Hi Brian --  I think magnetic mixing might be promising, but I have not evaluated it.  What I KNOW works is using a kitchen blender, which is probably more mixing than is really needed.  One advantage of the kitchen blender is that it BURNISHES the aluminum and tends to remove the aluminum hydroxide film mechanically and very effectively.  Also, if aluminum shavings are used, the shavings tend to get chopped up, providing a higher surface-to-volume ratio.  This happens as the aluminum is consumed (volume decreasing with time) and the chopping of the aluminum shavings tends to keep the aluminum surface area more constant -- thereby sustaining the hydrogen production at a more constant rate.  More info on this is online, on page 22 of www.PhillipsCompany.4T.com/ccs.pdf

One important point:  If you use anything other than aluminum powder (such as granules, shavings, etc.) you will probably find that having a sufficiently large aluminum area will require more volume of aluminum.  Calculations about this are online at

www.PhillipsCompany.4T.com/apa.pdf

If you need me, I am more-frequently accessable at hp@valliant.net

Kind regards,

Howard