Bare copper tubing ambient air cooled condenser. Can do?

[rezaxis]

I can lay my hands on 50' of 5/8" (1/2" ID) refrigeration copper and 30' of 3/4" (5/8" ID) refrigeration copper. Both unused and sealed and still in boxes, for scrap prices.

I have seen photos of a spiral still and Pints fan cooled condenser. Has any one successfully made an ambient air cooled condenser using bare copper tubing, that can keep up with a 15 gallon keg boiler and gas heat? I've seen the finned tube stuff and that's not where this is going.

I picture the 3/4" being used on the way up and then the 5/8" being used on the way down, with the 3/4" spiraling up, say in about a 10" in diameter coil and the 5/8" spiraling down around the upwards spiral with maybe a 14" diameter coil. Does my description make sense?

I would like to eliminate condenser water and pumps and the use of fans. I'll have to put some sort of pressure relief on my boiler for safety, but the main questions are: Is this a sound idea and is this enough copper to support this size rig?

I saw a Bokabob design that just has a single coil spiraling up and is open at the top, with condensate leaving as it drips back down the coil and before it re-enters the boiler. This looks good because of the open nature of the coil, but the condensate will come out hot and I don't like that.

Even at scrap prices this isn't going to be cheap and I don't want to muck it up, or worse, build something that just isn't going to work. Any experience out there?