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Rear Slam Panel Rust Repair.

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More progress. Tack welded into place. This metal is super thin and I was using Mig welder to join the pieces together. So it's easy to blow holes in it.









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So I started on this..





Managed to find some 0.75mm thick steel (nice and thin and pliable). 







So with the indentation (pressed area) in the middle of the bumper and the mounting locations I'm thinking I'll make those separately and then weld those sections into this piece.

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Tafe was cancelled last week due to the teacher being unwell..had my old teacher this week (between us, he's much better).








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Been a while between posts.

Finally cut off the old lower section, and tack welded in the new piece.

Had quite a bit of trouble creating the pressed section, I couldn't quite replicate the original shape exactly. But got close. Since it's hidden behind a bumper it won't be obvious. I also created the exhaust cut out section, but it's not exactly the same as original. I am contemplating cutting out the original section and welding it in. Either that or tidy up this piece more and perhaps use a bit of body filler to sculpt it.

I still have to create the bumper mounting points (pressed areas) I didn't want to rely on my template. So I decided I'd offer it up to the car and trace out the exact areas that need modifying and then modify it.







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So I haven't been entirely happy with my rear valance section - and decided I'd have a second go using a spare section I got for $50. Only problem is it had been hacked up already. So I figured I had nothing to lose. It also bothered me I had spent money on a reproduction lower section and not put it to use.

I figure if nothing else the practice is good for me.

1 major problem with the reproduction item is how thick the steel is. It meant that I couldn't give it that nice curve without it buckling in the middle due to the die pressing. So the solution was heat the panel with oxy and smack it down with a hammer using 2 blocks underneath to support the areas you don't want to bend.


Here is the butchered section I got as scrap for $50 with another 260z rear valance. All the weld marks are where I've added back in metal! This has been good practice given how fragile these sections are and thin! The lower section was already missing.


How the 2 pieces look mated together. I still haven't cut out the tail lamp sections yet or drilled the mounting holes.


Rough mock up on the car. I'm actually quite happy with it and this piece already has the cutouts for the rear bumper mounting holes.


A few more examples. Nothing is buttoned up or welded together yet!




Surprise the slam panel area is stuffed.. but with my new and improved oxy welding skills I think I can fix it easily. Also unlike the other piece I have something to work from this time!


You can see the dent in the rear tyre well from the rear end nudge years ago. I have to smooth that out and the rear boot floor.



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Spent some time this afternoon tracing out the original valance section (tail lamp sections).

Here it is for reference.


Which looks like this once traced out.


Transferred to my repaired panel.


Test fit 1 side done.



Time to do the other side also.


Still need to file it up and hammer dolly the folds better.


Top and bottom pieces haven't been joined yet. But already you can see it taking shape.




Still plenty of work to do, I must buy a compressor (and air tools) + oxy/acetylene welder because tafe has ended for the year and I don't have either of those tools at home.

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Nice work Gav that is a very tricky (and frustrating) section to get looking good. There are just so many angles, flat sections and holes in a small area.


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Thanks mate, I'm doing this for the challenge, only way to get better is practice. I was originally not going to use the reproduction lower valance section I had bought as the pressings are a little different to OEM, but I realise it is quite hard to pick for most.



The orange car here is using the same lower half.

I will try grinding the welds a bit flatter and then using a light skim of filler over the top if required or high fill primer (if I can get away with it).

I think I'll bite the bullet and finally buy a decent air compressor and oxy/acetylene bottles / set up to practice more at home. I've been relying on Tafe and their tools until now. So only get a few hours a week to work on this stuff.



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So last night I spent time doing a lot of manual filing and scribing the line from the upper half to lower half of the valance section. I then cut the really thick lower half along the scribe line, which was a workout in itself with tin snips. I didn't use a grinder or cutting disc since accuracy here is critical! Especially when oxy welding. You want to have 1mm gap between the 2 sections.

I don't have photos of it now, but we did tack weld in several places so the 2 pieces are now joined. We started from the middle working our way out towards the edges.

I may end up re-doing the tail light cut out section (cut out and re-weld another section in) to get the welds neater, although after grinding them down it does look a lot neater. However 1 thing I've learnt is the importance of accurate scribing and filing of the 2 edges you're going to weld together. If you get that right the welds are a lot better as you don't require filler rod.



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So attached are some of the images of progress. You can see the ends are not done yet.

But importantly you can see how close the gap is with an accurate scribe line. The X are there to help make sure the welds align with where the scribe was made since as you move along and weld things can shift.

Basically I couldn't get the lower portion to follow the right curve, so by welding it into place and following the line of the upper half, it's forcing it to align with that curve.







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Oh and incase anyone is considering buying this lower valance section for their 240z from here:




I honestly don't recommend it, the gauge of steel used is way too thick and this panel is quite flexible (OEM) which allows you to more easily manipulate it and fit it.

I've had to wrestle with this panel all the way, yes it will be far stronger and solid once on and probably far less likely to suffer rust issues in future, but the expense of USD->$AUD and shipping involved means I'd ask someone like @Ledge or @Léon to hand form this in house, or find a good donor (I haven't found 1 yet). Instead...

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Impressive work Gav. You're certainly a glutton for punishment. Looking forward to the final result.

Personally I've liked the American patch panels of various sorts which I've used on Mustangs, American made steel of decent gauge unlike the flimsy Asian made stuff. But I can well appreciate the difficulties you're having dealing with the compound curves on a rear valance panel. Unfortunately the S30 field is far less well served than for American cars.

You'll have to use a pretty robust surface prep and paint system though, all that welding heat tends to encourage the steel to want to rust faster than normal.

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Progress photos, long steady weld along the line here, requires ongoing hammer / dolly work and patience. I have had quite a bit of help from my tafe teacher (especially the tach welding stage) but I'm doing the long bead. The lower half is very difficult to manipulate given how thick the steel is, which makes it more difficult than usual, but overall very happy with what I have done so far in terms of weld work.

The goal was to improve my skills working on this piece and it certainly has forced me to improve that's for sure.

To get it to sit right on the car will require a bit of heavy handedness, given that the rear of the car is slightly bent down (I'll need to pull it out, but don't have the tools at home) when I do finally plug/weld or spot weld it into place again.










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On 3/13/2019 at 1:09 PM, gilltech said:

You'll have to use a pretty robust surface prep and paint system though, all that welding heat tends to encourage the steel to want to rust faster than normal.

I'll use kbs rust seal in the parts that will be behind the box section (once welded in) where they usually rust out, and copper primer in the areas that I spot weld. Lots of seam sealer to keep moisture from getting in and then epoxy primer on the external areas that will be painted body colour.

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Some updates, haven't finished welding the top right hand corner yet.

But it's starting to look like a complete panel, when I compare it to what I started with I'm sort of surprised it resembles something now.







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Top work Gav. It's coming along very nicely.

Cheers Jeff

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Slowly getting there, need to clean up the welds a bit still, and then put the brackets on that are missing for the rear garnish and the interior rear trim to clip into (since they were all missing as a result of the rusted areas).

The thing about oxy welding is it looks really rough until you wirebrush it or sandblast it, then once all the surfaces have a uniform finish it looks a lot better.

I will try and take a photo of how it looks underneath the slam panel area, since it actually looks quiet seamless and neat.

My welding abilities have come quite far after working on this, which is what I wanted. Although I may re-work sections if I decide I'm unhappy with the finish and I may revisit the other piece I made and re-do sections on that again.

It's only taken me what 4 years to get his far with it? :D





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