You could get away with heat (maybe!) if you know what your target temp needs to be and you can control your heat source really well, but my experience with composites says heat is a bad idea. Ask me how I know that 8^D
Introducing yet another heat cycle to that stuff could produce some weird (and maybe really bad) results.
Micarta (or any phenolic style material) is largely resin. That's why it is so much heavier than wood.
Even after having been "cured", resins like these maintain a certain amount of elasticity pretty much forever because they only cure to the maximum amount of heat applied to them. If at any point in time later on (even 50 years later) a "cured" item is subjected to a level of heat higher than that under which it was constructed it will again become somewhat fluid and cure some more. This can get really ugly if applied to something only in a specific area (like, say, only the grip) or to an item that was formed under pressure and heat- like in a bow vise in an oven.
That is the reason that leaving a laminted bow in a hot vehicle often shortens its life. The additional heat maybe isn't even all that bad really (depending on just how much more it is) but the fact that the bow has nothing to hold it together while it heats up and then cools back down is the issue.
And more sticky yet, that micarta resin was cured not only once when the bulk billet was first layed up but then again (and hopefully at a somewhat higher temp) when the limbs were bonded to the riser.
Only the individual who performed those two operations could say what temperatures it acheived either of those times and getting near or past the highest temp could vey well delam something.
I vote for Dremel on the lowest speed setting that will get the desired result!
