What Aerospace Special Processes Cost, and Why
Special processing is priced mostly per lot, not per part: a minimum lot charge, masking labor, the size of tank or furnace the parts need, the spec and class, any bake or test, and the certification for that lot. On small orders the minimum charge and the masking usually decide the price, and both are set largely on the drawing.
Updated
The short answer
An anodize, plating, passivation, heat treat, peening or NDT job costs what the lot charge, the handling and masking labor, the equipment time, any required testing and the certification add up to. For small aerospace lots, the processor's minimum charge is often larger than the per-part cost.
We looked for public price lists or government cost data for these processes and found none a buyer can use for a quote. What we did find is listed under public numbers below. This guide explains each cost driver, why it moves the price and how a buyer controls it. For the specs themselves, see our special processes sourcing page.
How a processor prices a job
Process houses price around their equipment cycle, not around your part count. A tank line, furnace load or peening setup costs about the same to run whether it holds one bracket or a full rack, so the quote is built to cover that run.
- Lot or minimum charge: the floor price for opening a job, racking, running a cycle and closing the paperwork.
- Per-part, per-area or per-load pricing: above the minimum, many processors price by piece, by surface area or by furnace or rack load.
- Handling and masking: cleaning, racking or fixturing, masking and demasking, often the largest labor line.
- Testing: thickness checks, hardness or conductivity readings, process control panels and any lot acceptance tests the spec requires.
- Certification: the process cert for the lot, plus any customer forms or extra data.
- Freight and handling between shops: often on your side of the ledger, not the processor's.
Cost drivers at a glance
These drivers move special process quotes the most. The right column is what the buyer can actually change.
| Driver | Why it moves cost | How the buyer controls it |
|---|---|---|
| Lot charges and minimums | Each run costs the processor a setup and a cycle regardless of part count | Batch part numbers that share a process; release in fewer, larger lots |
| Masking complexity | Masking and demasking are hand labor, and poor masking causes rework | Mask only what function requires; show masked areas clearly on the drawing |
| Tank, furnace or cabinet size | Large or long parts need large equipment that fewer shops own and that costs more per run | Send part envelope and weight early; avoid designs that just exceed common equipment |
| Spec, type and class | Hard anodize, thicker plating, chromate chemistries and tight thickness ranges take more time and control | Call out the type, class and thickness the function needs, not the most demanding option |
| Hydrogen embrittlement relief bake | Adds a timed furnace step soon after plating on susceptible steel | Give material and heat treat condition so the right bake is applied once |
| Nadcap and prime approvals | Approval requirements shrink the pool of eligible processors | Flow down only the approvals your contract requires, with the clause or list |
| Testing and certification per lot | Thickness, hardness, conductivity, test panels and certs are labor on every lot | Ask for the data the spec or contract requires; avoid custom forms |
| Sequencing and transport | Each processor in the routing adds a trip, a queue and a minimum charge | Group processes at one house where approvals allow; plan the route up front |
| Rework and strip | Stripping and reprocessing cost more than the first run and can damage parts | Get callouts, masking and sequence right before the first lot |
| Rush scheduling | Expedites break into scheduled runs or run a cycle for one lot | Give real need dates early; ask which step is the constraint |
Lot charges and minimums
The minimum lot charge is the single most common surprise on small orders. When five machined parts go out for anodize, the anodize line can cost more than the machining of one part, because the processor still opens a job, racks, runs a cycle, tests and certifies.
The lever is batching. Part numbers that share the same alloy family, spec, type and class can often run together. Standardizing finishes across a program, where engineering allows it, turns several small lots into one. If you buy machined parts and finishing together, ask the supplier to show the outside processing lines separately so you can see where minimums are adding cost. Our machining cost guide shows how those lines sit inside a part price.
Masking complexity
Masking is hand labor, often the largest labor content in a coating job, and the most common source of rework. Every masked thread, bore, bonding surface or peen-shielded area adds time to mask, time to demask and a chance of a defect.
