FRP, GRP, fiberglass and resin are not four different materials. FRP (fiber-reinforced plastic) and GRP (glass-reinforced plastic) are the same composite family, and "fiberglass" in everyday US English means glass-fiber reinforcement set in polyester or vinyl ester resin. Cast resin is a different process with no glass reinforcement, so it is brittle and unsuited to large outdoor sculpture.
The Short Answer: FRP, GRP and Fiberglass Are One Family
FRP stands for fiber-reinforced plastic. GRP stands for glass-reinforced plastic and is the term used in the UK, Australia and much of Europe. In a sculpture context, both describe the same thing: glass fiber, either chopped strand mat or woven roving, laid into a mold and saturated with liquid resin that cures hard. The glass carries the load, the resin binds it and seals it.
"Fiberglass" is the everyday American word for that same composite. When a US buyer asks for a fiberglass statue, they mean a glass-reinforced polyester or vinyl ester shell, usually built over a steel armature. There is no meaningful difference between a fiberglass sculpture, an FRP sculpture and a GRP sculpture. The difference that matters is how the part is built, not what you call it.
Where confusion starts is when a supplier quotes "resin" as a material. Resin is one ingredient in fiberglass, but cast resin is a separate product category with different properties, different cost structure and different limits.
Cast Resin Is Not Fiberglass: No Glass, No Structure
Resin casting means pouring or rotocasting liquid resin into a mold with no glass reinforcement inside. The cured part can look identical to fiberglass on day one, especially with a good gel coat and paint. It fails differently. Without glass fiber, a crack propagates straight through the wall instead of stopping at a fiber layer.
Cast resin is also heavy for the strength it delivers. A 6 ft cast resin figure can weigh more than a 6 ft fiberglass figure of the same shape because the wall has to be thick to compensate for the missing reinforcement. Wall thickness on cast resin typically runs 0.4 in to 1 in solid, while a hand-laid fiberglass shell runs 0.12 in to 0.5 in depending on span and load.
For indoor display pieces under about 3 ft, cast resin is fine and often cheaper on tooling. For anything life size, anything outdoors, and anything that has to survive wind load, cast resin is the wrong call. This is the single most common substitution problem we see on incoming purchase orders.
Side-by-Side Material Comparison
The table below compares the materials a US buyer is most likely to be quoted. Read the "structure" and "glass reinforcement" rows first, because those two rows determine everything below them.
| Property | Fiberglass / FRP (hand layup) | Cast resin | Polyurethane (PU) | Cold-cast bronze |
|---|---|---|---|---|
| Structure | Glass mat and woven roving in resin over welded steel frame | Solid or hollow cast resin, no fiber | Expanding rigid foam in a mold, often coated | Resin or fiberglass shell filled with bronze powder and resin |
| Glass reinforcement | Yes, multiple layers | None | None | Optional, depends on builder |
| Strength to weight | High | Low | Low to medium | Medium |
| Typical wall thickness | 0.12 in to 0.5 in | 0.4 in to 1 in solid | 0.4 in to 2 in foam | 0.12 in to 0.3 in shell |
| Outdoor suitability | Excellent with UV-stable gel coat | Poor, warps and cracks | Poor, UV degrades foam | Good indoors, patina shifts outdoors |
| Service life outdoors | 10 to 30+ years | 1 to 3 years | 1 to 4 years | 5 to 10 years |
| Cost band | Mid to high, scales with size | Low for small parts | Low to mid | High |
| Best use | Life-size figures, landmark pieces, themed facades | Small indoor props under 3 ft | Lightweight indoor decor, short-term sets | Gallery-style indoor figures, trophies |
What Buyers Should Specify on a Purchase Order
If you write "resin sculpture" on a PO, you can legally receive cast resin. If you write "fiberglass," you can still receive cast resin from a supplier who treats the words as interchangeable. The fix is to specify the build, not the material name.
Put these items in writing on the PO and in the drawing notes:
- Material: glass-reinforced polyester or vinyl ester, hand layup, minimum 2 layers of chopped strand mat plus 1 layer of woven roving.
- Internal frame: welded steel, hot-dip galvanized or primed with anti-rust coating, engineered for the stated wind load.
- Finish: UV-stable gel coat, Pantone color match to 98% accuracy, plus clear coat if the piece faces direct sun.
- Wall thickness: state a minimum, for example 0.2 in on a 6 ft figure, 0.3 in on a 12 ft figure.
- Fire rating: fire-retardant FRP if the piece goes into an indoor public space.
- Documentation: material spec sheet, frame photos before skinning, and a written 12-month warranty against manufacturing defects.
