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MG Midget and Sprite Technical - Butt or Joddle?

The Sprite is currently a candidate as a car for the Ant Hill Mob. I'm in the process of hunting for sound metal to weld a new floor panel to! I've already removed a number of patches from both sides of the floor but, as you'll see from the picture, there's still some way to go!

If this was a full restoration job, I'd hope to have the car upside down on a rotisserie and I would be fitting the full panel, but this is just a repair so that I can get the Sprite back on the road. The front and sill side should be straight forward as the flanges are OK, or will be after a bit of attention.

I don't want to disturb the floor panel beneath the chassis rail or cross member as the metal is OK there and access will be difficult working from underneath on the garage floor, so I will be cutting the floor about an inch away from the tunnel and cross-member flanges.

What type of joint would be best for a welder of limited expertise - a butt joint or a joddled lap joint?

Butt joints will require greater accuracy when cutting the panel to fit. I worry that my welding skills might not be up to it and would end up in a mess of holes and extra patches. I guess I could do most of the butt welding from above, and I think butt welding could be the neater option. I've got a set of Intergrip clamps in case I go that route.

Joddled joints would seem to offer better tolerance in the cutting and welding and would allow me to plug weld initially and then seam well the edge to satisfy Mr MoT man.

Any suggestions would be most welcome.

Colin


C Mee

To be honest, if it were me I’d cut a patch about half an inch bigger than the hole and weld it over. Then I’d weld it from the other side as well. Probably a bit of a bodge but will be stronger and also easier than joggling or butt welding.

If you don’t fancy that then I’d do the butt joint, making a patch with 3 or 4 joggled sides would be a nightmare.
John Payne

Butt welding isn’t that much harder, obviously your patch needs to be made accurately. It eliminates overlapping seams too which are prone to rust. Takes a bit more time to prep the patch. You may suffer with a bit of distortion due to heat but it won’t matter in that area.
Chris Madge

What I always intend but then fail to do is have a practice first - if you kept the an offcut of your floor and have a piece of new steel then clamp them in situ and try the butt weld. You'll be able to see if you can get the welder settings right, get comfortable etc, then make a nicer job of it when you start for real.

Being only an occasional welder I find myself diving in, blowing holes, making untidy beads, patching them up (hooray for being able to pulse the MIG) and eventually remembering how to do neatly it just as the job is finished....then it's out with the grinder and paint again and a resolution to do it better next time.
AdrianR

Quote:" Being only an occasional welder I find myself diving in, blowing holes, making untidy beads, patching them up (hooray for being able to pulse the MIG) and eventually remembering how to do neatly it just as the job is finished....then it's out with the grinder and paint again and a resolution to do it better next time."

I couldn't have put it better myself Adrian.

After my first recent blobby repair in the engine bay I got some practice by patching the holey wheel barrow - but that was only lap welding. A good number of holes, but then it was thin and rusty, my technique definitely improved though - especially the hole chasing!

In typical clumsy style, I thought I was using 0.6mm wire till it ran out and I found that my spare reel was 0.6 and I'd been using 0.8! The 0.6mm was much better.

I will definitely be doing a bit of butt welding practice on some spare thin stuff before I make my final decision.
C Mee

If you go for the butt welding then I find that to avoid the mig wire shooting through any gap angling the tip slightly from the side helps. It also helps to stop blowing holes in the weld.

I usually only use butt welds if I’m doing exterior bodywork (easier to grind back to almost flush) and use short bursts of weld and allow to cool between bursts. Basically do a nice big tack, still looking through the mask wait until you can’t see the red glow then tack again. It helps if you use your spare hand to steady your welding hand. Once you get going it is surprising how easy it is - until you blow a hole in it and have to fill it!

As you point out it’s only really a temporary fix until a new panel is fitted so I’d still go for a big patch, loads of weld, lots of grinding, a bit of seam sealer and under seal. And stay away from the MOT man!
John Payne

Well, after all that advice, I bit the bullet and butted!

Actually, I butted, plugged and lapped but didn't joddle at all.

Before I started I did quite a bit of practice on scrap and bits of removed floor, and started most days with a bit of a refresher session on the bench before starting on the car.

