Old car body repairs - advice sought...

[Mike Mitchell]

Nothing is structural about a modern monocoque body. The whole point is that the flimsy bits of sheet metal comprise structural stabilty - and designed-in crumple zones - together. Just having the doors and tailgate closed increases the structural integrity enormously.

I wouldn't fancy my chances in an accident if I knew there was this very solid "ladder" of a chassis about to slice my vehicle (and me) in two. Structure is for the birds, really. It's just the way Bentley built the world's fastest lorries, according to Bugatti. I believe my erstwhile Morris 8 Series E was one of the first British designs to use monocoque construction.

MM

[Mike Mitchell]

We also replicated spot welding, for instance where it was difficult to get the spot welding tips in, by drilling spot-weld size holes, then welding through. Yes, of course I would not use brazing for spring hangers, brackets, subframes etc. God, I lost count of how many rear Mini subframes I replaced - atrociously bad design.

MM

[Mike Mitchell]

Yes, but what if there *are* no such replacement panels available anywhere?

MM

[Grunff]

That's a meaningless question - it's a 1983 VW Passat.

[:::Jerry::::]

Yes you do talk utter nonsense...

Oxy-acetylene welding and brazing have been used for decades

But not within the last 20 years or so, Mig and Tig are used as Oxy-acetylene welding and brazing cause to much distortion (especially on modern sheet metals). Go and walk into any, modern, car bodyshop and ask if you don't believe me...

[:::Jerry::::]

So, yes, they do need treating with respect. Many people go out and 'collect' this sort of equipment whilst having little or no knowledge safe handling (in the broad sense of the word) and then use them without a clue. I once came across a oxy-acetylene rig were the anti-flash back arresters had been installed at the torch end and not regulator ends of the hoses, if 'professional' can make stupid mistakes like that just think what mistakes those that are clueless could make.

They are not bombs, but they dammed well are potential bombs in the wrong hands.

[Dave Plowman (News)]

Eh? Since car bodies became unitary construction, spot welding is the norm in production. And repairing a panel without distortion with oxy-acetylene welding is said to be very difficult in all the books I've read.

Besides, a MIG welder is the cheaper option.

[:::Jerry::::]

CTFL.........

Talk about ROFLOWPMS....

You are nothing but a trolling idiot if you think that, there is far more structural metal work in a modern monocoque body - far more than there ever has been as there is less metal used so all of what metal is used contributes to the structural strength of the body shell.

[:::Jerry::::]

I suggest that you radically update you skills set if you are regularly using brazing to attach panels to modern cars, there are very few places were braze is used nowadays in the building of a modern bodyshell and were it is used it does not attach the panel - rather it is used to finish off a seam etc.

[:::Jerry::::]

How many 'good' 1983 VW Passat have you seen lately, any such panels that are in scrap yards now will more than likely be in the same state of dis-repair as the original panels needing replacement....

[Grunff]

You can always find something. I once found a replacement door for my old GSA (which was 18 years old at the time), and those things came pre-rusted from the factory.

Point is, with an old banger like that there is no point in a) paying someone to repair it or b) spending 40 hours minimum doing a good job of the doors and tailgate.

[:::Jerry::::]

But there is no point in spending good money on old houses either, just go out an buy a new Barrette (sp?) one...

The point I'm trying to make here is that the car is worth what it would cost the OP to replace it, could he buy a good second-hand car for the price it would cost to have the old car repaired, also there is the saying - 'Better the devil you know than the one you don't', if the old car is still going strong mechanically there might be good reason to spend some money on the body work and getting two, three or more years longer out of the car IYSWIM.

[Grunff]

Hmm, only to some extent. Houses don't wear in the same way as cars. Cars have fairly short operational lives by design, whereas houses have relatively much longer lives.

[Andy Dingley]

Then learn how to do it right.

A bodyshop for modern cars ? Of course not - they barely weld at all. Modern cars don't rust (just remember the nasty old lace-curtain Escorts of 20 years ago), cars are so relatively cheap to buy that we just don't bother fixing the rough ones any more, and most bodywork that still gets done is simple panel-swapping accident repairs under insurance. MIG is used because it's _quick_, not because it's any better. And I've never seen TIG in a high-street garage.

Walk round to the railway arches and Old Bob's Beetle and Moggy Minor emporium and you'll see oxy-acetylene in use though. How else are you going to work those big curved panels, or shrink a spot ?

I've got two oxy-acetylene rigs here, propane and oxy-propane too, and I'm a woodworker !

[Andy Dingley]

It is if you're holding it. An oxygen cylinder though is still a major hazard if you're on the other side of a brick wall from it.

[Pete C]

Hi,

Try one of the online scrap thingies for spare parts. If you do have to repair it yourself use zinc rich primer, fibreglass for holes, and filler/stopper to get it level.

Get a cheap body shop to do a 'blow over' of the panels, and you'll get a better result than you ever will from an aerosol, especially if it's metallic.

cheers, Pete.

[:::Jerry::::]

What utter bull you type, I was in one today talking to a panel beater as he was preparing to weld a whole new rear 1/4 on. I was in there last week and he was welding a new side onto a panel van. I could go into many bodyshops and see the same any day of the week !

Well you should really open your eyes then, shouldn't you, mig is used because it causes less distortion than gas - FFS stop telling me what my frigging trade does...

And WTF has that got to do with welding ?! And FYI there are far more effective ways of shrinking etc. than using a oxy-acetylene now.

Sounds like you are talking about old time ludites that need to up date their skill sets, otherwise they will be coming very unstuck before to long - but then it could explain why they are only working on 30 year old cars....

Well that doesn't surprise me, you certainly don't work in the car body repair trade, that is plainly obvious....

[:::Jerry::::]

And see it fall out the first time someone slams the door....

I wouldn't be so sure, if you had implied paying the going rate for the paint work you might have a point, 'cheap' means something has been skimped on some place when talking about paint work, 75 percent of the cost is nothing but labour - go figure...

[Rob Morley]

Button welding.

[Pete C]

No. How would you do it? I wouldn't want to weld every little hole, especially if it meant taking a tailgate glass out.

OK, 'inexpensive'...

Correct, do the prep yourself and get them to just spray it. What would you recommend in the way of prep?

cheers, Pete.