Arc welding 0.8mm sheet steel

[GeorgeB]

I'm pleased with my attempts so far at using my £19 Wolf arc welder to fill in holes in car body thickness steel sheet. I'm using 1.6mm 6013 rods and have only a few minutes experience so this can't be very difficult. If I can do it, anyone can. The only special step I took was to flatten out a bit of 22mm copper pipe and put that behind the sheet. It serves to conduct away heat and, with the work horizontal, it means any puddle of molten metal can't really go anywhere, so it must reduce the chance of blowing holes. I like the fine control I appear to get with the tip of the arc rod. Slag is a non-issue. It just come away. The welds are far from perfect and might not pass any British Standards but the end result is good enough for my needs. Here's the first hole I plugged by cutting out a small rectangle of steel, then I filed it down to an oblong, to fit the hole:

Then I tack welded it and decided that was all I needed:

Next I cut and filed down a circular bit of metal to fill a hole. I tried to sort of seam weld this and nearly succeeded. But at '9 o'clock' I blew a small hole, which I subsequently filled (no problem). Also, there's a shortfall around '11 o'clock, but overall it's strong enough for my needs. Perhaps the hole resulted from the copper not being right up to the steel at that point.

Here's the reverse. If anything, there is insuffient penetration, rather than too many holes, but that's the least of my worries:

Finally, here's a hole which I plugged entirely with the steel from the arc rod, rather than by using a plate. This, and the earlier weld have been filed down a bit but never were very proud of the surface:

I also have a MIG welder but I hope I won't need it. The cost of gas and the much larger storage size of the MIG welder put me off, together with the likelihood of wire feed issues. I will press on with the arc welder before I even try out the MIG welder. Arc welding strikes me as cheap to buy, cheap to run and dead simple.

 

[runnach]

Geeeeez, of course it is easy to MMA weld, have you tried TIG yet? It's a dawdle too, take a look at this guy, he has put a new dimension on the meaning of positional welding!!!

I wonder how he manages to keep his pencil in his pencil holder???

http://www.youtube.com/watch?v=SeXQkuvoHWM

 

[malcolm]

I'm guessing that's an AC only arc welder too! Amazing to get that far with it on 0.8mm sheet. With small stuff like that the rod must be tricky to control. I wonder if AC only could actually help on really thin stuff.

What technique did you use? Non-continuous welding? Would be really impressed if you can create a weld with no holes or gaps left in.

 

[GeorgeB]

What technique did you use? Non-continuous welding? Would be really impressed if you can create a weld with no holes or gaps left in.

Malcolm - yes it's a very simple, AC only 'buzz' box as some people call them. Its simplicity is part of the appeal for me, in that there doesn't seem to be much to go wrong. As most people correctly predict, it does tend to blow holes on 0.8mm plate if you try welding without a heat sink, but add a small piece of copper to the back, and all that changes. The next thing I must try is a straight continuous length of a few inches, also with 0.8mmm sheet.

The tack welds were done one at a time. The three-quarters round weld was done all in one go, except it blew a hole at the end which then had to be filled. I don't know where the small craters came from in the first tack welds but once it was filed down and a bit of body filler was added, it looked fine, and seemed strong enough.

I also have a cheap DC inverter and, at first, I preferred that because it's easier to start the arc. But I seem to have learned the knack of starting an AC arc so that's no longer such an issue. It occurred to me that the pin point of an arc rod may be easier to position than the large head of a MIG welder but, as I haven't tried the MIG welder yet, I don't know. The quality of the AC welds seems better than the DC welds, so I've given up on the DC inverter for the time being. I'll keep the DC inverter for an attempt at cheap TIG welding.

 

[shenion]

If you can find some 1.6mm 7014 rods you will find it much easier.

Also try the inverter on DCEP, it will put less heat in the metal and you can keep the current up to help prevent slag inclusion.

 

[GeorgeB]

If you can find some 1.6mm 7014 rods you will find it much easier. Also try the inverter on DCEP, it will put less heat in the metal and you can keep the current up to help prevent slag inclusion.

Shenion - thank you very much for your suggestions. I will try and find some 7014 rods. What does DCEP stand for, please? I have only a cheap Chinese inverter but it works well as far as it goes. I fnd that the more current I use, with either welder, the easier the slag separates but, honestly, slag has never been an issue for me, at least for the modest standards of 'finish' and appearance which I seek.

 

[GeorgeB]

Before I try laying down a continuous seam, what's the basic approach for laying down the classic overlapped 'shell' look on arc or tig welds? Do you pause to lay down each 'layer' then move on to the next one, so the layers lay on top of each other, rather than look like a single seam, like in most MIG welds?

By 'overlapped shell' look, I mean the type of appearance shown here from expert Engloid's site, not that I will EVER be able to achieve anything 10% as good as this:

 

[shenion]

DCEP - Direct Current Electrode Positive

Basically, connect the electrode to the + terminal of the welder. Normally on DC welders, the electrode is negative.