The more cleaning back I did, the more dodgy patches I found. I ended up removing the complete footwell floor plus a bit more behind the cross-member. The underside of the chassis rail is sound, so I left that in place and cut the floor about an inch in from the flange. Fortunately I managed to make the cut reasonably straight and succeeded in cutting the repair panel to match. That edge and the back edge were butt welded, the front and sill-side had flanges which I punched and plug welded. The cross member had a couple of rusty patches, so these were replaced along with a small section of the floor behind the cross-member. There was a large rusty L section patch to the sill and floor and, although the floor was already plug welded to the sill, I decided that belt and braces were in order, so I also fitted (what I think is) a neater replacement. That just left the patch on the toe-board to replace.

The floor's since received a coat of Zinc primer ready for the seam sealer to go on tomorrow.

As the job progressed, my confidence with the welder improved. Having to reach into the footwell and work under the car on stands meant that there wasn't a single weld that was in a comfortable, easy-to-reach position, so none of the welding is up to exhibition standard, but I'm happy that it's better than an lot of the welding it replaced. Inevitably there was a lot of grinding back to tidy things up and I reckon more welding wire ended up as iron filings on the floor than ending up as part of the Sprite!


I'd like to say a big than you to Dave for his Restoration of a Midget thread as this helped me pluck up courage and have a go. Also, on nights when I couldn't sleep, I spent the small hours watching YouTubes on welding thin stuff. There are loads of them and many are rubbish but I found this guy's series of videos really helpful: http://www.youtube.com/watch?v=_u31t13QO6A.

With the floor welding finished, I've started on cutting out some very dodgy previous repairs on the triangle web panel on the driver's side. The first piece of rusty metal that I cut out was white enamel on one side, I suspect it started life as someone's washing machine!

I think I've got enough gas left for this job but before I start on the next one I'm definitely going to invest in a big bottle as I now have an embarrassingly large collection of empty disposable 'hobby' bottles!


C Mee

Well done, that looks good :)

I’m about to put a new floor in my friends car tomorrow. I hate welding in the footwell!
Chris Madge

Looks great, job well done!

One thing you learn with cars is that hardly ever will you do any welding that is easy to get to!

Right decision about getting a big gas bottle, those hobby ones are pretty useless.
John Payne

If working in confined spaces it's a good idea to get some ear plugs to keep weld spatter out of your ears as it can bounce around quite a bit DAMHIK, same applies to eye protection also for welding or grinding, I now have a nice pair of goggles with labyrinth vents. Going to A&E to have bits removed from your eye is no fun.
David Billington

David, definitely agree. I went to A&E to have bits of metal removed from my eye despite wearing glasses and safety glasses over the top of them. Not much fun. I use a face shield when I’m grinding now.
Chris Madge

Colin

Great to hear of progress - getting the car nice and strong for next hillclimb season.

All - what's the view of folk on here of a suitable diameter of MIG welding wire for such work with a typical hobby MIG welder (130amp) - 0.6mm, 0.8mm? (Colin suggested 0.6mm). I need to do some welding soon after a 11 year break, so descriptions above of need to practice and only getting good at the end of a job and then not doing some for years really resonates with me, and the advice and encouragement of this thread is very helpful.

Cheers
Mike
M Wood

I have always used 0.6 because thats what i was given, and learnt with. I use it on 1mm to 3mm steel and it does the job fine. Ill be interested to hear of peoples experiences with thicker wire.
Chris Madge

I used 0.6mm wire and the disposable gas bottles to do my entire car. I didn't count how many I got through, but it must have been a lot! It didn't really bother me at the time, as I was earning good money and the tool shop was on the way home. I shudder at the thought of the waste (money and bottles) now. I did always use the higher capacity 600g CO2 bottles if that counts for anything? *shrugs*

Good tip RE: ear protection. I had a big blob go in one of my ears when welding in the footwell. Damn that hurt!

Keep up the good work!

Malc.
Malcolm

I started out with 0.8 but switched to 0.6 after the first 5Kg spool ran out. I read that the thinner wire produced a more controllable weld pool and was less likely to blow holes in thin metal. I did find it easier and have stayed with that.

