When welding in new sheet metal at certain parts of the car the German inspection authorities demand the following:1) There has to be an overlap (no butt welding)2) Spot welding (no continuous seams)How the fuck do I protect my car against future rust issues then?Water will get in at the points where there is no seam and it will sit right inbetween the 2 sheets which overlap.A Weld-Thru Primer won't do the trick, will it? Maybe delay the issue a bit.What about using body solder?There is also the option to use a CuSi3 wire when welding, which technically makes this a soldering job.Then (apparently) the German inspection authorities do allow butt welding with continuous seams.Does anyone have experience with this? Is this strong enough to actually last and not cause further problems?
So it turns out when using CuSi3 you yould leave a small overlap of 2 or 3mm for the material the seep in according to this German video.https://www.youtube.com/watch?v=xhtoHYADrQM&t=385sFrom my research body solder on the other hand does not prevent rust, in fact the flux is corrosive and might seep into the gaps.Can anyone confirm this?This guy added body solder directly to a spot weld.https://www.youtube.com/watch?v=D9Y5LmVhLyg
>>29024508literally how will they even know? use some high tech bondage shit, weld it, paint over it, cover it in carpet or antirust spray or some shit.
>>29024508>germanyThere's not a single german car ever made where doing this is worth it. They're all built to rent, you keeping it on the road past its expiration date is a fools errand.
>>290245083M 08361 urethane seam sealer is designed to bond repair panels and keep them sealed after you spot weld them.It’s $50/310ml tube in the US, I’m sure it’s more in the EU, but it’s literally designed for your exact dilemma.
>>29024601>>29024601>literally how will they even know?That's a good point and I don't think they will.I'm just interested in whether such a repair could actually last for decades or not.>>29024605It's not specifically German car maufacturers that demand such repairs, it's just the car inspection authorities in Germany, TÜV etc.Not sure what it would be called in the US.The brand does not matter, could be Ford, Toyota, whatever.>>29024607Interesting. But can you just add body filler on top of it? Can you grind it down?
>>29024508>How the fuck do I protect my car against future rust issues then?simply do it ze right way>Water will get in at the points where there is no seam and it will sit right inbetween the 2 sheets which overlap.If only there were some kind of solution to this problem
Are you not allowed to caulk the exposed areas?
>>29024508>Spot welding (no continuous seams)What the fuck? That's exactly what they fail you for here in Finland, unless you've filled in the space between the welds completely, making it a continuous seam anyway.
>>29024733Continuous welds will fail all in one tear once they start to fail, spot weld plus filler urethane fails more gracefully. Repairs do not require inspection here, but this is why a shitload of spotwelds is taught for structural repairs and continuous welding is considered show car stuff (because it definitely cleans up easier and nicer).>>29024640Weldable seam sealer is urethane based, it can sand, but it takes a lot of sanding, using a rasp or rotary file to get it out of the way before filling is the best choice. How well it takes filler will depend on how god of a job you did welding. Urethane has some give to it, so if your weld job isn’t rigid, the panels will move when flexing if your welds don’t do a good enough job of unifying the pieces, and that will cause your filler to crack and fail.
OP here.My problems concern a few rust holes in the rocker panel.Apparently the repair method with the overlap and spot welds is the general technique one would use, that's not just a German thing.https://www.hemmings.com/stories/how-to-fabricate-and-install-a-replacement-rocker-panel/There is a German video that goes into detail:https://www.youtube.com/watch?v=j-RAr2JIzV0The original rocker panel is joined to the car body by spot welds too, so it makes sense that you have to replicate that.They are however doing a continous seam and butt weld when joining the original rocker panel and replacement.Maybe it's some form of internet legend that you can't patch small holes by doing butt welds?It would be great if someone could clear that up.
