I would, except it's not my car. So my friend isn't going to buy it or have a real use for it and I don't want to get a mount that only fits on his car.
My next idea is to try to use a trunk mounted bike rack to hold the board. I'm going to hang the board by the bindings and tie it all down so it won't fly off. I figure as long as the bindings are secure to the board and I tied it down that it should work.
I think that this is an interesting idea but I would not hang the board from the bindings but would tie the board directly to the rack. I've never done this but I would use padding. When I move boards around on my SUV if I don't put them inside I put them in a board bag with padding inside and then tie that directly onto my roof rack. I only do this for shorter trips in nice weather becuase I dont want my board bag to get all salty and nasty.
Webbed straps are much easier to tie things onto roof racks than rope, and bungie cords are NFW. Hardware stores sell ratchet straps that are easy to use, just be careful as the ratchets create a lot of leverage.
Having tied a lot of stuff onto racks I wouldnt be uncomfortable strapping boards with lost of foam padding directly onto roof racks with a couple ratchet straps. The purpose built carriers are nice and convenient but you should be able to tie stuff down securely without them. It may take a half hour or more to get everything snug but if it's a one off trip not such a big deal. Also the nice thing about ratchet straps is that they are easy to snug up, things often loosen up a bit after a few minutes on the road.
It's not fuckin' rocket science......just TIE it to the rack. Stop and check it once and awhile and you'll be fine.
Put it in a bag and call it a bag of shit an ask yourself how do I tie this bag of shit on my car and you will come up with a pretty fast easy solution. Tying down a 6 foot metal pipe is harder than tying down a six foot metal pipe in a bad with stuff in it, as long as the pipe doesn't go through the bag you are golden. You can even just tie it to the rear cross bar, put it in a bag , put a strap between the binding , stuff some clothes or boots in there. Bungee around the clothes or boots for pressure and be done. As long as you don't have 80mph cross wind you should be fine.
If I didn't have bike racks the bag would be right up against the pole. The bag is also to break up the wind so the board doesn't become a rigid sail.
The problem is that its not a roof rack, more like rails. So it's not the easiest thing to use to tie things down. Also I figure there will be less resistance behind the car.
What do you mean rails? If it runs across the car it is a roof rack, if it is flat and runs front to back it is tracks for mounting. If it runs across the back and you have one it is a spoiler, don't tie it to the spoiler.