Cost rises with the number of masked features, how close masked and coated areas sit to each other, and how sharp the boundary must be. Plugs and caps for standard holes are quick. Custom masking around complex edges, or on parts that need several processes with different masking each time, is slow. If masking is not shown clearly on the drawing, the processor either quotes for the worst case or asks questions that delay the job.
Ask engineering which surfaces truly must stay bare. Grounding and bonding surfaces may be better served by a conductive finish such as Class 3 chem film than by masking. Hard anodize and plating add thickness, so tight fits are sometimes machined undersize instead of masked. Each choice belongs on the drawing.
Tank, furnace and cabinet size
The equipment has to fit the part, and big equipment is scarce and expensive to run. A long tube, a large panel or a heavy weldment can rule out most processors before price is even discussed.
Large tanks hold more chemistry to heat, filter and maintain. Large furnaces take longer to load and bring to temperature, and heat treat furnaces must be qualified to AMS 2750 pyrometry for the temperature tolerance your spec requires, which adds survey and calibration cost that grows with the furnace. Large NDT booths, peening cabinets and blast rooms follow the same logic. When only a few shops can fit the part, they also tend to have the longest queues.
Send overall envelope, weight and the surfaces to be processed with the first request. A part that only just exceeds a common tank size is worth a conversation with engineering before the design is frozen.
Process spec, type, class and thickness
The callout sets the chemistry, cycle time and controls, so it sets much of the price. The most demanding option is not the safe default; it is the expensive one.
- Anodize: MIL-PRF-8625 Type III hard anodic coating runs longer and needs more process control than Type II sulfuric acid anodize, and it builds more thickness, which makes masking and dimensional allowance matter more. Class 2 dyed adds a dye step and color control over Class 1 non-dyed.
- Chromate chemistries: Type I chromic acid anodize and Type I chem film under MIL-DTL-5541 use hexavalent chromium. OSHA's chromium (VI) standard, 29 CFR 1910.1026, sets a permissible exposure limit of 5 micrograms per cubic meter as an 8-hour average, and on DoD work DFARS 252.223-7008 (January 2023) prohibits deliverables containing more than 0.1 percent hexavalent chromium by weight in any homogeneous material unless the contracting officer specifies otherwise. Fewer shops run these lines, which affects price and availability, and the clause flows down to subcontracts.
- Plating thickness: thicker deposits take longer in the tank, and tight thickness ranges need more measurement and sometimes more racking care. Precious metal plating adds material cost that moves with metal markets.
- Heat treat: the alloy, the required condition and the furnace class needed for the temperature tolerance decide which furnaces qualify and how long the cycle runs.
A callout that gives only a spec number lets the spec's defaults choose for you. State type, class, thickness and options so every processor prices the same job.
Hydrogen embrittlement relief bake
A relief bake on plated high strength steel adds a timed furnace cycle that has to start soon after plating, which costs furnace time and scheduling. It is a safety requirement, so the cost lever is applying it correctly the first time, not skipping it.
AMS 2759/9 ties bake requirements to the strength or hardness of the steel, and ASTM B850 notes that the bake follows plating and comes before any secondary conversion coating. The processor can only choose the right bake if the order gives the material and its heat treat condition. Without that, the processor either asks, which delays the job, or applies a conservative cycle. A missing bake found later can mean scrapping parts, because hydrogen damage is not something you can inspect away.
Nadcap and prime approvals
Approval requirements change cost by shrinking the pool of eligible processors and by adding the processor's own cost of keeping those approvals. Both show up in price and lead time.
Nadcap, administered by the Performance Review Institute, runs 24 critical process accreditation programs. Processors pay for their own audits. Boeing's supplier site, in an undated Nadcap FAQ, lists audit prices by audit length from $4,850 for a 2 day audit to $7,150 for a 5 day audit, including auditor travel, priced per special process commodity. Treat those figures as indicative, since the page carries no date. The same FAQ says the first reaccreditation audit comes within twelve months of the initial audit, with later audits at 18 or 24 month intervals under the Supplier Merit Program depending on performance. A processor holding several commodity accreditations carries those audit costs plus the staff time to prepare and close findings.