I used one disposable bottle, replaced with pub CO2 until the landlord retired and then on to bulk BOC bottles. But rental of those became ridiculous for my low usage so am now on rent (and deposit) free SWG 200litre bottles.
GuyW

I can recommend Hobby Weld bottles, no rental just a deposit. They are high pressure and come with their own regulator and last and last and last.
Chris Madge

I use 0.6mm but am mostly welding sheet metal. Rent free Argon/ CO2 gas from SGS gas which has many outlets.
Bill Bretherton

I use SGS Gases, I used to use BOC but their rental when through the roof, SGS charge for the bottle which you get back when you return it, so you just pay for the gas.

I use 0.6 wire for bodywork and 0.8 for thicker stuff.

I started with a SIP Migmate 130 which wasn’t bad but it has an inherent wire feed issue that I fixed with a separate PSU and relay, but this wasn’t before I bought an old Murex Tradesmig 160 from a car restoration business that stopped trading, it’s a beast of machine but it works brilliantly.

I’ve just come to the end of a weldathon on my Midget, I thought it was only a couple front rear spring hangers needed, as if! The only saving grace was I made a rotisserie before I started, I’ve done my share of welding up side down and didn’t wish to repeat it.

Bob
R.A Davis

Bob
I also have a Murex Tradesmig 160 I bought from a workshop sale. Great machine but quite bulky! It lacked a torch so I bought a Binzel euro style which is nice to use. The rectfiers packed up (I think it had gone half wave initially as was lacking power) so I replaced them and it's been fine since.
Bill Bretherton

I think that I have found a sneaky way to butt weld without blowing through. I have a 3/16" thick 2"x4" small slab of copper. I place it up behind the weld and you can use slightly lower voltage and weld away. Copper absorbes the heat and weld will not stick to it.
Sometimes I have to hold the plate in position by drilling a small hole and use a small self tapping screw to hold plate in position.
Sanders

Sanders, I made a welding shoe with a lump of copper (flattened 22mm copper pipe) ready for this job. In the end, I didn't manage to use it as my arms weren't long enough to hold the spoon beneath the floor of the footwell and the torch inside it!

I tried using another chunk of copper held in place by a screw jack. It definitely helped, especially if there was a bit of a gap between the edges being welded, but my technique also improved along the way and I managed to do most of the welding with out the copper backing.


C Mee

I know this is a bit late but for future welders...
This approach to butt welding looks ineresting if you have good access (I know, not always possible on an MG)..

https://www.youtube.com/watch?v=_u31t13QO6A

Best of...
MGmike
M McAndrew

Mike

I found the Fitzee videos really helpful - if only to make me realise that I didn't need to be scared of it and giving me the confidence to give it a go!

Here are just a few of his videos, I like the way he explains things.

Setting up welder for butt welds http://www.youtube.com/watch?v=qScAlxb34UA

Butt welding sheet steel the easy way http://www.youtube.com/watch?v=_u31t13QO6A

How to make more patch panels with ease http://www.youtube.com/watch?v=S-846X5W7Nw

How to repair rusty door bottoms http://www.youtube.com/watch?v=9MPykdZF9YU

Bending flanges for door bottoms with basic tools http://www.youtube.com/watch?v=yXRV2SeMUNc


There are loads more that I haven't watched yet.

Colin
C Mee

I watched a number of his videos prior to my Midget weldathon, I used his technique in a number of places including both floors, rear inner arch repair panels and both rear wing lower halves.

Bob
R.A Davis

I think I'm finally ready to start on the homeward leg and being reassembling things.

Having had some practice and become slightly more confident of my ability with the welder, I bit the bullet and took on the off-side web panel.

It had always looked ugly thanks to the amount of underseal covering whatever mysteries lay beneath. The first photo shows what removing the gunk revealed. The white you can see is enamel on what was presumably a washing machine once upon a time.

At first I didn't think the outer web was too bad, until I realised it, too was a replacement that has been made completely wrong, so out it came along with a section of the rear panel.

I bought an Ashley Hinton panel for the inner but only used part of it. The triangular opening and the profile of the recess didn't quite match the original but it was close enough for a non-concours job.

Using a cardboard template based on the AH repair panel, I made an outer panel.