Ask for in-process photos of the steel frame and the glass layup before gel coat. A cast resin supplier cannot produce those photos because there is no frame and no glass. That single request filters most of the risk out of a quote.
Spray-Up vs Hand Layup: Same Word, Different Quality
Chopper gun spray-up and hand layup both produce fiberglass, but they are not equal. A chopper gun cuts continuous strand roving into short fibers and sprays them with resin at the same time. It is fast, and it is common on high-volume flat panels.
Hand layup places mat and woven roving by hand, layer by layer, with resin rolled out to remove air. Fiber orientation stays where the builder puts it, which matters on a curved figure, a cantilevered arm, or a base that takes wind load. Hand layup costs more in labor and produces a stronger, more consistent shell.
For a landmark piece, the spec should say hand layup over a welded steel frame. FibraCraft builds this way as a custom fiberglass sculpture manufacturer, using marine-grade resin and UV-stable gel coat on every outdoor project. If a quote is unusually low for a 10 ft figure, ask which process is being used before you compare it to anyone else.
Price, Lead Time and Shipping Reference
The table below is a factory-direct reference for planning. Freight is quoted per project because volume and destination drive it. Sea freight door-to-door (DDP) to any US state typically runs 5 to 9 weeks total and is roughly 80% cheaper than air for large heavy pieces.
| Item | Typical range | Notes |
|---|---|---|
| Small props and figures | $1,200 to $5,000 | Under 3 ft, indoor or sheltered outdoor |
| Life-size figures | $4,500 to $12,000 | 5 ft to 7 ft, steel frame included |
| Large landmark pieces | $30,000 to $150,000 | 10 ft and up, engineered frame, site planning |
| Mold and tooling | $1,200 to $1,500 | One-time, reusable for repeat orders |
| Production lead time | 3 to 6 weeks | From approved design, standard pieces |
| Production lead time | 12 to 16 weeks | Very large or complex landmark pieces |
| Payment terms | 30% deposit, balance before shipment | Wire transfer and credit cards accepted |
| Warranty | 12 months | Written, against manufacturing and quality defects |
FibraCraft runs MOQ 1 piece, so a single custom figure and a batch order of 20 go through the same process. Quotes are itemized in USD within 24 hours, with mold cost, production, finish and shipping listed separately so you can see what each line actually buys. Send photos, sketches, drawings or 3D files to request a quote, and you get a free 3D rendering and design consultation with the inquiry.
Related Materials: Polyurethane and Cold-Cast Bronze
Polyurethane sculpture is molded rigid foam, often with a hard coating. It is light and cheap for indoor decor, and it is the right choice for a trade show set that ships in a crate and comes down in a week. It does not hold up outdoors because UV breaks down the foam and the coating separates from the substrate.
Cold-cast bronze is a resin or fiberglass shell loaded with bronze powder, then finished to look like cast metal. It reads well indoors and costs a fraction of a real bronze pour. Outdoors, the surface patina shifts with weather and the piece needs recoating more often than a gel-coated fiberglass sculpture.
If your project is a life-size figure, a themed facade element, or anything that stays outside year round, fiberglass hand layup over a steel frame is the material that meets the requirement. Browse custom FRP sculptures for build examples and finish options.
FAQ
Is FRP the same as fiberglass?
Yes. FRP means fiber-reinforced plastic, and in sculpture work the fiber is glass, so FRP and fiberglass describe the same composite. GRP is the British term for the same material. Expect a wall thickness of 0.12 in to 0.5 in on a hand-laid shell.
How do I make sure I get fiberglass and not cast resin?
Specify hand layup, minimum 2 layers of glass mat plus 1 layer of woven roving, and a welded steel frame, and ask for in-process photos before gel coat. A cast resin supplier cannot provide frame photos because there is no frame. Put the 12-month warranty in writing on the PO.
How long does a fiberglass sculpture last outdoors?
With marine-grade resin and a UV-stable gel coat, 10 to 30+ years is realistic. Plan a gel coat refresh every 5 to 7 years. Cast resin in the same location typically fails in 1 to 3 years.
What does a custom fiberglass sculpture cost?
Factory-direct bands run about $1,200 to $5,000 for small props, $4,500 to $12,000 for life-size figures, and $30,000 to $150,000 for large landmark pieces. Mold and tooling adds $1,200 to $1,500. Quotes are itemized in USD within 24 hours.
How long is production and shipping to the US?
Production runs 3 to 6 weeks from approved design for standard pieces and 12 to 16 weeks for very large landmark work. Sea freight door-to-door to any US state adds 5 to 9 weeks total and is roughly 80% cheaper than air for large heavy pieces.