On 19/05/2021 19:13, Scott wrote:
I am wondering if anyone has tried using Hammerite paint on a plastic
pipe. Mr Google seems to think it is okay. For context, I am
painting a steel fence so it would be very convenient to use the same
paint on the pipe even if it is over-specified but not if it is likely
to cause problems.

It depends on the Hammerite and on the plastic of the pipe.

Old very high VOC Hammerite with xylene you might embrittle the pipe
even if it is something nominally robust. If it is a polystyrene pipe it
will be destroyed.

Modern Hammerite might also embrittle pipes longer term but probably
isn't quite as damaging as the old formulation.

The only way to be sure is paint a test sample and see what happens.

On PVC pipe it might not even adhere for long if it gets in the sun.

A spill of Hammerite onto my HDPE green bin has just delaminated as a
sheet after a couple of years in the weather.

--
Regards,
Martin Brown