Custom FRP Manufacturing: Sizes, Resins, Colors, Molds and OEM Explained

In short: Most FRP products can be made to order. Sizes, resin system, color, surface finish, fabrication and branding can all be changed, and new shapes can be made with a new mold or pultrusion die. Some changes are simple, such as cutting to length or changing color. Others, such as a new profile shape, need tooling and more time. Knowing which is which helps you plan cost and lead time. FIBROVX makes every item to order in our own factory: sizes, resin system, color, molds and OEM branding.

What can be customized

Which changes need new tooling

The most useful question to ask early is whether a change needs new tooling. The table below shows the usual answer for the three main processes. Your supplier should confirm it for your exact part.

As a rule, anything that changes the material or the finish reuses existing tooling. Anything that changes the shape needs a new mold, die or mandrel. Fabrication such as cut-outs, holes and nozzles is done after molding and needs no tooling.

Size

Many products are already made in variable sizes. Molded grating panels can be cut to your layout, pultruded profiles can be cut to length, and filament-wound tanks are built to the diameter and height you need within the range of existing mandrels.

Resin system

The resin sets chemical, heat and fire performance. Common families are orthophthalic and isophthalic polyester, vinyl ester and phenolic. See polyester vs vinyl ester vs phenolic resin. Fire-retardant additives and UV inhibitors can be added where needed.

How the resin choice affects a custom order

The resin is a material choice, not a tooling choice, so it is one of the easiest things to customize. Send the chemicals, concentrations and temperatures, and ask for the proposed resin in writing. Our chemical resistance guide explains how to check a resin against your service.

Color and surface

Pigment is mixed into the resin, so color runs through the part. Give a RAL code or a sample. Surfaces include grit for slip resistance, concave tops for grating, synthetic surface veils for UV and corrosion resistance, and smooth gel-coated finishes for molded parts.

Molds and dies

A new shape needs new tooling:

• Molded grating and molded parts use steel or composite molds.
• Pultruded profiles use a heated steel die for each cross-section. See what is pultrusion.
• Filament-wound tanks and pipes use mandrels of a set diameter.

Tooling is a one-time cost. It makes sense when the quantity, or a repeat program, justifies it. Ask whether an existing mold or die is close enough before ordering new tooling.

Worked example: new die or existing section?

Suppose you need 3,000 m of a pultruded channel. An existing standard channel is a little heavier than your design needs. A new die would give a lighter section that uses less material. The numbers below are hypothetical index units, not prices, chosen only to show the method. Your quotation will have its own figures.

The custom section saves 1.20 units per meter, so the die pays for itself after 6,000 ÷ 1.20 = 5,000 m. At 3,000 m, the existing section is cheaper. If you have a repeat program of, say, 10,000 m a year, the new die is cheaper from the first year. Lead time matters too: a new die adds time for die making and trial runs, so check it against your schedule.

The same method works for molds and mandrels. Divide the tooling cost by the saving per unit to find the break-even quantity. Then compare that quantity with your total program, not just the first order.

OEM branding

FRP products can carry your brand: molded-in logos where the mold allows, printed labels, and custom packaging. Send vector artwork and the placement you want.

Tolerances and quality documents

Custom parts need agreed tolerances and checks. Useful references are:

• Pultruded profiles: EN 13706 covers specifications for pultruded profiles, including tolerances, and ASTM D3917 covers dimensional tolerances of pultruded shapes.
• Filament-wound and contact-molded tanks: ASTM D3299 covers materials, construction and dimensions. Its 2026 edition (D3299-26) also covers contact-molded tanks, which were in ASTM D4097 until ASTM withdrew it in 2026.
• Cure: Barcol hardness, measured to ASTM D2583, is a quick check that the resin has cured.
• Glass content: the ignition-loss method of ASTM D2584 measures how much glass is in the laminate.

Write the tolerances and checks you need on the drawing or in the purchase order. Agree which documents come with the shipment, such as a dimensional report, hardness readings and photos of marking and packing. Standards like these are references for the specification. They are not certifications, and you should ask for the actual test records for your order.

What to send with a custom inquiry

• a drawing or sketch with the key dimensions and tolerances (DWG, DXF, STEP or PDF);
• the application, loads and spans, and whether the part is indoors or outdoors;
• chemicals, concentrations and temperatures;
• color as a RAL code or sample, and the surface finish;
• quantity, delivery schedule and any repeat program;
• branding artwork and packing or marking rules;
• the destination port or site.

