Leakage Test by Kerosene

In automotive cylinder head testing, prior to modern pressure testing, an otherwise non-visible crack in a cylinder head that usually occurs between a cooling jacket and a combustion chamber could be detected by this process. First, an oxy/ acetylene torch is ignited, and the oxygen turned off. The resulting flame produces a very sooty flame that can literally be "flame brushed" onto the suspect surface. The resulting flat black surface is very even in appearance with no glossy spots due to the nature of the carbon black emitted by the acetylene flame. Then, after blocking off any open ports, the cooling jacket is filled with Kerosene. The entire setup may be left for several hours, or even as little as a few minutes. The kerosene will weep through the crystal structure of the metal (best on cast iron), and saturate the carbon black in such a way as to wet only the fracture line- thus indicating in detail the exact line of fracture. This is done using no external pressure, and relies only on the capillary action of fluid in a tiny space. Jim Simpson, ODD Parts Fabrication

Thank you for the explanation...this is the reason I am so happy to get the mail...

best

robert Ferreiro

Excellent post! Lots of good info.

On same above lines we kerosene leak test the welded coupon plates ( used in battle tank nose plate fabrication) of 80 mm thick or so. The welded plates are kept at fixed distance and fired with bullets on the weld surface to see whether it ( the base metal being shatter proof armored plate) will withstand the shock (impact) load.

But no acetylene flame is used here. Later keeping the plate flat, and with proper arrangements to hold, kerosene is poured from the fired side and left for min. 60 minutes . The kerosene will seep through the fractured line, if any - thus indicating in detail the exact line of fracture. No external pressure is used here and it smears through the other side due to capillary action of kerosene.

If the leak is seen the weld is rejected indicating unsuitability of the filler metal (or) the weld procedure to withstand the shocks. If it does not leak weld is accepted.

Sridhar