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Crack testing

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Does anyone know of companies offering crack testing (I don't know how it is done?) in Merseyside area and the approx cost? I need to replace a crack tested rear hub unit (a spare borrowed from a friend) who got it at Malvern a couple of years ago. The usual suppliers do not seem to do crack tested units.
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Mike in auto repair shops crack testing is in general done with a dye and a developer. It's the most inexpensive way of crack checking.

You spray a dye, mostly light red on the part, leave it for a short time and then wipe it off. After that you apply a developer to the part and any cracks will be displayed in red.


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As Jean says, dye penetrant testing is very common in engineering workshops, we used to use it regularly at work, it came as a couple of aerosols, it would be an easy DIY job so it might be worth your while phoning around some engineering suppliers.


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  • 3 weeks later...

A "home-brewed" method of testing is:


Place the part in a moderate oven till it is heated through.

Remove from oven and coat with oil - preferably a fine machine oil .

Place back into a HOT oven and bake until the outside surfaces are "oil-free" (the oil should burn off).

Remove (carefully!) from oven while hot.

Allow to cool slightly.

Dust with talcum powder.


If a crack is present, oil in the crack will "stain" the talc.    :)

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