Arc welding tips for cleaner welding please.

You can tell if it's cast iron, when you grind it the sparks are a dull red and further disintegrate in the air, whereas steel is bright orange and they just shoor off in the distance.

Trouble is - the original item is cast iron, but it looks as if he it patching with steel, as are the rods - so he needs to know which part he is grinding.
 
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I am sure, that the sparks are orange, but not really sure as I have the welder mask on most of the time, and I can hardly see anything, even when full arc

so, I brought a lot of sticks, I believe they are different due to the numbering on the sticks, so what stick should I use for cost iron?
When welding its important to completely remove any slag from the previous bead or it will blow holes in the new run

Cast rods are usually black and expensive, I keep mine under the wood burner
 

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I will get the other bed leg off today, the gap you see isn’t really caused my me. The leg was only weld on the T part, not the butt joint, so I had to bridge the gap, which is only 1-2 mm, I think I just made the hole slightly bigger, or should I say gap.

If I do the same thing on the other side, would that be strong enough to give me another 10 years worth of usage.

I know I have some low temperature melt aluminium (I believe) that melts in a kitchen flame torch, would that be better to use?

I am going to order some cast rods though
 
I will get the other bed leg off today, the gap you see isn’t really caused my me. The leg was only weld on the T part, not the butt joint, so I had to bridge the gap, which is only 1-2 mm, I think I just made the hole slightly bigger, or should I say gap.

There is a technique which can be used to fill holes - a matter of running the rod round in circles round the hole, gradually adding metal to the edge, until it is filled.
 
For any non-expert people thinking of an arc welder - I'd recommend a non-gas mig welder. A bit more expensive but much easier to use and get a decent finish.
 
Ideally cast iron should be preheated, this helps reduce cracking.

Brazing as posted by Justin, would be an easier option.

By the way, if they were my welds.....
I would cut them out with an Angle grinder, take them in the middle of the night, and throw them in the Canal.
They would then, never be spoken of again.
 
Ideally cast iron should be preheated, this helps reduce cracking.

Brazing as posted by Justin, would be an easier option.

By the way, if they were my welds.....
I would cut them out with an Angle grinder, take them in the middle of the night, and throw them in the Canal.
They would then, never be spoken of again.


Hey…!! I have to learn some how… lol only messing around with the hey…!! Btw,

I have loads of different rod types bronze, aluminium, steel, stainless steel but no cast iron… I have ordered some and should be here tomorrow, so should be good to repair. Okay… reading this back to myself I am unsure if it’s bronze or brass now…

Is there away to tell what metal something is without damaging it in anyway? My mum has my granddads outdoor table and chairs and there is a… well chip in it that needs to be repaired.

My mum took it to a sandblaster who quoted over £800 to finish removing the layers of old paint, and over £1000 to fix and fill the damaged part. I am going to take a picture. I don’t think it’s anything that will rust due to being half paint stripped for over a year now and no sign of rust.
 
It might be galvanised. In which case, don't try welding it!

Diagnosis? Sure - first look at it for colour and think what would make sense. Basically you'll have cast iron, mildish steel, hard steels Aluminium or Al-Si alloys, brasses (Lead-copper, etc) and bronzes (Tin-copper etc and junk metal like Mazac and other cast zinc alloys. Then there are about 3 main groups of common stainless steels. Then a million others but the above are mostly what you'll see.
Platings are likely to be zinc (galvanised), or nickel, plus a few.
A magnet will sort some of them obviously. Non magnetic stainless isn't really common, other than sinks, or in sheets, and even that can be a bit magnetically attracted.. Soft.
Density comes next, then it gets more difficult. Spark analysis is a little use, but without a surface spectrometer you're guessing after the first workings-out.
ANy alloy is going to take particularly badly to being welded. It's likely to become very soft or strangely hard and maybe brittle near your weld. Steel is an alloy, but "mild" steel has so little carbon in it it's almost pure iron. But Cast iron can be stuffed with ( a few %) carbon. Go figure.
In cast iron there's spheroidal graphite cast iron which gets called "ductile" , and flake graphite which is a sod. Wrought iron is wonderful, rare now - nearly no carbon at all. The nearest you get now is recycled Ford Cortina.
You will have all manner of trade names to confuse you. EG People think Meehanite is nice fine grained cast iron and it usually is, but the company made/makes all sorts.
Many you can guess from what they are - general purpose will be mild steel ( a very v little carbon) then low carbon steels are used for garden tools say, then more carbon in things like leaf springs. All are extremely useful as scrap if you can't get reliable supplies or prefer to womble.
 
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