Cutting out rust pointers

[sport1901966 8]

Thought I’d put this post in this forum as I’m looking for some specific pointers rather than it being an ongoing project record.

 

I’m chasing a load of rust that has developed around the driver side chassis leg-bulkhead seam and bottom a pillar area. It’s not too terrible as although there are a number of (awkward) areas it’s set in none of them have spread to far.

 

I had made a start on some repairs a while ago (as you’ll see in the pics) but they were put on hold with house moves/general life stuff. This time round I’ve decided to go a bit further with it and try and really get rid of all the rust I can. Anyway, some pictures will be an easier way to explain what I’m facing -

 

Lower A-piller/sill/wheel arch

 

 

 

 

 

 

 

Inner chassis leg/Bulkhead Seam

 

 

 

 

As you can see there are quite a few points I’ve had to cut into that, are areas where multiple panels join together, I was wondering if someone with experience might be able to suggest better cuts to make so that reassembly is easier/tidier/less prone to return of rust?

 

Cheers!

Edited May 18, 2020 by sport1901966

[DamirGTI 344]

Been there , done that , but mine was at least 50 times worse than yours !

 

From that perspective , i'd say you're doing good job . The advantage of working on these areas are , they're not "visible" , so being extra tidy isn't priority (for me at least) but more down to making good/strong repair and after the repair protection . 

 

Few things i might suggest , have an rattle can of zinc spray near you while you weld .. and once you finish or if you haven't and need to quit for the day - spray on the area which you've repaired/worked on as soon as possible , as microscopically the rust will start forming on bare metal in no time especially if it's damp , and especially on the actual welds (commonly it's the weds from which the rust first starts over) . It's good practice to clean up the welds with the wire wheel on a grinder before applying any coating paint etc. over .

 

 

 

For heat distortion control and minimizing burning trough while welding thin metal , it's handy to have an moist sponge near while welding , weld in short pulses and cool the weld in-between with the moist sponge as you make pauses ... weld for a few seconds then stop and press the moist sponge onto the weld to cool it down (and it'll minimize heat travel onto the surrounding metal/panels too) .

 

One more thing , while you're there , clean up and butt weld the bottom floor to firewall joint .. all the way across the length , to aid strength as anyways it's prone to split apart .

 

D

 

 

 

 

Edited May 18, 2020 by DamirGTI

[sport1901966 8]

I remember the thread! Yours was the marine issue 205 right?! I have definitely got off lightly in comparison 

 

You did give me a lot of very helpful advice when I first started tackling this rust (a good few years ago), and as you recommend I do indeed have zinc rich primer to hand. I like the tip with the wet sponge for speeding up progress though, I'll be giving that one a go.

 

Yes I'll definitely be tackling the floor-firewall seem - its pretty rotten on the engine bay side, and not sure you can see in the pics - but you can see daylight through the seem! As a side question - do the exhaust tunnels normally look as heat affected as mine?

 

I think the cause of my problems is in the past there has been a but of a shunt on the RH side that has been enough to split the paint/open the seams, allowing rust to start.

 

I have another angle of the corner where the sill/A-pillar/wheel arch meet - 

 

Ideally I think I'd keep cutting lower, but not knowing exactly how the panels meet, it's difficult to know the best places to cut, is it a case of just keep going at it do you think?

 

 

Edited May 19, 2020 by sport1901966

[DamirGTI 344]

Yes , that's the one ... "the aquarium" 205 , lacking just an big octopus guarding all that mess inside ! ... was an real bitch of a job , especially as i didn't have as much skill welding thin metal and panel fabrication at the time , was my second or third welding project aside from welding various non car stuff with stick/arc machine .

 

Kinda common yes for the exhaust tunnel to look like that in the center, it's the constant cycle of heating/cooling from the exhaust which does the damage .. also the entire joint is just spot welded thus not as strong , and with the joint lip protruding on the outside towards the engine bay where it's prone for moisture entering inside the seam (it's seam sealed from the inside but not the outside)

 

On the OE spot welded panels , seams are the main problem , almost all the rusting starts from there after the OE applied seem sealer cracks from age , heat (like on the exhaust tunnel area) or "panel shift" in the case of the crash/collision damage .. poor repair and protection done in the past and stuff like so . 

 

True , certain areas are a bit hard to detect where multiple panels join together , shell colour has some effect too in this aspect if you trying to detect by looking without grinding off down to the bare metal to see the joints and spot welds .

 

Can try looking on the parts catalogue in the bodywork section : 

 

http://www.miamistu.co.uk/pug/

 

... might give you some insight .

 

Anyhow , i'd just go and cut as you finding rusted areas ... mainly making sure that you cut all the affected metal off , no need to stretch the repair any further just so to speak to complete the OE panel shape , can always grind off the weld if you want and make the repair almost if not entirely invisible once painted .

 

Butt weld as much as you can all the patch panels , and keep in mind as you go to leave some space to reach the back side of the repaired sections so that you can paint and protect them from both sides .

 

D

 

 

 

 

 

Edited May 19, 2020 by DamirGTI

[sport1901966 8]

That’s a useful link, I’ve had a browse through and it does help to get a rough idea of how the panels go together.

 

I’ve done some more digging today and it does just seem to be a lot of rust in seams, which unfortunately does mean splitting quite a few panels/cutting out joins to repair. Fortunately though generally the panels themselves are still not too bad beyond the rust at the seams.

 

I have made a slightly more interesting discovery though... I’ll let the pictures speak for themselves -

 

 

To me that looks as though there’s been some repair work done for sure (partial ground welds at the edges of the panels). Again it seems to be mostly surface rust, what would people do? Clear all the rust then extend the existing weld ‘blobs’ to a full seam and ensure proper priming/undersealing going forward? Really don’t want all this creeping back a second time!

[DamirGTI 344]

Looks like someone has been naughty trying to do a plug weld ... partially successful .

 

Well i would , fill up (with weld) the voids/craters around "incomplete" welds as the rust might very well start from there first .. and might do some butt weld on a few spots along the panel joints with say 5cm gaps in-between , just to strengthen up a bit that previous repair .

 

Then grind off all those areas with the wire wheel rust free as much as you can and apply 3 coats of good quality rust converter .. pick something good like : Wurth , Loctite , Forch , Dinitrol , Fertan (this one is really good.. not sure which brands are "good ones" back there in the UK) , or you might try POR-15 rust preventive paint , it's a little bit different than the rust converters but really good and durable as an rust preventive coating .

 

Then the usual , paint (can even apply some epoxy primer for double protection if you wish after the rust treatment , but it's not necessary) and stone-chip coating on the end . That'll do .

On the chassis leg insides , spray some cavity wax after you're done with the welding .. of if you can be "creative" at making something to spray the rust converter inside the chassis leg first that would be even better (some of the converters you can thin down with tap water , but do read the product instructions first to verify that) . 

 

D

 

 

[Leslie green 116]

Looks like most of your rust issues are due to crash damage on drivers side which has split chassis rail and been putted back into shape and welded back up. The bulkhead seam rot is common where exhaust goes under it and the underfelt on mine was actually burnt and had started to melt so must have been near touching . I ground the seam down a bit for more clearance and welded it on the inside to add strength.

 

20180523_125613 by Leslie, on Flickr

 

 

20180524_152748 by Leslie, on Flickr

Edited May 22, 2020 by Leslie green