General Metal Finishing
Job shops and OEM paint lines order in small batches against a long colour list, and this range is organised to be bought that way. Primers, topcoats and single-coat finishes for tube, sheet, fasteners, frames, shelving, enclosures and hand tools.
Overview
Fabricated metal goods arrive in batches: tube, sheet metal, fasteners, furniture frames, shelving, enclosures, hand tools and sports equipment. General metal finishing is the coating work that sits between heavy industrial protection and vehicle refinish, and the boundary with Industrial and Infrastructure Coatings is worth drawing explicitly, because the two ranges share chemistry. Infrastructure work is asset protection on fixed structures and on pipe, specified against an exposure environment and a maintenance interval, often applied on site and repainted in place. General metal finishing is manufactured metal goods, coated in a shop in batches before the item is assembled or sold. If it stays where it was built, enter through Industrial and Infrastructure Coatings; if it leaves the shop as a product, enter here. The parts are varied, the batches are small and the colour list is long, so this range is organised to be bought that way, in the pack sizes, the sheens and the colours a job shop or an OEM paint line puts through in a week. Where the shop finishes by powder or by electrocoat rather than by liquid spray, the materials are described under Powder Coatings and Electrocoat, which are application technologies serving this market and several others.
Surface preparation is the technical constraint. Coating failures in this market are commonly traced back to what was, or was not, done to the steel before the gun was picked up: mill scale, drawing and forming oils, weld spatter and flash rust all shorten the life of a coating that is otherwise correct for the job. ISO 8501-1 exists for that reason, setting out the rust grades and the preparation grades used to judge a surface visually, Sa grades for blast cleaning and St grades for hand and power tool cleaning. As general industry practice, a zinc-rich primer protects galvanically only where its zinc is in metallic contact with clean bare steel, which is why blast cleaning is the normal requirement for that class. Where a shop cannot blast, the range covers systems formulated for hand and power tool cleaned surfaces, and we state the trade-off, a shorter protective life from the same chemistry, rather than leave it to be discovered on site.
Plant requirements depend on which end of the range is used. All of it starts with preparation: a blast facility, or at minimum a degreasing stage and mechanical cleaning, because no finish in the list corrects a surface that was not cleaned. Air-dry finishes then need a ventilated and filtered spray booth, a clean dry compressed air supply, rack or floor space while the film hardens, and solvent storage and extraction that meet the shop’s fire and ventilation rules. Force-dry grades need warm air or a low temperature oven, and in exchange they free the rack sooner. Stoving enamels need a baking oven and a line that can hold parts at temperature, which is straightforward for bare fabrication and not possible for assemblies already fitted with plastics, seals or electronics. The commercial constraint sits alongside all of that: this market runs on short lead times, small batches and wide colour variety, so availability and the turnaround on a colour match weigh as heavily in the decision as the coating chemistry does. General metal finishing is a new capability area for Arctic Materials, and every grade is supplied with a Technical Data Sheet and a Safety Data Sheet naming the system and the preparation it assumes.
The Arcmetal range
10 products in 5 families. Each is specified against the substrate, the process and the service conditions of the job rather than supplied from a fixed catalogue.
Arcmetal PR Universal Metal Primers
One-pack anti-corrosive primers for a shop that cannot predict next week’s substrate. They are formulated to key onto bare steel, zinc coated steel and aluminium from the same tin, and to accept alkyd, single-pack and two-component topcoats within a stated recoat window. The two grades differ by film build and by the service the primed part is going into.
Arcmetal PR 210 Universal Adhesion Primer
A fast air-drying, low build one-pack primer for mixed substrate job work, applied at 25 to 35 microns dry and recoatable within the hour. It is the grade a shop reaches for when the batch on the rack is part bare steel, part galvanised bracket and part aluminium extrusion, and a single primer has to key to all three. It buys adhesion and process speed rather than corrosion life, so parts going into damp, coastal or wash-down service are primed with PR 340 instead.
Arcmetal PR 340 High-Build Anti-Corrosive Primer
A zinc phosphate pigmented, higher build primer applied at 50 to 80 microns dry in one pass, for fabrication that will see weather, condensation or intermittent wetting. It carries the corrosion load of the system so the topcoat can be chosen for colour and gloss, and it is the primer specified under the Arcmetal 2K finishes on exterior work. It dries more slowly than PR 210 and needs the rack space that implies.
