MIG welding skills

Hey guys, so i properly tried out my welder today, and I'm really impressed with how simple MIG welding can be. I got some pretty nice looking lines of weld on a flat body panel and stacking tacks is super easy. So far i have found that the lowest power setting and a wire speed of about 7 gives me the best results for this.

The only thing i had difficulty with was butt joining two pieces of metal together. Admittedly the gap between the panels was 1mm (which is probably too much right?), but I'm sure this is something that i will come up against especially when fitting something like a replacement floor panel... What is the best method for butt joining panels? more/ less wire speed? tacks?

Well i think i nearly got the answer myself from this handy youtube video...

From what the guy described it's best to do lots of quick tacks, with a larger angle and longer wire length to keep the heat down. Plus always making sure you aim for the previous tack you laid to help disperse the heat. All sounding right so far?

Plus always making sure you aim for the previous tack you laid to help disperse the heat. All sounding right so far?

Apart from this bit - sounds like you're tacking right next to the last tack you did. Should be moving around - if you were welding a circular piece for example, and you did the first tack at 12 o'clock, your next one should be at perhaps 3 o'clock, then 6 o' clock, then 9, then you might go to 1.30, 4.30, 7.30 etc. Give each tack as long as possible to cool before you put another near it.

Play with your gaps between pieces too, with a mig personally I'd probably look for around a half mm gap all round, and run a bit less wire speed to slightly bump up the heat (assuming 0.8mm wire) Aiming for a flat puddle with good penetration to minimise grinding.  Different guys will like different setups, also depends on wire size and type.  Some can run beads of weld, and get less distortion than those who tack, but tacking is generally safer.

Can also hammer and dolly on the weld as it cools, to flatten it out a bit, but that gets painfully slow.  Some guys will also use a damp rag to stop heat spreading through the panel.

And if you go to a scrap metal place, you can often find a piece of copper plate that you can use behind the weld for a heat sink, and to stop the weld falling through (weld doesn't stick to copper).

Practice is the big key, along with cleanliness of metal...

Ah yes, i didn't mean just go around in a circle. Certainly don't want to warp the panel!

No, im using .6 wire because i was told that it will help reduce the heat which is crucial for these thin panels. Do you think i should be increasing the heat???

...run a bit less wire speed to slightly bump up the heat (assuming 0.8mm wire)....

I know its probably unethical but i changed from a 0.6mm wire to 0.8mm and my welds were alot better. Easier to weld discrepancies or larger gaps and i noticed the weld as a result is alot flatter and it doesnt heat the panel as much. Also more multi-purpose as i recently made a full exhaust with the same wire. I use lowest heat setting and 25% wire speed. For thicker things like exhaust or strut tube i used like 80% heat and 50% wire speed. For thin panels i found its best to quickly zap it and have the gas turned up higher so it cools the weld. Im no expert bit its what worked for me. And make sure the area your welding is CLEAN.

I prefer the .6wire my self. Especially for metal as thin as .8.

I get far flatter beads. The welder at work runs .8

And my welder at home is .6 I much prefer my home welder. I guess that shows how welding styles can differ

Chose what works best for you.

Well I've started with .6 now, and there's no reason why, that I can think of, it shouldn't be better to use on these extremely thin metal panels we are welding...

I guess the best thing is just to get the panel gap as close as possible. That's what ill practice next.

I got a cigweld 200 and a (ebay) mars 250 mig. Both same wire and set at near same settings and results are very different. I guess its what you feel most comfortable using. Once you get proficient you don't need gaps to be 100% flush as in the real world its very common to come across scenarios were there are 2mm+ gaps. You can also buy anti-splatter spray which will help you learn. As for the size wire. Each to their own..just don't diss it until you give it a try, it may work better for you as it did for me as thicker wire needs less wire speed for the same result. And can weld larger gaps with more penetration. Yes you may need to grind back more but for a beginner i believe its easier to use. Most reproduction panels are much thicker gauge steel so that may be a consideration as well.

