Arch welding

[burrows1980]

Hi,

Im restoring my Nissan Pulsar GTi-R and in need of some advice

Im nearly at the point Im dreading, cutting and welding the new patch panels in... I've cut, fabricated and welded in new sections everywhere I needed to, just a little bit left to do in rear arch, but in order to repair the inner arch panel properly I need to cut the rusty part of the arch away:



The cars upside down at the moment! There's very little rust on this arch compared with other side, but my question is do I cut on the green or red line? The green line would be easier to weld as its a flat area and will mostly be covered by a arch trim, the red line is a little more tricky, at the edge of the arch trim it curves away. Im worried when I start blending the welds im going to grind the panels by mistake causing the metal to be really thin in places.



Is it just a case of grinding the welds so its nearly flush then filling over and sanding?

All the welding ive done on the car wont be visable unless I run anybody over Ive ground the weld down so far just to tidy it up then painted over or just left it:



Anything like the above, then Ive just left as is and painted over, others ive ground down just to tidy it up:

before:



after:



Body kit completely covers these, so pointless trying to get a perfect finish and risking the good metal either side of the weld.

No panels are available for this anymore, so having to fab everything, definitely a learning curve, but im getting there now.. once the underside has a epoxy coating on, all welds and seams will be sealed before paint..

Thanks,

Gareth

 

[TwoThumbs]

Good job there and rare car! I think that you can get away with both green or red. Green might be easier to grind and fill like you said but there is one problem with green. If behind of the outer panel is compromised more than what you cut out it will cause problems, so in that way red would be safer bet. For grinding you want something like 60 grit flap disc, normal grinding disc is too aggressive and unforgiving for thin sheet metal. It may be that you don't need to grind it completely flat, sometimes when you weld it will deform slightly in a way that weld would sit inwards of the actual panel surface and filling over would make it flat.

Looked rest of your pictures and other side was more rusted like you said and there you likely need bigger patch to fix affected area.

 

[burrows1980]

Cheers for the reply, ended up cutting around the red line, wasn't much rust on it to be fair, the wheel arch is another story!!