Regarding the cost and time, if it's done carefully using paste solder, you can avoid a reblue. And it doesn't take 12 hours, unless your smith is a union man.
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I've got several problems with the above statement. For starters, have you looked at the ingredients in paste solder? Almost certain to include ACID flux, you don't want that acid left between the ribs. Proper procedure is to tin with acid flux, clean that up completely, then use rosin flux to do the final solder work. Second, while a small repair could probably be made without creating the need for a re-blue, that's not very likely, as the acid flux will generally start corrosion, immediately. Third, clean up through the several steps mentioned, especially the final, will require more than the,[apparently arbitrary],12 hrs. mentioned. Remember also, that while working one must be very conscious of not moving the existing spacers, or you're now into re-regulation.
Take a good look at the prices quoted here and there on this job. I've seen it range anywhere from $650 to $1150, but never any cheaper. Having done this, at the lower end, concerning price, I can fully understand the people asking more.
Jonty,
If you've got that much gap, you are correct in thinking there may be safety concerns. The only way to know for certain is to remove some rib and have a look. This means a relay anyway.
Jim
