And when you heat it up, it does it even faster[:'(]

I just weighted the oxygen bottle. I used 2/3 of it that is around 5 dollars worth of this gas. The muffler looks very ugly (like somone blew his nose on it[:'(]) but it holds up. I cleaned it a little with sanding drum mounted on dremel, and it looks like the balzing material sticks.

I think the main trick is in rubbing a hot aluminium part with brazing stick. It scraches the oxide from the surface and sticks to the raw material as it melts. It is just difficult to keep the aluminium part hot but to not melt the rod in the flame.

For this muffler it was impossible to heat up the whole part (not enough flame for that), soI heat up just a piece at the time by touching it the blue flame cone. For small parts hobby torch should be enough.