM guns as they are lying out of their teeth. What can do what you want to do is a Mini-Gun like the ASTRO Mini-Gun. I have a SATA Minijet IV and a Sagola Mini Extreme that cost five times as much as that HF gun both of which could do the job but the ASTRO is a lot of Mini Gun for about $100 and it has a six inch fan. People do these kind of jobs with 2K spray cans and a good Mini-Gun is miles better than a spray can.

 

[saltwater4life]

You’ll be fine for a bumper and small pieces. I’ve painted much more with much less.

 

[jhelrey]

Short answer is YES you will hate your life. A full sized gun will eat this compressor for lunch and don't believe what anybody tells you about so-called low CFM guns as they are lying out of their teeth. What can do what you want to do is a Mini-Gun like the ASTRO Mini-Gun. I have a SATA Minijet IV and a Sagola Mini Extreme that cost five times as much as that HF gun both of which could do the job but the ASTRO is a lot of Mini Gun for about $100 and it has a six inch fan. People do these kind of jobs with 2K spray cans and a good Mini-Gun is miles better than a spray can.

Do you have a PN for the gun you recommend from ASTRO?

 

[P0234]

Put some water in it, pretend you are spraying paint, see how it goes. IMO you will be fine. I've grossly undersized my compressors to spray guns for so many projects before I had a bigger compressor, you can make it work. With a 30 gallon tank you'll get plenty of warning before the party stops.

 

[jhelrey]

So many gun options... I think I've finally narrowed it down.

 

[dnschmidt]

Do you have a PN for the gun you recommend from ASTRO?

https://www.amazon.com/dp/B0042KJ5W8/?tag=atomicindus08-20

 

[jhelrey]

Thank you DNS for your expertise.

I looked at Astro but the paperwork I was reading indicates the CFM was significantly higher than what the Amazon link is showing or even other sites.

 

[Pinemarten]

From the Campbell Hausfeld site:
"What’s the difference between cfm and scfm?

The most common air compressor ratings are cfm and scfm (standard cfm). So, what’s the difference?

As a measurement, cfm will be a smaller number than scfm, because cfm values are taken under pressure (typically 90 psi), so the air volume is small. To calculate scfm, the air is expanded to a standard condition to take into account the variables of pressure, temperature and humidity: 14.7 psia (0 psig), 68 degrees Fahrenheit at 36 percent relative humidity. As a result, scfm values are larger. Campbell Hausfeld typically uses cfm values when talking about air compressors and scfm values when talking about air tools.

Campbell Hausfeld realizes that typical DIY users do not run their tools non-stop. Therefore, our air consumption ratings are based on an average usage or duty cycle. Average usage is based on the amount of time in an hour that the tool will typically run. Campbell Hausfeld rates air consumption in this manner to give a better indication of the approximate size air compressor needed for the tool to complete typical tasks — and by the average DIY user."

I would base my gun choice on your compressor's specs.

 

[Walkers]

Thank you DNS for your expertise.

I looked at Astro but the paperwork I was reading indicates the CFM was significantly higher than what the Amazon link is showing or even other sites.

I have used that gun, it is a good gun, very similar to what you have now, though it is of a little better quality. The reason CFM is different is that if you open the valves on the gun, and put in the biggest orifice (2.0 most likely), the gun will use a lot of air. With a 1.5 or 1.8 orifice (which is most common in most guns) it uses a lot less, then you reg down the pressure, turn down the fan, turn down the head pressure they don't use near as much. Either the gun you have or the astro will work just fine for what you are doing.

 

[dnschmidt]

Your compressor will handle the Mini-Gun no problem. Run the gun at 29 PSIG with the trigger pulled (DYNAMIC PRESSURE) and wide open on both the fluid and the fan.

 

[jhelrey]

Your compressor will handle the Mini-Gun no problem. Run the gun at 29 PSIG with the trigger pulled (DYNAMIC PRESSURE) and wide open on both the fluid and the fan.

I purchased the Astro based upon your recommendation.

 

[IndyGarage]

When I was younger I painted an entire car - actually multiple - with a small sears compressor and an old style gun. The limitation is the air in the tank, so you have to paint one panel at a time. Since you are only doing a few panels you should be OK.

 

[firebirdparts]

You'll be fine.

 

[strutaeng]

I have used that gun, it is a good gun, very similar to what you have now, though it is of a little better quality. The reason CFM is different is that if you open the valves on the gun, and put in the biggest orifice (2.0 most likely), the gun will use a lot of air. With a 1.5 or 1.8 orifice (which is most common in most guns) it uses a lot less, then you reg down the pressure, turn down the fan, turn down the head pressure they don't use near as much. Either the gun you have or the astro will work just fine for what you are doing.

Say what???

The needle size is for the fluid delivery. The air consumption is based on the air cap, which usually doesn't change unless you go from a HVLP to a Reduced Pressure cap (some guns have this option.)

True, larger needle size will probably require more CFM, but that's because you are likely spraying a heavier paint, which will obviously require more power to atomize properly vs a thinner one.

 

[Walkers]

True, larger needle size will probably require more CFM, but that's because you are likely spraying a heavier paint, which will obviously require more power to atomize properly vs a thinner one.

