Air Compressors: Single vs Dual Tank

[Splat]

It's time to replace my old Craftsman compressor. I've always had a single tank compressor, whether big vertical 30gal or smaller hotdogs or pancakes. My question is really more about rust and draining the tank(s). I see more dual tank setups with only one drain on the bottom tank. Dual tanks with individual drains seem rare, or only on more $$ setups. Keeping in mind draining after every useage, would a single tank be less susceptible to rust than a 2-tank/1-bottom-drain or is it really a non-issue? Thanks.

 

[aliva]

I think it's a non issue. You have 2 tanks you double the chances for rust, simple math. Put a drain on each tank , ( if they are mounted parallel) Tee them together with a single drain valve, manual or automatic. Both will drain at the same time. If the tanks are stacked one above the other, connect the drain from the top tank to the top of bottom tank, ( the top tank should drain to the bottom tank, when pressure is release from the system) then only one drain would be needed , from the bottom tank

 

[mksj]

The dual tanks I have seen are mostly on smaller portable or wheel barrel type air compressors most to make them more compact. The stacked tanks will drain down to the the lowest point, the parallel wheel barrel types have a drain for each tank. A bit moot as the biggest problem would be getting all the water out, and often they sit not level. In addition many of the newer tanks are aluminum. In either case, just draining a tank on a routinely is the most important procedure to tank longevity.

 

[darkzero]

Not really the same as a dual tank setup but I have a 17 gal horizontal tank piggy backed to my 60 gal vertical tank air compressor. The 17 gal tank sits behind my lathe like 6 ft away from the 60gal compressor which is in the corner of my garage. I used to check the 17 gal for moisture every few months but no moisture ever comes out it. Again not the same setup but maybe only one of the tanks on those portables accumulates moisture more & is why there is only 1 drain? Depends how they're plumbed too I guess & being so close together I would think the second tank would accumulate moisture also.

My 60 gal tank of course does get moisture but barely. I put a tiny little factory after cooler on it which actually made a noticeable difference on it. I drain the 60 gal once every 2 weeks now. Very little moisture comes out of it. But then again it doesn't run that much anymore due to the extra capacity & the fact that I pretty much retired all my air tools. The safety nazis might stone me for this but I leave my system pressurized all the time.

 

[Splat]

Ok. So its basically moot if you drain after usage. Thanks. Now, deciding which compressor to get. I'm eyeballing the Makita MAC700 and the MAC2400. I'm leaning towards the MAC700 for portability and fact I dont need any big tanks anymore. Thanks guys.

 

[addertooth]

I have a double stack compressor sold by California Air. It is all aluminum (including the tanks), which reduced my concerns about tank rust-through. It was purchased because it was Light, for it's given tank volume, and CFM.