User blog comment:Patrick x hunter/some nen ability's do not work/@comment-27459426-20151224000927/@comment-27459426-20151224205713

You actually wouldn't need to shield yourself for a considerable amount of time when using ice abilities in transmutation. If you create ice in transmutation in a manner that Grey (fairy tail) does then unless you actually wear it the amount of time you can transmute is quite a lot.

[ A simple way of thinking about it would be that Transmutation allows your aura to mimic properties of a substance, whereas Conjuration allows you to change your aura into actual substances. Transmuters can copy the properties of real things. For example, Killua Zoldyckuses his aura to copy the properties of electricity. Transmuters can also give their aura properties that don't necessarily mimic real things; Hisoka's "Bungee Gum" copies and combines the properties of rubber and gum, or Feitan whose aura replicates the solar sphere or Machi who transmutes her Nen into glowing threads. Transmuted substances are invisible to people unaware of the existence of Nen, and even to see transmuted aura, for a person well known to Nen, will require Gyo, or focusing the majority of Ren on one's eyes.]

Considering transmutation also mimics the properties instead of actually copying the substance itself copying the properties of Ice & poison gas would be a cake walk. You would'nt have to copy the mass of the substance unless its a conjuration which transmuters wouldn't have to worry about. To put is simply for a transmuter you would want to copy the properties of poison (lethality) and the properties of gas (being breathable, the way it moves and spreads in air, not being able to be cut, and limiations on area of effect). Same for Ice transmutation just copy ice's properties of crystalization and slowing molecules.