(800) 999-FINE

Gate/Sprue Related Porosity

Gate size and shape are important for low porosity casting. When casting simple designs with rounded shanks and only a few prongs, almost any gate - round or flared, light or heavy will function properly. A proper gate should be round and slightly smaller than the width of the shank.

A gate is designed to supply the molten metal into the pattern cavity. Assuming proper metal and flask temperatures, the gate is critical in properly filling the cavity and allowing a proper solidification. When a gate is too small, it will solidify before the part cavity. This may cause porosity at the gate-part interface. This is usually seen as a roughness or an indentation at the interface. In some circumstances, cracking may also take place, in a similar manner of a hot tear. When oxides are present, as when old metal is used, trapping of the oxides may take place. This appears as a gritty or sandy texture inside the cast part. A flared gate, hammered to expand the gate width is very popular. Flaring a gate makes it easy to engrave style number as well as increase the metal flow rate into the part.

NOTES: When solidification occurs in an angle, the outer edges solidify more rapidly causing a greater shrinkage to take place. The narrower the gate-part interface, the higher the velocity of the supplied metal. Round gates solidify in a more uniform manner than angled gates.

Precious Metal Spot Prices

  Bid Change
Gold $2,061.70 +$23.90/+1.17%
Silver $28.25 +$1.30/+4.82%
Platinum $986.06 +$18.46/+1.90%
Palladium $2,218.02 +$33.60/+1.54%
Gold 2020-08-06 8:18 AM
Bid/Ask $2,061.70/$2,062.68
High/Low $2,062.19/$2,034.67
Change +$23.90/+1.17%
Silver 2020-08-06 8:18 AM
Bid/Ask $28.25/$28.27
High/Low $28.26/$26.80
Change +$1.30/+4.82%
Platinum 2020-08-06 8:18 AM
Bid/Ask $986.06/$990.14
High/Low $988.10/$965.58
Change +$18.46/+1.90%
Palladium 2020-08-06 8:18 AM
Bid/Ask $2,218.02/$2,225.88
High/Low $2,221.95/$2,178.78
Change +$33.60/+1.54%

+ Show detail

Prices shown are for reference only. Please contact our trading desk for accurate, up-to-the-minute pricing.