A Photo & Discussion Forum for Wharram Design Enthusiasts
the idea is to roughen the surface so that the epoxy gets something to grip on to and the sanding also helps to ensure that the surface is free of contaminants like blush.
So you need to sand enough to scratch the entire surface where the fillet will bond and it may be a good idea to sand with water and wash with water after you sand ( water removes blush ).
Perhaps you should get the WEST system book (large PDF ) http://www.westsystem.com/ss/assets/HowTo-Publications/GougeonBook%...
More on this page: http://www.westsystem.com/ss/use-guides/
Thank you, Robert, nice and clear.
Therefore, it sounds better to coat all the sheets and sand the areas to glue before to cut and put the pieces together, must be more easy.
And your links are perfect, as well,