Aluminum Anodizing Guide: How to Choose the Right Type, Thickness, and Finish for CNC Machined Parts

Aluminum anodizing per MIL-PRF-8625F w/Amendment 2 converts a 6061-T6 CNC surface into a 5-25 µm (Type II) or 25-75 µm (Type III) aluminum oxide layer produced by EPOC CRAFTER surface finishing capability that grows 50% inward and 50% outward on every coated face. The layer is chemically integral to the base metal and cannot chip or peel. Because MIL-PRF-8625F allows six anodize types and two classes, the callout on your drawing controls hardness, salt spray life (up to 336 h per ASTM B117-26 for sealed Class 2 Type II), dimensional growth, and unit cost.

Every anodize spec reduces to three decisions, in this order:

• Type: Type II for cosmetic and moderate corrosion, Type III for wear surfaces where hardness matters.
• Thickness: chosen within each Type’s range to match service load and dimensional headroom.
• Finish: Class (dyed or not) plus seal method, which trades wear resistance for corrosion resistance.

This guide covers the T-T-F Decision Path for choosing Type, Thickness, and Finish, the 4-Element drawing callout that removes anodizer ambiguity, and the design rules that prevent thread and bore rejects.

1. Anodizing for CNC Parts and the T-T-F Decision Path

Anodizing for CNC parts is an electrochemical conversion of the 6061-T6 surface into an aluminum oxide layer, not a coating applied on top. Every anodize spec then reduces to three engineering choices, in order: Type, Thickness, and Finish. This T-T-F Decision Path defines the coating’s hardness, dimensional growth, corrosion life, and cost.

1.1 How the Oxide Layer Grows on 6061-T6

During anodizing, the 6061-T6 part is the anode in a sulfuric acid bath. Applied DC current pulls oxygen ions to the aluminum surface, where they react to form Al2O3. MIL-PRF-8625F §6.10.1 states each coated surface grows by approximately half the applied coating thickness, with the other half consumed from the base metal. A 20 µm Type II layer on a 6061-T6 CNC part machined for anodize adds 10 µm to the diameter per side, or 20 µm total.

1.2 Why Anodize Is a Conversion, Not a Coating

Paint, powder coat, and electroplating sit on top of the aluminum and can lift off at the interface. Anodize is different because the Al2O3 layer is grown from the aluminum itself, so no interface exists. The coating is immune to peel, chip, or flake failure and holds tightly under thermal cycling and impact loads that would delaminate paint. The trade-off is repairability. A scratched anodize surface must be chemically stripped and re-anodized, not spot-touched, which adds the full anodize lead time and cost to the repair cycle.

2. Choose the Right Type (Decision 1)

Type is the first decision because it fixes the electrolyte, thickness range, and hardness ceiling that every downstream choice depends on. For CNC parts, this reduces to Type II sulfuric anodize (5-25 µm, 200-300 HV) for cosmetic and moderate corrosion service, or Type III hard anodize (25-75 µm at EPOC CRAFTER, 400-500 HV) for wear surfaces. Choose Type before you specify color or thickness.

2.1 MIL-PRF-8625F w/Amendment 2 as the Governing Spec

MIL-PRF-8625F w/Amendment 2, dated 23 November 2020, supersedes MIL-A-8625F w/Amendment 1 and is the current controlling document for anodize on aluminum. It defines six types, not three: Type I and IB (chromic acid), Type IC (non-chromic mineral acid), Type II and IIB (sulfuric acid), and Type III (hard anodize). Type IC and IIB are non-chromate alternatives to Type I and IB for environmental compliance. For most commercial and industrial CNC parts, only Type II and Type III are relevant.

2.2 Type II Sulfuric Anodize

Type II is the default for aluminum machined parts that need corrosion protection and color. MIL-PRF-8625F §6.10.5 Table IV lists the reference range at 1.78-25.4 µm (0.00007-0.0010 in). EPOC CRAFTER production standard is 15-20 µm, which supports sealed Class 2 dye retention and passes 336 h ASTM B117-26 neutral salt spray on undyed sealed panels. Hardness runs 200-300 HV on 6061-T6. Adds roughly 1.0-1.5 USD per surface dm² at production quantities.

