I’ve had enough success, and stayed dedicated to composites as a hobby long enough now, that I feel it’s probably about time to spring for a vacuum pump. Before I do, would someone be so kind as to confirm that this should do all I need. It seems closely spec’d to the one I’ve been using, but never hurts to ask 
I would stay FAR away from HVAC pumps. They are not rated for continuous duty, which one needs if working with long epoxy cure times, or cold temps! I wasted 300$ on one, now it’s a 20lbs door stop I can’t sell!! Mine came with so many knobs and ports, I was so confused. AND the manual didn’t help.
Check out Gast. they are the only company I can think of right now. I would say google “lab surplus”, and there might be a few sites with pumps cheap.
good luck!
Well, the one I’ve used has been running for a few years now. I could hear it all last night, it was vaccing down a special cascade cooling system (at about 120 microns, aiming for a target of 50), it’s been running for 2 days now. I’ve seen the same unit vaccing down an entire buildings HVAC system, generally it’s left to run for more than a few days at once.
I would’ve thought the opposite applied, that HVAC ones were more likely to be rated for 24/7 usage. It’s not unusual to vac something for days on end in that game. They don’t seem to get very hot (pump body is a heatsink by the look of it), and if whatever you’re vaccing has no leaks, they don’t make much more than a light gurgling sound.
hmm…maybe the one I got just sucks then. WOuld explain why I can’t find much info on it. It’s a Watsco.
I just never understood the big knob on it, along with the 4 random ports.
Post a pic mate
I am new to this stuff but i am hvac tech for 14 years. i generally evacuate a large hvac system (15 ton or bigger) minimum overnight. any good hvac evac pump is built for continuous duty for days at a time. stick with a known brand such as robinair or yellow jacket or JB.