Combos Utilizing Goblin-Welder

Exchance them, gain life and tap the opponent's lands, creatures or artifacts

When big creature comes out, discard Monkey cage to do one damage then goblin welder exchanges horn for monkey cage. Surprise! lots of monkeys! Obviosly works with other spellshapers / artifacts

start w/ a helm in grave and a helm + gw in play. activate helm, respond by swapping helms w/ gw. when helm resolves, get a creature, you don't lose helm since the helm used is gone and replaced.

millstone 8 cards then untap with the keys, milstone again for another 8 cards, use caps for 12 cards from game, sac the keys to get caps back, use the caps again. thats 40 cards in one turn. hahahaha

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have a hornet cannon in the grave yard a welder, cathodin, and alarm in play switch cathodion with hornet cannon use the cannon and then switch with cathodion then repete

infinite mana infinite burn

buried alive for 3 junk diver's and play one. bust a cap and sac the diver to the welder to get the cap back in play and another diver in yur hand. do it again next turn and again etc. infinite caps!

with intrud alrm, gob weld and mindless auto in play, use the mindless auto to discard skelly to grave. swap skelly and mindless. when skelly comes in it untaps goblin. (infinate combo)

if you have simulacrum in play, and one in the graveyard... you can exchange them each turn with the welder. search your deck for a basic land and draw a card - add intrueder alarm to do it infinitely