2.3 Type III Hard Anodize

Type III is the coating for sliding, wear, and abrasion surfaces. MIL-PRF-8625F §6.10.5 Table IV lists 12.7-114.3 µm as the reference range, with a mandatory default of 50 µm nominal unless the drawing states otherwise (§3.4.3). EPOC CRAFTER caps Type III at 75 µm because thicknesses above that push dimensional growth past 37.5 µm per surface, which pulls precision bores and press fits out of tolerance faster than the corrosion benefit justifies. Hardness reaches 400-500 HV on 6061-T6. Adds roughly 2.5-4 USD per surface dm² and 2-3 days lead time over Type II.

2.4 When to Specify Which

Type III belongs on parts where a metal-to-metal sliding interface, a bearing race, or a linear guide sees repeated contact. Type II belongs on housings, brackets, faceplates, heat sinks, and any part where appearance and corrosion life matter more than surface hardness. According to Dewey Wu, General Manager & senior mechanical engineer at EPOC CRAFTER: “On 6061-T6, we see Type III at 50 µm hold up 4 to 6 times longer than Type II at 20 µm under Taber CS-17 abrasion, but the dimensional growth doubles. If the part has a press fit or an H7 bore, Type II with masking beats Type III with post-hone every time on unit cost.”

Table 1. Type II vs Type III at a glance (6061-T6, EPOC CRAFTER production data)

Attribute	Type II	Type III
Governing spec	MIL-PRF-8625F w/Amend 2	MIL-PRF-8625F w/Amend 2
Thickness range	5-25 µm (0.0002-0.001 in)	25-75 µm (0.001-0.003 in), EPOC CRAFTER cap
Hardness on 6061-T6	200-300 HV	400-500 HV
Salt spray (336 h ASTM B117-26)	Pass, sealed	Pass, sealed
Color range	Clear + full dye range	Natural bronze to black only
Cost adder (per surface dm²)	1.0-1.5 USD	2.5-4 USD
Lead time adder	Baseline	+2-3 days

3. Choose the Right Thickness (Decision 2)

Thickness inside each Type range trades corrosion life against dimensional growth. For Type II on 6061-T6, 15-20 µm passes 336 h ASTM B117-26 salt spray while keeping per-surface growth under 10 µm. For Type III, EPOC CRAFTER caps at 75 µm because growth above 37.5 µm per surface pulls precision bores and press fits out of tolerance. Pick thickness against the tightest feature, not the average feature.

3.1 Type II Thickness Selection

Type II runs from 5 µm for decorative parts up to 25 µm for outdoor service. EPOC CRAFTER production standard is 15-20 µm, which gives full Class 2 dye saturation on black and hits the 336 h neutral salt spray anchor on sealed panels. Going below 10 µm on black dye shows the base alloy through the coating as a gray cast. Going above 22 µm on Type II raises cracking risk at inside corners under 0.25 mm radius, so tighten radii before thickness.

3.2 Type III Thickness Selection

Type III delivers the full 400-500 HV hardness at 25 µm and above. MIL-PRF-8625F §3.4.3 sets 50 µm as the mandatory nominal default when the drawing does not specify thickness, which is EPOC CRAFTER’s baseline unless the print calls otherwise. EPOC CRAFTER caps Type III at 75 µm because at 100 µm and beyond, per-surface growth crosses 50 µm and the coating turns brittle at edges. According to Dewey Wu: “We have seen 100 µm hard anodize on a 6061 valve seat lose 15% Taber abrasion life compared to 60 µm on the same part, because the top layer of a very thick anodize is porous and shears off before it wears.”

3.3 Pre-Anodize Dimensional Offset

Every anodized surface grows by roughly 50% of the applied coating thickness per MIL-PRF-8625F §6.10.1. Machine the part undersize on external features and oversize on internal features by the amount in Table 2, or specify “ALL DIMENSIONS AFTER ANODIZE. MACHINE TO PRE-ANODIZE OFFSET.” on the drawing so the surface finishing team programs the compensation. Bores lose diameter at twice the per-surface offset because the coating grows on opposite walls.

Engineering note: For H7 bores under Ø25 mm, machining oversize by the offset in Table 2 leaves less than 10 µm of tolerance headroom on a 25-µm growth budget. Mask the bore instead when the H7 tolerance is critical.