I found 6013 rods hard to use on thin metal. Slag inclusions became a big problem. Flat, butt welds were not bad, but inside corner welds were near impossible. I had a thread on it here. Basically, since it was so thin and you had the current low, the slag cooled too fast and the rod did not have enough heat to burn through it. If you increased the amps to keep the slag fluid, you blew holes.

In the thread I was doing 1.1mm steel. I could do flat butt welds with no problem and no heatsink on the back. You can see the bad slag inclusion problems on the inside corners and how the 7014 rods made a world of difference. I bet all the odd pits and rings you have will go away.

 

[Drains]

George, you'd not normally try to do that on arc welds. You could do it I guess, in the manner you suggested - pausing to add extra filler - but it's pointless. A good strong arc weld will look good anyway.

On tig, it's just a function of one method of tigging - make weldpool, dab filler, move on... You'll also see on Engloids pics some totally smooth tig welds too. Different technique.

Just my opinion, but the overlapping dimes look favoured by american chop/car folk is overrated, and by no means as strong as a properly done weld. You won't find the technique in any welding manuals.

The exception is aluminium tig welding, where it is the norm.

 

[GeorgeB]

Simon - many thanks for your excellent clarification. I hope I understand now, that it's partly for choice/aesthetics. I guess my bicycle frame is alumimium and the overlapped effect is very obvious and neat on the frame joints. Is there a recognised name for that style of welding finish?

 

[Drains]

Simon - many thanks for your excellent clarification. I hope I understand now, that it's partly for choice/aesthetics. I guess my bicycle frame is alumimium and the overlapped effect is very obvious and neat on the frame joints. Is there a recognised name for that style of welding finish?

Dunno

. "overlapping dimes"?

Cheers George

Si

 

[Sparkey]

Eeeerrrrr.... can any of you nice gentlemen explain to me the difference between the buzz box??? and the inverter??

 

[snowcat]

Eeeerrrrr.... can any of you nice gentlemen explain to me the difference between the buzz box??? and the inverter??

A/C buxz box old fashioned nasty air cooled overheating lump of scrap, Inverters sex on legs, HTH

 

[Sparkey]

A/C buxz box old fashioned nasty air cooled overheating lump of scrap, Inverters sex on legs, HTH

funny, snowcat!
but i wasn't joking...
(heh, my arc welder is a buzz box then! it fits your description perfectly!!)

 

[GeorgeB]

A/C buxz box old fashioned nasty air cooled overheating lump of scrap, Inverters sex on legs, HTH

That's not the way I see it at all. Perhaps we'll have to agree to differ. It's interesting how different people can take such different views!

My £19 Wolf Arc welder is still a bargain at todays price of £29 as featured on another thread. It consists of little more than a single transformer, which looks very well made, to me. I reckon it should last almost for ever, as long as it doesn't overheat. With my low-current test welds, the transformer hardly gets warm. It's simple because it doesn't need to be complex. There's nothing old fashioned or nasty about it.

Inverters are made of a mass of electronic components.This allows more features but there is so much which can go wrong. I'd give mine 2 or 3 years before something blows. I'm not knocking it, as it should be fun to try TIG welding. For basic welding, I still reckon the arc welder is the better bet.

 

[shenion]

I have used those cheap 100A arc welders. Work, but a world of difference from a good welder.

Hard to start, low OCV. If I was to get a cheap one, It would be at least 200A.

Inverters are much nicer as they are DC. DC is much cleaner and has a more stable arc. A Good AC/DC transformer one would be good too. My Airco on DC is near spatter free, easy to use.

 

[Sparkey]

Transformer?????Inverter?????? aaaaaaaaaaaaargh!!!!
heh, AC/DC is a rock band right?
HELP!! can you explain the difference Shenion? pleeeaaaassse?

 

[SRG WELDER]

look at it this way small and light "invertor" . heavy a F**k "Transformer" :-)

ste .

 

[shenion]

Transformer - old-school, lots of iron/copper.
basically a big transformer and inductor for AC
add rectifier for DC.
Simple and reliable

Buzzbox - AC only version of above.

Inverter - Uses switching power supply for DC output. Where transformers run at 50/60hz, switching supplies run at tens to hundreds of kilohertz. The high frequencies allows the transformers, anc capacitors to be very small and light.

Also, the high frequency means there is only a very short time between current pulses. Requires much les filtering to maintain arc over 50/60hz.

Inverter is an inaccurate term, especially if the outout is DC. Inverters are used to generate AC from DC. "Inverter" welders do the reverse. More accurate would be "Switching power supply welder."

 

[Wozzaaah]

Sparkey, an inverter welder can weigh as little as 10 kilos or less, the equivalent transformer machine would probably be somewhere in the region of 20 kilos or more, they contain an awful lot of coiled wire rather than the inverter's electronics.