Rotational Molding for US Hollow-Part Buyers: Supplier Comparison

Compare Custom Roto-Molding and Forté

Compare Custom Roto-Molding’s stated tank applications and mold-building support with Forté’s engineering assessment and CNC finishing, then request the same written acceptance commitments from both. [1][2]

Custom Roto-Molding

• Application coverage: Lists industrial, marine/boat, agricultural, RV and water-storage tanks, plus battery boxes, refuse containers, fender skirts and water heater pans. [1]
• Tooling support: States it provides in-house design, mold building and mold repair. [1]
• Finishing capabilities: Ask which trimming or finishing operations the quote includes. [1]

Forté

• Application coverage: Cites particular expertise with large commercial parts such as fertilizer and water tanks; ask it to confirm experience with your specific application. [2]
• Tooling support: Lists a “Moldability” Engineering Assessment, in-house tool maintenance and finishing-fixture design/fabrication. Ask separately about new-mold construction. [2]
• Finishing capabilities: Lists 5-axis CNC trimming and finishing. [2]

Use these capabilities to build a shortlist, not to approve a particular application. Send both suppliers the same drawings, service specification and acceptance requirements.

Define the application and exact resin grade

Describe the application before requesting a material quote. Published tank applications include water, chemicals, fuel, agricultural liquids and industrial storage. [3][4]

Include these project inputs in the RFQ:

• Contents and service: intended contents, concentrations where relevant, operating conditions and exposure conditions.
• Part definition: overall dimensions, geometry, required capacity and installed orientation.
• Interfaces and loads: connection and mounting interfaces, plus expected loads.

Ask for the exact resin manufacturer and grade, proposed additives, suitability assumptions and information still needed. Forté lists LLDPE, HDPE, XLPE and nylon, with exact-grade selection driven by the application. [2] Thomasnet’s rotationally molded plastic tank listings distinguish HDPE, XLPE, PP and PVDF; a quote stating only “polyethylene” leaves the material choice unresolved. [6]

Require written, application-specific confirmation for potable-water, chemical or structural use, including supporting qualification evidence and required validation.

Confirm the proposed exact resin grade against the attached contents and service specification, and identify exclusions or required validation.

Set mold rights before paying for tooling

Custom Roto-Molding’s and Forté’s cited pages do not state mold ownership, title-transfer, storage, maintenance-charge, permitted-use, disposition or retrieval terms. [1][2]

Before paying for tooling, negotiate written terms covering:

• Ownership: Who owns the mold, and when does title transfer?
• Permitted use: Who may use it, and for whose production?
• Ongoing costs: Who authorizes and pays for maintenance, repairs and storage?
• Program end: Will the mold remain in storage, transfer elsewhere or be disposed of—and who approves?
• Retrieval: What conditions, charges and timing apply, and who prepares and packs the tool for transfer?

Treat these as negotiated terms, not automatic buyer rights. Make tooling authorization contingent on an approved design and signed commercial terms.

Approve parting features and inserts

Require a supplier-marked drawing before tooling approval:

• Parting features: Identify the parting line, draft, vents, shut-offs, flash allowance and acceptance criteria.
• Each insert: Specify material, location, orientation, positional tolerance, application compatibility and who installs it.
• Acceptance: Agree on applicable pull-out, torque and insert-leak requirements, including test methods and limits.

Get these acceptance details agreed in writing by Custom Roto-Molding and Forté. [1][2]

Thomasnet lists fittings, ports and manways, plus a Solar Biz stock-tank option with molded-in aluminum drain plugs and aluminum drain inserts described as leak-proof. That vendor claim does not validate another insert or application. [6] Include each insert interface in the agreed test coverage.

Require a wall-thickness map and minimums

Water Storage Containers and Plastic Water Tanks claim even walls; Jinhong acknowledges thickness variation and recommends cross-section checks and thickness mapping. These are vendor claims and guidance, not independent acceptance standards. [3][4][5] Request numerical nominal-wall, minimum-wall and allowable-variation limits from each supplier. [3][4][5]

Put these requirements in the drawing or inspection plan for supplier agreement:

• Wall requirements: nominal thickness, minimum acceptable thickness and allowable variation across the part.
• Measurement plan: locations and methods, including critical interfaces and application-relevant load-bearing areas.
• Approval evidence: recorded thickness results tied to the sample and checked against each agreed requirement.

For repeat orders, ask which sample, resin-lot and process records will be retained and linked to production. Jinhong recommends recording the approved sample, resin lot, mold finish and process settings. [5]

Specify trimming and finished interfaces

Forté lists 5-axis CNC trimming/finishing; request numerical trim tolerances and an edge-finish acceptance standard. [2]

Request a finished-part drawing defining dimensions, datums, tolerances, opening locations and acceptable edge condition for each assembly interface. Ask for inspection records showing compliance. Agree on permitted rework and who approves deviations before shipment, rather than relying on a general finishing claim.

Agree on leak-test acceptance before production

Water Storage Containers and Plastic Water Tanks describe “watertight” products and inspection against customer specifications; ask them for a complete leak-test protocol and independent leak-performance data. [3][4]

Ask whether testing applies and whether the proposed procedure suits the part and application; do not simply apply a liquid-tank test to every enclosure. Include this requirement in the RFQ:

Where leak testing applies, test using [medium] at [pressure or vacuum], for [hold time], at [temperature], with [allowable loss]. Cover [part areas, applicable inserts, fittings and other interfaces], using [sampling plan], and reject parts at [rejection threshold]. Provide [test records] and follow [failure disposition, authorized rework and retest procedure].

Make written protocol agreement and acceptable sample test evidence conditions of production release. Have the supplier confirm the proposed conditions before testing.

What to confirm with each provider

Ask Custom Roto-Molding and Forté to confirm pricing, commercial terms and delivery coverage. [1][2] Request:

• Itemized tooling, piece-part, finishing, inspection, storage and freight charges.
• Minimum orders, lead times, payment terms, warranty and cancellation conditions.
• Delivery confirmation for the actual destination.

Send both suppliers the same drawing revision and ask each to mark every requirement confirmed, exception taken or clarification needed. Resolve exceptions before selecting a supplier. Use this production-release checklist:

• Signed application and exact resin specification.
• Agreed tooling terms and approved drawings.
• Acceptable sample inspection evidence.
• Agreed leak-test acceptance, where applicable.

References

1. Custom Roto (customroto.com)
2. Custom Rotational Molding Products – Forté Products (forteproducts.com)
3. Rotational Molding CustomTanks Made To Your Specifications Call Us Today (water-storage-containers.com)
4. Custom Roto Mold Tank Made To Specification Save Money and Time Call Us (plastic-watertanks.com)
5. How Do Rotational Molding Products Meet Custom Color Requirements? – Jinhong (jinhongmold.com, 2026)
6. Rotationally Molded Plastic Tanks Manufacturers and Suppliers in the USA and Canada (thomasnet.com)