Arcmetal DT Direct-to-Metal Single Coat Finishes
Finishes that carry the priming and the topcoating function in one film, for work that is painted in a single pass. They are built on saponification resistant modified binders so that the same product can go direct onto zinc coated work as well as onto steel and aluminium. They are bought for throughput: one product, one gun setting, one pass, and the part leaves the booth. The higher grade adds film build and exterior durability where a single coat still has to survive weather.
Arcmetal DT 220 Direct-to-Metal Enamel
A single coat air-drying enamel on a saponification resistant modified binder, applied straight onto prepared metal at 40 to 60 microns dry, for interior and sheltered fabrication painted in one pass. The binder is the reason it goes direct onto zinc coated work where a conventional alkyd would not. It suits tube frames, shelving, brackets, light enclosures and hand tools, where the second coat would buy handling time rather than protection, and it is not a substitute for a primer and topcoat system on parts that will be wetted or washed down.
Arcmetal DT 380 High-Build Exterior Direct-to-Metal Finish
An acrylic modified single coat finish applied at 60 to 80 microns dry, holding colour and gloss outdoors better than a conventional alkyd of the same build, and saponification resistant enough to be taken direct onto galvanising. It is specified where the process constraint is one pass but the part still leaves the shop for exterior service, such as gates, frames, agricultural fittings and outdoor furniture. Where the exposure is coastal or chemically loaded, the two-coat route with PR 340 and an Arcmetal 2K finish gives the greater total build and a dedicated anti-corrosive layer.
Arcmetal AL Air-Drying Alkyd Enamels
Conventional and urethane modified alkyd enamels for shops with no oven and a long colour list. Alkyds remain the lowest cost route to a wide colour range with easy brush touch-in and straightforward recoating, and they are specified where the service is interior or sheltered and the film will be repaired rather than replaced. Because the alkyd binder saponifies on zinc and on alkaline surfaces, these grades are applied over a primer rather than direct onto galvanising.
Arcmetal AL 160 General Purpose Alkyd Enamel
A conventional air-drying alkyd enamel for interior and sheltered service, supplied across matt, satin and gloss sheens and matched to RAL, BS 381C, BS 4800 or IS references. It is the lowest cost route to a long colour list in small batches, it brushes and sprays without special equipment, and damaged film is touched in with the same tin. Alkyd films continue to harden after they are touch dry, so early stacking, strapping or wrapping risks print and blocking.
Arcmetal AL 290 Fast-Dry Urethane Alkyd Enamel
A urethane modified alkyd enamel that reaches handling strength faster than AL 160 and gives a harder, more abrasion resistant film. It is specified where the rack is the bottleneck and the shop wants alkyd economics with a shorter cycle, and it force dries well where warm air is available. It is still an alkyd, so exterior gloss retention is below that of the Arcmetal 2K polyurethane grades and the class chalks with prolonged ultraviolet exposure.
Arcmetal 2K Two-Component Polyurethane and Epoxy Finishes
Isocyanate cured polyurethane and amine cured epoxy finishes for parts that face weather, wash-down, solvents or chemical splash. They buy hardness, gloss retention and chemical resistance in exchange for mixing discipline, a pot life that runs whether the gun is working or not, and a recoat window that has to be observed.
Arcmetal 2K 430 Two-Component Polyurethane Finish
An aliphatic isocyanate cured acrylic polyurethane topcoat for fabricated metal that leaves the shop into full exterior service, applied at 40 to 60 microns dry over an Arcmetal PR primer. It holds gloss and colour under ultraviolet exposure longer than the alkyd grades and resists wash-down, fuels and dilute chemicals. Pot life runs from the moment the components are mixed, whether the gun is working or not, so batch sizes are set by the session and not by the tin.
Arcmetal 2K 560 Two-Component Epoxy Finish
An amine cured, high-build epoxy finish applied at 80 to 120 microns dry in one pass, for chemical splash, solvent contact, wash-down and mechanical abuse. It is used as a one-coat interior finish on plant fabrication, tanks, frames and machine bases, and as the build coat under 2K 430 where the part is also exposed outdoors. Epoxies chalk under ultraviolet light as a class, so it is not specified as the final coat on exterior work, and a fully cured film is washed to remove amine blush and then abraded before it will accept the next coat.
