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Your lost wax casting partner since 1940s.

Castaldo® has been a major part of jewelry casting since the industry's beginnings in the late 1940's.


Made in USA

Castaldo® products are manufactured in our new factory in Franklin, Massachusetts, located between Boston and
Providence, R.I
Dr. Ferdinand E. Knight applied the scientific training he had acquired as a medical student in Vienna, Austria before World War II to the new field when he arrived in the United States as an immigrant in 1938. His father, Dr. Leon Knecht, had been a dentist in Vienna and also ran a dental supply house there. During that period the techniques of dental casting, still practiced today, were first developed.

Castaldo- RTV Jewelry 

 -0% Shrinkage RTV.
-Not an expensive hard-to-mix silicone rubber!
- Not an amateur “bake in the oven” material!
-Makes strong, flexible, easy to cut molds.
-Inexpensive and easy to use 1:1 mix ratio.
• Clear as Glass.

Castaldo - LiquaFast ICE RT  

-Rapid Molds from Rapid Prototypes.
-Finished Molds in as Little as 30 Minutes.
•-Ideal for all CAD-CAM, RP, SLA WAX and Resin Models.

That means that you can make a mold from your CAD CAM, RP and SLA models in the morning, shoot waxes 30 minutes later and cast them that afternoon. No more waiting.
LiquaFast ICE works well with all RP types, including hard-to-mold Solidscape® designs. LiquaFast Ice’s low viscosity makes it easy to measure, mix and pour.

Castaldo -
 Super High Strength™ 

Castaldo Super High Strength™ Item #800
A superior quality medium hardness jewelry molding rubber with extreme tear and tensile strength for every application including spirals, cores, cut-outs & plugs as well as for general purpose use. 

Castaldo -Silicone Rubber

Castaldo® Gelato® Super High Strength Silicone Jewelry Molding Rubber cuts like butter. It resists tearing and is strong enough to make complex molds that are stronger than any other silicone molding rubber on the market. Molds last and last.pp.

Castaldo jewelry molding rubber 

5-lb. Convenience Strips

The same as our 50 lb / 22.7 kg. box, but packaged in small lots weighing 5 lbs / 2.27 kg. each. Just enough jewelry molding rubber to make 15-25 standard size jewelry molds. Provided in an attractive consumer-oriented box that is easy to handle, easy to sell, easy to ship and keeps the rubber neat, clean and fresh. Available in White Label® (regular/firm), Gold Label® (premium/soft), Titanium Label® (extra firm) and No Shrink Pink®.

Titanium Label

Castaldo Titanium Label jewelry molding rubber packs, cuts, bends, flexes and stretches just like our standard White Label® and Gold Label® rubber.

It is so hard it can be clamped at much higher pressures without mold distortion and injected at higher wax pressures and at lower wax temperatures. The combination of those factors means Better Detail and Reduced Wax Pattern Shrinkage.

Castaldo Econosil Molding Rubber Strips

This is a harder, firmer version of "Super High Strength" jewelry molding rubber at lower cost. Econosil is a putty-like material that makes strong, tough rubber molds. Red brown in color, it cuts like butter, gives waxes a high shine finish and requires no messy sprays. Waxes self release easily.

Vulcanizes at 330°F - 15 minutes per layer of rubber.

18" x 2-7/8" x 1/8" Strips | 5lbs

Castaldo SuperStretch™ 

High-performance High-elasticity Silicone Rubber

Molds that normally require many parts to release complicated or difficult patterns cannow be done easily and simply.

Castaldo SuperStretch™ was able to mold this hollow gold spiral sea shell charm without complicated multi-part inserts. The thin spiral core needed to reproduce the shell is strong and elastic enough to be withdrawn from wax patterns 100’s of times.

LiquaCast Long-Life 

0% Shrinkage RTV Liquid Jewelry Molding Rubber

It’s compatible with mostcomputer-generated CAD-CAM resin and difficult to mold CAD-CAM wax patterns.
Ordinary low-cost RTV liquid rubber molds become soft and unusable over time, wasting the time, effort and skill invested in making them. Sometimes they even turn back into liquid rubber! LiquaCast® Long-Life™ 0% shrinkage RTV rubber is formulated to last for decades without softening, distorting or degrading in any way.

Castaldo LiquaCast

Safely molds just about anything without shrinkage!

It is a 0% shrinkage room temperature vulcanizing liquid rubber that lets you make molds of delicate objects that would not survive the heat and pressure of the normal vulcanization process. Typical uses include making molds of CAD-CAM, RP and SLA resin models, wax carvings and wax injections. Also possible are objects from nature — leaves, plants, flowers, fruit, insects – anything!

Castaldo QuickSil®

- No careful measuring
- No messy liquids
- no vacuuming
- no 12-24 hour wait 
- no vulcanizer needed
- no release sprays

Castaldo QuickSil® is a two-part putty that is mixed by hand, not a liquid rubber, making it ideal for users without a vulcanizer or a vacuum pump. It cures to a strong rubber mold in only 15 minutes at room temperatures. Only slight pressure is needed to form the mold and drive out air bubbles. Bench vises, book presses and even C-clamps can be used with good results.

Castaldo Liquid
Mold Frames

• For use with all RTV liquid rubber molds.

• Makes molds 1 7/8" (46.7 mm) up to 5 1/4"(13.5 cm) high.

• Available in the following thicknesses:

3/4" - (19 mm)
1" - (25 mm)
1 1/4" - (32 mm)
1 1/2" - (38 mm)

Heavy duty industrial bands fit all frame sizes; additional bands are provided with each frame.

Our vision is to provide our customers  the most innovative machinery  with manufacturing techniques and processes with cutting edge technologies proven from around the world with our local knowledge for the Great China Market and Southeast Asia. 

Hong Kong, China-based Kingsway Jewelry Supplies Co Ltd serves as a distributor of alloys and equipment for a number of major brands in Asia. Gilbert Kwok, managing director of the company, shares with JNA the qualities that make Kingsway an ideal partner for jewellery-manufacturing equipment and materials in the region.

We have been a major supplier of casting and melting machines in Asia for more than three decades.

We keep a close eye on the latest industry developments, from electronics to modern engineering technology. By doing so, we are able to identify the technologies, which we believe would better serve the needs of the jewellery industry.


Kingsway mission statement is to accelerate the technology advancement, efficiency and scalability of the jewelry industry in Asia by offering best softare/hardare and international experience. 

We excel not only in China but also have experience throughout Asia. 


Kingsway is only a engineering company wants to link its decades of trade experience, knowledge network and local Asian knowledge to serve our customers with better, more efficient and new processes of tomorrow. 

We never counterfeit or copy our supplier products or customer designs to make quick money. 

In the jewelry world, Kingsway is the firm that you can trust. 

Based in Hong Kong, China, Kingsway has been serving all our customers with integrity and decades of  trade specific experience.


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