S13 chassis rail, more holes

More pain. I took off the tension rod mounts to get to the slightly scabby paint on the under side of the driver's chassis rail, the hole looked like the ones to the left and right where it looked like one layer had corroded through. The thing that concerns me is I made the hole with a knotted wheel, which suggests to me that the area is pretty knackered.

http://i555.photobucket.com/albums/j...psrnovyd8u.jpg

Going to cut it out, but stay away from the mount hole. I'm not sure whether to try and build it up sheet by sheet or clean it up as best I can and weld some 2mm plate over it. Second option makes me cringe.

Help!!!

ive seen a few where the captive nut has sheared off inside the chassis rail.

if you just plate it then the rust left inside will start attacking your fresh metal.

chop the whole section out and let in a new section.

Thanks, I wanted another pair of eyes on it, sometimes I think I'm being overly cautious and taking far too much time on things. I'm going to try to split the layers from the wheel arch side, they've already started separating, and just go at it very carefully with a cutting disk

You can see it's rotten on the inside there, it's best to cut it open and weld in new metal, it's looking abit ropey on the bottom left there as well.

I feel your pain. I've found similar stuff on mine and have plated it. It is worrying tbh. I'm going to have another look soon.

So I cut out as little as I thought I could get away with;

http://i555.photobucket.com/albums/j...psrzvhj1mb.jpg

Had to go a little bit further. Luckily I struck metal so cut out the rotten stuff as best I could and cleaned it up. Now it's soaking in de-ox gel for 24 hours;

http://i555.photobucket.com/albums/j...psievfnkk2.jpg

Obviously the passenger side, the side that's supposed to be rusty was almost perfect;

http://i555.photobucket.com/albums/j...psl3cdz6qe.jpg

My main worry is how much weld I'm putting down, because I've never done anything like this I sometimes think I'm over doing it and removing any flex so it almost ends up too brittle.

R3K, I'd opened up that seam to clean it out, looks much worse in the photo.

you've not got much choice on the welding to be honest - officially if it's a patch repair like that, you have to seam weld for MOT.

you can use the 'original method of construction' but that would involve taking more of it out and spot/plug welding something in.

Seam weld all the things!

https://imgflip.com/s/meme/X-All-The-Y.jpg

I wouldn't bother trying to make all the separate layers. its just not going to happen.

look how think the combined thickness is and make your repair piece out of steel that thick.

firstly I would square up the edges of you freshly made hole.

get some cereal box type cardboard out the recycling bin, and start making a template of the repair panel (for this type of job I would butt weld the join). you wont get it all as 1 so concentrate on 1 part/edge at a time and just stick it all together with masking tape. (this is the real important part and needs to be spot on so take your time).

then copy it to your steel and cut it out.

lay it in the hole and trim/file it to match, you want to obtain a 1mm(ish) gap between the repair patch and the old metal for your weld pool.

clamp/magnet/hold/what ever your patch on then tack it near each corner and in the centre of the long parts. the weld an inch at a time in opposite places leaving a period of time between each weld to give it time to cool to reduce distortion. (decent song on radio helps here). then go along and fill in the gaps.

where it joins the original seam that was spot welded I would drill 8mm holes through the old seam and plug weld onto the repair section.do this one at a time between welding your inches.

once done grind off the top of your welds then finninsh up with a flap disc.

TBH I would just cut the tension rod mounts off to get a nice rectangle hole and put new ones in the repair patch. mark on the chassis/ use the tension rod mount to align when tacking up/welding.

welding is all about preparation/setup/good penetration.

Jon Ill speak to you about this on Sunday. Ill sort you where ever I can and get your other bit done for you that I have had for ages.