Checking for cracks

Gliden07

Gliden07

Well-Known Member
I read a recent post on here that questioned the use of used steel for knives. The question I have is could you Magna-Flux the steel to find cracks? I know they have dye kits for around $70. I don't know how cost effective it would be and I don't know how much steel the kit would do. But has anyone considered this other than me over thinking stuff! LOL!!
 
A much easier/simpler method, and one you can do on any profiled blade material..... balance it on a finger, the tap it with another piece of steel..... it should "ring" like tuning fork (whether heat treated or not). If there is a dull "thud" then there is a crack, break, or some type of inconsistency with the piece....toss it.
 
EdCaffreyMS said:
A much easier/simpler method, and one you can do on any profiled blade material..... balance it on a finger, the tap it with another piece of steel..... it should "ring" like tuning fork (whether heat treated or not). If there is a dull "thud" then there is a crack, break, or some type of inconsistency with the piece....toss it.
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I've never heard that one. Might be a good test on any knife.
 
The problem with dye is it would only show surface cracks where the dye could penetrate. Internal cracks wouldn't show up - would they? I would expect the cost of Magna-Flux to be fairly expensive - not sure. Perhaps the OP has an idea of cost?

Interestly they mentioned the "ring" vs "thud" on FiF last episode.
 
KenH said:
The problem with dye is it would only show surface cracks where the dye could penetrate. Internal cracks wouldn't show up - would they? I would expect the cost of Magna-Flux to be fairly expensive - not sure. Perhaps the OP has an idea of cost?

Interestly they mentioned the "ring" vs "thud" on FiF last episode.
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The dye kit looks to be about $70.
 
EdCaffreyMS said:
A much easier/simpler method, and one you can do on any profiled blade material..... balance it on a finger, the tap it with another piece of steel..... it should "ring" like tuning fork (whether heat treated or not). If there is a dull "thud" then there is a crack, break, or some type of inconsistency with the piece....toss it.
Click to expand...
Good tip and looks like it saves about 70 bucks. :D
 
Well I've never done it and posed the question to see if any had. When I was building engines they would use a fine Magnetic powder and and strong magnet to find fine cracks in engine blocks. The die looked like something that would work?
 
Gliden07 said:
Well I've never done it and posed the question to see if any had. When I was building engines they would use a fine Magnetic powder and and strong magnet to find fine cracks in engine blocks. The die looked like something that would work?
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Dye penetrant and developer is fantastic for finding basically anything that is not perfect. Application may take some practice depending on your surface. But we use stuff that is certified for nuclear applications. It will usually find porosity in a weld.
 
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