(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 $1,421.08 -$3.54/-0.25%
Silver $16.42 +$0.06/+0.37%
Platinum $853.00 +$4.50/+0.53%
Palladium $1,505.74 -$11.95/-0.78%
Gold 2019-07-23 11:33 AM
Bid/Ask $1,421.08/$1,421.61
High/Low $1,430.76/$1,414.29
Change -$3.54/-0.25%
Silver 2019-07-23 11:33 AM
Bid/Ask $16.42/$16.43
High/Low $16.54/$16.18
Change +$0.06/+0.37%
Platinum 2019-07-23 11:33 AM
Bid/Ask $853.00/$853.62
High/Low $856.48/$843.66
Change +$4.50/+0.53%
Palladium 2019-07-23 11:33 AM
Bid/Ask $1,505.74/$1,534.36
High/Low $1,530.37/$1,514.38
Change -$11.95/-0.78%

+ Show detail

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

Start Chat