Changing metal Incinerators into plastic Psycannons..

[Lord Commander Vulkus Dorn]

So I'm playing Grey Knights now and I recently got some stuff off of eBay. Needless to say, I have a lot of oop minis from the 1st release of GKs from 3rd ed. Swapping the halberds out for swords won't be hard but I don't want to use incinerators as psy cannons are much more lethal and better imo. So has anyone else done this? I'm trying to find a cheap method to do this so any ideas or suggestions are most welcome. Thanks and have a great one!