[mercedes_sl1970]

Hi there

I wanted some advice about about a refractor I am about to build with a 100mm f13 lens. Given what's available locally, I'm leaning towards having a metal tube rolled to the diameter I want: inside diameter, say, 114mm and a length of 1100-1200mm. Note I haven't settled on the tube length yet as I have to finalise my measurements.

My question is whether to go with aluminium or thin wall steel? With aluminium, I was thinking of about 2mm or going to a maximum 3mm thickness. For steel (galvanised, I'd say), I'm not so sure as I am unfamiliar with thicknesses/stiffness/weight. If I choose aluminium I can have it welded and probably have a fairly neat seam. For steel I guess I would end up with spot welds?

Anyway, appreciate any thoughts.

Thanks

Andrew