Ok, so there was a little misunderstanding but I know what you're talking about... I've used that stuff before called Alumalloy and it does work very well and makes really strong bonds with the metal but you need to be able to ensure you're at the right temperature and the metal surfaces must be clean clean clean before it'll stick, that's why you see the guy brushing it as he's heating it up etc, but the other side is getting the metal at just the right temp... too cold and it won't melt and flow properly, and to hot and it won't stick or you can damage the part you're working, a cheap infrared thermometer is a great help here... just keep the metal super clean and keep the temp as close to 700 as possible and it'll do good for you.
I still wouldn't trust it for a frame repair but it's probably strong enough if done right.
