quick interfacing question:

[abinitio.livejournal.com]

i understand you're never supposed to iron synthetic yarn - EVER. but i just made a scarf and i need to sew on the backing. i'm predicting it will be a huge bitch to sew it if i didn't have interfacing. would it be okay to use the fusible kinds? i'd have to set it to low heat (so i've heard) anyway to avoid melting of any sort. oh dear jeebus, help a confused gal out.