Custom Fiberglass Parts RFQ Checklist: What to Send Your Manufacturer

Incomplete information does not necessarily prevent an initial discussion. A sketch, sample, installation envelope, or description of the application may be enough to identify the next questions. However, better project inputs generally reduce assumptions and help the supplier compare tooling, material, process, inspection, and logistics on a consistent basis.

Not every project requires every item below. Use the checklist according to the part’s function, development stage, risk, and procurement requirements. Where information is not yet known, state that clearly instead of allowing the supplier to assume.

Quick RFQ Checklist for Custom Fiberglass Parts

1. Send a Drawing, CAD Model or Physical Sample

Useful starting inputs can include a 2D drawing, a 3D CAD model, STEP data, IGES where appropriate, a PDF drawing, an existing physical sample, or clear reference photographs for early-stage discussion. A controlled sketch with dimensions may also be useful when the project is still being defined.

Photographs can show general shape, installation, cosmetic condition, and neighboring components, but they normally do not establish production geometry by themselves. Manufacturing usually requires controlled dimensions, approved CAD, a master sample, or another agreed geometry source. State the revision and identify which document controls if several files are supplied.

2. Define Dimensions and Units Clearly

State whether dimensions are in millimeters or inches. Include overall length, width, and height; controlled wall thickness where applicable; hole locations; flange dimensions; openings; edge conditions; and interface dimensions. Datum or reference information can help when features must be located relative to mounting points or mating components.

Ambiguous units and missing references create quotation risk because the manufacturer may estimate tooling size, material usage, trimming, inspection, or packaging from an incorrect scale. If a dimension is approximate during early development, label it as approximate.

3. Identify Critical Tolerances

Not every dimension should automatically receive the same tight tolerance. Identify mounting interfaces, mating surfaces, hole positions, alignment features, sealing surfaces, and dimensions that directly affect assembly or function. Separate these from noncritical cosmetic or envelope dimensions where appropriate.

Achievable tolerance is project dependent. It can be influenced by geometry, molding process, tooling, laminate construction, cure behavior, trimming or machining, fixtures, and inspection method. Asking the manufacturer to review the critical features before tooling can help align the drawing with a practical production and measurement plan.

4. Provide Quantity and Expected Production Volume

Provide the prototype quantity, initial order quantity, expected repeat quantity, and annual volume if known. Also mention whether demand is stable, seasonal, uncertain, or still in validation.

Volume can affect tooling choice, manufacturing process, production planning, and unit economics. A low or uncertain quantity may justify a different tooling approach from a stable repeat program. The Hand Lay-Up vs RTM vs SMC guide explains how process selection interacts with tooling, repeatability, surface requirements, and production demand.

5. Explain What the Part Does

Describe the equipment and application, whether the part is structural or non-structural, whether it has a cosmetic role, and whether it acts as a cover, enclosure, housing, guard, panel, or support. State whether people may step, sit, lean, or apply loads to it, when relevant to the design.

Explain the mounting method and identify neighboring components, movement, clearances, service access, and maintenance needs. This context helps the supplier interpret which features are functional and which changes may be feasible during manufacturing review.

6. Describe the Operating Environment

Relevant exposure may include indoor or outdoor service, sunlight or UV exposure, rain, humidity, immersion, salt environments, chemical splash, cleaning chemicals, operating temperature, vibration, and abrasion. Note whether exposure is continuous, intermittent, or associated with maintenance and cleaning.

Material suitability remains specific to the selected resin, reinforcement, laminate, surface system, hardware, and service conditions. For chemical exposure, provide the actual chemical, concentration, temperature, and exposure mode where available.

7. State Resin and Material Requirements, If Known

A buyer may specify polyester, vinyl ester, epoxy, another approved resin system, or an existing material specification. If the resin is not predetermined, provide the operating environment, loads, finish requirements, process constraints, and approval needs so options can be reviewed.

The Polyester vs Vinyl Ester vs Epoxy Resin guide outlines qualitative trade-offs involving project economics, environment, adhesion, cure, and processing. No resin family is universally best for every FRP component.