Table 2. Pre-anodize dimensional offset on 6061-T6, per MIL-PRF-8625F §6.10.1

Type	Nominal thickness	Per-surface growth	Bore diameter loss	Shaft diameter gain
Type II	10 µm	5 µm	10 µm	10 µm
Type II	15 µm	7.5 µm	15 µm	15 µm
Type II	20 µm	10 µm	20 µm	20 µm
Type III	25 µm	12.5 µm	25 µm	25 µm
Type III	50 µm	25 µm	50 µm	50 µm
Type III	75 µm	37.5 µm	75 µm	75 µm

4. Choose the Right Finish (Decision 3)

Finish combines two sub-choices: Class (Class 1 undyed, Class 2 dyed per MIL-PRF-8625F §3.5-3.6) and seal method (hot DI water, nickel acetate, sodium dichromate, or unsealed for Type III max wear). Class controls color. Seal controls the corrosion-versus-wear trade-off. Get both wrong and a Class 2 Type III part can lose both dye retention and abrasion life in the same batch.

4.1 Class 1 vs Class 2

Class 1 anodic coatings are not dyed or pigmented per MIL-PRF-8625F §3.5. Natural color from the alloy composition after anodizing is not counted as dye, so a Class 1 6061-T6 part appears clear silver and a Class 1 Type III part appears bronze to dark gray without any coloring step. Class 2 coatings are uniformly dyed after anodizing and before sealing, per §3.6. Class 2 requires uniform color on wrought alloys, which is why EPOC CRAFTER controls batch color to ΔE ≤ 2 in CIE L*a*b* on production lots. Class 2 adds one dye tank cycle and roughly 15% cost over Class 1.

4.2 Three Seal Methods Compared

MIL-PRF-8625F §3.8.1.1-3.8.1.2 permits three seal chemistries for Types I, IB, IC, II, and IIB. Hot DI water at 95-100 °C is the default and cheapest. Nickel acetate at 0.5% and pH 5.5-5.8 delivers higher salt spray life on dyed parts and prevents dye bleeding on Class 2 black. Sodium dichromate at 5% and pH 5.0-6.0 gives the highest corrosion resistance for aerospace and marine service but requires hexavalent chromium waste handling that adds cost and lead time. Pick the seal against the service environment, not the shop’s default.

4.3 Type III Sealed Versus Unsealed

Type III splits from the other types on sealing rules. MIL-PRF-8625F §3.8.2 states Type III shall not be sealed when maximum abrasion or wear resistance is the main function. For exterior non-maintained parts requiring corrosion resistance and permitting reduced abrasion, the contract or drawing shall require sealing. This is a binary engineering choice, not a shop preference. A sealed Type III on a sliding wear surface can lose 20-30% of its abrasion life because the seal fills the porous outer structure and the softer sealed layer wears first. On a corrosion-critical bracket that never slides, sealing lifts salt spray life from roughly 100 h unsealed to 336 h sealed on the same 50 µm Type III coating.

Table 3. Three seal methods on Type II and Type III sealed applications

Method	Reagent	Temperature	Cycle time	Salt spray on Class 2 Type II	Cost vs baseline	Note
Hot DI water	Deionized water	95-100 °C	15-20 min	336 h pass	Baseline	EPOC CRAFTER default
Nickel acetate	0.5% Ni(OAc)2, pH 5.5-5.8	88-95 °C	15-20 min	500+ h pass	+10%	Best dye retention on black
Sodium dichromate	5% Na2Cr2O7, pH 5.0-6.0	90-100 °C	15 min	750+ h pass	+25%, hex-Cr fees	Aerospace, marine only

5. Alloy Compatibility for Anodizing

Alloy chemistry sets the ceiling on anodize quality before any process variable does. 6061-T6 is the default for anodized CNC parts because it gives clean clear and full dye range. 7075 works for Type II but shifts color toward yellow-gray. 2024 and most cast aluminum grades are not recommended for cosmetic anodize because copper and silicon leach into the coating and turn it patchy.

5.1 6061-T6 as the Default

6061-T6 anodizes with the widest color range and the most predictable dimensional growth of any structural aluminum. The 0.4-0.8% silicon and 0.15-0.4% copper stay low enough that Class 2 dyes hold true across Pantone-matched batches. 6063 gives even cleaner clear anodize than 6061 because silicon is capped at 0.6%, making 6063 the standard for architectural extrusions and leaving 6061 the standard for CNC parts.

5.2 7075 Caveats

7075 anodizes for Type II with acceptable results, but the 5.6% zinc content shifts clear anodize away from the neutral clear of 6061 toward a warm gray-yellow cast. Type III on 7075 works, and reaches similar 400-500 HV hardness, but the coating runs darker naturally and yellow dyes turn muddy. Match all 7075 anodized parts within one anodize batch to hold color consistency, or expect ΔE > 3 batch to batch.

