Oh, and another thing, what kind of stirring are you using? Do you even use any stirring during the main reaction?
Raf shook flask with hands,it's not that heavy.When temp reached 90 and rx kicked in,he didn't bother anymore cuz it was foaming heavy and ammonium chloride was dissolved already.He didn't use condenser but drove these nasty fumes outside(he did NOT dream in city but in rural area with closest houses being at few hundred meter away and there aren't lot of fumes,but they smell very nasty(formaldehyde and formic acid plus some volatile rx byproducts,methyl formate maybe.)