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shop air system / upgrade yet again . . .

sweetk30

sweetk30

Back to play nice .
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so the new shop I got with the house has a colman powermate black max air comp in there .

its a 6.5hp 2 stage unit with 80 gal tank . online specs show 15cfm @ 100psi and 13cfm @ 175psi .

so the other day I fired it off and the tank started with 50 psi in there . after over a min the tank was @ just over 100 psi .

the comp wasn't making any NOT normal noise and temp seemed o.k. it was warm and couldn't hold my hand to the body of the comp but could touch it .

lookg for iif fro others who haveorhad one to know if the running time is o.k. or is it just me ? ? ?

and if o.k. I do plan to add a second 60gal storage tank on the other side of the shop for storage and faster air tool recovery times.

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I had the same compressor made by Devilbiss for years until I finally stepped up to a big 24 cfm compressor. Seems like my compressor would take about 5-6 minutes to fill the empty tank to 170 psi. The pump spins pretty fast so it runs hot, definitely should have synthetic compressor oil if you plan on using it much.
 
Man, you have no idea how long it has been since I had to do these type of calculations.......

OK, an 80 gallon tank is about 10.7 cubic feet.
I have been up since before daylight, so this may be wrong. But, I think if you double the amount of a gas in a volume, you double the pressure.

Its basic gas law stuff, but I am crashing, and its been 40 years since I had to remember the gas laws.

It should be a simple variation on Boyle's Law, but I may be wrong......

Plus, as you can see from the specs, volume produced by the compressor goes up with lower pressure.
So, it should have been able to produce more volume at 50 than 100. At 100, it should be putting out 15 cubic feet per minute.

So, to double the pressure by doubling the volume, means it had to put out 10.7cf. Therefore, it should have been able to do that in less than a minute.

But, that is with a new compressor, and the starting pressure at exactly 50 and the ending pressure exactly 100 plus careful timing.

So, it sounds like it might be a little slow, but probably in the ballpark.
 
Fordum said:
Man, you have no idea how long it has been since I had to do these type of calculations.......

OK, an 80 gallon tank is about 10.7 cubic feet.
I have been up since before daylight, so this may be wrong. But, I think if you double the amount of a gas in a volume, you double the pressure.

Its basic gas law stuff, but I am crashing, and its been 40 years since I had to remember the gas laws.

It should be a simple variation on Boyle's Law, but I may be wrong......

Plus, as you can see from the specs, volume produced by the compressor goes up with lower pressure.
So, it should have been able to produce more volume at 50 than 100. At 100, it should be putting out 15 cubic feet per minute.

So, to double the pressure by doubling the volume, means it had to put out 10.7cf. Therefore, it should have been able to do that in less than a minute.

But, that is with a new compressor, and the starting pressure at exactly 50 and the ending pressure exactly 100 plus careful timing.

So, it sounds like it might be a little slow, but probably in the ballpark.
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i think you are pretty close, but I seem to remember something about every 10 degrees the temperature goes up the pressure increases a certain amount too. been too long since I have done any of the calculations. I know when my compressor shuts off at 175psi when its hot after it cools down it loses 5-10 psi. and I don't have any leaks.

I have a quincy 2 stage and it is 15.4 cfm at 100psi I believe. it takes awhile to fill up. It sounds like yours is fine to me.
 
well in the shop MAN CAVERN all day and fired it up from around 70psi and let here run till she shut off by her self.

did good I think . temp on head to jug gasket area was 140-145* with ir temp gun .

I think it was just me . I was use to big comp in shops over the years .

now to flush the 2nd tank and plumb it in the other corner for better shop use and balanced air flow needs . :thumb:

oh ya and 2nd tank is 60 gal same color / brand / model . . was a c-list special with no motor and dead comp . so I scored it and striped it of unused parts and made it a storage tank that will make it all look factory .
 
Nice! I have been watching c list for something like that for when my shop is built. I have had my compressor up to 245 degrees while I was sandblasting all day with it.
 
I keep my old 60 tank down at work to help the little gas dewalt one I paint boats with...

the 60 quincy at home does fine for everything I do.. and that's a lot..
 
so its been a bit all is good for the most part .

but the compressor is taking for ever to reach shut off psi and also cant keep up with a basic air cut off grinder .

so what new compressor unit should I get to swap this one out for ? don't need new tank or motor .
 
so the other day tank @ 50psi turned the comp on . after 6-7 min run time and still going I turned it off @ 110psi . spec is 145on/175off . the head was at 298* temp with my ir temp gun . :eek:

so I know the comp unit has problems. parts for top end reman are in the 200-250 range.

so I found this on c-list the other day and it was still there this morning till I stoped in and got it for $220 bucks.

IR t-30 style 2545 comp unit . 35cfm @ 175 psi :eek1:

also friend has a compressor he is getting rid of the a electric motor the size I need to run this unit for less than the price of me buying the new electric motor to run it .

so with 35cfm & 80gal tank main & 60 gal reserve tank I should be real good. :grin:

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JoshHefnerX said:
35cfm at 175psi... That may be overkill.. lol
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that's the ck5 way . . . .

and yep I like to have to much on lots of specific things like this . = last forever for me.

also plan to have a sand blast cabinet or unit to do my own stuff in shop . so this would be a big help for that stuff.

oh ya these are basicly no duty cycle to run as much as needed . . . .:cool1:

parts list :

check valve https://www.grainger.com/product/CDI-CONTROL-DEVICES-Brass-In-Tank-Check-Valve-6X210
 
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so my current setup was a 1/2inch tube to the check valve and that's looked to be a 3/4 pipe thread in the bung on the tank . from the 1" pipe thread outlet on my new to me IR t30 I need to up the size of this sucker.

flow specs for the current one are looking to be in the teen's maybe 20cfm max . my IR t30 unit is 35cfm .

looked on granger and found this guy https://www.grainger.com/product/CDI...ck-Valve-6X210 only problem is I need to change the hole size on the top of the tank from 3/4" pipe to 1" pipe. its a welded in bung with a decent amount of meat left so looks like I just need a 1" tap to hog it out .

also found this one https://www.grainger.com/product/CON...nloader-12U306 its a inline unit . figure maybe reduce it just before tank bung to the 3/4 size to no extra tap work needed ? ? ? I think this one might work better for my needs maybe :dunno:

this tank is a 80gal unit . I also have a 60 gal in the other end of the shop/line for reserve use for a 140gal total capacity .

whats your guys fellings on this ?

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shop is hard plumbed 3/4" black iron now.

I run 3/8 hose and ends but I do have a 1/2" hose and few big boy air tools that need that size hose .

plan is to be able to media blast my own parts and frames when I am ready .
 
3/8 hose is going to be the restriction. Don't think necking it down is going to do much harm. However retapping that bung on a pressurized vessel could cause a bad situation.
 
guys on the garage journal site say drop in a new 3/4 to 3/4 check valve and call it good . as the cfm @ 7.5hp range I am running with this setup will be around 28cfm . so should be good to go then and just run it . this will make it a no tap on the bung job . . . . :whistle::surepal::shocked::grin:
 
Think you won't even miss that couple of cfm, and not messing w/ the factory bung is waaay safer.
 
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