I think we had this conversation about soldering some months ago.
In a joint where the "inserted crud" is weaker than the parent materials between which it is inserted, the absolute minimum amount of "stickum" that fully wets the surfaces of the parent (legitimate or otherwise) surfaces produces the strongest joint.
Second response to Bill D:
I assume that I you recognized my assumption that you've tried out what you do and it works for you. If you're getting a good "filler" out of mixing wood dust with cyano, you're apparently using well cured wood (with low moisture) to make the dust. My comments were biased by the common use I've seen trying to glue metal or other non-porous surfaces, and by the fact that I can't afford good wood so I use construction grade which is "wet" and doesn't work well with superglues.
For "household" use, my kind of wood is more common. For skilled craftspersons appropriately cured woods would be the rule, and I'll make a note that you're in that latter *^@#&$! class.
One of the cardinal rules with cyanoacrylate adhesives is "If it works keep doing it like that. If it doesn't, use a different glue, or a different method."
General (and much too lengthy) reply:
The reason it's called "superglue" is because it will stick to things that other glues won't. Note that they didn't call it "miracle glue," because it won't stick to everything - which would be a miracle.
The primary method of "curing" cyano glues is by removing oxygen from the joint being glued. When the dissolved oxygen that prevents polymerization "in the jug" is removed from the glue, the material gets hard, and the best adhesive properties are obtained.
Two conditions are required for an "optimum polymerization." You must prevent new oxygen from getting to the glue in the joint by making the joint "tight fitting," and you must remove the existing oxygen that's dissolved/absorbed/adsorbed in the glue you put within the joint.
Some materials have sufficient surface energy to adsorb enough oxygen from the adhesive you apply, and the bond is created almost instantly, it the joint fits fairly closely.
Many materials have "inactive surfaces" or surface layers (often oxides) that prevent the material being bonded from "sucking out" the oxygen dissolved in the "glue." This prevents effective polymerizing of the superglue and produces, usually, a weak joint.
For these kinds of materials, primers are available that remove surface oils, and sometimes oxides from the parent material, and that also deposit a colloidal (usually silver) coating on the bonding surface. When the "glue" is applied, and the joint is placed together, the silver colloid adsorbs the oxygen from the glue and permits the intended full hardening. The "fit" of the joint must prevent additional entry of inhibiting oxygen.
Liz (07 May 06 - 10:59 AM) could possibly glue her plastic staps with superglue if she used an appropriate primer before adding the glue, but of course the primer doesn't come with the consumer packages. Most plastics simply won't adsorb enough of the O2 to allow optimum hardening of the glue. If the glue "wets the surface" - i.e. when you spread it on it makes a film instead of clumping up in globs - superglue will (nearly always) make a bond if you have, or create, a sufficiently active surface to suck the oxygen out so it can harden.
The alternate curing method is to "clabber it up with something wet." This is basically what you do when you use it on wood, or with wood filler. The polymerization of the glue is less strong than when O2 exclusion is used to obtain hardening, but is often sufficient for good effect.
Again: If it works once, do it again. If it doesnt' work, there are techniques and materials to help, and there are other glues.