MTFCA Forum

What would be the best rod to use for welding a small crack in an engine block base?

Earlier I was told mild steel, but I forget the number.

Recently, I was told stainless steel.

Now a guy wants to use nickel that is a lot more expense.

If you can gas weld the old 1/4 rings work really well recycle the old iron.

If cracking of the perimeter of your new weld results, you may use nickel cadmium rod. I use it for early drawn rear end housings and engine pans, for this very reason.
Regards,
Scott

The stainless rod with tig also works well for me. I used 308 rod.

If you are using a TIG welder... you may consider using silicon bronze filler rod. Sticks well to cast iron, and requires far less heat as you don’t liquify the base metal

J1MGOLDEN wrote: ↑

Tue Dec 07, 2021 1:25 pm

What would be the best rod to use for welding a small crack in an engine block base?

Earlier I was told mild steel, but I forget the number.

Recently, I was told stainless steel.

Now a guy wants to use nickel that is a lot more expense.

I hope that it's not his first welding job on cast iron?
Main thing is to preheat the area to be welded.
Kevin Pharis mentioned to tig weld with bronze.
This procedure works really well and doesn't work harden the iron. This example is one we did on a 312 Ford.

You must be careful with the silicon bronze if you intend to machine afterward. I’m not sure if it’s carbides being formed or nickel getting pulled out of the iron... but I’ve found my share of impossibly hard spots imbedded in the bronze

J1MGOLDEN wrote: ↑

Tue Dec 07, 2021 1:25 pm

What would be the best rod to use for welding a small crack in an engine block base?

Earlier I was told mild steel, but I forget the number.

Recently, I was told stainless steel.

Now a guy wants to use nickel that is a lot more expense.

My experience is to stay away from the welding rods. Makes it much harder to grind out and braze it up properly. The nickel makes you remove more cast iron when trying to fix the awful boogers! IMHO.

If you are planning to stick weld, I recommend a soft rod such as 6011 or 6013. I used to successfully weld engine blocks and heads in the 1960s. Haven't tried it in 50 years.

Preheat

Weld for a short time.
Immediately after stopping, strike the weld with a chipping hammer with a sharp point while the bead is cooling. This reduces the shrinkage while the Bead is cooling. Make sure the slag is removed.

Start welding again with the same procedure.

Make sure all oil and grease are cleaned off all nearby surfaces otherwise the heat will induce hydrogen imbrittlement.

Good luck.

Art Mirtes

When I have welding jobs about which I am uncertain, I take the job to a pro, especially if cast iron and subsequent machining/drilling/tapping are required. It saves me stuffing it up and perhaps making it worse.

Allan from down under.