What can it NOT do? Primarily and at the moment I need something to run a Fluid Film operation (personal use). Come to find out it can't really run a sander or a paint gun. Well, I may want to dabble in auto painting at some point. Those of you who have a 20 gallon rig, do you paint with it? What are the consequences? If it's a matter of a slow paint job I can deal with that, such as waiting between sweeps of the gun, but below here some guy said metallic paints require more oomph and most everything has metallic paint. Yes, I'm trying to cheap out. There seems to be a big price leap above 20 gallon-sized rigs.
20 Gallon Compressor (dis)abilities
- Thread starter Nayov
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I have a 27 gallon compressor. If you are trying to use it for fluid film, a 20 gallon will be ok for you. You'll have to wait after the air supply depletes for it to refill before spraying the next area. That will take a few minutes each time. We
If you want to remove fasteners with big torque requirements like crankshaft bolts or nuts on shock absorbers, the 20 gallon may not be able to keep up. If your tool needs over 4 CFM of air the compressor will be struggling.
Plus if the compressor is a singke stage it will be super noisy and that may be an issue for you.
I wouldn't try to paint a car with a small compressor. I think the spray pattern would be affected.
If you want to remove fasteners with big torque requirements like crankshaft bolts or nuts on shock absorbers, the 20 gallon may not be able to keep up. If your tool needs over 4 CFM of air the compressor will be struggling.
Plus if the compressor is a singke stage it will be super noisy and that may be an issue for you.
I wouldn't try to paint a car with a small compressor. I think the spray pattern would be affected.
I started out that way with a cheap 30 gallon compressor, and yes it would kinda run most air tools for a bit, but they cannot maintain the proper working pressure. After that I thought a 5hp 60gal single stage would work. But after struggling with that for a few years, still not being able to maintain pressure with many air tools, and a lot of water, I got a 5hp 80gal 2-stage compressor. That is the ideal size, without being overkill for anything I want to do. It will surprise you how well your air tools perform with pressure to spare. I also use copper air lines all over my garage to help cool the air, Plus I run it through a refrigerated air dryer for really dry air. I could run a die grinder all day, and not see any water. You pretty much get what you pay for with compressed air.
The place I retired from had three 500 horsepower compressors. They ran them 2 at a time continuously to maintain 105 psi of line pressure through the whole million square foot factory.
The place I retired from had three 500 horsepower compressors. They ran them 2 at a time continuously to maintain 105 psi of line pressure through the whole million square foot factory.
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The price leap has to do with the motor... going over 115V/ 20 amp (2 HP) takes larger-than-household outlets.
A 5 HP motor that plugs into a standard wall socket isn't really 5 HP.
Tank gallons don't matter too much; they are just an accumulator so the motor cycles less.
The flipside is if you see a used 230 Volt compressor somewhere you may have less competition buying the thing.
Or, go big with three phase. May be able to "upconvert" to it.
A 5 HP motor that plugs into a standard wall socket isn't really 5 HP.
Tank gallons don't matter too much; they are just an accumulator so the motor cycles less.
The flipside is if you see a used 230 Volt compressor somewhere you may have less competition buying the thing.
Or, go big with three phase. May be able to "upconvert" to it.
a 20 gallon tank cannot allow the air to cool enough for spray painting. Those compressors are not rated for continuous duty, so heavy use such as sanding, or painting they can over heat. They may cook the oil, seize or break a reed valve. You can point a big external fan so it blows hard on the compressor and tank, use syn reciprocating compressor oil and help things a bit. You are flirting with disaster. You can often buy used 50 gallon propane tank cheap, this can make a nice additional receiver.
Rod
Rod
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If you only want to do single panels and touch up work I did a review of an Italian made midi gun some months ago, search the forum for it in the tool section.
It will run on your compressor with no trouble, you will need to add a water filter and regulator at the gun but it does a great job on bumper covers, fenders, etc and saves a lot of paint and clear.
It is a decent little gun at any price but it is inexpensive enough.
Large HVLP guns take a tremendous amount of air to atomize properly, 60 gallon isn't cutting it. The gun I use most with a breathing mask needs 25 CFM @ 90 psi minimum to operate properly, IIRC the gun alone needs 19 CFM.
It will run on your compressor with no trouble, you will need to add a water filter and regulator at the gun but it does a great job on bumper covers, fenders, etc and saves a lot of paint and clear.
It is a decent little gun at any price but it is inexpensive enough.
Large HVLP guns take a tremendous amount of air to atomize properly, 60 gallon isn't cutting it. The gun I use most with a breathing mask needs 25 CFM @ 90 psi minimum to operate properly, IIRC the gun alone needs 19 CFM.
