Tig cast iron

[Portable]

Got a Bbq grill
cracked
can i just tig it with no filler?

[Oldgrandad]

Probably Not. I would groove it a little and use either stainless or silicon bronze rod because they are the best choices out of the rods I have in house. That being said you have nothing to lose by trying a fusion weld first.

[ryanjones2150]

I think you will be sad if you try to fusion weld it. To me, the idea is to melt as little of the cast iron as possible, none of it if you can. I have had great success with aluminum bronze, tig brazed using AC. The cleaning action of AC helps burn the schmoo out. One job I did was a repair on one of my vises a few years back and it's still holding. To me, aluminum bronze flows better, is stronger and more ductile after the repair. And because of the aluminum content, AC really helps. I generally set my cleaning action up pretty high too. Another repair I made that might be similar to what you have was a cracked banjo bracket for a small craftsman metal lathe. This bracket holds the gears that transfer power from the power head to the lead screw. Beveled out both sides and brazed her up. I ran my first bead in there and then went over it again to make sure things were good and hot and everything stuck together. Worked great.

[Ltbadd]

ryan's advice sounds good, I've used silicon bronze with success as well.

BTW it so happens that the topic of this weeks welding tips and tricks podcast is welding cast iron.

[Jayare123]

I've definately successfully tig welded cast with 309 without preheat or post or peening. Still holding today been at least a year ago and the part in question heat cycles frequently. Get some 309 and go for it

[Olivero]

Do it with 308L all the time. never fails.

[Crepe Myrtle Farmer]

Not sure about TIG with its concentrated heat on cast iron. Oxy/A would be a better process.

[ryanjones2150]

I prefer to tig braze, but only because I'm more familiar with the process. Torch brazing would sure help with the pre and post heat. Either way, I'd braze it before I welded it.

[Olivero]

I prefer to tig braze, but only because I'm more familiar with the process. Torch brazing would sure help with the pre and post heat. Either way, I'd braze it before I welded it.

What do you use to braze it with? what rod?

[ryanjones2150]

Oli...I prefer to use aluminum bronze over silicon bronze, but either will work. I think the aluminum bronze wets out better and it's stronger and more ductile. Plus using AC helps burn the goop out.

Oddly enough, had a friend of a friend call me a day or so ago and ask a similar question as the OP has presented. He needed to repair a small cast iron BBQ grate for a pit on a sailboat. As I understand it, it's an old boat and this part is not available anymore. I explained how I would repair it but that I couldn't get to it until next week. Well, he went after it with an O&A and apparently this BBQ grate has met its doom. Maybe the focused heat from the tig torch for brazing would've been the ticket, I don't know. But I hear he pretty much burned it up.

[Olivero]

Oli...I prefer to use aluminum bronze over silicon bronze, but either will work. I think the aluminum bronze wets out better and it's stronger and more ductile. Plus using AC helps burn the goop out.

Oddly enough, had a friend of a friend call me a day or so ago and ask a similar question as the OP has presented. He needed to repair a small cast iron BBQ grate for a pit on a sailboat. As I understand it, it's an old boat and this part is not available anymore. I explained how I would repair it but that I couldn't get to it until next week. Well, he went after it with an O&A and apparently this BBQ grate has met its doom. Maybe the focused heat from the tig torch for brazing would've been the ticket, I don't know. But I hear he pretty much burned it up.

Interesting, I never really had a problem actually TIG welding it with stainless but I guess keeping it below the liquidus temperature probably helps keep it from cracking and messing up.

So what, you run your torch on AC but use brazing rod?

[ryanjones2150]

Pretty much. To me, it's best to not puddle the cast iron at all if you can avoid it.