High Melts vs. Low Melts

Casting metals, tools, and tips

The best casting methods for different metals



As metals with high melting points are too dense to use in a vacuum and freeze quickly, centrifugal casting machines are the preferred option. Avoiding shrinkage and gas porosity is always a challenge, but with the right machine and the right attention to detail, you can get great results.


Vacuum casting uses air pressure and a vacuum to suction molten metal into the mold and is the best method for low melting points. Vacuum casting is ideal for when air entrapment is an issue or when precise control over metal flow is desired to achieve highly complex designs.



Platinum is incredibly dense, strong, and best cast through centrifugal force. Platinum’s low viscosity makes it ideal for detail work, although its density means designs can be costly and require more material.


Since gold casting encompasses a range of colors and karats, evaluate processes and limitations of the alloys used.


Palladium is gentler on investments and less dense than platinum, allowing for more affordable, lighter designs. Since it doesn’t fill as well as platinum, avoid thin sections and small prongs or cast them separately. This filling difficulty means palladium requires more auxiliary sprues on thin sections.


Improper spruing can cause a silver (or gold) piece to not fill, but increasing the flask temperature can cause porosity. Proper spruing and staying within temperature range is critical for avoiding porosity with low melts.


RDO CSI Centrifugal Casting System

Cast high melt alloys using the RDO CS1 Centrifugal Casting System and achieve increased consistency among products. Advanced diagnostic features, precise controllability, and temperature regulation make this machine perfect for high-volume shops. Recommended skill level: intermediate/expert.

Stuller Master-Cast 120V Pro Caster

Perfect for vacuum casting low metals and accommodating flasks as large as 5"×7", it has an expected output of 15-20 casts per day, making it ideal for small to medium-sized shops. Recommended skill level: beginner/intermediate.


Plasticast® PT Investment & Binder

This two-part, water-based binding material is intended for investment and burnout of rapid prototype patterns, wax patterns, and high-temperature alloys. No acid handling or special flask preparation is required.

R&R® Plasticast

Handles expansion demands with no compromise on mold surface and dimensional integrity. Perfect for investing CAD/CAM resins and wax/plastic, it is easily removed with water yet strong enough to handle high material expansions.

Prestige Ferro-Vest

This two-part, high-temperature investment is optimal for casting platinum and palladium. Ferro-Vest contains unique additives that eliminate air bubbles and yield a smoother surface in the finished product, resulting in less finishing work, more consistent casts, and saved time.

R&R® Ultra-Vest Maxx

For yellow or white gold, it eliminates orange peel defects with metal/mold reactions and flashing and spalling defects acquired during resin burnout. Recommended for gold, silver, brass, and bronze alloys.


Enjoyed this post? Read more in Stuller’s FTB publication.

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