Interested in Language
Checking of condition.
Valves may be re-used without refinishing when:
* by inspecting cracks, using illuminated magnifying glass or powder-spraying procedurę and/or in the flux procedure, no crack formation is established at the valve cone face.
Shouldn't it be: * by inspecting FOR cracks, using illuminated magnifying glass or powder-spraying procedurę and/or in the flux procedure, no crack formation is established at the valve cone face.
No, because you're looking at the actual cracks, not looking for cracks. As long as the cracks aren't on the valve cone face, the valves can be re-used without refinishing. However, during your inspection of the crack, if it extends to the valve cone face, then you'll have to refinish the valve.
You inspect the crack by using an illuminated magnifying glass, powder-spraying procedure, and/or the flux procedure.
Without some more context, I can't tell you exactly what the flux procedure involves. A flux can be something to retard oxidation during melting, or it can be a process meaning to wash out.
I suspect the latter for inspection purposes, but again you'd need to reference the text regarding what exactly the flux method entails. Feel free to post that text if you need help interpreting what it involves.