Casting Methods: Advantages & Disadvantages
There are several factors that should be considered when selecting a casting material (e.g., desired weight, appearance, durability, texture, cost, timing). One of these factors is the casting method. Popular methods include:
- solid pour
- gel coat and layup
- slush casting
- rotational casting
- injection
- solid pour with vacuum or pressure
- direct layup/spray (without a mold)
[If a mold also needs to be made, it is important to select the casting method beforehand so the mold can be constructed appropriately. A mold used for rotational casting may be designed differently than a mold made for solid pour castings.]
There are advantages and disadvantages to each casting method and certain materials can work more efficiently for one method over another:
| Casting Methods | ||||
|
Method Defined |
Advantages |
Disadvantages |
End Uses |
Recommended Polytek® Product(s) for Method* |
|
Solid Pour Material is poured into the mold, resulting in a solid casting. |
Fast Strong |
Heavy Potential high cost |
Small objects Industrial tools |
All Casting Materials (View Casting Plastics, Foams & Epoxies, View Casting Rubbers) *Epoxy Resins should not be used for large castings – it can be dangerous. |
|
Gel Coat and Layup A thin surface coat is applied and then subsequent layers of reinforcing materials (e.g., fiberglass mat and resin) are built-up to a thin, strong laminate. |
Lightweight Uses less material
|
Time-consuming
|
Rigid molds Mold shells Large Objects Props and displays Bonded bronzes |
Poly 15 Series with thickening agent (e.g., PolyFiber II) |
|
Slush Cast Casting material is manually rotated in the mold, creating a thin layer, which results in a hollow, lightweight casting. |
Lightweight Uses less material |
Time-consuming
|
Props and displays Art objects Bonded bronzes |
|
|
Rotational Cast A closed mold is rotated by machine as a small amount of casting material coats the surface and sets, which results in a hollow, lightweight casting. |
Fast Easy Lightweight Six-sided parts |
Requires a rotational casting machine
|
Large statues Props and displays Hollow parts |
|
|
Injection Liquid is forced into the mold under pressure. |
High quality parts
|
Requires setup time Requires a machine or pressure pot |
Thin-walled parts
|
All Casting Materials (View Casting
Plastics, Foams
& Epoxies,
View Casting
Rubbers)
*Epoxy Resins should not be used for large castings – it can be dangerous. |
|
Solid Pour with Vacuum/Pressure Material is poured into the mold and then vacuum or pressure is applied, which eliminates bubbles in the resulting casting. |
High quality parts
|
Requires setup time Requires a vacuum pump or pressure pot and chamber |
Prototypes Figurines Clear castings |
All Casting Materials except PolyFoam *Epoxy Resins should not be used for large castings – it can be dangerous. |
|
Direct Layup/Spray (No Mold) Material is sprayed over a screen armature or foam substrate. Surface detail is sculpted into the wet casting material or cured plastic hard coat. |
Lightweight Uses less material |
Time consuming Often requires equipment Produce single part |
Amusement/themeparks Sculpted rocks Props and displays |
|
*The recommended products listed above are provided as general advice. Material requirements vary from project to project; please contact us to discuss the right choice for your particular application.