In a message dated 5/03/2001 1:39:18 AM, Tom C. wrote: <<.................... I notice that you make no mention of drying the board, or does that go without saying? And while we're at it, would it add even more tension to dry the shims as well?">> Tom; I am not at all convinced of the needfullness of "drying the board" and of any benefit of doing so. On the other hand I see no harm from doing so within reason........If the board is 'dried' too much..... might it add to the propensity of shims splitting when the board regains moisture? Doesn't 'drying' the board cause it to flatten out, i.e., lose apparent crown? Doesn't a board, as it gains moisture from its 'dried' state, regain crown thus exerting more tension to the 'surface' of the board? Does a board that has been 'dried' exert enough 'tension so that even a dried shim will have a tendency to split/crack along the glue line when it regains its moisture equilibrium? <<"And what about glue? Thinking about PR-J's statement about shims cracking, would it make sense to use epoxy to glue in the shims?">> Hmmm there have been so many answers as to what kind of 'glue' is best that it seems as there is no lack of available products here! :-) As for "shims cracking" it depends on why they are cracking I suppose. (Reference the above questions) Some causes of cracking are due to improper soundboard crack preparation, IMO. If a shim is just 'forced into a crack there is bound to be some cellular damage to the board and/or the shim and if this damage is great enough there will be shim cracking no matter the adhesive used. Also if the crack is just forced open by crushing the cracks' walls by a wedge shaped instrument then no amount of drying/adhesive/shim fitting is going to keep that shim/glue line/board from cracking in the future as that crack is built in due to the improper preparation. Some thoughts on "cosmetic" cracks would have to include the consideration of a "cosmetic" crack creating the tendency of edges pulling away from members/ribs and thus creating a problem if not "cosmetically" repaired. :-) If a boards surface is continuous than the forces acting on that board are more evenly distributed along larger areas both on the surface and on the rib side of the board...right? A "cosmetic" crack does not have this continuous mutual support and will have two edges under tension trying to pull away from the ribs in different directions...kinda like peeling an orange:-) Well, the same princiiple applies to oranges and boards in that it is easier to peel either than it is to remove the entire thing, or even large sections, at the same time. Therfore to my way of thinking anything that contributes to unifying the board will be of benefit in the long run. course this is just my view. Jim Bryant (FL)
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