I've never used anything but woodflour on any of the boats I've built.

Laszlo

hi mrosie, 

as laszlo points out, you can do a lot with woodflour and can complete a boat without cell-o-fill.

that said, they are a bit different in their properties....though i doubt they are different enough to make a measurable difference in strength that you would be able to detect.

my perspective on this is that if you are only going to use woodflour, you need to be more attentive to consistency and clean work.

on consistency, typically in construction, the wood flour typically is going to be used in thicker mixtures (peanut butter, mayonaise).  and the cell-o-fill is going to be uses in mixtures more like honey where it is typically used for bonding.   as long as you get the consistency right, i agree with laszlo that you can work with just the wood flour.

on clean work, woodflour is more visually detectable becuase it is brown/opaque.   cell-o-fill mixtures can often appear clear.   so if you are doing a bright finish, you may find it more challenging, if you are not attentive to clean work (e.g., using tape to keep the woodflour mixture only where you want it to be), to getting the look you want.

h