With foam a hot wire cutter is essential, no need to buy one, i just made my own out of an old laptop charger a couple of nuts and bolts and some nichrome wire that you can buy pretty much anywhere for cheap (this is the best type of wire as it is stronger when hot), guitar strings work kinda but are more expensive and not as strong when hot.
A home made one is better than a bought one for 4 reasons:
1) It is MUCH cheaper, always good.
2) You can design it and readapt it easily to match your exact required jigging.
3) You can design in your own rheostat by simply putting a crocodile clip on the wire, the shorter the distance the hotter it gets so can eliminate all that nasty smoke and have a slower but smoke free melt.
4) Its cool and you made it yourself

I will post some pics of how i made mine if you are interested for future trials. Litterally took me < 30 minutes.