Rightyo then,
Lets get into the nitty gritty here. I have a baby Mig which is almost worn out from building my car trailer (pics in link in sig), and feel I'm handy enough with it to have a go at some serious body burning. But first some questions:
1. When we talk about seam welding a car shell, say a 116 coupe, I assume one does not continuously weld the factory spot welded seams, but instead stitch-welds in sections ? If this is the case, how long should each weld be, and what is the spacing between welds?
2. On the aforementioned 116 coupe shell, what are the important areas to seam weld, given that the cage will provide considerable bracing/support/rigidity ?
1. Yes that is right - basically you are looking an weld of about 2" long about 6" to 8" apart or thereabouts depending on the section being welded.
2. You are going to weld all the major structural areas of the car - we have a "map" of the areas we weld but it is not hard to identify the areas on a stripped shell.
This is an important part of chassis prep and should not be overlooked or it importance underestimated.
I don't think that any of the Group S Alfas (105 and 116) running in NSW are seam welded. All our cars are road registered and most have bolt in cages. (Mine is welded in steel.)
I'm sure that a lot of the MGBs and similar are seam welded, but I'm betting that quite a few aren't (especially the Porsches.)
I know that if my Alfetta GT was seam welded it would have been written off in my Eastern Creek crash. As it was just the front end crumpled and the screen, roof and floor was not effected. Believe me Alfettas are pretty strong from standard!
I'm not saying that seam welding isn't worthwhile, but I don't think that the mechanical grip that we derive from our 14 inch sticky road tyres (as oppossed to slicks) makes it imperative though. However I think that a welded in cage is worthwhile for the improvement in rigidity.
Cheers
Paul