Try practicing on horizontal surfaces then move to vertical. Try pull welds and then learn to push, left to right or right to left, weld towards or away from you or side to side etc..eventually you will find a method that is easy for you and in no time you will be a gun. Put up some pics of your practice welds and we can help. Good luck

Well I've started with .6 now, and there's no reason why, that I can think of, it shouldn't be better to use on these extremely thin metal panels we are welding...

I guess the best thing is just to get the panel gap as close as possible. That's what ill practice next.

Makes no real difference at all, 0.8mm is just more commonly found in most peoples welders, hence my guess.  As you picked up, ideally I'd close the gap up a bit with the 0.6 wire, maybe try something like a 0.3mm gap.  I like to have a little gap when using a mig, as I find it easier to get a flat tack with decent penetration.  Think from memory Zeds are about 0.8mm thick panel steel, so a 0.3mm gap being filled with 0.6 wire should come out as a pretty low profile weld needing minimal finishing - depending on operators level of practice!  I don't like 'airtight' gaps when I'm using a mig for panels, I find it harder to pick the sweet spot between blasting everything out the backside of the panel, and having a big lump sitting on one side with no penetration.  And of course too big a gap equals more time stuffing around filling the hole, more heat input, and more time grinding...

As you're starting to see above though, everyone has their own approach... Try fiddling with all the variables, find what works for you.

K, thanks guys. I think i should be able to manage this all now. Next weekend I'll have a bit more of a go butt joining with my new knowledge and I'll report back.

I'm getting really excited now MIG welding is great!

Well I've started with .6 now, and there's no reason why, that I can think of, it shouldn't be better to use on these extremely thin metal panels we are welding...

I guess the best thing is just to get the panel gap as close as possible. That's what ill practice next.

You should find the .6 wire is better for the thinner sheet as you need less heat to weld and when working with sheet heat distortion is something you want to avoid. also with the wire are you using the standard copper/bronze coated wire or the silicone bronze wire??

providing you have some delicate areas where you need to keep the heat down to a minimum you can try using a water and rag to cool the weld area down before continuing each tack/weld

No idea what the wire is.... i thought they were all the same (besides alu and stainless wire).

Yeah the wet cloth idea sounds good.

NO wet cloth! The water will introduce corrosion into the panel & potentially make it start to rust over time...

Just use compressed air too cool the weld after the molten weld pool has solidified. 

The idea is to keep as much heat out of the panel as possible.

Also, you can't panel beat Mig weld very successfully as it's a very hard weld & tends to crack. Hence why I use a Tig now

Well that does make sense!

Eh I got the mig now, I know the job won't be perfect the first time, but I can always grind and reweld (not ideal I know).

NO wet cloth! The water will introduce corrosion into the panel & potentially make it start to rust over time...

Just use compressed air too cool the weld after the molten weld pool has solidified. 

The idea is to keep as much heat out of the panel as possible.

Also, you can't panel beat Mig weld very successfully as it's a very hard weld & tends to crack. Hence why I use a Tig now

Water works fine but blowing it with air afterwards does help. but at the end of a day im only a lowly boilermaker so i could be wrong.......

Well from my couple of hours experience that i now have under my belt i now know realise perhaps the most important part about welding.

Just like getting a professional paint job, 90% of the skill in welding seems to be preparation. In the sections where i had edges butted right up against each

other, i found welding them to be effortless, and my results were near on perfect. Where there was a gap of over half a mm, things got a little more tricky, and i really had to aim for one side, and then shoot for the other in a crisscross pattern (intermittently). The results here were not so great, but acceptable. Where the gap was over a mm I really had to work and found I had to pile on a mile of weld before it was all covered. I suspect the best thing to do in that situation is do a preliminary welding with a few holes, grind it back, and then fill in the gaps.

So now i need to learn how to prepare the panels and get them to perfectly match the holes.

It's really enjoyable this welding biz!