Welding Cast Iron

[Bill Edwards]

Thanks. Well I'm not going to get any better at stick by not doing it so I'll pop into my local supplier and see what they've got. If I can pick up a few nickel rods at a sensible price I will.

I assume since my broken lid is such a small piece, I might as well get it good and hot before I weld it, then let it cool slowly. I'll probably clamp it to a bracket and heat that too.

Would you recommend peening immediately after welding? Would you weld it all in one go in say 1-2 inch sections with a minute or so between welds?

There's a video of the job in the projects section and I'll be videoing the repair come what may!

http://www.mig-welding.co.uk/forum/threads/fancy-french-stove-restoration.67381/#post-881957

S.

You're way off with how much weld you can lay down in one go and the cooling time. Aim to be able to put your hand on it and just keep it cool. Peen the weld immediately after putting the stinger down until ready for the next run. You're expanding the weld metal as it cools (and tries to contract).
It will be slow unfortunately but don't rush and it will work.

 

[Bill Edwards]

Thing is with a good number of cast iron repairs, is the casting is likely to be dirty (an exhaust manifold or engine block for instance), and in cases like this I have always found it easier to make defect free repairs with Tig brazing rather than MMA, which is a do or die process, which doesnt offer the possibility of gently heating the area to be repaired, to assess just how dirty the casting is before making a repair.

Not so if the repairs are on new of very clean castings, but unfortunately most are neither new or clean, so its certainly worth looking at tig brazing, especially for those who have never tried it before.

My method works for old cylinder heads and blocks. It also works with old exhaust manifolds even sticking steel to CI (where the studs have gone).
Thinking about it brazing normally requires cleanliness whereas stick tends to tolerate dirt.

 

[henry Kadzielski]

Good morning gents.
May I interject here. I have been reading these post as have a cast iron job to do. This is a Volvo marine engine exhaust manifold and from the pic there is a small hair line crack in the bottom of No5 exhaust port. I have Ni MMA rods coming, so the question is, is to heat or not to heat. The affected area will be 'cleaned' correctly and as all can see there is insufficient space to TIG so MMA will be the method. Please gents any recomendations. The crack is only about 15mm long and was only discovered due to me pressure testing it. I have been told to peen the weld, which I can do with a needle scaller as can't get anything else in there. Please gents what is the process for this

 

[Parm]

I like debates like this, as many opinions as there are people involved. All right and all wrong, but most importantly they all work in thier own ways. Just goes to show how much skill, knowledge and experience there is on here

 

[Richard.]

No.
But brazing requires the part to be heated a lot, I don't need personal experience to know that. With heating is the hardest part as it must be done slowly and uniformly, there's no way to escape that.

Not tig brazing bill.
You don't heat it up you pretty much get fired into it with fill on strike up.
It's still not a method I'd adopt if I can weld it.

 

[Bill Edwards]

Good morning gents.
May I interject here. I have been reading these post as have a cast iron job to do. This is a Volvo marine engine exhaust manifold and from the pic there is a small hair line crack in the bottom of No5 exhaust port. I have Ni MMA rods coming, so the question is, is to heat or not to heat. The affected area will be 'cleaned' correctly and as all can see there is insufficient space to TIG so MMA will be the method. Please gents any recomendations. The crack is only about 15mm long and was only discovered due to me pressure testing it. I have been told to peen the weld, which I can do with a needle scaller as can't get anything else in there. Please gents what is the process for this View attachment 92549

You don't want a needle scaler to peen, just a typical chipping hammer. You only want to touch the weld and not with great force.
You probably want to do it in two runs on your job but I can't work out the thickness so aren't sure.

 

[henry Kadzielski]

Good morning Bill.
I am only assuming that it is about 4mm maybe 5mm thick. The cooling jacket water surrounds that portion

 

[Chris Stevens]

I suggest you try tig brazing cast iron, before suggesting its not as effective or fast as the MMA process. I have tried both and for most jobs tig brazing is for me the better choice.

 

[Chris Stevens]

No.
But brazing requires the part to be heated a lot, I don't need personal experience to know that. With heating is the hardest part as it must be done slowly and uniformly, there's no way to escape that.