5.3 2024 and Cast Alloys

2024’s 4.4% copper leaches into the sulfuric bath during Type III anodize and creates burnt-black patches on the coating surface. Cast alloys A380 and A356 carry 7.5-9.5% silicon, which forms silica particles inside the oxide layer and produces a mottled gray finish that no dye covers. Machined 2024 and cast aluminum accept chemical conversion coating better than anodize when corrosion resistance is the driver.

Table 4. Alloy compatibility for MIL-PRF-8625F anodizing

Alloy	Type II clear	Type II dye	Type III	Notes
6061-T6	Excellent	Excellent	Excellent	EPOC CRAFTER default
6063	Excellent	Excellent	Good	Architectural extrusions
5052-H32	Good	Good	Good	Sheet metal parts
7075-T6	Fair (yellow cast)	Fair	Good (dark natural)	Batch-match required
2024-T3	Fair	Not recommended	Not recommended	Cu leach on Type III
A380 / A356 cast	Not recommended	Not recommended	Not recommended	Si mottle, use conversion coat

6. The 4-Element Drawing Callout and Test Anchors

Anodize callouts fail at the anodizer for one reason: the drawing leaves choices open. A complete callout closes all four choices in one line: Spec, Type, Class, and Thickness plus seal condition plus masking. Add the two acceptance test anchors (336 h ASTM B117-26 salt spray and ASTM D3359-23 cross-hatch adhesion) and the anodizer quotes to a fixed target instead of a shop default.

6.1 Element 1 Spec Reference

Reference MIL-PRF-8625F w/Amendment 2, 23 November 2020, on the drawing. MIL-PRF-8625F §6.2.2 states that when the drawing does not specify anodize type, the contractor may furnish Type I, IB, IC, II, or IIB within the spec limits. The same clause allows either Class 1 or Class 2 when class is not specified. Both defaults favor the shop’s cheapest process. A part called out as “anodize black” with no MIL reference has no recourse when it comes back at 8 µm instead of 20 µm.

6.2 Element 2 Type

State the Type explicitly: I, IB, IC, II, IIB, or III. For CNC parts, this reduces to Type II or Type III in almost all cases. Type IC or IIB is called out only when hexavalent chromium restriction is contractually required.

6.3 Element 3 Class

State Class 1 (undyed) or Class 2 (dyed) per MIL-PRF-8625F §3.5-3.6. For Class 2, add the color designation. For color-critical parts, add a Pantone or RAL number so batch color control targets a specific ΔE.

6.4 Element 4 Thickness, Seal Condition, and Masking

Give nominal thickness in µm with tolerance range. State seal condition explicitly for Type III (sealed or unsealed). Call out mask zones by drawing region for threaded holes, ground contacts, and press fits. MIL-PRF-8625F does not publish a verbatim callout example; the format below is EPOC CRAFTER’s recommended construction based on §6.2 acquisition data.

Four complete callout examples (EPOC CRAFTER recommended, not standard-original):

1. Cosmetic bracket, black: ANODIZE PER MIL-PRF-8625F w/AMENDMENT 2, 23 NOV 2020, TYPE II, CLASS 2, COLOR BLACK, THICKNESS 15-20 µm, SEAL HOT DI WATER. MASK ALL THREADED HOLES.
2. Outdoor housing, clear: ANODIZE PER MIL-PRF-8625F w/AMENDMENT 2, TYPE II, CLASS 1, THICKNESS 20 µm MIN, SEAL NICKEL ACETATE. MASK PRESS FIT BORE Ø25.00 H7.
3. Wear surface, hard anodize: HARDCOAT ANODIZE PER MIL-PRF-8625F w/AMENDMENT 2, TYPE III, CLASS 1, THICKNESS 50 µm NOMINAL, UNSEALED. ALL DIMENSIONS AFTER ANODIZE. MASK BORE Ø20.00 H7 AND ALL M4 THREADED HOLES.
4. Marine corrosion, sealed hard anodize: HARDCOAT ANODIZE PER MIL-PRF-8625F w/AMENDMENT 2, TYPE III, CLASS 1, THICKNESS 50 µm ± 10 µm, SEAL SODIUM DICHROMATE. MASK RACK CONTACT ZONE PER DETAIL A.

