Ive used the baking soda trick , not so much for its adhesion ,but more as a gap filler .
Its best built up in layers , so first a drop of super glue in the gap , then sprinkle on the baking soda , another drop of glue then another sprinkle of powder , build things up then sand it back to where you need it . Ive seen a similar technique used on guitar necks with hollows worn in fingerboards except instead of baking soda wood dust is sprinkled over the glue , its usually done in conjunction with a re-fret.
Sorry Andre , I'd assumed you were making a reverb plate , what is it your making?