Since there is so much talk about this, I suppose we should get into what is happening and how it can go wrong...
Wood is made up of hollow cellulose fibers, glued together with lignin, and still contains what is left of sap, which includes other oily or resinous materials.
Cutting open these cellulose tubes at the surface allows the glues (whichever ones you use) to flow into the opened fibers at the surface and greatly increases the surface area that the epoxy can grab. Machining, sanding and even scraping with a cabinet scraper does this when the cutting tool is sharp, and they all have been demonstrated to work well.
An easily imagined error state is a planer with cutting edges that are becoming dull. While sawdust is created, the last few thousandths of the wood is not removed, but is instead burnished, with most of the surface fibers compressed and not open to our glue. We can make it worse by running slowly or dwelling in spots, which melts and flows the lignin, sealing over the wood surface with a now continuous layer of this resin. My wife (a material scientist with a long background in polymers) describes a burnished lignin surface a "low energy" surface and thus likely to produce only a poor bond.
Robust prevention may be tough to achieve by keeping cutting tools sharp, but sanding, as recommended by the makers of our common epoxies, is pretty darned robust at making sure the surface is all opened... and the wife describes a sanded surface as a "high energy" surface and thus more likely to produce high strength bonds.
Next, epoxy penetration into the wood. Gougeon Brothers (makers of the excellent West System and ProSet epoxies) has done extensive testing on their epoxies and on "penetrating" epoxies. Their finding is that "penetrating" epoxies are poor wood adhesives. These products are epoxy thinned with a solvent. and in all manner of tests, they produce lower strength bond than with the resin systems we know to work well. The goal in bonding wood is to produce a bond where wood fails and no failure occurs in the cured adhesive. These "penetrating" epoxies frequently produce failure in the resin... So, do not worry over the lack of penetration due to the formulation of the common resins. West and T88 are the standby products because they have been demonstrated to be reliable, durable, and a pleasure to work with.
Now to acetone. It is a nice solvent if it does not have oil in it, as observed by other folks. I attended a session on repair of composites some time back, and the trainer recommended wiping a sample of your acetone on a clean glass surface and watching it evaporate. If it does not leave the glass as clean as it started, it has oil remaining from the distillation process. This oil will interfere with bonding. The only acetone his aerospace repair facility allows on site is reagent grade acetone. Yeah, it costs more to distill the acetone to that level. You know where the impure condensate from distilling goes? It becomes hardware store acetone. Alternatives are other solvents, which should also be checked by the same methods, but are way more likely to leave really clean surfaces.
Water on wood anytime near bonding time? Not if you want good bonds. Every bit of instruction on bonding with epoxy, painting with various systems, etc say to dry a water wetted surface and then allow it to stand for some period before the next operation. Yeah, even water borne paints (Stewart System) tell us to let them dry for intervals after wetting with 90% propanol wipe. Wood stores water inside the fibers and then gives it up slowly over time, so I would avoid water application anytime near when I expect to bond surfaces.
Billski
Losing a fight with my wife has too many consequences 