Prime approved source lists, such as Boeing's D1-4426, narrow the field further, sometimes to one or two processors for a given spec. When few shops qualify, buyers have less room to compare prices. Flow down the approvals your contract actually requires, by spec and process code, and no more.
Testing and certification per lot
Every lot carries its own inspection and cert, so small lots pay that cost more often. This is real labor and it is not optional when the spec or contract requires it.
Depending on the process, a lot may need coating thickness readings, hardness or conductivity checks after heat treat, Almen strip verification for peening, penetrant system checks for NDT, or test panels processed with the parts. Some specs also call for periodic process control tests that the processor runs on a schedule and spreads across its customers. The cert itself, with processor, spec, type and class, lot, date, results and signature, takes quality time. Custom data formats and extra test reports add more. Our first article inspection guide explains how these certs feed AS9102 Form 2.
Sequencing and transport between processors
A routing with several processors costs more than the sum of their prices, because each hop adds packaging, freight, a queue and another minimum charge. Moving parts is often the hidden cost.
A steel part that needs heat treat, penetrant, plating, bake and paint may visit three or four shops. Each one has its own receiving inspection, its own lot charge and its own cert. Parts can also be damaged or mixed between lots in transit. Where approvals allow, using a processor that holds several of the required processes cuts trips and handoffs. Fix the sequence on the drawing or routing before release so nobody has to stop and ask mid-route. Our lead times and delivery reference covers how routing affects schedule.
Rework and strip
Rework is the most expensive way to buy a finish. Stripping a coating, reprocessing and recertifying usually cost more than the original run, and some parts cannot survive it.
Stripping removes base metal along with the coating, which can take a tight feature out of tolerance. On susceptible steels, stripping is itself one of the processes that can introduce hydrogen and require a bake. Repeat heat treatment may not be allowed by the spec or the customer. Most rework traces back to a missing callout, unclear masking or a sequence error, so the cheapest fix is a complete drawing and purchase order. If rework is needed, decide in writing who pays and require the strip and reprocess to appear on the certs.
Rush scheduling
Expedites cost more because they disrupt a schedule built around full loads. A processor that runs a heat treat cycle or a tank line for one rush lot gives up the load it would have run.
Some batch processes run on fixed days, so a rush may mean a dedicated cycle or overtime. Approved source limits make this worse, because there may be no second shop to try. Tell the supplier which step is the constraint and whether partial shipments help. We do not promise lead times; we prioritize rush requests and tell you what is realistic once we see the routing.
Public numbers worth knowing
We checked government and industry sources for processing price data. None publishes a usable price list for anodize, plating, heat treat or NDT. These are the figures we could verify.
- Price trends: on the Producer Price Index published by the Bureau of Labor Statistics and charted by FRED, the industry index for electroplating, anodizing and coloring metal rose about 6 percent between August 2025 and August 2026, and the index for metal heat treating rose about 8 percent. Recent months are preliminary and can be revised.
- Operator pay: BLS reports median annual wages in May 2025 of $43,960 for plating machine setters, operators and tenders and $48,750 for heat treating equipment setters, operators and tenders. A processor's price also covers chemistry, energy, waste treatment, equipment, quality staff and approvals.
- Accreditation cost: the Boeing Nadcap FAQ audit prices described above, $4,850 to $7,150 per audit depending on length, undated.
Compare complete quotes on the same callouts, quantity and approvals rather than any single unit price.
Ways to lower special process cost
- Batch part numbers that share a spec, type and class into fewer lots.
- Mask only what function requires, and show it on the drawing.
- Call out the type, class and thickness the function needs.
- Give material and heat treat condition on every plating order.
- Flow down only the approvals the contract requires.
- Plan the full routing and sequence before release, and group processes where approvals allow.
- Give real need dates early instead of paying to expedite.
Our aerospace RFQ checklist covers the rest of a complete request. For background, see our library pages on surface finishing, heat treatment and nondestructive testing. Fluid and propulsion parts that need cleaning are covered on our precision and oxygen cleaning page.
