cast ?

[bluebobtail]

Hi a quick one here,
Can i weld cast iron with or at least i think it is, how can i be sure for definite what it is.
Its for a non structural piece. Its just a pivoting lever that moves a plunger back and forth against a spring.
Its lifted by hand with very little effort now the pin isn't seized.
Any ideas or is it just a case of pre heating with a v prep all the way round?

 

[Tigman]

to test for cast iron , put a grinder to it and the sparks are dull not bright like steel !

v prep is good but depending on the thickness pre heat may not be required !

are you stick welding this , what rods are you using ?

 

[gordon stephenson]

You could always V it and braze if you have gas bottles.

 

[TechnicAl]

You can weld some cast irons. Unless you go to some expense its difficult to tell them apart so you have to assume its a weldable one until it cracks and falls to bits.
If its not an important part you could try getting it hot and using a 7018 or a 7016 rod. The hotter the better.

Ideally you should use a proper cast iron iron rod and do it cold.

 

[bluebobtail]

Thanks for your replies, I only have MIG tig and mma, no gas bottles. Don't really want to buy some special rods as its a one off. Could I try preheat then tig it with mild steel rods, or preheat and just MIG it ?

 

[dannyp]

you can buy cast rods in small packs, a 5kg pack is rather expensive

 

[TechnicAl]

Thanks for your replies, I only have MIG tig and mma, no gas bottles. Don't really want to buy some special rods as its a one off. Could I try preheat then tig it with mild steel rods, or preheat and just MIG it ?

You could try to TIG it but you will need some good gloves. You need to get it really hot first.

MIG might be less of a problem.

 

[shenion]

There are small packs of cast rods. Stainless filler will work too.

I did a vice using 7018 rods and it promptly broke due to dilution into the weld and causing it to be brittle (was very grainy.) Redid it with proper rods and no problems.

 

[bluebobtail]

Thanks for that, I'll give it a go, i have some stainless filler

 

[Engineer]

TIG brazing works very well on cast iron, and can even be used to repair cast exhaust manifolds, which are sometimes very difficult.

 

[bluebobtail]

Thanks for everything.
Have got the part welded up it works sweet as a nut.