What's wrong with my welding?

[bmcecosse]

Yes - I'm afraid you do need to get back to good solid metal. Welding in a patch needs much tack welding - then short runs at opposite corners with grinding down/rewelding - till they all meet up! I can't see that I could ever manage a 'watertight' weld with MIG -which I can do quite easily with my oxy/acet . However - I have to save that for emergencies since I don't know how I will ever refill the bottles......

[rogerowen]

Yes - I'm afraid you do need to get back to good solid metal. Welding in a patch needs much tack welding - then short runs at opposite corners with grinding down/rewelding - till they all meet up! I can't see that I could ever manage a 'watertight' weld with MIG -which I can do quite easily with my oxy/acet . However - I have to save that for emergencies since I don't know how I will ever refill the bottles......

That's very encouraging information, think I've probably been expecting too much too quickly. My main issue is getting a good stick to the parent metal. Practice, practice - and a bit more practice me thinks.

[bmcecosse]

Start on the parent metal and roll on to the patch.....

[rogerowen]

Start on the parent metal and roll on to the patch.....

That makes sense! Ta.

[Ufudu]

For what it is worth... as a newbie MIG welder I can appreciate all that has been said.

A MIG welder can be a delight to use, under ideal circumstances, clean metal, good lighting, good access, good posture etc..!

But upside down, under the morris, less than clean metal that because of corrosion is of unknown thickness, no light, bloody helmet getting in the way, bifocals not focalling properly... you know what I mean!

Even in ideal conditions, the variability of height from the welding piece and the rate of weld makes it a bit unforgiving.

So, what I have found can work, under some circumstances such as butt welding a patch is to use the 'on-off' method described in the MIG forum. It means you can position the torch better and if you hit a bad patch and burn through you see it immediately. It is also good for weld filling burn through or holes in metal by allowing you to build up with new weld. It may seem that this method will take a long time along a seam, but at the end of the day you make steady progress and a reasonably professional weld that takes less grinding & cleaning.

Erwin

[rogerowen]

For what it is worth... as a newbie MIG welder I can appreciate all that has been said.

A MIG welder can be a delight to use, under ideal circumstances, clean metal, good lighting, good access, good posture etc..!

But upside down, under the morris, less than clean metal that because of corrosion is of unknown thickness, no light, bloody helmet getting in the way, bifocals not focalling properly... you know what I mean!

Even in ideal conditions, the variability of height from the welding piece and the rate of weld makes it a bit unforgiving.

So, what I have found can work, under some circumstances such as butt welding a patch is to use the 'on-off' method described in the MIG forum. It means you can position the torch better and if you hit a bad patch and burn through you see it immediately. It is also good for weld filling burn through or holes in metal by allowing you to build up with new weld. It may seem that this method will take a long time along a seam, but at the end of the day you make steady progress and a reasonably professional weld that takes less grinding & cleaning.

Erwin

Nice to hear from someone who's in the same boat!

migwelding.co.uk is a great site - and there are excellent tutorials and video clips;

http://www.mig-welding.co.uk/mig.htm

[mabelminor]

should have gone to specsavers!!! .8mm wire, high setting ,look at what you are doing ,make sure you have a good earth(clean)

[aupickup]

HI lizzie how you keeping
are you at the festival of transport this year at hellingly

[chickenjohn]

More POWER - and faster wire feed... What size wire are you using? I found 0.6mm to be useless - 0.8 mm better and as before - the 0.9mm gasless much better......

Not true at all!!!!

I restore cars professionally and always use 0.6mm. 0.8 mm requires too high a power for car bodywork.

And "gassless" wire should only be used on car metalwork when welding outside in breezy conditions. Gas mig is far superior to gassless.

It does sound like you have too low a power setting and the weld is not penetrating, also you need to practise more as I suspect you are holding the torch too far from the work and due to lack of experience are going off the join with your weld bead.

I second the comments about how good the migwelding.co.uk site is. Wish it was on the web when I learnt to weld. Also second the comments about using the stop start or "pulse" technique to make a weld which is a series of overlapping spots and very short beads to make a continuous weld. The Mig welding site calls this the "thin metal technique" and this is how to weld 1 or 1.2mm steel we find on classic cars. Continuous beads are only really viable on 1.6/ 2mm or thicker steel.

Good luck and please post more pics!

[chickenjohn]

And if you can, get an experienced thin metal welder to give you a lesson and practice on lots of 1mm off cuts.

[rogerowen]

More POWER - and faster wire feed... What size wire are you using? I found 0.6mm to be useless - 0.8 mm better and as before - the 0.9mm gasless much better......

Not true at all!!!!

I restore cars professionally and always use 0.6mm. 0.8 mm requires too high a power for car bodywork.

And "gassless" wire should only be used on car metalwork when welding outside in breezy conditions. Gas mig is far superior to gassless.

