Welding Cast Iron

[henry Kadzielski]

Good afternoon gents.
Just an update I also tried to weld up a CI water cooled exhaust manifold. This also proved unsuccessful. Blasted the manifold in the blast cabinet to remove the contamination in the offending port. This much better revealed the crack, used a die grinder with small tungsten cutter to grind the affected area and welded it with Nickle electrodes. 1st run fizzing and much porosity in the weld metal as well as the flux. Again ground back and tried again, this time after testing the electrodes are OK, upped the amps to 120 and weld much better. Thsi all proved to be nought, as the CI would crack just some where further, as was evident on pressure testing.
Access inside the exhaust port was poor which didn't help, but, some you win and some you loose. This time I lost
Brand new genuine manifold coming up, thankyou

 

[HughF]

All my cast iron repair work has been done with oxy-prop and brazing rod...

 

[Screwdriver]

Well, I guess I ought to share the result. There is more to come but this is a cracking video.

S.

 

[eSCHEn]

Ba dum tiss!

I thought you very reserved in your choice of swearing

 

[Screwdriver]

Haha. It's virtually the first time for everything so constructive criticism is more than welcome.

I kinda know what went wrong. That plate is too thin and too fragile to take a weld unless the whole thing is hot. Very hot. And because it's thin it cools quickly. Bit later on I tried welding it hot and you can tell just by watching that it would have worked too had I been able to keep the propane torch on it at the same time as welding...

But I don't want to give the game away. Editing the next session now.

S.

 

[Hood]

I am certainly not an expert in cast welding, probably only done 20 CI repairs in the time I have been welding.
Have never heated anything, just used stick and never done more than 10-15mm before I peen. I use a small ball pein hammer and am very gentle with it, just letting it fall under its own weight from a few mm above the weld, much lighter touch than you were doing. I peen for a good 2mins before I put in the next 10-15mm weld.
Never had anything crack but maybe just been lucky with the type of iron being repaired.

 

[Screwdriver]

Have you ever welded anything like the above? It's about 2-3mm thick.

S.

 

[Hood]

Yes, did a housing for a pump a month or two back, certainly no more than 5mm thick and parts were maybe 2mm..

 

[Screwdriver]

Hmm. I think the big problem was that it was flat so has no strength at all when it distorts. Would the housing have been a shaped piece?

I have seen a fair few vids during my research (into the Swindens repair some time ago) and received wisdom tells me some castings just won't weld. Later on with this piece, I discover some spider-thread-like, glassy hard inclusions when I try to grind the casting.

 

[Hood]

It is hard to put in words so will do a quick sketch and post in a bit.

 

[Hood]

Actually I can't even remember exactly how the main part of the housing was shaped but the bit that was broken looked like this, black lines where the its were broken.

 

[mpats]

Sorry your repair didn't work out first time round Screwdriver, but on the plus side I did enjoy your video and have subscribed so I can see the successful repair.

 

[Hood]

and received wisdom tells me some castings just won't weld.

Yes I think that is probably true, most of the stuff I have done has been from old machine tools, covers, guards etc so probably reasonable quality.

 

[Gritineye]

Nice video, obvious question but why didn't you just screw it together?

Snigger....

 

[Screwdriver]

Nice video, obvious question but why didn't you just screw it together?

Snigger....

Same reason I didn't just get the oxy kit out and braze it. I wanted to have a go...

Just practicing my editing skilz and generating a workflow, getting started really. I mostly do motorbikes but there's a Bridgeport to reassemble, I want a forge and a furnace too. Lots of projects on the go and I am doing this to try and motivate myself into getting it done.

Oh and I'm gonna need a decent stove!

S.

 

[Monkey Harris]

Brandon has a go...

 

[Richard.]

Well done mate you gave it a shot and that's what counts.
I think you were on a battle to nowhere with that welding it cold. Like you said in the vid the part was quite hot which is bad news if trying to weld cold. Uneven expansion has caused the break. I use both the cold and hot method and it really does depend on the size and thickness of the part.
I would of still happily welded that and hoped for sucsess but it's never guaranteed but I'd of spent time getting it very evenly hot before hand and allowed to cool over many hours after.
As Al said some grades just don't weld. In this case your flogging a dead horse.

 

[Screwdriver]

Thanks for the comments. If you thought my welding was bad, watch this!

I think that's the last for now. I need to finish off (!) the rest of the stove which will probably end up in a different thread.

S.

 

[Bsmith]

I would vee out the cracks on the other side and also braze them. Clean besides the cracks well and braze at least 1/2" wide. I don't think braze will stick to where there is nickel.

 

[WorkshopChris]

What did you film that with nice and clear with good sound, often YouTube videos suffer with poor auto focus.