Liquid metal or knifing putty?

[smac4494]

I've got some alloys and fibre glass with some refurb/flattening needed. Also want to smooth over some chassis welds in the engine bay.

Anyways my question is what should i use? I've not used either knifing putty or liquid metal before. And just want to know what's more appropriate for each kind of material

 

[dajones]

Last time I did alloys I used liquid metal. Was pretty good. But of a nightmare if put on too think though