To correct some misinformation in a previous post…

The original MAPP (sic) gas – a mixture of methylacetylene and propadiene – is no longer available. MAPP substitutes seem to be propylene. Both burn in air with a higher flame temperature than propane, which burns hotter than propane/butane mixtures, which burn considerably hotter than butane. As a self-contained, hand-held torch, a 'MAPP' torch makes a butane torch look rather silly.

In your application, you probably need to concentrate on heat output, rather than temperature, so propane feeding a larger burner will almost certainly be better than a self-contained 'MAPP' torch. Large bottles of Propylene are available (in USA, at least), but I don't know about in UK; pity us in backward NZ, where, apart from MAPP-substitute hand-held torches, the best we can get (easily) is a propane/butane mix (of no standardised proportions). It's not too bad with Sievert burners, but, for small jobs, I still go to my MAPP-subs. torch.