and compression porous cap 112 allows gas present in barrel 100 to vent when depressing piston plunger 102 while retaining calcium phosphate powder 101 in barrel 100 compression of the calcium phosphate powder in the device to 0 8 g cc or less produces a poorly and ineffectively mixed paste following hydration the same powder when compressed to a density of 1 0 g cc and hydrated is effectively and uniformly wetted and mixed with reference to fig2 and 3 the mixing device also includes barrel 106 which is adapted to accept a needle e g a 16 gauge needle which is attached at the distal end of barrel 106 liquid 110 e g usp saline is drawn into barrel 106 through the needle by suction pressure by retracting piston plunger 107 the needle is removed from the distal end of barrel 106 and barrel 106 is coupled to barrel 100 using luer fittings 104 to form luer connector 105 the saline is injected into calcium phosphate powder 101 by depressing piston plunger 107 which injects the saline into barrel 100 after a brief delay to allow the liquid to wet the powder air is vented by disconnecting barrel 100 from barrel 106 and slowly depressing the plungers barrel 100 and barrel 106 can be composed of clear polycarbonate to allow easy visualization during the venting step barrel 100 is reconnected to barrel 107 and mixing is performed by alternately and rapidly depressing pistons plungers 102 and 107 several times until a uniform mixture e g a paste is formed approximately 3 20 times in the event not all material passes between barrel 100 and barrel 106 a series.