Our customer is an aerospace MRO (maintenance, repair and operations) company based in the UK. They were looking for a level 3 fluorescent penetrant that they could apply to a small area using an aerosol. In particular, they wanted a penetrant that could be removed with water.
To date, in accordance with the approved technical data, our customer had used ZYGLO® ZL-60C, a level 2 waterwashable fluorescent penetrant. This inspection, however, of a titanium inlet valve, had to be carried out on the wing using a level 3 penetrant.
Our customer normally uses ZYGLO® ZL-27A, a level 3 solvent-removable aerosol penetrant, to inspect highly critical non-titanium components. After inspection, they would use our solvent remover, SPOTCHECK® SKC-S, to remove the excess penetrant using the solvent-wipe technique.
In this case, however, the use of solvent was not permitted due to the complexity, location and the material specifications of the inlet valve.
After consultation with the customer, we advised that the remover/emulsifier ZYGLO® ZR-10C can be applied using a spray technique, where the concentration of the ZR-10C is much lower than if used in the immersion dip method. Effectively, this meant our customer could create their own aerosol version of ZR-10C using a standard spray bottle.
The customer actually ended up applying a diluted version of ZR-10C very gently using a brush. This was possible because the test area was very small, although they had to take care to not break down the penetrant using the brush. The excess penetrant was then removed using water.
The lesson here is that a very simple adaption of technique allowed them to solve the problem with materials that they already had available, so no extra cost was incurred.