6.5 Salt Spray Anchor for 336 h per ASTM B117-26

MIL-PRF-8625F §4.5.3 specifies 336 h neutral salt spray for Type II corrosion process control, run per ASTM B117-26 with the significant surface inclined 6° from vertical. ASTM B117-26 §10.1 sets chamber temperature at 35 ± 2 °C, §8.1 sets salt concentration at 5 ± 1 mass parts NaCl in 95 parts water, §8.2 sets collected pH at 6.5-7.2, and §10.2 sets fog fall-out at 1.0-2.0 mL per 80 cm² per hour. ASTM B117-26 §1.2 and §5.1 state the standard does not establish pass/fail criteria; use “passed 336 h” only when the acceptance criterion and the governing drawing or product specification are cited alongside.

6.6 Cross-Hatch Adhesion Anchor per ASTM D3359-23

ASTM D3359-23 Test Method B evaluates adhesion of coatings under 125 µm using a lattice cut and tape pull, rated 0B to 5B. The standard covers organic coatings on metallic substrates; anodize adhesion testing follows by reference, not by direct scope statement in D3359 §1.1. EPOC CRAFTER runs D3359-23 Method B on every anodize lot and reports the rating on the FAI report. A 4B or 5B result confirms the anodize layer holds under tape pull without lattice edge loss.

7. Design Rules That Prevent Anodize Rejects

Anodize rejects trace back to four design details, not to the anodize shop: sharp inside corners on Type III, unprotected small threads, unvented blind holes, and undefined rack contact zones. Each one is fixable at the CAD stage and adds zero cost when caught before the drawing releases. Each one turns into a scrap batch and a two-week rework loop when caught at incoming inspection.

7.1 Corner Radii for Type III

Type III grows perpendicular to every surface, which concentrates coating stress at inside corners under 0.3 mm radius. EPOC CRAFTER minimum is 0.3 mm on inside corners and 0.25 mm on outside edges for Type III at 50 µm nominal. At 75 µm, raise inside radii to 0.5 mm. Sharp corners crack the coating within the first thermal cycle and expose the base 6061-T6 to corrosion at the exact spot the anodize is supposed to protect.

7.2 Threaded Holes and Masking

Threads under 1/4-20 or M6 lose engagement after Type II anodize because the pre-anodize etch removes 5-10 µm of material and the anodize adds 10-15 µm per flank. EPOC CRAFTER masks all threaded holes below M6 by default and taps oversize by 0.05-0.10 mm on M6 and larger when the drawing calls for anodized threads. Call out masking explicitly on the drawing to keep the anodizer from making the choice. Unmasked M3 threads on a Type III part strip the tap on the first bolt install.

7.3 Blind Holes and Drainage

Blind holes deeper than 3× diameter trap electrolyte and rinse water. Trapped fluid runs down the part during racking and leaves streaks along the entire flow path. Add a 1.0 mm drain flat at the closed end of any blind hole deeper than 10 mm, or specify hole orientation for racking on the drawing.

7.4 Racking Marks Placement

Anodize requires electrical contact through titanium or aluminum racks that leave 1-3 mm uncoated marks. Identify one non-cosmetic surface on the drawing as the acceptable rack contact zone. Undefined rack zones default to the shop’s fastest position, which lands on visible faces roughly half the time.

8.Frequently Asked Questions

Q1. What is the difference between Type II and Type III anodizing?

Type II sulfuric anodize produces a 5-25 µm coating with 200-300 HV hardness and full color range, and Type III hard anodize produces a 25-75 µm coating with 400-500 HV hardness and natural bronze-to-black color only. Both run in sulfuric acid electrolyte per MIL-PRF-8625F, but Type III uses higher current density and lower bath temperature to grow a denser oxide. Type II covers cosmetic, moderate corrosion, and outdoor housing service. Type III covers sliding wear surfaces, bearing races, and linear guides. Type III adds 2.5-4 USD per surface dm² and 2-3 days lead time over Type II at production quantities.

Q2. How much do dimensions change during anodizing on a 6061 CNC part?

Every anodized surface grows by roughly 50% of the applied coating thickness per MIL-PRF-8625F §6.10.1, with the other 50% consumed from the base metal. A 20 µm Type II coating adds 10 µm per surface. A bore loses 20 µm total in diameter because the coating grows on both walls. A 50 µm Type III adds 25 µm per surface and 50 µm to the bore diameter. For precision fits, machine the part undersize on external features and oversize on internal features by the offset in Table 2, or specify “ALL DIMENSIONS AFTER ANODIZE” on the drawing so the anodizer programs the compensation.

