Home shop crack detection?

[Cord]

Have a piece of cast iron that was previously welded and the weld didn't hold. I'll be grinding it out and replacing the welds. I can see several cracks which are parallel to the original weld that will now need to be repaired as well. Once I start grinding out the welds I'll probably loose sight of these secondary cracks. I've heard of people mixing chalk with acetone, but I don't want to risk contaminating the weld. Is there something else that can be used in the home shop? Please don't say manga flux because that's prograde stuff that requires special equipment.

 

[tomplum]

Would naval jelly be an option to accentuate the crack?

 

[bcp]

One old way was gasoline. It evaporates quickly from the good surface, then seeps from the crack for a while.

Bruce

 

[tjkubota93]

Mark them with a file?

 

[rustyshakelford]

Drill the ends? Do you have any plumbers in the family?

Brett

 

[TCJatko]

How about dye penetrant? That should work; it should show any cracks. As for contamination, you're going to want to grind out any cracks for welding/brazing anyway. Be sure to stop drill ends of cracks if possible.

 

[Egon]

As suggested, Dye Penetrant in a spray bottle might be one way.

You may have to do more grinding than anticipated.

 

[Cord]

I did a little research last night and was able to find this stuff: Products | Detroit | Weld-Aid You need all three products and they're roughly $10 a can. I placed an order with Grainger and it'll be available on Tuesday. I'll report the results when available.

 

[CincyFlyer]

Have a piece of cast iron that was previously welded and the weld didn't hold. I'll be grinding it out and replacing the welds. I can see several cracks which are parallel to the original weld that will now need to be repaired as well. Once I start grinding out the welds I'll probably loose sight of these secondary cracks. I've heard of people mixing chalk with acetone, but I don't want to risk contaminating the weld. Is there something else that can be used in the home shop? Please don't say manga flux because that's prograde stuff that requires special equipment.

What is the part? If it's critical to safety, and it has parallel cracks, it should be professionally tested! I usually tig-braze cast iron, unless I can heat the whole piece, then I weld it with nickel. It's my least favorite material to weld (I'd rather weld titanium!)

 

[Cord]

Engine block