Thread: Slag holes- newbie help

hi mate,

i wouldn't weave quite so much, cut it way down to about a mm or 2. also when you say you are circling, when you weave side to side 5-6mm are you also jumping forward 5-6mm in big leaps/circles? try just moving at a steady pace, just barely shuddering from side to side over the joint and see if you get any better results

Originally Posted by Corgan

hi mate,

i wouldn't weave quite so much, cut it way down to about a mm or 2. also when you say you are circling, when you weave side to side 5-6mm are you also jumping forward 5-6mm in big leaps/circles? try just moving at a steady pace, just barely shuddering from side to side over the joint and see if you get any better results

+1... yeah make sure your 'weave' is always at the leading edge of the puddle - not going back over old ground so to speak. Why weave at all though? Cheers - Mick

Yeah I would try no or very little weave. I think if you are getting slag holes on your first pass you may need to up the power a bit. It's a juggling act getting enough current in there to weld the two edges together and not blow through which is controlled by your travel speed vs current.
I don't know exactly what current I stick weld with because I sort of just wind it up until it's working for me, but possibly a starting point would be around 80 - 90 amps for 2mm steel.
And the less the angle of the joint the more power and bigger the angle back the power off a bit.
Just hours on the torch and try different things will help a lot.

Originally Posted by fatty500

So I'm trying to butt weld some 2mm square tubing for racking.
Currently using an el cheapo AC stick machine set at about 50-60 amps, 2mm 6013's, flat on the ground, dragging angle half way between 90 and 45 degrees, weaving/circling about 5-6mm wide pattern, arc looks to be short - the bead is flat. But I'm getting slag holes, sometimes a few over a 5cm joint. What am I doing wrong? Am I weaving too aggressively or too wide. Maybe I'm burning through occasionally.

I've tried to make a second pass on higher setting, say 70-80 amps to fill in the hole/pockets, but it doesn't always fill in- the bead gets fatter but the hole isn't filled .

The joint needs to be strong; do filled in slag holes weaken it much?

Thanks

Fatty.

Why are you using 2.0mm electrodes? They are much harder to use, (far more prone to slag inclusions as you have discovered), than 2.5mm in my experience.
My recommendation would be a good 2.5mm E4112 electrode at around 75 amps-use as much power as you can and definately do not weave, there is no need. Obviously the better you fit your joints, the easier it will be. I am a great fan of E4112's for thin tube work as the viscous, fast freezing slag is of great benefit when performing out of position work, (vertical down).
Many of the 2mm electodes one comes across are of the chinese persuasion and I have found that many of these produce copious amounts of slag that can be very challenging to deal with, even for an experienced welder. One stand out 2mm electrode I have found is the Murex Speedex 12 and I have used these to weld 19x1.2mm galv conduit, these are also available in 2.5 and 3.2 mm sizes and are one of my favourites. As a bonus they are also much cheaper than many of the big name offerings.

go for 2.5mm electrodes, 65 ampres is ok, keep your arc length at a good length, not too close, watch closely and you will see the weld pool swirling, thats a good thing if it does, if your getting slag inclusions clean your lens and have a good look at the weld while your laying it down and you will see the two halves not meeting in the middle as you weld. no need to weave, if you get slag inclusions sharpen an electrode and pick it out. good luck.

Many thanks for all the help.
I've had a few more practice runs with no weaving, or as little as possible- just slowly straight down. About half have come out looking great , shiny bead, flux comes off easily, no holes. The other half still look a bit dodgy, mostly from sticking mid weld. Can anyone advise why this happens and how to stop it. I think it's from having the electrode too close to the metal; maybe the amps are too low, but I really don't want to burn through.

I'll have to get a box of 2.5mms and give them a try.

Cheers,
Fatty.

if you can get your hands on stainless electrodes (off a mate, for free) give them a go (2.5mms) you can run them at lower amps then a gp and get the same result, that is if you are using a gp and what sort? cheapo chinese ones are pretty ordinary so, don't expect too much if thats the case. if you do have a mate in the welding game see if he can score you a few Fe22, iron powder electrodes , great for a down hand and the slag peels off like you wouldn't beleive.

as for the slag sticking in places could be the type of rod your burning or your getting over roll in places ( electrode too close ) but then again with under cut (arc too big) a slight chanel is cut in around the edge of the weld and the slag likes to stick into it, take a close look at what your getting and just practice.

Dont weave at all just try to go straight keeping the bead width the same as you go along the electrode should only be slightly back off 90 degrees. If the rod is sticking you may need to increase your arc length a bit, but it should still be pretty close to the steel just slightly off it. You can get slag holes from to long an arc length but if your rod is sticking to the steel when it is to short the slag tries to go past where you are welding.

Is the steel galv if so remove the galv at the joint