Certainly OA brazing requires a fair amount of heat, but tig brazing isnt the same process at all, and for something like an exhaust manifold say, the heat put into the part for an effective repair is a lot less than OA.

 

[Burdekin]

Would be good to see some of the repairs you guys have done! Any pics?

Many years ago we used stick or metal spray to repair castiron, but wouldn’t know what is the best approach and what lasts the best as I just did what my boss at the time told me.

 

[Chris Stevens]

Best method of CI repair I have ever used is powder welding, but no doubt fans of MMA who have never tried powder welding, and dont have the gear, will claim that MMA is far superior......................lol

 

[Richard.]

Would be good to see some of the repairs you guys have done! Any pics?

Many years ago we used stick or metal spray to repair castiron, but wouldn’t know what is the best approach and what lasts the best as I just did what my boss at the time told me.

I'm sure I've got some pics kicking about from previous CI jobs. It's not as common as my usual trend of work but the unusual stuff I tend to take a photo
I'll have a look when I'm back home.

 

[TechnicAl]

Best method of CI repair I have ever used is powder welding, but no doubt fans of MMA who have never tried powder welding, and dont have the gear, will claim that MMA is far superior......................lol

Again you have to get it locally very hot which creates the previously mentioned potential problems

 

[Chris Stevens]

Again you have to get it locally very hot which creates the previously mentioned potential problems

Unfortunately all brazing and welding repairs on CI mean a fair amount of heat. Powder welding though is probably the one needing least heat though, as its a microfusion process and like tig brazing doesnt involve the base metal being melted. Not something I ever went further with, but I guess specialist CI repairs would be quite lucrative, and powder seems to be the way to do these?

 

[Shedendman]

I like debates like this, as many opinions as there are people involved. All right and all wrong, but most importantly they all work in thier own ways. Just goes to show how much skill, knowledge and experience there is on here

Its making a very good read i must say,learning a few things here myself

 

[TechnicAl]

There are quite a few specialist CI weld firms. I used to deal with quite a few. I never saw any of them using gas welding in any form but as I said before its a process that was used successfully for many years.
These days the biggest firms use MIG but the jobs are repeat and its always SG Iron

We actually used to use OA powder welding to reclaim some components used in wire drawing. It was build up (powder spraying) rather than repair and the thickness was more controllable with powder than any other way.

 

[Chris Stevens]

Several years ago I had a long chat with tech manager at Eutectic, who had a friend who specialised in CI repairs. These were on things like marine engine blocks which would be very high cost to replace. They would build a fire brick enclosure around the part to be repaired, preheat with gas burners sometimes for 24 hours or more, then carry out repairs using OA and CI filler rod. That was a big commercial operation though, and the beauty of powder welding is that its garden shed process and accessible to anyone with OA gear, and able to use Ebay to get hold of powder welding gear (often very cheap!).

 

[TechnicAl]

The Tech Manager at Eutectic used to be my "apprentice"

 

[Screwdriver]

Thanks. Well I'm not going to get any better at stick by not doing it so I'll pop into my local supplier and see what they've got. If I can pick up a few nickel rods at a sensible price I will.

I assume since my broken lid is such a small piece, I might as well get it good and hot before I weld it, then let it cool slowly. I'll probably clamp it to a bracket and heat that too.

Would you recommend peening immediately after welding? Would you weld it all in one go in say 1-2 inch sections with a minute or so between welds?

There's a video of the job in the projects section and I'll be videoing the repair come what may!

http://www.mig-welding.co.uk/forum/threads/fancy-french-stove-restoration.67381/#post-881957

S.

Oh well, popped over there only to discover my local little welding corner shop has closed down. Mind you, he was a right miserable b'stard.

So I bought these http://www.ebay.co.uk/itm/142118230117 and will have a crack at stick welding.

S.

 

[Chris Stevens]

Oh well, popped over there only to discover my local little welding corner shop has closed down. Mind you, he was a right miserable b'stard.

So I bought these http://www.ebay.co.uk/itm/142118230117 and will have a crack at stick welding.

S.

Seems a shame you are unable to try the powder welding gear you got from me a few months ago. That would have been perfect for the CI repair you are wanting to do, certainly a lot better than MMA.