Hello friends,
Haven't been around lately. Leave it to an old friend to come around only when he needs something.
We have a cast iron engine block with a threaded bolt hole. Half of the surrounding iron is broken off. The broken piece is long gone. My first thought was to build up a new boss around the hole. Since 309 rod has been my go-to filler for most ferrous metals I imagine it might do the trick. Here's a crude pic of the hole. Hopefully you can zoom in and see the remaining threads.
After the metal is built up around the hole it can be drilled and a heli-coil insert installed.
Now what say the experts?
Don
I know this will sound cheesy, but if it is not a hole with a lot of load or stresses, I have seen success with JB weld build up and then drill and tap the hole. Although never in a direct application as this.
One thought on the 309. I believe it will work, but it will be a hard material to drill and tap, especially if you cannot get to it very well.
What say the others?
-Jonathan
I suppose that is plausible, but if it is a block worth saving, then it must be worth something, and the owner shouldn't mind buying some Nickel99 (I believe it is called), a brand new drill bit, and a brand new tap.
I just dipped into tig welding cast iron for the first time the other day. I welded a crack on an old cast iron carburetor bowl with 309 rod. It turned out fine but I had a hard time facing it off with a flap disk compared to a mild steel weld with E70S2 rod. It worked great but it was one of those practice pieces as i call them. If it works then great, if not we had an extra carb on the shelf it was just good practice but it worked for me. I didn't pre heat or any thing I just went at it but like I said I was just filling in a leaky crack.
It's always best to build your own, especially when it comes to hitches!!!
Matt
Oscar wrote:I suppose that is plausible, but if it is a block worth saving, then it must be worth something, and the owner shouldn't mind buying some Nickel99 (I believe it is called), a brand new drill bit, and a brand new tap.
I have posted this before, but this is a rod I have had a 100% success rate with so far. The only two draw backs I see are cost and slag inclusions/porosity in such a small area to build up. It will probably work as well.
Oscar,
I believe this is what you are referring to. http://www.use-enco.com/1/1/44657-erni9 ... -rods.html
-Jonathan
Attachments
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Last edited by Superiorwelding on Mon Apr 28, 2014 11:18 pm, edited 1 time in total.
Building up that much 309 is not likely to succeed. The repeated shrinkage from the built-up layers will cause cracking out.
How much load does this lug see? Would it be possible to clean, flux, and tin the broken surface with silver solder or bronze, insert a bolt with matching threads, build a tinker's dam (yes, that's a real phrase), pre-heat, and pour bronze to it? This would save the heli-coil step.
The Ni99 rod will be successful, but with more caution in pre and post heat, and more careful work in aligning the new threads.
Otto Nobedder wrote:Building up that much 309 is not likely to succeed. The repeated shrinkage from the built-up layers will cause cracking out.
Steve S
Steve,
Even if he let it cool between passes, do you think it would still crack? I don't think I have ever built up that much 309 so I can't speak from direct experience.
-Jonathan
Otto Nobedder wrote:Building up that much 309 is not likely to succeed. The repeated shrinkage from the built-up layers will cause cracking out.
Steve S
Steve,
Even if he let it cool between passes, do you think it would still crack? I don't think I have ever built up that much 309 so I can't speak from direct experience.
-Jonathan
I believe it will. I've done this on cast steel, as well, and suffered cracking from several layers. This doesn't mean one can't chase the cracks... grind and re-weld each time as needed, but it gets frustrating after a bit.
Perhaps a better approach would be to "butter" the surfaces with a couple layers of 309, and then build with e70S-6 MIG in short bursts? One could then use a carbon rod, like an arc-air rod, in 3/8, to build on, so the bolt hole is at least partially formed.
Just trying to imagine what I'd try, if this task were handed to me...
Otto Nobedder wrote:Building up that much 309 is not likely to succeed. The repeated shrinkage from the built-up layers will cause cracking out.
Steve S
Steve,
Even if he let it cool between passes, do you think it would still crack? I don't think I have ever built up that much 309 so I can't speak from direct experience.
-Jonathan
I believe it will. I've done this on cast steel, as well, and suffered cracking from several layers. This doesn't mean one can't chase the cracks... grind and re-weld each time as needed, but it gets frustrating after a bit.
Perhaps a better approach would be to "butter" the surfaces with a couple layers of 309, and then build with e70S-6 MIG in short bursts? One could then use a carbon rod, like an arc-air rod, in 3/8, to build on, so the bolt hole is at least partially formed.
Just trying to imagine what I'd try, if this task were handed to me...
Depending if it's only a fixing hole for someting like an oil pan or bracket (nothing structural) you might get away with not welding, but brazing/filling it with silicon bronze and then drilling and re-tapping it?
Thanks AK, Jonathan, Oscar, Matt, Steve, Arno.
Can't tell ya how much I appreciate your input. This forum is stocked with some people of character and is a great resource for wanna-be welders like me.
The guys are pulling that engine. We will get a better look at the damage soon. The hole is for an engine mount. 2 other bolts hold the mount to the block. The main stress on the repair should be the purchase pressure on the threads axialy. The aluminum engine mount brackets are designed to break on impact to protect the cabin from intrusion by the engine. Lateral stress should be minimal. The possibility of brazing a nut behind the original hole would depend on access to the back side of the threads. We shall see. More photos soon.
Don
