Rich, your friendly neighborhood chemist replies:

Differences of copper and steel:

Copper is lighter than steel, it is also a better conductor (not that that has anything to do with golf). It is a softer metal than steel as well with a lower melting point. Beryllium Copper (as first popularised by Karsten Solheim in his now much sought after Eye 2 BeCu) has similar properties to most standard types of steel but with greater thermal conductivity properties (again no use in golf). BeCu is easier to machine than steel. In so far as the advantages over steel in golf clubs go, there really isnt any its all down to personal preference. Most of the mild steel and raw steel wedges these days give exactly the same if not more spin than the BeCu wedges. The newer wedges (Cleveland BRZ for example) are a different compound (containing Cobalt and Nickel among other more exotic metals) which has much the same properties as BeCu, but are used since BeCu is (environmentally at least due to its requirement for rather toxic mixtures in its machining processes) rather unfriendly and now restricted in use worldwide (golf clubs being quite far down the list of necessary uses).

Graphit vs Steel shafts in wedges:

As far as shafts go, steel is best for any club in which distance is not the primary concern. A steel shaft has zero torque (twisting on impact) compared to the best graphite value of around 2 - 2.5. Graphite is used because of its light weight compared to steel (steel driver shaft 100-140 grams, graphite driver shaft 60-110 grams) The lighter the shaft the lighter the club and the more clubhead speed can be achieved and hence the more distance gained. Graphite also allows more weight to be placed in the clubhead (in the sole for example to generate more height in the shot). In crude terms Graphite is a distance shaft and steel is an accuracy shaft. The ultimate in accuracy is an X-300 flex shaft which is both heavy and stiff giving the club less opportunity to flex off target ideally your wedge shafts shhould be X-300's but very few players can generate the clubhead speed required to get any distance and height out of such a shaft. Most tour pros play X-100, S-400 or S-300 depending on their personal preference (I use True Temper nomenclature here because of the widespread popularity of their shafts, you could say Rifle 6.0 6.5 or 7.0 for example)

Hope this helps your decision.

D.