Anodising quotes for UK part owners: compare suppliers

To obtain comparable anodising quotes for aluminium parts you own, establish supplier eligibility first, then send the same material, drawing, coating and inspection requirements. SPA Aluminium explicitly accepts customer-supplied parts; Hard Anodising offers a quote route but needs to confirm acceptance of your job.[2][1] Parallel Precision’s 2020 article excludes standalone anodising, describing a service for its CNC-machined aluminium components instead.[5]

Compare the three suppliers

SPA Aluminium

• Service eligibility: Accepts customer-supplied parts, extrusions and assemblies, from one-offs to ongoing projects, at what SPA describes as its in-house facility in Kent.[2]
• Published coating capabilities: Natural/silver anodising at 5, 10, 15, 20 or 25 microns; colour anodising at 20 microns. Listed colours are Light Grey, Light Bronze, Medium Bronze, Dark Bronze and Black.[2]
• Available price evidence: The cited free-issue service page does not state a price; request a quote for your parts.[2]

Hard Anodising

• Service eligibility: Offers a quote-request route. Acceptance of your customer-owned parts needs confirmation before including it in a standalone finishing shortlist.[1]
• Published coating capabilities: Advertises Hard, Chromic and Soft Anodising; request the thickness specification applicable to your job.[1]
• Available price evidence: Published Minimum Order Charges are £250 for Hard Anodising, £300 for Chromic Anodising and £200 for Soft Anodising—not prices for your defined job.[1]

Parallel Precision

• Service eligibility: Its article limits anodising to orders for its CNC-machined aluminium components, excluding standalone finishing of parts you already own. Confirm whether that policy remains unchanged before pursuing a combined order.[5]
• Published coating capabilities: The article introduces Natural, Colour and Hard Anodising as general types and gives a general oxide-layer range of 5–100 microns; these describe anodising in general, not Parallel Precision’s own process capability. It outsources anodising to audited approved suppliers, using ISO 9001:2015-approved suppliers where possible.[5]
• Available price evidence: Its historical worked prices are in GBP plus VAT and concern anodising costs, although it does not offer a standalone anodising service.[5]

SPA’s published thicknesses and the general range in Parallel Precision’s article do not establish equivalent processes or drawing standards. Use them to check feasibility, not as a substitute for the specification on your RFQ.[2][5]

Send eligible suppliers the same RFQ

Use one drawing revision and a shared checklist. Hard Anodising requests material, dimensions, quantity, drawings, coating type, thickness, standards, finish, turnaround, documentation and delivery details; Yishang’s guidance adds masking, appearance and pre- or post-finishing dimensional control.[1][4]

• Part identification: Part number: ___; drawing revision: ___; drawing/CAD reference: ___.
• Material: Alloy grade: ___; temper: ___; material thickness: ___; available material/lot information: ___.[1][4]
• Size and quantity: Component dimensions: ___; batch quantity: ___; repeat-batch requirements: ___.[1][4]
• Coating: Designation/type: ___; required thickness: ___; applicable drawing standard: ___; surface preparation/finish target: ___.[1][4]
• Masking and appearance: Masking drawing/reference: ___; coating-free surfaces: ___; cosmetic faces: ___; colour reference and/or approved sample: ___.[4]
• Inspection: Critical dimensions and tolerances: ___; dimensions checked before coating: ___; dimensions checked after coating: ___.[4]
• Documentation and logistics: Requested certification: ___; delivery location: ___; required turnaround: ___.[1]
• Supplier response: Ask for exclusions, assumptions and proposed substitutions to be listed against this RFQ.

Fix the alloy, drawing and coating-free surfaces

Identify alloy and temper, datum references, fit-critical dimensions and surfaces that must remain coating-free. Yishang warns that anodic build can affect holes, slots, tabs, hinges and gasket grooves, so state whether each controlling dimension applies before or after finishing.[4]

Mark masking zones explicitly, including relevant mating faces, earthing points and interface/contact surfaces. Yishang cautions that unclear coating-free requirements can leave parts meeting the stated specification but failing fit or visual acceptance.[4]

For formed parts, include relevant grain direction and bend details. For welded or assembly-dependent parts, show weld locations and provide mating-part information or a fit sketch.[4] Ask suppliers to record their proposed dimensional allowance and rack/contact-point locations for approval rather than leaving those decisions implicit.

Specify thickness and colour approval

Put the coating designation, numerical thickness and applicable standard into the RFQ; Hard Anodising explicitly requests these inputs.[1] SPA’s natural and colour offerings are provider-specific descriptions, and Parallel Precision’s 5–100 micron figure is a general description of anodising rather than a supplier capability; neither is an interchangeable process specification.[2][5]

For appearance, identify cosmetic faces and define the target with a reference sample, colour reference or both. Yishang recommends approving prototypes against the same drawing, material grade, surface requirements, masking notes and inspection basis intended for production.[4]

Yishang says alloy lot, pre-treatment timing, rack loading and other processing conditions can affect batch appearance; this is supplier guidance, not independent evidence of the compared providers’ performance.[4] Ask each supplier to propose a written colour acceptance method and explain how later batches will be assessed against the agreed reference.

Agree inspection, certification and rework

Yishang identifies holes, mating areas and other fit-critical features as inspection priorities, with controlling dimensions explicitly checked before or after coating.[4] Turn those priorities into written acceptance requirements before authorising processing:

• Inspection: Identify controlling dimensions and datums, then agree measurement methods, sampling, allowable deviations and the report format.
• Certification: Specify the certificate required, its measurement content and applicable standards—not simply “certification included”. Hard Anodising asks customers to state certification and documentation requirements.[1]
• Traceability: Specify the lot-record fields and material-lot evidence required. Yishang identifies alloy-lot variation as a possible influence on batch appearance.[4]
• Rework: Agree rejection notification, remedies, responsibility for nonconforming work, permission to strip and re-anodise, and rework limits, including any maximum cycles.

What to confirm with each provider

Ask SPA Aluminium, Hard Anodising and Parallel Precision to confirm detailed acceptance, traceability, rework and commercial terms for your job.[2][1][5] Request written, job-specific confirmation of:

• Acceptance of the parts and specification, including any exceptions or substitutions.
• Dimensional and colour acceptance, rack/contact marks, measurement methods and sampling.
• Certificate content, lot records and material-lot evidence.
• Rejection remedies, warranty and stripping or re-anodising limits.
• VAT treatment, quote validity, payment and cancellation terms.
• Turnaround, delivery and charges for preparation, masking, inspection and documentation.

Compare scope before comparing totals

Check each returned quote against the same RFQ revision, specification and quantity. Ask suppliers to itemise preparation, masking, inspection, documentation, delivery and exclusions so differences in scope are visible.

Hard Anodising’s Minimum Order Charges and Parallel Precision’s historical bundled examples do not establish a comparable standalone price for your alloy, geometry, thickness, colour, masking and inspection package.[1][5]

For customer-owned parts, approach SPA for its explicit free-issue service and ask Hard Anodising to confirm eligibility.[2][1] Treat Parallel Precision as a machining-plus-anodising route under its stated policy.[5] Resolve differences in thickness, masking, colour approval and inspection before choosing a quote and authorising work.

References

1. Hard Anodising (hard-anodising.co.uk)
2. Free Issue Aluminium Anodising Service UK | SPA Aluminium (spaaluminium.com)
4. Anodised Aluminium Quote Risks: What Buyers Must Lock Before Pricing Sheet Metal Enclosures, Brackets, and Frames – Yishang Metal (zsyishang.com, 2026)
5. How Much Does Anodising Cost? | Parallel Precision (parallelprecision.co.uk, 2020)