I've bought a couple of second hand ones over the years. Both from shops, one got shipped.
Both still going strong (1 is over 5 years old).
I prefer 2nd hand masts, at least I know they won't go bang when they're first rigged up.
Oi,
I bought a 2nd hand 430 RDM North mast from Simon @ Boardcrazy Qld.No drama's.It was packed in its cover and a sail delivery cardboard box.
I have purchased some other stuff from Simon @ very reasonable prices 
I bought a 2nd hand RDM from WA , two bottoms turned up one rdm and one sdm , I rang old mate and told him what he sent me he appologised and sorted it out . Have them bubble wrap it a couple of layers and you will be fine .
I did have to leave work early to winch the delivery van off my letterbox 
Just don't buy 100% carbon (unless it is an RDM) as race masts can go bang for no reason
And don't buy from wavesailors 
Don't buy SDM masts secondhand. The wall thickness is less than 2mm. A few seasons of use can really compromise them.
www.seabreeze.com.au/forums/Windsurfing/General/Not-quite-so-reinforced-as-you-think/
Last used mast (RDM) I bought was from an interstate shop (seabreeze advertiser), turned up with crushed ends (the cardboard wrap looked like it had been thrown around a bit & the mast had actually pushed out through about 10 layers of packing tape & had a forklift or something very heavy sit on it), I sent the shop an email, no reply so called...was told, "oh, that's no good - nothing we can do about it"...so cut off 80mm & so-far it's still in one piece.
That's the first time I've had damaged gear turn up, also first time (& last) I'll buy from that shop, so 1 out of about 10 purchases damaged isn't too bad?
I have bought RDM masts and had them couriered.
In both cases, the packaging was very important, in that they were surrounded by bubble wrap and then a cardboard carton. They were also marked top-load-only, and I assumed that the courier handled them like this.