The welding went OK even though much of it was very awkward to get at but, thankfully, not quite as difficult as the footwell. I should probably have been more radical with what I removed as the metal that was left was quick to turn into a hole once the welder approached. I think I've developed the car restorer's equivalent to 3D printing by hand, managing to make metal appear where there was none previously in a welding blow hole! The A sides look OK, the B sides are a mass off lumps and protruding welding wire, fortunately they'll be out of sight when the car's back up and running. A lot of grinding back was involved!

The Sprite is a dull maroon colour but all the grinding, sanding and cutting back revealed quite a lot of the original Tartan Red and I was tempted to use that shade for repainting the engine bay. I'm not ready to do a full repaint and have more body work to do, such as replacing the bottom of the driver's door, so I decided to stay with the maroon for the time being. My supplier's photo-gizmo had identified it as BMW Titian Red (or Tizan Rot as they say in Germany) and this would be an opportunity to test the quality of the match. I quite like the shade it appears in the photo but sadly that's due to the work light flattering it somewhat.

Ah well, now to find where I've put all the ancillaries and get reassembling to see if I can get it out on the road before Christmas.

Thanks again for the advice given previously, it really helped a lot and was much appreciated.

Colin





C Mee

Looks good, nice job.
Chris Madge

Neat work Colin, its looking good.
What paint were you using - sprayed I assume?

A little tip for dealing with brake pipes like that which you may not want to remove when spraying. Wipe some ordinary grease along the pipe with your finger or a small paint brush. Then after you have sprayed the grease, with paint, will just wipe off or clean down with something like white spirit.
GuyW

Thanks Chris.

I think it's OK, I just hope the MOT guy does too!
C Mee

Looks great. Nice one.
Malcolm

With another, unexpectedly large bout of welding just completed, I thought I'd report back.

Having been really apprehensive about doing butt joints, especially where bought-in thin gauge panels were involved, I am actually pleasantly surprised with my results. In fact, my butt welds have tended to be the neatest, though still not neat enough to show off!

As well as butt welds, I've also done quite a lot of plugs and a lot of lap welds. I have a hand punch for creating holes for plug welds but at 5mm they were a bit small and I struggled to get decent results. The best results were where I used a spot weld cutter to remove duff plugs giving me an 8mm hole that meant that I could create a decent weld pool and get good penetration.

A lot of the work has been on the underside or on awkward to reach spots in footwells, so a lot of it is not very pretty to look at but the grinder has helped to improve the looks a bit and many of the welds are hidden by trim anyway.

It all feels and sounds pretty solid now so I'm hoping Mr MoT man is happy with the results.

Thanks for all the advice, it was very encouraging and helpful.

Colin
C Mee

Colin
When first trying to do plug welds I struggled a lot with failed or weak joints. I agree that 8mm holes are best. Also, you have to get the MIG wire very close to the panel you are welding to so that the arc makes good contact with it. I also found you had to turn the voltage quite high to get good penetration and that satisfying blip behind the panel. But, well done! Welding can be a frustrating process I find.
Bill Bretherton

If doing plug welds a lot then getting a pronged shroud can be useful as it maintains a consistent distance from the panel.
David Billington

The Sprite passed it's MoT today!

I'm really happy that my welding stood up to inspection, that has boosted my confidence no end.

Thank you to everyone who offered advice and encouragement. I can now get onto some of the cosmetic work that the Sprite needs - and enjoy driving it, of course.

With my welding meeting with Mr MoT Man's inspection, perhaps it's time to start thinking about tackling my Morris Minor's sills, floors and cross-members, it's only been waiting 25 years!

Colin
C Mee

Well done Colin.

Leave the Minor for the times you can't drive the Sprite in the winter - and get driving the Sprite.
Nigel Atkins

Nigel, I only said that perhaps it's time to start thinking about tackling the Minor.

I fully intend to use every one of my insurance miles this year - I might have to pay for a few more!

My previous policies were unlimited mileage and for years I did less than 1000 between MoTs. This is the first year with a limited mileage and at my current rate I'll reach the limit in a couple of months.
C Mee

Nice one Colin. Never in doubt, your repairs looked great!

Malc.
Malcolm

This thread was discussed between 05/08/2020 and 18/06/2021

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