stick welding cast iron

[christofloffer]

i am sure this is a well covered subject but i cant seem to find a definitive answer. there seems to be numerous opinions as to wether its strong enough or neat enough. there seems to be a lot of folks saying it can only be brazed.
the job is a old Victorian heavy garden roller. the actual roller part has two cracks in, one that goes edge to edge and one that reaches about half way across. i am getting into using my stick welder now and i am wondering if this would be a good job to do. obviously to try and get it looking right i would want to weld it right then grind the profile down to smooth again.
is it strong enough to hold on a big roller (about 3ft diameter)?
if its going to wreck it then i wont bother and i will sell it to a restorer to do. if its viable though i would quite like to put it right.

 

[the snooper]

with cast iron you need to pre heat the object to be welded as it can crack due to localised heat from welding it

 

[gordon stephenson]

And have the correct rods, I believe nickel are recommended.
.

 

[J.B. Welding]

with cast iron you need to pre heat the object to be welded as it can crack due to localised heat from welding it

Bang on, it's quite hard to predict the pre-heat for old cast, and how far to take it on a big heavy lump like a roller. You may find yourself chasing a few cracks around here and there, but eventually it should turn out ok. An even heat/cool process is what your after, a good V.prep and correct cast iron welding rods of the right diameter.<> Don't be scared

 

[dannyp]

with old cast iron don't expect it to be easy, but how hard it's going to be is very varible deending on the actual metal it's made out of, shape, size and favor of the gods. some stuff will weld relativly easy some will be an absolute pig and really slow going. other stuff just won't have it no matter what you do.

i woudl suggest getting some dcent nicel rods, clean up a small patch and apply a mild bit of warmth on such a big thing your never going to get it hot enough to weld it the hot way so don't try it'll ause more problems, just take the chill off it, you want to be abel to touch it after heating, then put a small weld in like 1/2 inch . once it done gently peen it then listen for pinging sounds, if all is quiet all is good.

you can then start to stitch it together with short welds well spaced out. but go very slowly, maybe 1/2 weld every 4 - 6 " then leave it to cool for a while, then another 1/2 of weld on the end of each weld and leave. if in dought as to it been to hot leave it. get it to hot and your back to stage 1. i tend to do a few stiches every couple of hours throughout the day. and if it takes a few days or a week that how long it takes

 

[christofloffer]

wow, those rods are pricey!
ok i will take it on myself and i'll try and find a couple of other projects to do. that way i can buy a bigger pack.
going to leave it for now though, and get some more practise in with the welder. they are far too expensive to waste on poor technique so i will wait until i am more confident on the results.

thanks for the info guys.

 

[MattF]

With that partial crack, just drill a small hole at the absolute end of the existing crack. It'll just stop the crack from progressing any further.

Bearing in mind that I know chuff all about welding, I'd personally be more inclined to have it brazed, simply for the fact that it's easier to tidy up afterwards. You can subtly file braze, whereas most weld I've come across is a dog to file, and grinding takes some doing to be done subtly, especially on a curved surface.

 

[JDJones]

Hi Christo
Go to top of the page, click Arc welding, page down to cast iron, tells you exactly how to do the job also the reasons for carrying out the process.
The nickel electrodes are easy to use ie striking the arc and flow smoothly but will encourage you to push on quickly a very large roller like yours will take some time to COLD WELD, try to have some insulation handy to slow down cooling and maybe a hot sunny day outside would help, anything you can think of.
Be patient take your time and good luck Des

 

[Bill Edwards]

It's very easy to do and very strong - more than adequate for a roller.
To make a decent job and avoid cracking don't preheat the metal, just weld it a bit at a time. Keep the whole thing cool enough to be able to keep your hand on it, and once you have done a weld peen it while it cools - this is important.
Done properly it always works.

Yes, rods are expensive - the best part of £2 each. Make sure to get good ones.