Mk2 Golf GTI - Full restoration

[GolferGraeme]

@jo1010 Oil based inhibitors... something else I need to read up on. I used to know a welder with a Series 2 who after restoring his frame sprayed the whole thing - bare metal - in a homebrew mix of wax and engine oil. It formed a really nice film to be fair and seemed to work well. Bit hardcore for the Golf though!

​

 

[Cris B]

Looking forwards to following this one, always had a soft spot for these cars!

 

[GolferGraeme]

Right so had a bit of a setback... managed to give myself tinnitus following a long stint with the angle grinder removing underseal. Don't think it was so much the grinder as the resonance off the floor pan amplifying the sound/vibration. So went on light duties; removing soundproofing, stripping down and cleaning wax off doors ready for sanding, removing decals... all the boring stuff I'll be glad I did at a later date.

Anyway after 3-4wks the tinnitus has died down and what remains is obviously sticking around so time to crack on with the noisy jobs, this time with ear defenders. Started off by getting a feel for my welder with some 1mm cold rolled sheet. Welder is a Clarke 135TE running 0.6mm wire and Argon/CO2 (5%) at 8 l/min. Straight away I found I had no problems running a seam but my tacks - and I want to keep to tacks to keep the heat down - were lousy. Basically too tall with poor penetration.

So I had a read on the forum which suggested I needed to up the voltage from what was good for a seam to account for the cold start and also leave a root gap. So I upped the voltage from 1min to 1max (the 135TE goes 1min, 1max, 2min, 2max) and left a 1mm gap and sure enough problem solved. So onto the easiest job on the car, deleting out a drain hole. Started by chopping a square around it and removing the paint (inside and out).

Then drew around the bit I'd chopped out to make a patch.

Big magnet on the back.

Then tacked in place. For some reason if I leave the torch to sit for a few minutes the pressure builds up to the point that the trigger is really stiff to press (dodgy regulator?) so I'm having to turn the gas bottle on/off a lot. The two nasty tack are where I forgot to turn it back on again

Now the metal on the car is 0.8mm and I'd been practicing on 1mm and so I pretty quickly found myself blowing holes. So I turned the voltage back down to 1min to finish off which stopped me blowing holes but at the expense of cold tacks again. Here's what I ended up with.

And the rear.

Not great - my aim is obviously a bit off, a lot of the tacks have either not fully penetrated and/or are spaced too far apart and it needs a couple more tacks to fill the hole in the corner once it's ground back. But given it's not structural it'll do.

Plan for tomorrow is to cut some 0.8mm metal out of my old doors and practice with that for a bit, try get my aim a bit better, maybe go back to 1max on the voltage and try reducing the root gap to suit.

 

[jo1010]

Good start.......
Underseal is horrible, just burn and scrape it off first to leave the underlying paint. Just simple propane torch will do it. Careful bc it will drop off like burning tar and ignite any inflammable floor covering .
Your welding machine is one problem I'm afraid. That Clarke is a 30 amp min machine so you'll likely burn through on runs with 0.8mm metal - and lots of tacks aren't really the best way. Also remove any magnet once you've got a few tacks on the panel - magnets will mess up your welds a lot.

But your real problem in thin stuff is the machine.... a 20amp min machine running 0.6 wire will make your life a lot easier

 

[GolferGraeme]

Had another play with the welder today using some 0.8mm cut from the door that got mangled in the attempted break in. Found that with the voltage on 1max - which was working a treat on the 1mm sheet - I was blowing holes for fun. Playing with the wire speed and ditching the root gap helped a bit but not much so dropped the voltage down to 1min and problem solved. Then I tried welding a strip of 0.8mm to 1mm and I had the same penetration issues I had yesterday on the car. The photo below shows 0.8mm to 0.8mm (top) compared to 0.8mm to 1mm (bottom).

And the rear.

No doubt an experienced welder could find a way to make it work but I'm not that so I'm going to do what I should have done to begin with and buy some 0.8mm, make life easier. My mate who restores cars for a living will find a use for the 1mm so it won't be wasted. You live and learn.

 

[atomant48]

I’m not sure your welds are as bad as you think they are. I reckon you’ve got something to work with there. I used to use a Clarke with the same settings and it seemed ok. I did swap out the earth lead which made a massive difference to the weldability. There’s a few threads on that mod in this forum somewhere.

FWIW (and I am by no means an expert or even professional!!) in my experience there’s much more in technique than in the actual amperage you’re getting when you get down to those 20-30 numbers. I think you’re going ok.

 

[Misterg]

You live and learn.

I've seen a lot worse from people who've been paid to do it.

Far from an expert, but try turning each tack into a short bead (~3mm long). Run each one back to the previous one.

 

[GolferGraeme]

I’m not sure your welds are as bad as you think they are. I reckon you’ve got something to work with there. I used to use a Clarke with the same settings and it seemed ok. I did swap out the earth lead which made a massive difference to the weldability. There’s a few threads on that mod in this forum somewhere.

