Extending picatinny rails

[jmichelin84]

I'm trying to extend a couple rails for my hand guard, they are 12 inches long and I want to extend them a few inches, I was thinking cut with a dremel or a hack saw with it on a vice for a super straight cut, and chamfering the cut ends then brazing with a propane torch and a aluminum brazing rod, seeing I do not have a welder lol.
Anyone try this, or something remotely close?

 

[dieseldog]

Is brazing absolutely necessary? Make a clean butt up and if you want a perfectly seamless look epoxy and paint/ coat which is good enough for myself. Just a suggestion---Dieseldog!