This was kind of my point.

 

[dnschmidt]

I purchased the Astro based upon your recommendation.

Once you get it let me know how you like it. I use Mini-Guns a lot. Bumpers and door jams are well suited for these.

 

[ctandc72]

I must be missing something. You're painting a bumper cover and small odds and ends? While I am definitely a fan of good touch up guns and have used them plenty of times....I'm wondering why people think he'd be 'hating life' using a full size gun with his compressor? You're painting a bumper cover - not a complete car or even large panels.

Regardless of what equipment you use (whether it's a high $$ gun, or even 2K spray cans) the end product is more impacted by the PREP work and the quality of materials (and using compatible materials) and following manufacturer directions for their product (temp, humidity, flash time etc) than anything else...

Not counting mistakes made in application (regardless of equipment used).

I've done multiple bumper covers with spray cans. That is actual base coat for the factory paint code put into a spray can by a auto body paint / supply shop + 2K Urethane clear from a can. I won a bet with a painter friend long ago because he told me I was lying when I told him I used rattle cans.

There are tons of other factors that come into play that many times have nothing to do with whether it's a spray can or a high dollar paint gun.

- Metallic paint
- Color of paint

Go look at brand new cars - depending on color - the OEM painted bumper covers sometimes appear differently than body panels.

 

[jhelrey]

I'm painting a steel bumper, two mirror caps, and the Platinum plaque. My truck is an F150 in Antimatter Blue. The price of the items to paint the truck have been offset by the seller of the truck not realizing the bumper was scratched and deducted $500 off the already great price on the truck. I'm taking advantage and painting the other items and having a tool to use in the future for other projects.

 

[Michael_in_DE]

let us know how it comes out.

 

[jhelrey]

Finally got around to using the Astro spray gun. Put down 3 coats of epoxy primer. What a great gun, much better than a rattle can. My compressor had zero issues with pressure or keeping up. 80 PSI at the tank, 29 PSI at the gun.

I went as far as moving the air hose (finally had a reason to do so), plumbed in a copper cooling/moisture loop, installed filters, etc. and a dedicated air hose to spraying with a filter on the gun as a last resort. The desiccant barely started to turn pink on the very bottom of the bowl. I had zero moisture in the separators or drains, minus the compressor.

 

[jhelrey]

I personally want to thank DNSchmidt for answering several questions of mine in private chat.

 

[CGarage]

Go look at brand new cars - depending on color - the OEM painted bumper covers sometimes appear differently than body panels.

Why is this?

Thank you.

 

[drtyler]

Why is this?

Thank you.

Painted at different times (with different batches of paint).
Material & primer differences.

I worked at Textron one summer, and they manufactured and painted the bumper covers. Then shipped the painted covers to the car manufacturing plants for install. While this was 20+ years ago, it possible that this way of doing things may still be used by some car factories.

 

[CGarage]

Painted at different times (with different batches of paint).
Material & primer differences.

I worked at Textron one summer, and they manufactured and painted the bumper covers. Then shipped the painted covers to the car manufacturing plants for install. While this was 20+ years ago, it possible that this way of doing things may still be used by some car factories.

Amazing. I did not know that “batch production” occurred like this.

 

[dnschmidt]

Yes, it does. Not only that the paint will be the same color code but there is no guarantee that the paint comes from the same manufacturer. The car maker may use PPG and the fender vendor BASF, Akzo Nobel or Axalta if they get a better deal from them.

 

[Michael_in_DE]

waiting on pics!

 

[jhelrey]

Mistakes were made, but no lives lost. I learned so much as frustrating as it was at times. Pictures were after the final coat of clear as you can still see the haze in the air.

 

[dnschmidt]

Well, with all those holes and pockets I hope you can see why I recommended the ASTRO Mini-Gun to be able to get to those spots. Since I have a fairly huge spray gun collection I would have used a full size gun for most of it and then finished up with the Mini Gun, but for a newby the Mini Gun was certainly the way to go as there was a lot less chance of runs

 

[Toold_up]

It looks like you fixed the factory orange peel too! Nice work.

 

[jhelrey]

Morning pictures... I held up one of the mirror caps to the side of the truck. With garage lighting, it's spot on. I'm curious to see how it will be in the sun.

I have a dog with extremely fine hair. In the second picture, you can see where it embedded in the clear. Unless someone tells me a simple trick, it's staying. I can think of my dog every time I see it.

100s of hours of prep work. 2 hours of actual spraying time.

 

[allinon72]

I got these results from a 5 gallon pancake compressor and a $15 HF gun. If you take your time and use quality materials, you can get a better than factory finish.

 

[welder4956]

My truck is an F150 in Antimatter Blue.

Love that color.

 

[jhelrey]

I'm impressed with the color match.

 

[Toold_up]

I got these results from a 5 gallon pancake compressor and a $15 HF gun. If you take your time and use quality materials, you can get a better than factory finish.

That's nice!

I enjoy painting but I **** at it. I spray something and all the paint runs off onto the floor and forms a puddle... with orange peel.

 

[Jazz1]

Use a conventional spray gun if your compressor is less than 12 CFM at 90psi...