(still) struggling to obtain success on vehicle welds

[thepurpleblob]

I've had a mig for a while now and have got the point were I'm quite confident welding on the bench. Even repairing old bits of car where the metal is less than fresh.

However, actually welding some patches into the vehicle is just a mountain of frustration. The bit of work I am doing is semi-upside down and I can only just see what I'm doing (a section of inner wing). I just seem to blow holes all the time and the welds I do get are a smoky mess.

I've tried things like clamping copper on the other side but it didn't make any difference. To be honest, the access wasn't great and it wasn't as flat to the metal as I might have liked.

I think I've now been two months on and off trying to weld the same 6-inch-ish bit and I'm just making a mess.

Any words of support much appreciated

 

[octo0072000]

sounds like inner wing is a bit thin pitted always harder to weld on the car than the bench
better to take outer wing off to get to inner wing?

 

[thepurpleblob]

I've shifted everything I can unbolt to improve access. It's a heavily contoured bit of panel. I actually chopped a bit out of a (better) scrapper. Some slightly frilly edges on the chopped out bits I welded up no problem (on the bench) but welding them into the car is just about defeating me. You're right - it's not brand new shiny metal on either side, so I'm not making my life easy.

Maybe I just have to keep at it. I'm starting to get good (well, let's call it better) at welding up blown holes

 

[J.B. Welding]

Short bursts of slightly over powered weld then aim at the blob you created to get the arc going and try on the next 'tack' to run the bead a mm or so, then wait a second for that bit to cool and arc up on the weld again, and repeat. If you try a run or start to weld on the thin stuff you will easily blow a hole, but the weld tends to be thicker so it can take a bit more heat. You can fill holes like this too, little tacks and patience.

 

[Istayinalot]

I've shifted everything I can unbolt to improve access. It's a heavily contoured bit of panel. I actually chopped a bit out of a (better) scrapper. Some slightly frilly edges on the chopped out bits I welded up no problem (on the bench) but welding them into the car is just about defeating me. You're right - it's not brand new shiny metal on either side, so I'm not making my life easy.

Maybe I just have to keep at it. I'm starting to get good (well, let's call it better) at welding up blown holes

Keep at it you'll get there, There's nothing like welding clean steel to rust and underseal for improving your technique

 

[Bill Edwards]

The problem with welding on the vehicle is that as well as hot spatter and rust you struggle to clean off the position is often uncomfortable which never helps and when doing vertical welds it's even easier to blow holes than when it is all laid flat.

I suggest you try welding with the metal in the same positions on the bench as you are on the car, you may discover that you need slightly different settings and techniques.

 

[thepurpleblob]

I'm already welding in short bursts but I've got the welder set as low as I can get it (it's a Cebora 130). Should I be up a 'click' on the two power switches?

I guess I've just got to stick at it.

 

[steveo3002]

how about some pics of where youre trying to repair?

i tend to go with having a look with the mask up ...quick weld then look again and so on

 

[thepurpleblob]

I'd ground this down a bit to see where I was. You can see where I've been chasing around trying to fix all the holes I've been blowing. More to fix (which will create even more I expect)

 

[J.B. Welding]

getting there mate just keep at it half an hour more and you'll be done!

 

[thepurpleblob]

I have to stop every ten minutes to put the kettle on... otherwise I'd attack the welder with an axe or something

 

[steveo3002]

did you cut it well beyond the scab? ive made the msitake a few times of cutting a small hole to repair only to realise its still a bit thin there

would a bright light under the car help at all?

 

[ben8vgte]

I use the overlapping tacks when I'm migging cars, drag the torch and watch carefullly as each tack starts to cool to dim glow in the mask fire the next just onto the edge of it. Also a leather jacket, hat and a somthing to lean on like an old cushion helps you get comfortable and relax, not too mention good lighting I have a magentic LED I stick on to see the weld and a headtorch mounted on my mask. Just get as comfortable as you can, good lighting and most importantly relax, if a bit blows leave it and go back to it later or you will just put too much heat in that part.

Oh and get the area as clean as you can and remove the underseal for a good 50-70mm around the weld.

 

[thepurpleblob]

I have a big 2D work light down there, so it's not too bad. If I was doing it again - which I will be on the other side - I'd cut back a good bit further. I guess it's a classic rookie mistake to be conservative in chopping out metal. Found out the hard way!

Head torch - brilliant idea

 

[bert]

Was doing this yesterday. I use overlapping spots too and wait a few seconds once its stopped glowing.

 

[thepurpleblob]

That's what I've been doing but it still blows quite often on the 'new' bit. Probably just a matter of sticking at it and more patience.

 

[bert]

If it still blow then the metal is a little thin so patience is needed. Try turning the machine as low as you can whilst still getting penetration.

 

[thepurpleblob]

Right - thanks everybody. It appears I'm not being completely mental. More making life difficult for myself by the look of things. A good learning experience if nothing else!

 

[Richard.]

I'm surprised this has not been asked or maybe I'm missing something but what is your set up, what wire type, size , gas/gasless , type of gas if your using it.
Then we move to the machine what is the minimum setting on it and what are you finding the best results with regarding heat/wire speed. These things need to be bang on if your to have any chance. Also I particularly liked the advise given from ben8, those instructions are also a must if your to be successful.

 

[thepurpleblob]

Fair comment...
- It's an old Cebora Turbo 130, modded to a Eurotorch
- 0.6 wire
- Hobbyweld 5 welding gas
- welder is set to the minimum setting which is 30A I think
- the wire speed is about a 3rd of the way up which works fine on the bench (at least). I'm a bit unsure about setting wire speed thb