Restore What Others Replace with Metal Spraying& Component Refurbishing
Franklin Engineering Services provides specialist metal spraying and component refurbishing for worn, damaged or out-of-tolerance engine and equipment parts. We build surfaces back to original dimensions and extend the working life of components that would otherwise need replacing.
Restoring Worn Components to Original Specification
Metal spraying — also known as thermal spray coating — is a process where molten or semi-molten metal is applied to a surface to restore lost material, rebuild worn dimensions, and protect components against further wear. It is one of the most effective ways to extend the service life of high-value engineering components: shafts, journals, bores, bearing housings, hydraulic rods and other precision parts that have worn beyond tolerance but are otherwise structurally sound.
The case for metal spraying often comes down to cost and availability. A new crankshaft or heavy shaft assembly is expensive, and for older engines or specialist equipment, replacement parts may simply not be available. Metal spraying allows Franklin Engineering Services to build the worn surface back up to the correct dimension, then machine or grind it to the required finish and tolerance. The result is a component restored to specification, at a fraction of the cost of replacement, with a surface hardness that can match or exceed the original.
Franklin Engineering Services has been carrying out metal spraying and component refurbishing as part of its in-house service offering for many years. It is a capability that supports and extends the rest of the workshop's reconditioning work: crankshaft journals that need building up before grinding, hydraulic cylinder rods requiring surface restoration, worn bearing housings on marine or industrial equipment. Customers with components that have been assessed as beyond standard repair often find that metal spraying at Franklin Engineering Services is the practical path back to service.
Component Restoration Across Engine, Drivetrain and Industrial Applications
Franklin Engineering Services applies metal spraying and refurbishing across a wide range of heavy diesel, marine and industrial components. The service is used both as a standalone repair solution and as a preparatory stage within broader reconditioning work, building worn surfaces back to the correct dimensions before final precision machining.
COMMON APPLICATIONS:
- Crankshaft journal restoration and build-up prior to grinding
- Shaft and spindle diameter restoration
- Hydraulic cylinder rod refurbishing
- Worn bearing housing restoration
- Camshaft and auxiliary shaft surface repair
- Pump and housing bore build-up
- General component build-up for out-of-tolerance parts
INDUSTRIES SERVED:
- Heavy Transport & Haulage
- Earthmoving & Civil
- Marine & Ferry Operations
- Agricultural & Farming
- Hydraulics & Industrial Equipment
Surface Preparation, Application and Final Machining
The quality of a metal spray job is determined as much by what happens before and after the spray as by the spray itself. Surface preparation is critical. The base material must be clean, correctly profiled, and free of contamination for the sprayed metal to bond properly. At Franklin Engineering Services, this preparation work is done in-house, as is the final machining or grinding that brings the restored component to its required dimensions and surface finish. The whole process — from stripped component to finished part — is handled by one team, in one workshop.
Franklin Engineering Services uses arc spray and flame spray processes depending on the application and the base material. Arc spray uses an electric arc to melt wire feedstock, producing a dense, well-bonded coating suitable for most shaft and bore restoration work. Flame spray is used for applications where a softer deposit or specific material properties are needed. Both processes allow Franklin Engineering Services to apply a range of metallic coatings matched to the wear characteristics and service requirements of the component being restored.
The metal spraying process at Franklin Engineering Services:
Assessment & Feasibility
The component is assessed to confirm that metal spraying is the right solution — considering the extent of wear, the base material, and the dimensional requirements of the finished part.
Surface Preparation
The worn area is cleaned, degreased and grit-blasted to create a profile that allows the sprayed metal to bond correctly. Precise masking protects adjacent surfaces.
Metal Spray Application
Sprayed metal is built up in controlled passes to the required deposit thickness, using arc spray or flame spray depending on the application and material specification.
Rough Machining
The sprayed deposit is rough-machined back towards the target dimension, removing any irregularity in the as-sprayed surface and checking for bonding quality.
Final Machining & Inspection
The component is finish-machined or ground to the final dimension and surface finish, then inspected to confirm it meets the required tolerance before being signed off.
Metal spraying lets Franklin Engineering Services restore worn components that would otherwise be scrapped — saving operators significant cost and lead time, particularly on older engines and specialist equipment where replacement parts are hard to source.
Talk to Us About Your Component Refurbishing Requirements
Tell us what the component is, what equipment it came from, and what has worn or failed — and the Franklin Engineering Services team will come back to you with an honest assessment of whether metal spraying is the right solution and what that work involves.
Frequently Asked Questions
What is metal spraying and how does it work?
Metal spraying is a thermal spray process where molten metal is projected onto a surface to build up worn or undersized areas. At Franklin Engineering Services, the sprayed deposit is then precision-machined back to the required dimension and surface finish. The process bonds well to most ferrous base materials and can be matched to the hardness and wear characteristics required for the application. It's an established engineering repair method — not a patch or stopgap, but a proper restoration when done correctly.
What types of components can be metal sprayed?
Metal spraying is suitable for most cylindrical or flat surfaces where material has been lost through wear, corrosion or damage — shafts, journals, bores, spindles, hydraulic rods, bearing housings and pump casings are common examples. The key factors are that the base material must be sound (no cracks or significant structural damage), the component must be a practical size and geometry for the process, and the dimensional requirement must be achievable through spray and machine. FES can assess any component and give a straight answer on whether metal spraying is viable.
Is a metal-sprayed component as strong as the original?
In most applications, yes — and in some cases the sprayed surface can be harder and more wear-resistant than the original. The strength of the bond depends heavily on surface preparation, and the final surface properties depend on the spray material and process used. FES selects the spray method and material based on the application — matching hardness and wear resistance to what the component actually needs in service. A well-prepared and correctly sprayed component will give reliable performance.
Is metal spraying more cost-effective than sourcing a replacement part?
Frequently, yes — particularly for older engines, specialist equipment or imported machinery where replacement components are expensive or have long lead times. A new crankshaft or heavy shaft assembly can cost significantly more than a spray-and-regrind repair, and may take weeks to source. For operators who need equipment back in service quickly and economically, metal spraying is often the most practical option. FES can give a cost comparison once the component has been assessed.