mixing pitch(es?)

[NickD]

If they're both the same basic components - e.g. pine resin based - it should be OK.
If one is bitumen and the other pine, then no, that's not going to work. I'd not even layer them in that case.

Thanks v much for the replies.
I have Cookson's chasers' pitch and was thinking about adding the red pine pitch.
The problem is I've been attempting to chase a cup which meant filling it with what's in the bowl.
To work from the inside I needed to take this out but at the moment need to reuse it . I just don't have enough.
Maybe I'll just have to wait until Cookson's get a supply.
If I ever buy again I won't use this.