It does sound like you have too low a power setting and the weld is not penetrating, also you need to practise more as I suspect you are holding the torch too far from the work and due to lack of experience are going off the join with your weld bead.

I second the comments about how good the migwelding.co.uk site is. Wish it was on the web when I learnt to weld. Also second the comments about using the stop start or "pulse" technique to make a weld which is a series of overlapping spots and very short beads to make a continuous weld. The Mig welding site calls this the "thin metal technique" and this is how to weld 1 or 1.2mm steel we find on classic cars. Continuous beads are only really viable on 1.6/ 2mm or thicker steel.

Good luck and please post more pics!

That's very useful, thanks. I had heard of using the on/off method to limit heat distortion - but it will also help me to be more accurate at the weld point. I also heard that rather than building up a bead in the same place you should dart around a bit so that the heat is dissipated (not sure about that as that might lead to gaps.

Where do you stand on type of gas to use?

I've cut back the rot on the car much further now and I'm going to attempt but weld rather than overlaid patch - just will take me longer to get the replacement piece to the right shape.

Can't send pictures myself at the moment to this site for some strange reason.

[chickenjohn]

Good Roger, sounds like you are putting the pieces of experience and knowledge together needed to be proficient at restoring your car. I would also add, always butt weld where the metal was originally one layer as overlapped welding traps moisture and can rust out very quickly.

If you do overlap, such as where sill panels or inner wings meet a body flange then always punch holes in the top layer and use the plug welding technique. This is also the acceptable method for areas of potential distortion on visible outer panels such as Lower door skin repair panels. But use a weld able primer here and inject wax afterwards.

I might also add, get an experienced thin metal welder from your local branch to give you a lesson in plug and butt welding and practice on lots of 1mm off cuts. You can often get off cuts from local light engineering companies. Ask in your local industrial estates! cheers Johnm

P.s. as for shielding gas, I use CO2 as I'm used to it. Although Argoshield type mixes to give a smoother looking weld. Look up your local Adams gas supplier and compare prices. The quality of wire you use can make a big difference as well.

[don58van]

This guy isn't the slickest of presenters, but his technique for sheet metal is definitely worth a look.
www.youtube.com/watch?v=i4q1TExpmfY

Cheers
Don

[rogerowen]

Thanks everyone for the tips, advice and words of encouragment. After several days of practice I have grown more confident and have a better understanding of the fine line of betting it right.

[bmcecosse]

Practice practice practice. This is where the gasless wire - being so inexpensive - allows experience to be gained for little cost....

[mogbob]

Roger
Use plenty of cereal packet cardboard for your templates.It's cheap and bendable and you can make three D models with for the really complicated structures / joints.
Another tip I was taught , where you have access to the back of the piece, is to use a strip of flat brass metal.I've got a couple
with my welding set up.One piece I rounded off , with a file , to cope with the curves.
If you clamp up tight the brass behind the patch and perimeter of the hole, you will be amazed how much easier it is to butt weld.
Bob

[rogerowen]

Roger
Use plenty of cereal packet cardboard for your templates.It's cheap and bendable and you can make three D models with for the really complicated structures / joints.
Another tip I was taught , where you have access to the back of the piece, is to use a strip of flat brass metal.I've got a couple
with my welding set up.One piece I rounded off , with a file , to cope with the curves.
If you clamp up tight the brass behind the patch and perimeter of the hole, you will be amazed how much easier it is to butt weld.
Bob

Thanks Bob, The brass plate is an interesting concept - the video (a few posts up) shows a dolly covered in copper. I guess it's the same priciple - i.e. the weld does not adhere to the brass/copper and prevents 'burn through'??

[mogbob]

Roger
You've got it in one ! Some people resort to flattening copper pipe in the vice because even a little brass plate strip isn't just pennies these days.But... once you've tried it , you try to use it every time...unless there is no access behind.Plus your skills
have improved time.
Re assure yourself that all welders started off by making a hash of it.We all have our own tales of rubbish welding.Mine is the first time the gas supply run out and I hadn't checked.. didn't listen for the hiss when I pulled the trigger.As you can guess I'm
an Argoshield X man although my mig will do gas less.
Bob

[rogerowen]

Roger
You've got it in one ! Some people resort to flattening copper pipe in the vice because even a little brass plate strip isn't just pennies these days.But... once you've tried it , you try to use it every time...unless there is no access behind.Plus your skills
have improved time.
Re assure yourself that all welders started off by making a hash of it.We all have our own tales of rubbish welding.Mine is the first time the gas supply run out and I hadn't checked.. didn't listen for the hiss when I pulled the trigger.As you can guess I'm
an Argoshield X man although my mig will do gas less.
Bob

Thanks Bob, that's really useful. Sadly, I'm reverting to gasless for the time being - I just can't justify the cost of equiping and the ongoing expence of gas at the moment.

[bmcecosse]

Don't be sad - it makes perfectly good welds.....