New body panels currently from Porsche

[Barry]

Thanks everyone (Barry, Gary & Hillclimber) for replies.

What if the parcel shelf sides are in good condition and don't need attention? Can the cut/join line be lower than Gary's?



I found a picture online (not mine) this morning of a targa panel showing the hoop provision as Barry explained:

My default is to go from the 1/4 light rear curve (the one that's about 3in tall): half way up that and then do an arc that ends up running 15mm or so below the gutter line. You could certainly go lower. I use that height as it allows excellent access and leverage for the PDR rods, and yet keeps the weld fairly short and very well supported.

I always replace the flange on the top of the inner wing: by time it's been shaved right down in the factory, been spot welded and these then drilled out, there's rarely much left that's worth fiddling about with. Better just to take it down to 2mm or so, put a nice wide new flange on as Gary mentions, then shave that down after welding.

Obviously it's an insignificant job to remove the Targa hoop pressing area of the wing top flange, but as I suggested above, template off the original wing flange just to see how similar or not that is to the Targa version.

The long and short of it is that, yes, I'm sure much of the wing will be usable, but if this means great long welds then the attraction is going to wane somewhat.

I take it you have a good pair of Targa 1/4's to hand?

If someone wants to host some pics for me, I'll e-mail some pics of how I tackle this area over.

[IanM]

If someone wants to host some pics for me, I'll e-mail some pics of how I tackle this area over.

Yes, sure, you can email them to me:
ianm19@gmail.com

No, I don't have any targa 1/4 panels, but I think they are probably easier to find than coupe versions. Also the shipping will be easier as the box size doesn't need to be as tall.


Do you agree with what Rob said (below)?

All I can add from a common sense point of view is that the narrower the join the less sensitive it will be to inaccuracies, visually I mean. So better up where the join is short

[Barry]

If someone wants to host some pics for me, I'll e-mail some pics of how I tackle this area over.

Yes, sure, you can email them to me:
ianm19@gmail.com

No, I don't have any targa 1/4 panels, but I think they are probably easier to find than coupe versions. Also the shipping will be easier as the box size doesn't need to be as tall.


Do you agree with what Rob said (below)?

All I can add from a common sense point of view is that the narrower the join the less sensitive it will be to inaccuracies, visually I mean. So better up where the join is short

Ah, well if you've not bought the panels, it's easy peasy: just get coupe ones, no contest. I assumed you had a pair of NOS Targa ones that owed you nothing and needed using up. If you're starting from scratch just get the correct items. I'll pop some pics over in the next day or so if you'd then like to post them up for reference (for what it's worth).

Yes, you'd usually aim to have any join as short as possible. As I'll show, you also want to avoid straight lines: welding curves is always better as the join is more stable. Likewise (as an aside) any patch repairs should avoid having corners, they should always have radii where possible.

[IanM]

If someone wants to host some pics for me, I'll e-mail some pics of how I tackle this area over.

Courtesy of Barry:

this is actually from many years ago and these days the front of the join is carried out a little lower, more like just above the rearmost of the ¼ light return curve, so two or three inches lower than the red clamp here.

The principle remains though, about ½ below the gutter to maximise weld support, and a curve from there forward which helps to support the weld. I then use PDR rods to pick up the weld ready for final linishing.

Should have started here!

The join goes up a little further than I’d like for reasons Gary described, but again, same principles as before: keep the weld near the gutter, then a curve down to the ¼ light area.

Now, if the gutter area is swollen or obviously poor, then you’d want to do a full wing replacement, but be aware forming up the gutter accurately is not easy at all. I’ve got a special dolly formed to the correct inside shape as when it arrives, the wing’s gutter area is very indistinct and there’s way too much metal there. You have to form up the correct gutter shape, then trim the excess before starting to mount the wing, and later, form the gutter return.

Thanks Barry

[Barry]

[IanM]

Reviving this thread.

Quote from Barry:

I always replace the flange on the top of the inner wing: by time it's been shaved right down in the factory, been spot welded and these then drilled out, there's rarely much left that's worth fiddling about with. Better just to take it down to 2mm or so, put a nice wide new flange on as Gary mentions, then shave that down after welding.