Not all compressors are created equal. A cheap 20 gal from Harbor Freight will be outperformed by a brand name 20 gal. I have painted with an oil-less 20 gal, but not an entire car. I'm sure it would have been ok for an entire car as long as you give it a chance to recover while you re-position, move your air hose and step stool (if used).
The same compressor would run continuously while using a DA sander and after a while you had to stop sanding and let it recover.
Use a good quality oil/water separator if painting.
The same compressor would run continuously while using a DA sander and after a while you had to stop sanding and let it recover.
Use a good quality oil/water separator if painting.
Originally Posted By: Trav
If you only want to do single panels and touch up work I did a review of an Italian made midi gun some months ago, search the forum for it in the tool section.
It will run on your compressor with no trouble, you will need to add a water filter and regulator at the gun but it does a great job on bumper covers, fenders, etc and saves a lot of paint and clear.
It is a decent little gun at any price but it is inexpensive enough.
Large HVLP guns take a tremendous amount of air to atomize properly, 60 gallon isn't cutting it. The gun I use most with a breathing mask needs 25 CFM @ 90 psi minimum to operate properly, IIRC the gun alone needs 19 CFM.
Dang Trav, Are you painting the Goodyear blimp with that type of gun?
If you only want to do single panels and touch up work I did a review of an Italian made midi gun some months ago, search the forum for it in the tool section.
It will run on your compressor with no trouble, you will need to add a water filter and regulator at the gun but it does a great job on bumper covers, fenders, etc and saves a lot of paint and clear.
It is a decent little gun at any price but it is inexpensive enough.
Large HVLP guns take a tremendous amount of air to atomize properly, 60 gallon isn't cutting it. The gun I use most with a breathing mask needs 25 CFM @ 90 psi minimum to operate properly, IIRC the gun alone needs 19 CFM.
Dang Trav, Are you painting the Goodyear blimp with that type of gun?
Originally Posted By: ragtoplvr
a 20 gallon tank cannot allow the air to cool enough for spray painting.
I did some sandblasting with a 30 gal and it was not meant for constant use like that. I was just blasting small sections and I had to wait and the air got really hot. There's a reason why compressors for body shops are 60 gal 2 stage minimum, any high volume air tool will empty even a 60 gal tank quickly.
a 20 gallon tank cannot allow the air to cool enough for spray painting.
I did some sandblasting with a 30 gal and it was not meant for constant use like that. I was just blasting small sections and I had to wait and the air got really hot. There's a reason why compressors for body shops are 60 gal 2 stage minimum, any high volume air tool will empty even a 60 gal tank quickly.
Originally Posted By: JC1
Originally Posted By: Trav
If you only want to do single panels and touch up work I did a review of an Italian made midi gun some months ago, search the forum for it in the tool section.
It will run on your compressor with no trouble, you will need to add a water filter and regulator at the gun but it does a great job on bumper covers, fenders, etc and saves a lot of paint and clear.
It is a decent little gun at any price but it is inexpensive enough.
Large HVLP guns take a tremendous amount of air to atomize properly, 60 gallon isn't cutting it. The gun I use most with a breathing mask needs 25 CFM @ 90 psi minimum to operate properly, IIRC the gun alone needs 19 CFM.
Dang Trav, Are you painting the Goodyear blimp with that type of gun?
No, that's a primer gun, I spray epoxy primer then a poly primer if any metal work was involved before color and clear. The color gun uses about 13 CFM and the mask 6 CFM. Always be careful spraying 2K, Isocyanate poisoning is real bad.
Clear gun and color gun.
This is the mask I use (not my photo).
Originally Posted By: Trav
If you only want to do single panels and touch up work I did a review of an Italian made midi gun some months ago, search the forum for it in the tool section.
It will run on your compressor with no trouble, you will need to add a water filter and regulator at the gun but it does a great job on bumper covers, fenders, etc and saves a lot of paint and clear.
It is a decent little gun at any price but it is inexpensive enough.
Large HVLP guns take a tremendous amount of air to atomize properly, 60 gallon isn't cutting it. The gun I use most with a breathing mask needs 25 CFM @ 90 psi minimum to operate properly, IIRC the gun alone needs 19 CFM.
Dang Trav, Are you painting the Goodyear blimp with that type of gun?
No, that's a primer gun, I spray epoxy primer then a poly primer if any metal work was involved before color and clear. The color gun uses about 13 CFM and the mask 6 CFM. Always be careful spraying 2K, Isocyanate poisoning is real bad.
Clear gun and color gun.
This is the mask I use (not my photo).
