3600 E Marginal Way South

From I-5 N or S

get off on spokane street overpass
immediately exit onto 4th ave S
once you're on 4th ave, make a U-turn
turn right onto Spokane Street
[you're underneath where you were on the viaduct]
cross 1st ave south and two sets of train tracks

Alki Foundry is in the big building right after the second set of tracks,
just west of the irish foundry between 1st and e marginal way