How do you calculate riser yield impact?

Divide total riser and feeder weight by total pour weight, then multiply by 100. With 950 lb of risers in a 6,200 lb pour, that is 950 ÷ 6,200 × 100 = 15.32%.

What is a good riser-to-pour ratio?

It varies with alloy and freezing range, but many sand-cast steel and iron jobs target roughly 10-20% riser share. The example's 15.32% sits in a normal band and is just under its 16% target.

How does riser weight affect casting yield?

Riser metal is the largest non-shipping component of most pours, so it directly suppresses yield. Cutting riser share while keeping the casting sound is usually the fastest route to a higher casting yield number.

Can I just make risers smaller to boost yield?

Only up to the point where they still feed solidification shrinkage. Undersize a riser and you trade a better yield number for centerline porosity and scrap, which costs far more than the metal you saved.

What tools help reduce riser size safely?

Exothermic and insulating sleeves keep feeder metal liquid longer, so a smaller riser feeds the same volume. Solidification simulation lets you right-size risers before cutting a pattern, hitting a target share like the example's 16% with confidence.

Is a positive gap to target good or bad here?

For riser share, lower is generally better, so being under target is favorable. The example is 0.68 points under its 16% target, meaning slightly less metal in risers than planned — fine as long as castings stay sound.

Foundry & Forging calculator

Riser Yield Impact Calculator

Riser yield impact measures what fraction of your total pour weight is tied up in risers and feeders — the metal added solely to feed shrinkage as the casting solidifies. Because every pound in a riser is a pound that cannot ship and must be remelted, this share is the single biggest lever methoding engineers have over casting yield. Melt-deck supervisors and rigging designers track it to see whether their feeding system is sized correctly or whether oversized, conservative risers are quietly bleeding capacity and energy. Trimming riser share even a point or two, while keeping castings sound, directly lifts overall yield and lowers cost per good pound.

What this calculator does

Calculate how much riser weight affects casting yield for a mold or casting family.
Use it when evaluating riser sizing, feeding practice, simulation changes, exothermic sleeves, chills, or pattern changes.
It divides riser and feeder weight by total pour weight and multiplies by 100, then subtracts your target riser share to show the gap in points.

Formula used

Riser Yield Impact rate = riser and feeder weight ÷ total pour weight × 100
Riser Yield Impact gap to target = calculated rate - target riser weight share

Inputs explained

Riser and feeder weight: Enter total riser, feeder, sleeve, and neck weight removed from the casting system.
Total pour weight: Use casting, gate, sprue, runner, riser, and overflow weight for the same mold or lot.
Target riser weight share: Use the engineering target or historical riser share for this casting family.

How to use the result

Use it when reviewing a rigging design or methoding simulation to judge whether feeder metal is in a reasonable range for the alloy and section thickness.
A low riser share is only good if the casting still feeds soundly — undersized risers cut this number while inviting centerline shrinkage, so never optimize it without porosity checks.

Current U.S. benchmarks

The producer price index for steel mill products stands at 348.53 (BLS, May 2026), up 6.7% from a year earlier. Quotes priced off last quarter's material cost miss this move.
The U.S. has 3,569 primary metal manufacturing establishments employing about 354,911 workers (Census County Business Patterns, 2023).

Common questions

How do you calculate riser yield impact? Divide total riser and feeder weight by total pour weight, then multiply by 100. With 950 lb of risers in a 6,200 lb pour, that is 950 ÷ 6,200 × 100 = 15.32%.
What is a good riser-to-pour ratio? It varies with alloy and freezing range, but many sand-cast steel and iron jobs target roughly 10-20% riser share. The example's 15.32% sits in a normal band and is just under its 16% target.
How does riser weight affect casting yield? Riser metal is the largest non-shipping component of most pours, so it directly suppresses yield. Cutting riser share while keeping the casting sound is usually the fastest route to a higher casting yield number.
Can I just make risers smaller to boost yield? Only up to the point where they still feed solidification shrinkage. Undersize a riser and you trade a better yield number for centerline porosity and scrap, which costs far more than the metal you saved.
What tools help reduce riser size safely? Exothermic and insulating sleeves keep feeder metal liquid longer, so a smaller riser feeds the same volume. Solidification simulation lets you right-size risers before cutting a pattern, hitting a target share like the example's 16% with confidence.

Last reviewed 2026-05-12.