cleaning gears and bearings after dye penetrant inspection
cleaning gears and bearings after dye penetrant inspection
(OP)
Are Spot Check developer and penetrant abrasive or otherwise harmful to carburized gears and roller bearings?
In place inspection of gears in gearboxes is desired, and cleaning will be incomplete.
thanks
Dan T
In place inspection of gears in gearboxes is desired, and cleaning will be incomplete.
thanks
Dan T





RE: cleaning gears and bearings after dye penetrant inspection
RE: cleaning gears and bearings after dye penetrant inspection
RE: cleaning gears and bearings after dye penetrant inspection
RE: cleaning gears and bearings after dye penetrant inspection
Oil contamination, not so much. The cleaner, and the 'vehicle' in the developer is a middle-cut of naptha [Zippo lighter fluid], and the quantity used and not removed by wiping during the PT process is waaaay less than an ounce. Plus, the solvent flashes [evaporates] at room temp. Never seen a gearbox that runs cold to the touch.
The developer is chalk, ground to face-powder consistency and suspended in solvent [naptha]. Unremoved developer powder might act like 'jewelers rouge', but I suspect not. It is just too soft to 'lap' your steel gears. And essentially all of this white powder is easily removed with proper PT post-cleaning
The penetrant is a light oil with mysterious additives. If the PT tech applies the dye with a small brush, ALL the dye that has not wicked into cracks and pores must be removed during the PT process to allow the developer to show [only] surface-breaking defects. Nature of the PT process.
Thus the liklihood of contamination is minute-to-nil, if the PT is done to ASME/ASTM spec's. 'Spray & Pray' by an uncaring mechanic is a different story. Penetrant getting into your lube oil is a probabil;ity in that case.
RE: cleaning gears and bearings after dye penetrant inspection
Proper cleaning entails removing all surface contaminants that will prevent the penetrant from wetting the test piece surface and any contaminants that are in the discontinuity that you want to detect. Precleaning the part in preparation for testing is typically the most expensive time consuming part of the penetrant test. Improper cleaning is often the reason the penetrant test fails to locate discontinuities of interest.
Best regards - Al