After having problems getting an even mix after mixing with various items and having sticky patched on the surface I thought of a small battery operated paint stirrer a check on ebay came up with several in UK & US they were expensive with post added, I already had a 65mm Graupner prop on a 4mm shaft I'd used for mixing Auto paint set me searching what I had in small props and found these.
I have no idea where I got them l & rhd 30mm on 1.5mm shaft on screw driver speed it produced a mini cyclone effect in a cut down 50mm plastic pill bottle and the result was a perfect cure.
I expect these shaft/pros could be found in elcheapo kids boats.
Damien.