which compressor technology?

[Michael Marcinelli]

Hey folks,
I'm searching for a good compressor for DIY use but one that'll serve all purposes from finish nailing to framing to possibly a spray gun. I'm looking at the Porter Cable C3151 single hot dog. I'm trying to evaluate the different technologies: double hot dog vs. single, pancake, oil free vs oiled, etc. I thought this PC unit is a good balance for all occasions.

Any thoughts?

TIA,
Michael

[JayStPeter]

It's not that simple to really say one compressor is the best. It depends on your needs, both air requirements and space/portability issues. In general, a small hot dog unit isn't going to have enough air to run a sprayer. But, it could work if you are patient and stop when it kicks on to wait for it to refill. If your planned general use includes spraying, impact wrench, or air ratchets, I'd say look to at least the 25 gal models. But, find some examples of the tools you want to use and check the air requirements of them. They are usually listed as CFM@pressure. For example 4CFM@90psi means it wants 4 cubic feet per minute at 90 psi pressure. Compressors have maximum CFM listed as part of their specs. They are the most meaningful of the machine specs. If a tool lists too high a rating for your compressor, it doesn't mean you can't use the tool. It just means you can't use the tool continuously. OTOH, only getting a half second burst for your impact wrench isn't really going to do much for you so you need to be somewhere close.

[Tom Majewski]

I have 2 compressors. One day I tried painting with the little 2.5 gallon. I got about 6 passes (10 seconds) of spray before the pressure dropped too low. Then wait another minute or two to build back up.
They do handle a finish nailer pretty well. If portability is a concern, I'd consider one, but if it's a shop compressor, get a much bigger tank- like Jay said >25 gallon.
I'd go with an oil lubed for longer life, and twin cylinder belt drive for quietness.

[Michael Marcinelli]

thanks. what are the downsides to an oil lube version? can't use on an incline? more maintenance? how much less life will i get with an oil-less?

michael

[Chris Bolton]

thanks. what are the downsides to an oil lube version? can't use on an incline? more maintenance? how much less life will i get with an oil-less?

michael
Personally, I think there are more downsides to an oil-less compressor. Although they might require a little less maintainence, they typically don't last nearly as long. They are usually a LOT noisier than a belt driven oil compressor.
The downside with an oiled compressor is that it can produce and oil mist but this is easily corrected with an inline filter. You'll usually get a lot more life out of the compressor if it is an oil based unit.

As a couple of people have mentioned, you really want to figure out what tools you'll want to be using and then size the compressor to the tools.
A small compressor will work great for things like brad-nailing but if you plan on using something like a sandblaster/ paint-spraying a car or using any sort of "continuous use" tool like a sander, you'll want the most SCFM you can. If all you want to do is pop in a few brads or something like airbrushing then even a little HOT-DOG or pancake will do the job just fine. I've laid lots of hardwood flooring with a 2gal. unit and it worked fine, although the compressor cycled a lot and you have to wait for it to "catch up" (build enough air pressure to drive in the fastener).

The compressor you mentioned though, The PC C3151 seems to be a pretty decent unit at Air delivery 7.7 SCFM @ 40 PSI, 6.0 SCFM @ 90 PSI. This is about in the "middle range" for most units. You'd be able to pop in brads all day long, but you wouldn't be able to spray paint your car using an HVLP gun and it would run an air sander in 'burst' mode only. If painting "middle sized" or smaller projects, it would likely be ok. It *is* loud though, at 90 decibels. Your neighbors will know when you're using it :)

[Tom Majewski]

I personally don't know any downsides. They hold some oil in the pump crankcase, just like the oil sump in your car engine. They can be used on any reasonable incline (just like a car engine) but I'd not run it at 35 degrees or more. Pretty much maintenance free, just change the quart of oil every few years- 3 minute job.

Lifespan of an oiless is based on mine and a friends experience only. Though they never broke, they wore out and had to cycle on and off more. They're noisier and run hotter right out of the box. All this is from a closet hot-rodder who used to do a lot of car painting in the garage.

For light to medium use, either kind is good. In the warmer, more humid months, drain the moisture tap at the end of each days use. Some days they get so much condensation that I spit water out of my nailers. If you're going to paint, you will need an inline moisture trap.

[John Ricci]

I'm another one with two (actually three but one is used as a vacuum pump) compressors, a Husky twin cyl. 15a/7.5a 26 gal.that I run on 240v and a small single cyl. twin tank 4 gal on 120v for small jobs. The big one will handle pretty much whatever I throw at it and have used it for painting numerous times with no grief. The small one is great for both my brad and framing nailers as well as some air tools in a pinch...it also handles impact wrenches really well.

Both of the described compressors are oil lubed and I can't see doing it any other way given that a lot of what I have read about the oil/oilless debate shows that the 500 hr. oil change interval is about the average lifespan of an equivalent oilless pump:mad:. The one I use for a vac. pump is an oilless twin cyl. Thomas unit that I believe was designed to run a dentist's drill:eek: but it will drive an airbrush nonstop or suck a gluing bag flat and tight:cool: