Composite Costing

Composite Part Cost Estimation and Quoting: What Really Drives Price

A cost-focused guide to quoting composite and fiberglass parts: the real drivers of cost per unit, how to amortize tooling, and the estimating errors that erode margin.

Composite cost per part splits into five buckets: material, labor, cure and machine time, scrap and rework, and amortized tooling and overhead. On a typical aerospace-grade prepreg part, material and labor each run 30 to 40 percent of variable cost, cure adds 10 to 20 percent, and scrap quietly eats 5 to 15 percent. The Composite Part Cost calculator rolls direct cost per part times quantity, then adds fixed tooling, engineering, and qualification. On 36 parts at 1,280 dollars direct plus 6,200 dollars fixed NRE, total is 52,280 dollars, or 1,452 dollars per part once the NRE is spread.

Material is where quotes are won or lost because carbon prepreg is expensive and perishable. Aerospace prepreg runs 40 to 120 dollars per lb; industrial dry carbon fabric is cheaper at 20 to 45 dollars per lb. The Carbon Fiber Material Cost calculator takes issued weight times purchase cost times scope, then adds cold-chain freight and qualification. Buy net weight from the nest, not gross: at 40.6 lb net and a 68 dollar per lb prepreg, the fiber alone is 2,761 dollars before a 750 dollar freight and handling adder. A 5 percent price swing on that line moves the quote by 138 dollars per part.

Labor is the second lever and the least predictable. Price it as loaded hours, not headcount. A fully burdened laminator rate of 55 to 85 dollars per hour, applied to the 14 layup hours from the layup labor model, is 770 to 1,190 dollars per part before cure or trim. Skill matters: a certified layup tech places good plies 20 to 30 percent faster than a trainee and scraps far less, so a lower hourly rate with a slow, error-prone crew often costs more per good part. Quote the crew you will actually staff, not the ideal one.

Cure and consumables are fixed-cost machines you must keep full. The Autoclave Cycle Cost calculator charges cycle hours times operating cost plus fixed setup and quality. At 14 cycle hours times 360 dollars per hour plus 950 dollars, one load costs 5,990 dollars. That is why loading matters: spread across 20 parts it is 300 dollars each, across 6 parts it is 998 dollars each. Vacuum Bagging Cost adds up faster than people expect too. Bag film, tape, peel ply, breather, and flow media at 2.45 dollars per sq ft over 620 sq ft is 1,519 dollars per part in consumables alone.

Scrap is the margin killer estimators forget to price in. Prepreg scrap from nesting, trim, and freezer expiry commonly runs 15 to 30 percent of purchased material on complex parts. The Prepreg Scrap Cost calculator makes it visible: 42 lb of scrap at 84 dollars per lb plus 250 dollars disposition handling is 3,778 dollars gone per work order. Trim adds more once the part is cured, since Trim Scrap Cost values the full processed laminate, not raw fiber. Fold an expected scrap factor into your material line rather than pretending yield is 100 percent.

Tooling and NRE must be amortized honestly across realistic volume. A carbon mold can cost 15,000 to 200,000 dollars depending on size and tolerance. If you spread it over an optimistic 1,000 pulls that never materialize, you underquote every part. Model good part capacity first: 2 parts per cycle over 500 cycles at 94 percent availability and 96 percent yield yields 902 good parts, not 1,000. A 40,000 dollar mold over 902 parts is 44 dollars per part; over the optimistic 1,000 it is 40. Quote to the realistic number and protect the margin.

Overhead and margin sit on top of variable and amortized cost. Composite shops carry 20 to 35 percent overhead for climate-controlled space, freezers, autoclave depreciation, and inspection, then add 10 to 20 percent margin. Do not bury margin inside inflated hours; keep it a visible line so buyers can negotiate scope, not your cost basis. A defensible quote reconciles top-down (last similar part per lb) against bottom-up (the calculators summed). If they disagree by more than 10 to 15 percent, one of your assumptions on nesting yield, cure loading, or labor pace is wrong, and you find it before you sign.

Common estimating failures share a root cause: stale or optimistic inputs. Using last year's 55 dollar per lb prepreg when the invoice now reads 68 understates material by 24 percent. Assuming full autoclave loads that never happen inflates capacity and hides per-part cure cost. Quoting first-article labor as if it were steady-state ignores a learning curve that can double early-run hours. Rebuild the quote from current invoices, actual nest yields, and observed cure loading every program, and the Composite Part Cost rollup stays defensible under audit rather than collapsing on the third purchase order.

Published 2026-07-01.