tining help

hi, im in the middle of doing some body work and learning to lead load. only on thicker metal places
rather then filler and stoppers.

my question is about tinning the metal, basicly i got a lead free body kit from frost and a real good gas torch
and mapp gas i was all ready to try to learn  but couldnt get the metal to tin?

ive watchd many videos and been on rot rod fourms with no luck.

melting lead and paddel work is fine but the lead dosnt seem to stick as well a i think it should and
the metal dosnt come up shiney after the tin/fluxing

any help ?

cheers alot

Rob