Which, as you know, means this:

Most metal workers, if not all, use a special drill bit for removing spot welds but unfortunately the drilling sometimes damage the second layer.

So, I've been researching to see if there are newer technology out there and I came across this article about PLASMA CUTTER.

https://www.motortrend.com/how-to/quick ... ma-cutter/

Video:
https://www.youtube.com/watch?v=NhHxJJD4C_w

Hopefully, this method will be much less invasive to the second layer while removing spot welds. I'd like to hear your thoughts.

Thanks.

[Gary71]

To be honest that looks as risky as using a spotweld drill! One wrong move and you are straight through the second layer.

It’s an interesting method to try if you happen to have a delicate plasma cutter in the workshop.

Given the example above on the quarter panel in very thin steel (and still needing to grind the centre away) you will still end up with a thin, wobbly flange that can’t be trimmed to match the new quarter.

If it was a thick v thin steel example of a boot floor on a chassis rail then it’s probably going to work well as you wouldn’t be trimming the flange in afterwards.

[deano]

Some thoughts on spot bits and an alternative from me...

The tips on spot weld bits do differ slightly, and this can affect the outcome - some bits make a deeper pilot hole (too deep), which leaves a hole or crater in the centre of the second panel. I managed to find some which produced almost no pilot hole, only just enough to keep the bit centred on the panel. The Dormer A723 bits are a good example. You can sometimes see from the pictures online how much higher the centre is from the cutter edge. With these small or no crater bits, it is a good idea to go bigger than the spots as smaller bits tend to leave edges that need to be chiselled free.

A good-fast alternative to spot bits, only if you are throwing away the top panel, is to grind through the spot welds using a power file (the Black & Decker electric is great). You can use course belts e.g. 40 or 60 to get close fast, and then switch to 180 for finer control. Bear in mind that the grinding tends to hide the break between the two panels - wiggling the panel enthusiastically will show when you are through each spot weld. Bear in mind also that the course grits will heat the metal, so do a bit at a time and move between spots to keep the temperature down.

[IanM]

.

[IanM]

Given the example above on the quarter panel in very thin steel (and still needing to grind the centre away) you will still end up with a thin, wobbly flange that can’t be trimmed to match the new quarter.

If it was a thick v thin steel example of a boot floor on a chassis rail then it’s probably going to work well as you wouldn’t be trimming the flange in afterwards.

I know what you mean but the guy in the video recommends setting the plasma cutter to its lowest level (10 amps or lower) and switched to gouge setting.
I was thinking whether it would be possible to insert feeler gauges in between the first and second layer for added protection while using the plasma cutter?

Anyway, I've just checked purchase prices for such a machine - it costs around £3K for the Powermax 45 (output current 10 to 45A).

[sladey]

How can you insert a feeler gauge? Surely the spot weld is in the way

[IanM]

How can you insert a feeler gauge? Surely the spot weld is in the way

Right next to the spot weld.

[Gary71]

Unlikely to be able to put it in with a old, probably rusty flange?

Sounds like massive over complication for me

[IanM]

A good-fast alternative to spot bits, only if you are throwing away the top panel, is to grind through the spot welds using a power file (the Black & Decker electric is great). You can use course belts e.g. 40 or 60 to get close fast, and then switch to 180 for finer control. Bear in mind that the grinding tends to hide the break between the two panels - wiggling the panel enthusiastically will show when you are through each spot weld. Bear in mind also that the course grits will heat the metal, so do a bit at a time and move between spots to keep the temperature down.

Hey Deano,
Thanks for the advice. I just saw this video:

https://www.youtube.com/watch?v=C5Ge1TRk7I4

This type of work does look very practical.

[IanM]

Another question

Will the later gussets (kidney bowls) as pictured below, fit to pre-73 911?
It seems to me that this gusset being L-shaped will add more rigidity between the B-pillar and the rocker. Another advantage is that it has a jacking point integrated with it, so that's probably a good thing.