Q3. Can Type III anodize be dyed black?

Type III accepts black dye but the result varies with alloy and thickness. On 6061-T6 at 50 µm, Type III dyed black gives a uniform matte black finish that meets ΔE ≤ 2 batch to batch. On 7075-T6 at the same thickness, the natural bronze base shifts the black toward warm gray-brown. Above 65 µm, Type III becomes naturally dark bronze even without dye and any dye adds only marginal saturation. Class 2 Type III per MIL-PRF-8625F §3.6 requires uniform color on wrought alloys, so batch-match all Type III black parts within one anodize run.

Q4. Do I need to mask threaded holes before anodizing?

Mask all threaded holes below M6 or 1/4-20 by default, and mask larger threads when the drawing calls for after-plating fit. The pre-anodize etch removes 5-10 µm from the base material and the anodize adds 10-15 µm per thread flank, which pushes an M3 or M4 tapped hole out of engagement after Type II and jams solid after Type III. For M6 and larger with anodized threads, tap oversize by 0.05-0.10 mm before anodize. MIL-PRF-8625F does not mandate masking, so the drawing must specify mask zones explicitly per finishing.com and Practical Machinist shop consensus.

Q5. When should I choose sealed versus unsealed Type III?

Choose unsealed Type III when maximum abrasion or wear resistance is the main function, per MIL-PRF-8625F §3.8.2. Choose sealed Type III when the part sees a corrosive environment and can accept reduced abrasion resistance. A sealed Type III on a sliding wear surface loses 20-30% of its abrasion life because the softer sealed outer layer wears first. On a corrosion-critical bracket that never slides, sealing lifts salt spray life from roughly 100 h unsealed to 336 h sealed on the same 50 µm Type III coating. This is a binary engineering choice, not a shop preference.

Q6. What does “passed 336 h ASTM B117 salt spray” actually mean?

ASTM B117-26 §1.2 and §5.1 state the standard defines the salt spray environment (35 ± 2 °C, 5 ± 1 wt% NaCl, pH 6.5-7.2, 1.0-2.0 mL per 80 cm² per hour fog fall-out) but does not establish a universal pass/fail criterion. “Passed 336 h” is a complete claim only when the acceptance criterion and the governing drawing, product specification, or purchaser-seller agreement are cited alongside. On an anodized 6061-T6 part, the criterion cited is usually “no pitting, no rust bloom, no coating lift within 336 h per ASTM B117-26 acceptance zone.”

The T-T-F Decision Path collapses the anodize spec into three choices: Type, Thickness, Finish. The 4-Element Callout Framework closes those choices into a drawing line the anodizer cannot misread: Spec, Type, Class, Thickness plus seal plus mask. Every reject we have traced back through incoming inspection started with one of these six fields left open.

Before you release your next 6061-T6 print for quote, download the EPOC CRAFTER Anodize Drawing Callout Checklist and run each of the 8 fields against your drawing. If a field on the checklist is blank, the anodizer will fill it with the shop default. Upload your anodize-ready CAD and drawing to EPOC CRAFTER RFQ for a 24-hour DFM review that flags Type, Thickness, Finish, and masking gaps before the first part goes into the tank.

Related Resources

Related Capability. EPOC CRAFTER Surface Finishing Services. Type II, Type III, chemical conversion, electroless nickel, and powder coat run in one supply chain with a single FAI report.

Related Article. Type II vs Type III Hard Coat Anodize: The Deep-Dive Selection Guide. Expands on the wear, corrosion, and cost trade-offs for engineers picking between the two dominant CNC anodize types.

Related Article. Anodize Thickness, Color Consistency, and Corrosion Life. Covers ΔE batch matching, Class 2 dye chemistry, and how thickness maps to salt spray life on 6061-T6.

Related Material Guide. 6061-T6 Aluminum Properties and Machinability. The alloy chemistry, T6 temper condition, and CNC machinability data behind why 6061-T6 is EPOC CRAFTER’s default for anodized parts.

Related Standards Reference. Tolerances and Standards for Anodized CNC Parts. MIL-PRF-8625F w/Amendment 2 quick reference, ASTM B117-26 test conditions, and ASTM D3359-23 adhesion rating on anodize.

Related Article: Anodizing vs. Electroless Nickel vs. E-Coat vs. Powder Coat