The welds on the 0.8mm to 0.8mm I can certainly live with, especially once it's ground back. And I'll check the earth mod, cheers

 

[GolferGraeme]

I've seen a lot worse from people who've been paid to do it.

Far from an expert, but try turning each tack into a short bead (~3mm long). Run each one back to the previous one.

Thanks! If I can get the welds on the car looking like they do on the top strip in the pic I'll be happy enough but short, overlapping stitches might help where I've missed little bits. Will have a play when I get the 0.8mm sheet tomorrow.

 

[jo1010]

Hmm. Closely spaced tack welds are not acceptable for the UK mot for panels that were not originally spot welded. Yes I know the piece you showed is probably not structural, but the general point stands.

There's also the longer term problem that the tiny gaps left between the welds are ideal as moisture traps and therfore rust - you might rely on paint or finishing materials to sort this out, but this would not be a 'proper' restoration - more of a back street bodge.
Honestly, my view is: sort out these problems using scrap steel before setting to on the car itself. But it's your car so you will do what you will. I won't make further comment on these aspects.

 

[Exuptoy]

@jo1010 a little bit harsh there pal.
Here’s a guy making essentially a first attempt at welding and you’re calling it a bodge.
I’d personally be happy with this work and trigger time will improve what is in my eyes probably a 4/10. Most ppls first attempt looks like pigeon **** and barely follows the line.
Graeme if you are concerned about gaps, grind it back (a finger file is better than a flap wheel as they make the surrounding area thin) and hit it a second time or alternately grind back the back side and hit that the second time around. That way you’d no doubt be able to get a run rather than tacks.
I think you’re doing well.

 

[jo1010]

....a little bit harsh there pal.

Maybe. The welding might pass for an odd patch panel, but OP says this is a 'full restoration...' so I viewed the welding with that in mind....
The idea of learning on the job isn't a new one and we all start somewhere I know. I'm just making the point that if approaching a BIG project such as full resto ( and with the kind of intended perfection expressed in OPs earlier posts) that this kind of welding on the thin stuff has a few defects to remedy. The machine will be fine on the slightly thicker structural stuff though

 

[Melvyn Best]

Try putting a piece of copper sheet behind the area you are welding

 

[stichill99]

I think that welding looks pretty good!

 

[Turbo]

Tack your panel all around with the tacks spread apart.
To weld in between the tacks start your weld on a tack and weld away from it, creating an overlapping tack.
Keep doing this until its all welded.
Swap from one side to the other to keep heat and distortion down.

This will help avoid having any pinholes in the weld. The overlapping means it's easier to get the weld pool started on solid metal before welding the joint.

 

[GolferGraeme]

Appreciate all the comments. Also appreciate that the tack approach isn't best practice and I certainly won't be using it on such as the a- and b-pillar - they'll be left to a proper welder with a proper welder. Full resto might have been overselling it a bit... it'll be my daily so not looking for perfection but I do want it solid and MOT-able and if there's a better way to do it I'm all ears.

I'm picking some 0.8mm sheet up tomorrow so will have another go at running seams using a copper backing plate and starting on tacks as advised. I can run seams fine on 1mm so I'm not a million miles off. But I'm also happy using the tack, tack, tack approach if necessary, so long as I can get it as tidy as on the 0.8mm to 0.8mm practice piece shown earlier it should grind back to something pinhole free (finger file duly swiped from my dad's garage, cheers @Exuptoy).

And if it's good enough for this bloke it's good enough for me:

 

[jo1010]

......and if it's good enough for this bloke it's good enough for me....

I'm not sure what you mean. He did a good seam mig weld on the panel - the vid shows a good SEAM weld on the panel and he then flipped the panel over to show the messy reverse side - which does look like your reverse side, but the process of getting there has been very different.

 

[Exuptoy]

@jo1010 I don’t get on here much these days and have not had the pleasure of your input on one of my threads but, man, you have no filter!
You every thought of retraining as say a crisis negotiator or something. I reckon building jumper deaths would increase tenfold

 

[GolferGraeme]

I'm not sure what you mean. He did a good seam mig weld on the panel - the vid shows a good SEAM weld on the panel and he then flipped the panel over to show the messy reverse side - which does look like your reverse side, but the process of getting there has been very different.

Well I didn't see him run a seam but he could well have done. The reverse side at 18:39 just looks like a series of tacks which might have thrown me a bit. In any case I'm going to have another go at seams on the 0.8mm with a backing plate, will post an update later

 

[DanZac]

Well I didn't see him run a seam but he could well have done. The reverse side at 18:39 just looks like a series of tacks which might have thrown me a bit. In any case I'm going to have another go at seams on the 0.8mm with a backing plate, will post an update later

Keep at it, I'm a long way from an expert, but it looks to my untrained eye that your heading in the right direction and most importantly your ironing out the wrinkles and perfecting your technique before committing to the important stuff.
Practice makes perfect and all that.