Power Scrapper Hammer GW2 Scrapper WvW Builds
Scrapper replaces your tool belt 5 with 
Function Gyro: a lightning field that summons gyros to finish downed enemies and revive downed allies inside it. Most of the specialization is bolted to that one button — 
Gyroscopic Acceleration makes it hand allies 
Superspeed, 
Expert Examination makes it hand them 
Protection, 
Kinetic Accelerators turns it into a blast finisher. The utility skills it unlocks are wells: you place them, they pulse where you put them, and they stay there when you move on.
We run two Scrappers and they do not overlap. The power build is a Hammer bruiser leaning on 
Object in Motion, which raises your strike damage while you hold 
Stability, 
Swiftness or Superspeed and compounds it with every boon you carry — so the movement the line generates is also its damage. The heal build is Minstrel's on double Shortbow, and its cleanse runs through protection: 
Anticorrosion Plating strips conditions from every ally you grant protection to, and 
Bulwark Gyro covers them in 
Barrier while you do it. Both are written for a squad. The heal build in particular does nothing on its own.
2 Scrapper builds
Power Scrapper Hammer Heal Scrapper Shortbow Playing Scrapper in WvW
The mechanic asks you to read the fight a beat early. Wells land where you cast them, so a Purge Gyro dropped on the squad's current position is a Purge Gyro the squad has already walked out of. The rest of the kit is short-ranged and physical: hammer gives you 
Electro-whirl for reflects, 
Shock Shield to block while gaining Barrier per enemy hit, 
Rocket Charge to close, and 
Thunderclap to stun.
Both builds share the same movement engine. 
Speed of Synergy gives Superspeed around you whenever you use a heal skill, and Gyroscopic Acceleration adds more on every well's first pulse — which is a squad utility on the heal build and, through Object in Motion, a damage stat on the power one. 
Impact Savant converts a slice of your strike damage into Barrier, so the power build carries a little sustain that scales with how much damage it is actually landing.
Where it struggles is reach. Everything Scrapper does well happens inside the melee ball, and its support lands on the ground rather than on the people. If the enemy is winning at range, or your group is scattered, a Scrapper is an expensive body.