Get special processing quoted on your real routing
Send the drawing, the process callouts, the material condition and the quantity through the special process quote form. Lot size and approvals decide which processors can take the job and how much of the price is minimum charges, so stating them first gives you comparable numbers. A person replies within 1 business day, and rush requests are prioritized. We do not run tanks or furnaces. We match your parts to processors whose approvals fit your specs, flow down sequence, masking and source requirements, check each process cert, and give you one quote, one point of contact and one purchase order even when several processors are in the route. Every order ships with a certificate of conformance. If the drawing is ITAR or CUI controlled, see our confidentiality page and controlled programs instead of attaching it to the form.
Send the job. A person replies within 1 business day.
Part, quantity and date are enough to start. Drawings and the mutual NDA follow by reply, and controlled programs never send technical data through this site.
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Questions
Why does anodizing a few parts cost so much?
Most processors charge a minimum per lot because opening a job, racking, running a cycle, testing and certifying cost about the same for one part or a full rack. On a small lot the minimum often outweighs the per-part price. Batching part numbers that share the same spec, type and class, or releasing fewer and larger lots, is the usual way to bring the cost per part down.
Does Type III hard anodize cost more than Type II?
Usually. Under MIL-PRF-8625, Type III hard anodic coating runs a longer, more tightly controlled cycle than Type II sulfuric acid anodize and builds more thickness, so masking and dimensional allowances matter more. Dyeing for Class 2 adds another step. Call out Type III where wear resistance needs it, and Type II where corrosion protection or color is the real requirement.
Does requiring a Nadcap accredited processor raise the price?
It can, mostly by narrowing the choice of processors and by adding the processor's cost of keeping accreditation. Processors pay for their own audits; Boeing's undated Nadcap FAQ lists audit prices of $4,850 to $7,150 depending on audit length. When your contract requires Nadcap or a prime approved source, it is not optional, but flow down only the approvals the contract actually names.
Who pays if parts have to be stripped and reprocessed?
It depends on the cause. If the processor made the error, many will strip and reprocess at their cost. If the callout, masking or sequence on the drawing was wrong or missing, the buyer usually pays. Agree in writing before reprocessing, and require the strip and reprocess to appear on the certs, because stripping can affect dimensions and can require a hydrogen relief bake on susceptible steel.
Are there published prices for plating or heat treat?
We did not find a government or neutral industry price list. The BLS Producer Price Index tracks price changes: the electroplating, anodizing and coloring index rose about 6 percent and metal heat treating about 8 percent from August 2025 to August 2026, as charted by FRED. Those show direction, not your price. Comparing complete quotes on the same callouts and lot size is more reliable.
How can I cut special process cost without changing the design?
Batch part numbers into fewer lots, show masking clearly so it is quoted correctly, give material and heat treat condition on plating orders, plan the full routing so parts make fewer trips, and give realistic need dates early. Asking the supplier to show each outside process as its own line also shows where minimum charges are adding cost.
Related
Sources
- U.S. Bureau of Labor Statistics, Occupational Outlook Handbook: Metal and Plastic Machine Workers (pay, May 2025)
- FRED, St. Louis Fed: PPI by Industry, Electroplating, Anodizing and Coloring Metal (PCU332813332813)
- FRED, St. Louis Fed: PPI by Industry, Metal Heat Treating (PCU332811332811)
- Boeing Suppliers, Nadcap Accreditation FAQ (undated, viewed October 2026)
- Performance Review Institute, Nadcap program overview
- Acquisition.gov, DFARS 252.223-7008 Prohibition of Hexavalent Chromium (January 2023)
- OSHA, 29 CFR 1910.1026 Chromium (VI)
- SAE International, AMS 2759/9 Hydrogen Embrittlement Relief (Baking) of Steel Parts
- BSI Knowledge, ASTM B850 Standard Guide for Post-Coating Treatments of Steel for Reducing the Risk of Hydrogen Embrittlement
- DLA ASSIST via ibiblio, MIL-A-8625F Anodic Coatings for Aluminum and Aluminum Alloys
- Boeing Suppliers, Q020 D1-4426 Approved Process Source clause
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