The more of this you send at the start, the fewer questions we need to ask and the faster the technical review runs.

How a custom order runs

1. Inquiry. Send application, drawing or sketch, quantity and destination.
2. Technical review. We check loads, chemicals, sizes and tooling.
3. Quotation. Price, lead time and any tooling cost.
4. Drawing approval. You approve the shop drawing.
5. Tooling or sample. New tooling is made, or a sample is produced for approval.
6. Production.
7. Inspection. Dimensions, appearance and agreed tests.
8. Packing and shipment.

What sets the lead time

Lead time depends mostly on four things:

• Tooling. Existing tooling starts production quickly. A new mold, die or mandrel adds tooling time and a trial.
• Approvals. Drawing and sample approvals hold production until you confirm them. Fast replies save time.
• Material. Standard resins and glass are usually in stock. Special resins or additives may need ordering.
• Fabrication and testing. Cut-outs, assemblies and agreed third-party tests add time after molding.

Ask for the lead time broken into these steps. Then you can see which steps you can shorten, for example by approving drawings quickly or choosing an existing section.

Customization

FIBROVX builds FRP molded grating, pultruded profiles, tanks, acid fume scrubbers and cable trays to order. Tell us what you need to change, and we will tell you whether existing tooling fits.

Common mistakes

• Ordering new tooling when an existing size is close enough.
• Choosing color without a RAL code or sample.
• Leaving out chemicals and temperature, which set the resin.
• Skipping drawing approval.
• Not planning tooling time into the schedule.
• Changing several things at once without a sample. A sample or first article confirms color, surface and fit together.
• Not agreeing who owns the tooling. Put tooling ownership and storage in writing.

Key terms

• Tooling: Molds, dies or mandrels used to shape FRP.
• Pultrusion die: Heated steel die that sets a profile's cross-section.
• OEM: Products made under the buyer's brand.
• RAL: A color reference system.

Watch: Custom FRP Manufacturing in 27 Seconds

FAQ

Can FRP products be made to my size?

Usually yes. Many sizes need no new tooling.

When is a new mold needed?

When the shape or cross-section is new and no existing tool fits.

Can you put our logo on the product?

Yes, with labels, packaging or a molded-in logo where the mold allows.

Is there a minimum order?

It depends on the product and whether tooling is needed. Ask with your quantity.

Can you match an existing profile or part?

Often, yes. Send a drawing or a sample with the key dimensions. If no existing tool fits, we can quote a new mold or die.

Who owns a custom mold or die?

That should be agreed in writing at the quotation stage, together with how long the tooling is stored and whether it can be used for other customers.

Can I order a small trial batch first?

It depends on the product. Where existing tooling fits, small batches are often possible. Where new tooling is needed, the tooling cost is the same for any quantity, so check the break-even point first.

Does a custom color cost more?

Usually a little, because a non-standard color may need its own batch. Give a RAL code or a sample to avoid a mismatch.

Related guides

• How FRP Is Made: 4 Processes Explained
• FRP Pultruded Profiles: Shapes & Specs
• FRP CAD Drawings: Which Files to Request
• Polyester vs Vinyl Ester vs Phenolic Resin
• How to Import FRP from China
• Industries we serve
• FRP Quality Control: Barcol Hardness, Glass Content and Traceability
• Bio-Based and Recyclable Thermoset Resins: What Is Coming for FRP

Sources

• RAL colors, official color reference: https://www.ral-farben.de/en/
• BSI / CEN, EN 13706, Specifications for pultruded profiles: https://knowledge.bsigroup.com/products/reinforced-plastics-composites-specifications-for-pultruded-profiles-specific-requirements
• ASTM D3917, Dimensional Tolerance of Thermosetting Glass-Reinforced Plastic Pultruded Shapes: https://www.astm.org/d3917-15.html
• ASTM D2583, Indentation Hardness of Rigid Plastics by Means of a Barcol Impressor: https://www.astm.org/d2583-13a.html
• ASTM D2584, Ignition Loss of Cured Reinforced Resins: https://www.astm.org/d2584-18.html
• ASTM D3299-26, Filament-Wound and Contact-Molded Glass-Fiber-Reinforced Thermoset Resin Corrosion-Resistant Tanks: https://store.astm.org/d3299-26.html
• ASTM D4097, Contact-Molded Glass-Fiber-Reinforced Thermoset Resin Corrosion-Resistant Tanks (withdrawn 2026): https://www.astm.org/d4097-19.html