Matching painting compressor specs with paint sprayer

[Primitive Pete]

I have an old 12 gallon Sears Paint Sprayer Air Compressor. The specs are 8.1 SCFM displacement with delivery of 6.4 SCFM@40 PSI and 5.4 SCFM@90PSI. This unit has a regulator but I have no idea what the SCFM will be at other PSI settings.

Questions - How closely do the paint sprayer and compressor specs need to match? Does the 6.4@40 psi mean any sprayer that requires 6.4@40 psi OR LESS will work? What about sprayers that require 4.5@30 psi?

Looking to understand what sprayer specs will work with my compressor. Choice NOT limited to the list below but have included some examples of paint sprayers I think will work based on SCFM@a given PSI.
Have included product links if interested.

Central Pneumatic 93312 from Harbour Freight - Air requirement: 3.5 to 14 SCFM @ 10 to 30 PSI
http://www.harborfreight.com/air-tools/paint/professional-spray-gun-kit-93312.html

Astro Pneumatic AS7SP from Amazon - Air consumption: 4-12 CFM at 50-60 PSI
http://www.amazon.com/Astro-Pneumat...f=sr_1_19?s=hi&ie=UTF8&qid=1309391654&sr=1-19

Campbell Hausfeld DH3800 (HVLP) - Amazon - Air pressure 20-45 P.S.I., air requirements 3.5 to 5 SCFM.
http://www.amazon.com/Campbell-Hausfeld-DH3800-Pressure-Feed-Spray/dp/B0018S8JC4/ref=pd_sim_sbs_hi_2

Have also looked into airless sprayers listed below,

Wagner 0515022T Reconditioned Pro Coat Airless Paint Sprayer from Amazon
http://www.amazon.com/dp/B003BOYC9W...e=asn&creative=395093&creativeASIN=B003BOYC9W

Can apply latex or oil-based paint, stains and sealers with adjustable pressure up to 2800 PSI. with 0.24 GPM paint flow rate. One of the featured sprayers from the Wagner high performance series. Can draw paint directly from a 1- or 5-gallon pail. Includes 0.515 reversible spray tip for wide variety of spray situations.

Milwaukee ZRM491020 Airless/Fine Finish Paint Sprayer from Amazon
http://www.amazon.com/Factory-Reconditioned-Milwaukee-ZRM491020-Airless-Sprayer/dp/B003WJK10A

Works as airless sprayer or an HVLP fine finish sprayer. Can easily switch between airless and HVLP fine finish applications. Base is compatible with containers up to 5 gallons in size.

I will be painting a 16 foot aluminium Jon Boat that only sees fresh water. Plan to use self etching primer and Rust-Oleum paint. Marine paint is way too pricey for me.

Thanks

 

[Woodonglass]

Re: Matching painting compressor specs with paint sprayer

Find the highest possible CFM rating that the HVLP paint gun will run on. Multiply the highest CFM rating by 50 percent. Add this number to the total CFM required. The number you come up with will be the highest rating of air compressor you should be looking for, as CFM ratings within 15 percent of this number will allow you to run your tools without over-taxing the compressor.

 

[Primitive Pete]

Re: Matching painting compressor specs with paint sprayer

Thank you. As an example the Campbell Hausfeld DH3800 (HVLP) from Amazon requires a max of 5 CFM. Plug that into the formula you gave and we have 7.5 @ 20 - 45 PSI. My compressor delivers 6.4@40psi and 5.4@90psi. CFM increases as pressure drops so thinking this gun will work if pressure is cut back to 30 psi or so. Correct?

You previously replied to my post on painting a 16 foot Jon Boat. Thank you. Am going to follow your directions for painting with Rust-Oleum. I assume you used the regular Rust-Oleum and not the Marine paint. What self etching Rust-Oleum primer did you use? I think there are 2 primers made for painting metal. Also, can you tell me what paint gun you used and what the specs are on your compressor?