Changes in the pink lapping film

The Group is aware that there may be a change in the pink lapping film.  Several Group members have reported higher than usual PTVs when using wet pink lapping film as part of the pendulum verification process.  Values of 66 – 68 are being reported – the range given in the current Guidelines is 59 – 64.

We have seen no evidence that the values obtained on the wet float glass or the wet pavigres tile are affected.

We recommend you continue to undertake the verification process using the 3 verification surfaces and report any unusual values to the Secretary.  We may need to revert to the earlier method of determining the target value for each batch of the pink lapping film.

—

Published 06/2023

.