Quote Originally Posted by m_c View Post
Main reason the cast iron is quieter, is it runs slower.
Personally, I'd be dubious about secondhand compressors unless you know their history. Admittedly Hydrovane's can be rebuilt for not that much, but it depends on just how much they've been neglected/worn.

I do happen to have two Hydrovane's tucked away in the shed. One's a 1.1KW which I'm wanting to get plumbed in for general use, and the other is an engine driven one equivalent to a 2.2KW. They're pretty much identical airheads, just one runs at twice the speed of the other (I'd like to know if there are any actual differences between the airheads as I'd like to swap the motor on the 1.1KW to double it's output, but have so far not found any suitable parts manuals).

If you're going to be running the compressor a lot, I would consider a new Hydrovane, or even a screw compressor, as even a quiet piston compressor will annoy you if running nearby for any length of time. Plus vane/screw compressors are more efficient, but they do have to be run for an extended period occasionally to make sure the oil gets hot enough for long enough so too much moisture doesn't build up in the oil, or just change the oil more regularly.
Hydrovane's can be had in single phase for under £2000 (search HV01RM or HV02RM), or screw compressors for just over (ABAC Spinn C40 are available in 2.2KW single phase)
Thanks, thing is, these are big money for hobby use. I was told that the Hydrovanes have a fairly irritating higher pitched noise, suppose its all relative. Im expecting some prices from a guy called 'compressorman'. He advises not buying on ebay due to uncertain quality but a lot of it sounds like scare tactics me thinks ...