Porsche Enthusiasts Club Forum

I ve finally had time to go back into the man lab and finished preparing my inner sill for a new centre and outer.

Once the parts came through, I called in my welder, who is a professional welder by trade.

With myself doing all most the labour, my sill was only rusty at the bottom, cut out, cleaned up and treated ready for minimal work by the welder, I set him to task.

After clamping the centre sill in place he started to tack in the corners to hold it while he did the major job,

Using his mig, he found that the old metal of the car seemed to burn away and says that I need to get him a spot welder as the original metal is too old and doesn't like to be welded, and this was on the top, door seal edge, let alone anywhere near the previous rusted area.

Has anyone else come across this problem, and is the spot welder the way ahead, even if I do have to pay out the £500 for one or hire one in? Or is there an alternative method?

Maybe you need a new welder.

Part of me feels that he wasn't really up for the task in hand, hence why he was suggesting a piece of equipment he doesn't have,

I served my time as welder and have welded new metal into the wings of my 1984 944 no problems. It sounds like the two metals are a different thickness to each other. All repairs now for an MOT need a full seam weld even if they were originally spot welded so he is talking rubbish on both counts.

Obviously not the best welder out there lol. I have to weld different thickness materials every day, old to new, new to old etc etc. Sometimes 944 weld a bit different as they have galvanised metal, but nothing a proper welder cant easily deal with.

Many thanks guys, panels are the same thickness, well should be as it's a genuine outer. Must probably be the galvanised content of the older metal compared to the new, black covered panels

I'm by no means a welder, well a floor layer but I managed to weld both of mine with my trusty mig. I'd say ike the others on here... Find a new welder, in most trades the saying "a poor tradesman blames his tools" is always used when we here this!

I did an apprenticeship as a Fabricator/Welder too. AFAIK the galvanising is plated onto the steel so a grinder would take that off in seconds. Any amateur welder should be able to tack sills on with a MIG provided the wire and gas are right.

ok, so to be fair a spot welder would on this point and situation where the door seal edge is, be the tidiest way to do the job.

I think a few people are getting confused with 2 pieces of metal joining on a flat(ish) surface, not as in this case meeting at an edge.

I should however say that he should be able to weld it without one but it is a pretty messy way to join the 2 pieces.

As far as I am aware for mots that seam welding is only required within a specified distance of a load bearing point (i think its 30cm). Not as stated for all welding, this would obviously be better but isnt a requirement.

There is a reasonable piece on welding in car mechanics this month, if you fancy a read while the lady does the shopping!

You could drill and puddle weld in that situation.