Best and most reliable vacuum pump for purging

I started this thread because i bought a pump and it does not hit full vacuum. Pro runners please help us noobs on what pump to buy!

I use a master cool 6 cfm single stage. But I think I like my old pump better its a mastercool 3 cfm 2 stage what size purge chamber u have

Have u gone over ur setup for leaks etc before u blame the pump

i have a 3 gallon chamber

And i bought a 5 cfm 2 stage pump about 2 weeks ago and am already looking for a new pump cuz it only gets to 27.8 -28.2 hg

so can u explain your leak checking method please

Um not really a method actually dnt really check. If I think I have a leak I will just redo all seals.......if anyone does have a exact method for doing it would like to know

If you spray alcohol or acetone at the suspected leaks, the vacuum gauge will show a rise when it sucks them in.

I like our 5 year old CPS 6.2 cfm single stage. It has never missed a beat and we have used it for many different experiments, besides its duty operating a Terpenator or vacuum oven.

your cps hits full vac?

can you explain why exactly the gauge sees a rise when it sucks alcohol in?

json/mtl said:

your cps hits full vac?

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Yes, I am under 100 feet elevation and it pegs the gauge. It was factory tested at 65 microns and I only want about -29.5" Hg, so as to not boil away the cannabinoids.

vacpurge said:

can you explain why exactly the gauge sees a rise when it sucks alcohol in?

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We used acetone in vacuum casting and heat treat industry, but when the liquid is sucked into the vacuum, it boils and expands rapidly. That causes the vacuum gauge reading to rise.

so youre saying that under 27.5" which is my max, if I poured a splash of everclear on my lid around the fittings, if there were a leak, my gauge would go above 27.5?

vacpurge said:

so youre saying that under 27.5" which is my max, if I poured a splash of everclear on my lid around the fittings, if there were a leak, my gauge would go above 27.5?

Click to expand...

If the gauge is reading -25" Hg, and the solvent is sucked into the chamber, the vacuum gauge reading should change to read something between 20 and 25" Hg. In this case zero being atmospheric pressure and -29.92" Hg being full vacuum.

will 99% iso work for the leak test?

I would give a try. I have personally only used acetone for the leak test, but ostensibly any high vapor pressure solvent would work.

i am looking at a cps 2 stage but why issnt ther a ehaust for the oil? does your cps have one? FADEDAWG

Our CPS single stage has the oil breather mounted on top the pump.