welding sills for an mot pass

[Nad-5GTT]

I'm welding in some new sills, not the whole lot but just where it needs it, do I need to seam weld from underneath the sill where it lips onto the inner sill/floorpan. Or can I just plug weld every half inch?

[Goobie]

I plug'd weld mine every inch, there like this from factory. :agree:

[evogill]

wouldn't you be better off putting the first couple of inches up the sill , and the full / half length in by the time you have done patching? more solid and neater. your o.k plug welding flange lip, but if you fail mot they make you seen weld lip.

[Nad-5GTT]

I've only done the drivers side and I've replaced from where the join is by the rear door shut backwards to the end. Not just patches :agree:

[NRG]

Anything structural must be fully welded all round. Also, if you spot or stitch on a sill, the water will get in and you'll end up with more rust than you started with unless you use liberal amounts of anti stone chip to seal up after welding .
Guess it all depends on the quality of the welding too.

[Goobie]

Just to be clear if anyone finds this thread in a future search, obviously there are/were seam sealed as well after spot/plug weld from factory along the bottom. :agree:

In fact, the whole car is spot welded together. ;)

[evogill]

I work in an pas 125 bodyshop approved were every replacement panel has a methed of fitting, a sill pinch lip will always be mig pluged or mig brazed pluged or bonded and spot welded. as goobie stated the rear or the inner sill always should be prepped and sealed and stone chipped or shults for protection. all sills usually have open lets to let any water/ moisture out. non gen usually are straight and don't have these. I usually put a blunt chisel/ screwdriver every 12 inch or so between welds and pry just enough to open. but never seal that gap. you then can waxoyl from inside and see it flow threw bottom made gaps, you know then that's the best protection you have given a new sill.

[Nad-5GTT]

Anything structural must be fully welded all round. Also, if you spot or stitch on a sill, the water will get in and you'll end up with more rust than you started with unless you use liberal amounts of anti stone chip to seal up after welding .
Guess it all depends on the quality of the welding too.

Ye I've fully welded along the top and sides and have plug welded every 20mm along the bottom. I've then ground all welds down flush and filled and ground any pin holes with weld. I will be covering the whole lot with a skim of seam sealer, anti stone chip, then high build primer and then a body colour top coat. Also everything I couldn't get to has been treated with a coat of weld through zinc paint. Water getting in is not a problem :agree:

[Nad-5GTT]

I work in an pas 125 bodyshop approved were every replacement panel has a methed of fitting, a sill pinch lip will always be mig pluged or mig brazed pluged or bonded and spot welded. as goobie stated the rear or the inner sill always should be prepped and sealed and stone chipped or shults for protection. all sills usually have open lets to let any water/ moisture out. non gen usually are straight and don't have these. I usually put a blunt chisel/ screwdriver every 12 inch or so between welds and pry just enough to open. but never seal that gap. you then can waxoyl from inside and see it flow threw bottom made gaps, you know then that's the best protection you have given a new sill.

Good tip

[evogill]

use acid 8 etch primer on all bare metal. its about best iv used. Halfords do it around £12.50 a can. dosnt rub off. used it for years