Rust in bottom of front wing

[waltermk3 15]

My MK3 Cortina deserves better that a botch to cover the blister that's recently appeared on the bottom of the offside front wheel arch. I have decided to cut out the rust and weld in a patch. Sounds like I know what I'm doing but my welding is not very good. I have applied Jenolite after wire brushing. After welding, grinding, filling etc I will try and force wax between the two layers of metal from inside the wing. If any of you have been this way before and have any advice it would be appreciated. Thanks. Walter

[Steve Walton 128]

Hi Walter,

The best way to repair this is to "Joggle" the edge of the hole in the wing and set your patch into the recess made by the "Joggling" Then weld and dress back and make good with a light skim of filler. You can get a hand Joggler or if you wave a compressor I have an Air Joggler I could bring through and help you out.

 

Cheers

Steve

[Darlington]

[maurice 0]

ill second that

[maurice 0]

or better still f you can get the wing off, cut out a nice new piece of metal the same size as the hole, with the use of a couple of magnets to hold the new metal in place and weld from both sides. Once welded grind welds flush, apply some rust converter, then a skim of filler,

[waltermk3 15]

Thanks. Interesting that you advise joggling which I have done in the past on other cars. My local bodyshop whom I am friendly with advises a patch the exact size and but welded round. This is also how Pete does in is great videos. The corrosion must start from behind as there is a dirt path through the wing bottom. I can only wax after welding. Great to hear your ideas though

[RT 1006 137]

If you've got rust behind the wing better to take the wing off and get rid of the rust. Spraying wax on top of rust will slow down the rate of advance but won't stop it. So called 'rust converters' are nothing short of an expensive con, they don't work. Put some on a piece of rusty metal, let it dry, scrape it off and you've still got rust underneath. Don't put it on clean metal either thinking it will stop rust, it won't, that's what primer and paint then wax is for.

[Danish 294]

Thanks. Interesting that you advise joggling which I have done in the past on other cars. My local bodyshop whom I am friendly with advises a patch the exact size and but welded round. This is also how Pete does in is great videos. The corrosion must start from behind as there is a dirt path through the wing bottom. I can only wax after welding. Great to hear your ideas though

It's a common place for rust on a Mk3.

 

I don't weld much now, but the last major job I did I used these sort of clamps to help with butt welding. They leave a tiny gap just right for filling with weld.

 

[Beowulf 87]

Also when you weld that it will distort the panel. Do a bit at a time and move round to a cool place and do another bit until its all complete. It may help to use a compressor (if you have one) to blow cold air on it to keep it as cool as possible. I can guarantee it will still warp but hopefully will not be as bad and a little panel beating and a skim of filler will sort it out.

[nascar66 74]

The best way is always to completely cut out the rust. A patch that fits perfectly with no gaps. You are more likely to get problems with distortion if you leave a gap which means more filler.

You also need to planish each and every tack weld to undo the shrinkage that occurs from the welding process.

However you obviously need access to the back of the panel which may not be possible.

Joggling leaves the repair prone to ghost lines in the paint due to the area being thicker than the rest of the panel which means it will expand and contract at a different rate than the rest of the metal. Moisture can also get trapped in the overlap.

 

If you can't remove the wing the repair won't be as good as it would be with the wing off the car but the most important thing is to eliminate all the rust.

 

This type of repair can in most cases be done without the need for filler. It just takes time and patience. If I ever need to use filler it is just the slightest amount that you can almost see through but I still feel like I've failed if I've had to use it.

 

My mk2 needs a similar repair and the wing is staying on so some filler is inevitable.

 

Another point is getting your welder dialled in to achieve full penetration. It's tricky as you can have it set up perfectly for the first few tacks and then all of a sudden you've blown a hole. The difference is that now there is heat in the metal which affects the parameters. Therefore it is a slow process.

It's tempting to rush it but try not to.

[waltermk3 15]

I have done minor jobs like this before but it's great to be able to get guidance from more experienced people. Job done and thanks for your advice. Oh dear I now have a 2 tone and I had the paint mixed to code by a supplier to the trade as well. Oh well. I have tried to make the dividing line level with the door bottom so it will not notice so much to anyone standing up. But I know.

[nascar66 74]

Considering the wing was still on the car that's pretty good 👍🏻

[Tigdlo 26]

That’s not bad at all! I think red paint is almost impossible to match, and even if you do get a good match at first, it nearly always changes after time.

[waltermk3 15]

I know this thread has been dormant for a while but here is the latest which may help somebody. You will notice that the new paint is darker than the original as mentioned earlier. I had 1 ltre made up to Sunset Red by a bodyshop supplier. My local friendly bodyshop told they used another local company who have a colour measuring device. This will measure the actual colour from the car so sun fading doesn't matter. I had a rattle can made up of Valspar 2k and it's a fantastic match.