A planning resource for brand and sourcing teams. Engineering recommendations are not a statement of a particular project's specification, inspection standard, price, MOQ or delivery commitment.
Compare the job the part must do
A display shell, a load-bearing connection and a flexible accessory do not present the same problem. First identify the component's role: does it preserve a sculpted outline, locate two shells, withstand handling or bend intentionally? Next describe the conditions in which it must perform. This turns a vague request for strong plastic into a testable material brief.
The table gives starting points for an engineering discussion, not guaranteed outcomes. Material suppliers offer grades with different flow, impact, heat and surface properties within the same polymer family. ITTAK produces components in HIPS, ABS and PVC in-house; the references below do not imply that any particular supplier grade is used in your project.
| Material family | Potential kit role to evaluate | Checks before approval |
|---|---|---|
| HIPS | Rigid shells, detail parts and runner-based components | Feature filling, runner removal, rigidity, surface and the chosen joining method. |
| ABS | Rigid components with demanding handling or connection requirements | Actual grade data, fit, repeated handling if relevant, decoration and joint stress. |
| PVC | Components needing a specified rigid or flexible response | Compound hardness, shape retention, finish, contact with adjacent parts and packaging. |
HIPS: specify more than high-impact polystyrene
HIPS modifies polystyrene to improve impact behavior. That does not make every HIPS grade equally rigid, glossy or suitable for the same thin detail. Resin suppliers publish grade-specific information precisely because these properties vary. For a model kit, connect the selection to small-feature filling, cosmetic surfaces and how parts are removed from their runners.
If the assembly instructions call for a polystyrene cement, identify the actual adhesive and test the selected material and joint design. Do not extend a successful result on one part to every material in a mixed-material kit. The user experience includes the cut edge and assembled seam, not only the appearance of an untouched runner.
ABS: evaluate the connection, not just toughness
ABS is a family of engineering thermoplastics with grades offering different balances of processing, toughness and appearance. It can be considered where a rigid component has demanding handling requirements. However, selecting ABS alone does not establish the strength of a pin, the durability of a socket or the fit of a snap connection.
Define what the connection must do: permanent assembly, occasional repositioning or repeated movement. Check it in molded samples with the proposed geometry. If painting or adhesive application is planned, test that process on representative parts, including stressed interfaces. A material datasheet and an assembled-product evaluation answer different questions.
PVC: specify the compound and required flexibility
PVC is not automatically a soft plastic. Its formulation, including plasticizers where used, can produce a wide range of rigidity and flexibility. A brief saying only PVC leaves important questions unanswered. Describe whether the finished component must bend, return to shape, support another component or retain a fine silhouette during storage.
Include the intended hardness and test method when known; otherwise ask for a material-selection discussion. For a flexible accessory next to a rigid shell, assess the assembled contact and the finished surfaces together. Packaging must not hold a flexible part in an unwanted position without checking the resulting product condition.
Can one model kit use several plastics?
Yes, when the product design justifies it. Create a part-level material map rather than selecting one plastic for the whole box. Show which components mate, which receive paint or printing, and which arrive attached to a runner. The map also helps distinguish visually similar parts that must not be substituted during production or packing.
Changing a resin after tooling is not merely a purchasing decision. Material behavior affects molding and final dimensions, while appearance or joining requirements may change too. Recheck the affected parts and interfaces before treating an alternative material as approved. Do not infer interchangeable grades from a shared acronym.
A useful material approval checklist
- List part numbers, intended functions and the proposed material or open selection question.
- Record visible faces, color references and planned paint, print or adhesive systems.
- Define critical interfaces and the assembly or handling checks needed for acceptance.
- Retain the agreed grade information, sample revision and criteria for material substitutions.
- Identify the sales markets and required product documentation; a resin family name is not a product compliance certificate.
Common buyer questions
Is ABS always better than HIPS for model kits?
No. Better depends on the part, selected grade, geometry and required assembly experience. Compare the actual materials against the same acceptance criteria instead of ranking polymer families with a single strength claim.
Can HIPS, ABS and PVC use the same glue and paint?
Do not assume so. Follow the finishing-product supplier's compatibility guidance and validate the intended system on representative molded parts. A successful finish on one polymer or grade does not establish compatibility with the other components.
Does ITTAK make HIPS, ABS and PVC components?
Yes. ITTAK produces components using HIPS, ABS and PVC in-house. The material grade, finish, assembly method and acceptance criteria are defined for the particular model kit project.
References and further reading
- INEOS Styrolution: 2026 styrenic materials portfolio
Primary resin-manufacturer reference for impact-modified polystyrene and variation between grades, not a statement of ITTAK's resin sourcing.
- INEOS Styrolution: styrenic material families
Primary reference distinguishing ABS and polystyrene product families; specific performance requires grade data and application validation.
- British Plastics Federation: PVC overview
Industry reference on PVC formulation and rigid versus flexible forms; not a model-kit compliance determination.
Plan your next step
- In-house molding and manufacturing capabilities
- How plastic model kits are made
- Snap-fit model kit design
- Model kit quality control
Start with a non-confidential overview. Ask about an NDA and an appropriate transfer method before sending unreleased designs.
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