8. Specify Reinforcement or Structural Requirements

If known, provide fiberglass mat or fabric requirements, a laminate specification, a structural drawing, relevant load requirements, or an approved material specification. Identify local loads, fastener areas, spans, supports, impact concerns, and stiffness expectations that may affect laminate design.

If the reinforcement is not yet defined, application and loading information may support an early process review. Final structural requirements, analysis responsibilities, validation, and acceptance criteria should be agreed for the project rather than assumed from a generic laminate.

9. Define Surface Finish and Appearance

State whether the part requires a molded finish, gelcoat, paint, smooth or textured surfaces, a particular color, or a gloss or matte preference. Mark which faces are visible or cosmetic and which are concealed in the assembly.

Where color standards are referenced, confirm the required standard, sample, viewing condition, and acceptance method during project review. Tool surface, reinforcement print-through, cure, trimming, repair, and post-finishing can all influence appearance.

10. Show Mounting and Interface Features

Show holes, flanges, brackets, bosses, inserts, embedded or bonded hardware, cutouts, access openings, and mating components. Identify critical datums, fastener types, edge distances, load directions, sealing interfaces, and any hardware supplied by the buyer.

Feature feasibility depends on geometry, tooling access, laminate construction, molding process, trimming, machining, bonding, and inspection. A clear interface definition helps the supplier review whether features should be molded, machined, bonded, or assembled.

11. Manufacturing Process Preference

If a process is required by an approved specification or existing program, state that requirement. Otherwise, buyers do not need to choose hand lay-up, RTM, SMC, or another route before the first inquiry.

Process choice may depend on geometry, quantity, surface requirements, repeatability, tooling economics, structural needs, material system, and available equipment. The supplier may need to compare more than one route before recommending a quotation basis.

12. State Inspection and Documentation Requirements

If required by the project, specify dimensional inspection, visual inspection, first-article documentation, material documentation, inspection reports, customer-specific forms, traceability, or approval records. Identify critical characteristics and the expected reporting format where available.

Do not assume that every document or certificate is included by default. Documentation scope can affect material sourcing, production records, inspection time, and quotation structure, so it should be discussed before order placement.

13. Packaging and Shipping Requirements

Provide the shipping destination and known transport mode, along with individual protection needs, stacking limitations, fragile or cosmetic surfaces, crate or pallet requirements, lifting points, and export packaging requirements where applicable.

Part size, geometry, finish, quantity, and route can affect how components are nested, supported, restrained, and protected. Special handling or destination requirements should be included in the RFQ rather than added after packaging has been planned.

14. Prototype and First-Article Requirements

State whether the project needs one or more prototypes, a dimensional review, a fit check, appearance approval, functional testing, or a sample before repeat production. Identify who approves the sample and which requirements are reviewed at that stage.

Prototype scope is project dependent. A prototype may evaluate geometry or fit without representing every aspect of repeat production, so the purpose and acceptance criteria should be clear.

15. Communicate the Target Schedule

Share the desired prototype date, production date, project launch date, and required delivery date. Distinguish a preferred target from a fixed downstream constraint.

Timing must be reviewed against design approval, tooling, material availability, production method, quantity, inspection, packaging, and logistics. If the design is still changing, include the expected drawing-release or approval date.

Example: Weak RFQ vs Useful RFQ

What If I Do Not Have a Complete Drawing Yet?

An early discussion may begin with sketches, reference photos, an existing sample, installation dimensions, or key constraints. Explain what is fixed, what can change, and which interfaces must be preserved.

Final manufacturing normally requires sufficiently controlled geometry and specifications. The next step may be measurement, CAD development, sample review, design clarification, or formal drawing approval, depending on the project and the supplier’s agreed scope.

Copyable RFQ Checklist

This on-page checklist can be copied into an inquiry or internal purchasing worksheet. It is a preparation aid, not a requirement that every box be complete before initial contact.

FAQ

This checklist provides general RFQ-preparation guidance. Final material, tooling, process, inspection, commercial, and delivery requirements should be confirmed for the specific project.