Hello, I have a 70mm aluminum 2 blade prop for a crackerbox I'm building and was wondering if it needs to be sharpened and balanced. Thanks in advance.

Yes they do need to be sharpened and balanced. Just don't do any mods like back cuts or bar cuts. It will weaken the blade and it can come apart.
Ken

Thanks for the reply Ken, I wasn't sure I thought I read somewhere that you didn't have to do the aluminum props but I can't remember where, it could have been something else I was doing, my hobbies blend together sometimes! I'll have to pick up a balancer and put a edge on it, thanks again.............Steve

I would assume that they are no different than any other prop. Do you have it yet? If not I'd just ask the seller if they are sharpened and balanced already. If you have it already I'd just put it on a balancer anyway and check.

I do know they are not recommended in high mod engines. I hear the blade may actually bend or curl. The Chinese props that are aluminum sometimes are not a very tough aluminum. Worth a try but be careful. Get air and come back down under full throttle and really load the prop might cause the failure

The prop came from Zipp kits, I bought the boat kit and hardware together. I went on Zipp kits web site and found the prop (470 alloy prop) and it says "ready to use" so maybe it was prep'ed already. I'll email them anyway and find out, thanks all for the advice.

Nope they dont need it most come allready done,also theres some that are cnc machined that are better than the cast ones.
cgi.ebay.co.uk/Aluminum-CNC-Pr...=item439cdf2482

Thanks for the link, the one I have does look cnc machined so I'll just use it as is.

I have one here (X470 aluminum), 99% sure it's from Zippkits..one it at a raffle at a race...anyway, let me be 100% clear here: if your prop is anything like mine, it is nowhere near ready to use! If I were to run this prop here on a boat, it would need full left rudder to keep the boat straight at speed! Definitely needs sharpening at the leading edges and then be balanced.

Must be different from the ali props ive had then as ive never had to do anything to mine and theyre fine,theyre so light i doubt you need to ballance them to be honest.I wouldnt run them on a modded motor though but the cnc ones i would for sure,some guys here are running those on inlines.