Decadence75

iTrader: (17)

The way I understand using a compressor for something like a paint gun, the size of the tank is fairly immaterial. What you need to pay closer attention to is the SCFM that the compressor is capable of putting out and as long as it is above the tool's requirement you should be fine so long as you don't mind listening to the compressor running a good bit of the time. Looking at the HFT site these are the advertised stats for those compressors:

2HP 8gal
4.5 CFM @ 90PSI
5.5 CFM @ 40PSI

2.5HP 10gal
5.3 SCFM @ 90PSI
6.2 SCFM @ 40PSI

2.5HP 21gal
4.7 SCFM @ 90PSI
5.8 SCFM @ 40PSI

Why the 8gal unit only lists the air movement as CFM as opposed to SCFM I don't know. It may be a typo on the site or it could be that it can not maintain that pressure once the tank drops below the target PSI.

The $20 Professional Automotive spray gun from HFT shows that it needs:

Pressure between 20-55 PSI
6CFM (stated), 1.5CFM @ 30PSI suggested

http://www.harborfreight.com/industr...gun-43760.html

I personally have owned the 2.5hp 10gal unit for a bit over a year now and it has been great for doing whatever I need around the shop along with running a few air tools when I was remodeling part of the house.

Unless I am just totally off on this, in which case someone feel free to correct me.

AGearHead4Life

iTrader: (5)

Good info to consider.

Looks like that ten gal would be a good all around compressor for more DIY jobs.

snyousef

iTrader: (11)

Well this 8 gallon one won't hold enough pressure to take off the crank pulley bolt....have you done something similar to this with yours and worked? I don't mind using my breaker bar to get the bolt off but its a PITA right now cuz the engine is on a stand and it starts tipping with pressure from the bar....I've been comparing cfm's because the gun says it needs 6cfm @ 90 psi and even though neither of them give it the guns top rating is 700 ft-tq, so even with less cfm it should be able to unbolt the pulley (at least IMO). But with the 8 gallon I hold the gun down and it runs out of pressure fairly quickly and can't get the bolt loose....

Yes, I've been looking at this for a while tonight. The 21 gallon has the same motor as the 10 gallon so I am confused as to why it would move less cfm, I guess it uses a weaker pump???

I don't want to get the 10 gallon and end up having the same issues I am having now with the 8 gallon. But the 10 gallon gives the most cfm out of all of them for some odd reason.

This is the paint gun I was planning on using and at the 40 psi the 21 gallon gives it 5.8 out of the 6 that its recommended so that's pretty close, shouldn't be an issue. Of course the 10 gallon would give it that actual output it needs (6.2).

http://www.harborfreight.com/20-oz-h...gun-47016.html

I question hft specs on these tools as they don't add up to me. I suspect the 8 gallon is in cfm because in scfm it would give a lesser value, I don't believe it's a typo. I was using my 3/8" ratchet, it recommends 6 cfm at 90 psi to run good and I had to turn the pressure up to 100+ to get it to run at a point where it was worth using (actually pulling off bolts quicker then hand tools). I think the 2 hp, 8 gallon is weaker then whats advertised from personal use. I have used a similar craftsman model rated almost exactly the same and it worked much stronger.

FWIW I've read the reviews and a few guys have painted using the 21 gallon.

Decisions, decisions.....tomorrow I'll be taking back the 8 gallon, what do you guys recommend I get? I'm leaning toward the 21 gallon even though the cfm is slightly lower then the 10 gallon....this is my first compressor so I am not sure but all I know is I was not much impressed by this 8 gallon one.

snyousef

iTrader: (11)

Btw AGearHead4Life, sorry for hijacking your thread and turning it into a compressor thread lol.

I'm the one that recently sub'd to your youtube profile under the username TheMaximaKing, I used to own a few Maxima's that I heavily modified a couple years ago. They are pretty decent cars for a 4 door grocery getter lol.

AGearHead4Life

iTrader: (5)

I have used it once for this. I was in the same situation as you. I had this 21gal compressor but my old impact would budge it. My buddy brought his Ingersal Rand Impact from Sears over and it pulled the crank bolt off pretty quickly. So I went as as soon as I had the cash and bought that same impact. lol

So, yes this compressor has pull the crank bolt out with engine on a stand.

AGearHead4Life

iTrader: (5)

Not a problem man. As long as something positive is coming out of this is all that matters.

Yea, Maximas are bad. I use to have a Stanza back in the day that I think is close to the same. Was a good car. Thanks for the Sub man!

snyousef

iTrader: (11)

Perfect thanks, sounds like my impact is the issue then. Looks like I'll be going to pick up that 21 gallon one....

