Thanks for all your replies and suggestions.
The front wheel with mudchatcher rim is still intact so I will get it welded as this bike (like all my bikes) doesn't have to be show quality but will be ridden.
for the record I feel safer on a bike with a cracked rim than I do riding a bike with loose or missing spokes
Good enough for me Doc and I would rather spend a bit to repair a rim than fork out for a new one. I do know that "Superior" mudchatcher style rims were $300.00 to purchase about this time last year here in Aus. Will ask a mate who prepares and races sidecars and owns a fabrication shop who he would recommend for the job.
other than the crackling at the weld the rim is in very good shape for its age......