Originally Posted by chainblu
Not all compressors are created equal. A cheap 20 gal from Harbor Freight will be outperformed by a brand name 20 gal. I have painted with an oil-less 20 gal, but not an entire car. I'm sure it would have been ok for an entire car as long as you give it a chance to recover while you re-position, move your air hose and step stool (if used).
The same compressor would run continuously while using a DA sander and after a while you had to stop sanding and let it recover.
Use a good quality oil/water separator if painting.
I wouldn't discount the one from Harbor Freight. While I don't use mine heavy (like every day) I have been pretty satisfied with mine. I have used a smaller Kobalt spray gun for varnishing chairs and furniture, and it actually works well. I actually plan to use it to paint my truck in the spring with a lower volume gun. While not optimal I don't really see any issues. Would I use it for nice metallic jobs or higher volume guns, uhh, no. There's my thread on it still on the front page.
Not all compressors are created equal. A cheap 20 gal from Harbor Freight will be outperformed by a brand name 20 gal. I have painted with an oil-less 20 gal, but not an entire car. I'm sure it would have been ok for an entire car as long as you give it a chance to recover while you re-position, move your air hose and step stool (if used).
The same compressor would run continuously while using a DA sander and after a while you had to stop sanding and let it recover.
Use a good quality oil/water separator if painting.
I wouldn't discount the one from Harbor Freight. While I don't use mine heavy (like every day) I have been pretty satisfied with mine. I have used a smaller Kobalt spray gun for varnishing chairs and furniture, and it actually works well. I actually plan to use it to paint my truck in the spring with a lower volume gun. While not optimal I don't really see any issues. Would I use it for nice metallic jobs or higher volume guns, uhh, no. There's my thread on it still on the front page.
The important factors in specification are motor power and FAD, free air delivered. Tank size is an almost irrelavent consideration. Next is duty cycle. Lots of DIY puffers are rated at 3kw, but for how long?! If duty cycle is even provided in the spec, the small puffers will rarely have a more than 30%, thats 30% on 70% off. Or they may say, after 5, or 10, or what ever minutes of operation, allow the compressor to cool down for 20 mins or what ever. This is because the motor and pump just don't have the thermal capacity to run continuously for more than a few minutes, before they heat soak and then overheat and fail.
For frequent continuous operation, like spraying, blasting etc, you need to go for a compressor that is at least twice as big as you need in FAD. Compressors with cast iron pumps and industrial frame motors are the best to go for. If you can't afford, or accomodate an industrial quality unit, go for 2 or more smaller DIY types and gang them up together, so they run in sequence, one on, one or more off and so on. I've seen this done on 4 such units, so no single unit runs for longer than it should for reliability and longevity.
Personally I run a small Hydrovane for low demand jobs, like light tool use, and an old school 3kw V Twin Ingersol Rand for the heavy duty stuff.
For frequent continuous operation, like spraying, blasting etc, you need to go for a compressor that is at least twice as big as you need in FAD. Compressors with cast iron pumps and industrial frame motors are the best to go for. If you can't afford, or accomodate an industrial quality unit, go for 2 or more smaller DIY types and gang them up together, so they run in sequence, one on, one or more off and so on. I've seen this done on 4 such units, so no single unit runs for longer than it should for reliability and longevity.
Personally I run a small Hydrovane for low demand jobs, like light tool use, and an old school 3kw V Twin Ingersol Rand for the heavy duty stuff.
I ended up getting this gem:
https://www.walmart.com/ip/Campbell-Hausfeld-20-Gal-Compressor-Kit/114226798
Works great and is super quiet for an oilless unit. Fits perfectly in the corner in the garage and handles the 15amp connection surprisingly well. I know there are cheaper ones on HF especially with coupons, but this one seemed less awful (we are in the bottom feeder zone, after all) . I have a weiner one for bike tires and this thing is quieter.
It pushed Fluid Film with ease. I primarily bought it for that. FF, incase anyone didn't know, is thick as honey from the pail, even in warm weather. The rattle can configuration is completely different - watery.
It sure won't last forever...it has scary plastic (or rubber?) piston rings. Yikes.
https://www.walmart.com/ip/Campbell-Hausfeld-20-Gal-Compressor-Kit/114226798
Works great and is super quiet for an oilless unit. Fits perfectly in the corner in the garage and handles the 15amp connection surprisingly well. I know there are cheaper ones on HF especially with coupons, but this one seemed less awful (we are in the bottom feeder zone, after all) . I have a weiner one for bike tires and this thing is quieter.
It pushed Fluid Film with ease. I primarily bought it for that. FF, incase anyone didn't know, is thick as honey from the pail, even in warm weather. The rattle can configuration is completely different - watery.
It sure won't last forever...it has scary plastic (or rubber?) piston rings. Yikes.
I am guessing the piston rings are teflon.
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