Update: I finally switched from a 6-inch riser to an 8-inch on our main pour line after a spill last week.

I always thought the bigger diameter was overkill until I saw how much smoother the flow was and how it cut down on splashback and waste, so what's your go-to setup for high-volume aluminum pours?

3 comments

3 Comments

emery_taylor1mo ago

Hold on... bigger risers just hide a flow problem you should fix at the source. That extra diameter is a band-aid for bad gating or poor metal quality. You're adding more hot metal in the system that can cool wrong and cause other issues. I've seen shops chase bigger risers and end up with worse shrinkage because the thermal mass is in the wrong spot. My go-to is always to tune the sprue and runners first before just making everything bigger.

matthew8641mo ago

Wait, you've actually seen shops make things worse by just making risers bigger, @emery_taylor?

andrew8541mo ago

Wait, you've actually seen shops make the shrinkage worse by doing that? That's wild. It makes sense though, just dumping more hot metal in the wrong spot sounds like asking for trouble. I guess it's like trying to fix a leak by turning up the water pressure instead of finding the cracked pipe. Gotta get the basics right first.