Thanks for all the info....I'll also try to document my paint job and findings as well so others can learn from it.

AGearHead4Life

iTrader: (5)

I dont know what impact you have but the 700ftlbs sounds strong to me. I dont think my new one is that strong. My old one was Snap-On, but it was from like 1850! so it was very week. Maybe just test with somebody elses who has a known good impact.

Either way, I still agree that you'll appreciate the 21 gal in the long run. Its nice to know you have that large reserve. Its also good for JIK. Like when our power goes out, it feels good knowing that I still have the tank full for JIK.

snyousef

iTrader: (11)

It's the hft 1/2" earthquake impact, working is actually 50-500 tq I just read. I doubt it even puts out its ratings, lol but if it can get out 350-400 tq that bolt should come right off.

I went to return the 8 gallon but had to bring it back to drain the oil.....then I'm going back and hopefully will come home with the 21 gallon

Btw what's JIK?

AGearHead4Life

iTrader: (5)

JIK=oops=JIC=Just In Case

Good luck on the exchange!

snyousef

iTrader: (11)

Oh ok, you leave air in the tank....I thought it is always best to empty it when done?

The exchange is done, I haven't broke it in yet because the old man is napping and the garage is right under his room lol. I'm excited like a kid on Christmas

Decadence75

iTrader: (17)

It is because that same motor is having keep the specified pressure level in a tank that has just over twice the volume. For example if you were to put that same 2.5HP motor on a lower capacity tank, it would push even more SCFM because it doesn't tank as much effort to fill the smaller space.

The main problem you are having with the current compressor is that it has a smaller motor. The other two have one rated at 25% more power than the current one. The 10gal should work fine but if you want to hear the compressor motor being on less then the higher capacity tank would be better.

Decadence75

iTrader: (17)

Ideally, you should empty the tank and open the relief valve so that it will remain dry. Keeping it full can cause the inside to rust.

snyousef

iTrader: (11)

Thanks for weighing in Decadence75, I now have the 21 gallon one....I hoping it works out for what I need. Just broke it in and getting ready to use it.

It should be sufficient for the painting as well, if not then idk lol I don't have 240V in the garage. If I end up needing a better compressor I'll have to run 240V to the garage and get a good 220V compressor. It's also why I don't have a welder because the good ones are 220V, so running a dedicated 240V circuit to the garage might be a good idea in killing two birds with one stone for both a welder and compressor.

AGearHead4Life

iTrader: (5)

This is true! But as often as I use it, it wouldnt make sence for me to empty it every time. I just bleen the moisture often.

Also, I love having air ready on standby for when every I need it. I've needed it for tire and other things when the power has gone out and was glad to have the reserve. We had tornados come through here a lil over a year ago that knocked power out for two weeks.

For me, I'd rather see how long the tank lasts before it rusts out.

AGearHead4Life

iTrader: (5)

I've had those same decisions lately. I wound up going with good 110v's because the military moves me and dont want to have to install 220v ever where they put me. Just picked up a 130A Blue Point welder about a month ago. From what I've heard this welder should weld most anything I do.

snyousef

iTrader: (11)

I was thinking about getting the 90A HFT one, I'm only going to be using it to put an exhaust together or weld up little brackets.....I'm guessing it will hold up fine for the minor stuff I need....I don't feel like shelling out hundreds of dollars for something I'll use once a year lol

I understand now why you don't bleed the air out of this thing.....it took forever haha I might as well have left it in there. I was using it and finally got of my crank bolt but I did have to use some persuasion from my breaker bar. Other then that this thing was a blast with my air ratchet....got the old cam out and new cam in real quick, I can get used to this

AGearHead4Life

iTrader: (5)

Awesome! Yea, I think you'll be happy with that compressor. As for the welder I just couldn't. I've never used one of there's though.

snyousef

iTrader: (11)

Yea I was looking at impact guns and seems like hft one I have is more cfm demanding then other equally rated craftsman, etc. So far it's done what I wanted it to do, if anything I'll buy another gun if need be.

The 90A hft welder is on sale for $80 with a coupon sometimes, **** for that price if I put one exhaust setup together it's a win since the muffler shop charges me a couple hundred. I have never welded before so I have no idea, I wanted to get a flux core one as a starter welder and after I got a little good then I can upgrade to something better...it's all decisions, decisions, lol....no one said this hobby is cheap but it damn sure is fun.

Once something is complete that feeling of accomplishment is like no other!

AGearHead4Life

iTrader: (5)

Yep! Thats the best high I've found!