Arcmetal WB Water-Based Industrial Finishes
Waterborne finishes for shops constrained by ventilation, solvent storage or odour rather than by performance. They are specified where those constraints are real and the drying conditions can be controlled, because waterborne films dry by evaporation that depends on air movement and relative humidity rather than on solvent volatility alone.
Arcmetal WB 140 Water-Based Direct-to-Metal Finish
A single-pack waterborne acrylic finish applied direct to prepared metal at 40 to 60 microns dry, for interior and sheltered work in shops constrained by odour, solvent storage or extraction capacity. Guns, pots and lines are cleaned with water while the material is wet, which removes a solvent stream from the shop. It dries by water evaporation, so it is specified where air movement and relative humidity can be held within a working range and not where parts dry in a still, humid corner.
Arcmetal WB 270 Water-Based Two-Component Polyurethane Finish
A waterborne two-component polyurethane finish that brings the hardness, chemical resistance and exterior gloss retention of the 2K range to a shop that has to keep solvent content down. It is applied at 40 to 60 microns dry over an Arcmetal PR primer and cures by both water loss and crosslinking. The polyisocyanate reacts with water as well as with the resin and that side reaction releases carbon dioxide, so film build per coat is held to the stated range and pot life ends without the viscosity rise that signals it in a solvent-borne product, which is why mixed material is timed rather than judged by eye.
Typical operating window
The figures below are the typical operating window for this range, not a measured result for any one batch. Confirmed values are issued with the Technical Data Sheet and Certificate of Analysis by our laboratory.
| Property | Typical operating window | Method |
|---|---|---|
| Volume solids | 35 to 45 per cent for air-drying alkyd and water-based grades, 45 to 60 per cent for direct-to-metal and two-component polyurethane grades, 60 to 75 per cent for high-build epoxy | ISO 3233-1 |
| Viscosity, supply and at the gun | 60 s to 120 s as supplied in a 6 mm cup, adjusted to 20 s to 25 s in a 4 mm cup for conventional and HVLP spray | ISO 2431, flow cup at 23 degrees C, cup orifice stated with every result because the cups are valid only between about 20 s and 100 s |
| Dry film thickness per coat | 25 to 35 microns for low build primer, 50 to 80 microns for high-build primer, 40 to 80 microns for single coat direct-to-metal finishes, 40 to 60 microns for topcoats, 80 to 120 microns for high-build epoxy | ISO 2808, wet film checked by comb to the same standard during application |
| Surface drying and through drying, air dry at 30 degrees C | Surface dry 20 minutes to 4 hours by class, through dry 6 to 24 hours; force dry 20 to 40 minutes at 60 to 70 degrees C after a flash-off at shop temperature | ISO 9117-3 for surface drying, ISO 9117-1 for through drying |
| Pot life and induction, two-component grades | Induction 10 to 30 minutes on solvent-borne grades, pot life 2 to 6 hours at 25 degrees C for solvent-borne and 1 to 3 hours for water-based, roughly halving for each 10 degrees C rise; water-based grades are emulsified by stirring and show no viscosity rise at the end of pot life | ISO 9514 |
| Specular gloss | Below 10 units matt, 20 to 45 units satin, 80 to 95 units full gloss | ISO 2813, 60 degree geometry, with 85 degree geometry used for matt films reading below 10 units at 60 degrees |
| Adhesion | Cross-cut classification 0 to 1 on correctly prepared substrate for films up to 250 microns | ISO 2409 cross-cut; ISO 4624 pull-off where the film is thicker than the cross-cut range or a numerical value is required |
| Flexibility, cylindrical mandrel bend | No cracking at 4 to 6 mm for alkyd and water-based single-pack films, at 8 to 10 mm for high-build epoxy | ISO 1519 |
| Impact resistance, falling weight | 1 kg falling weight, no cracking or detachment from 500 mm to 1000 mm by class and film build | ISO 6272-1, large-area indenter |
| Neutral salt spray to first rusting | 240 h to 500 h for a primed and topcoated system over power tool cleaned steel, 500 h to 1000 h over blast cleaned steel at full two-component build; the test ranks systems against each other and is not a service life prediction | ISO 9227, degree of rusting rated to ISO 4628-3 |
| Accelerated weathering, fluorescent UV | Aliphatic polyurethane grades typically retain more than 60 per cent of initial gloss at 1000 h; alkyd grades chalk and lose gloss well before that and are specified for sheltered service | ISO 16474-3 |
| VOC content, ready for use | 380 to 550 g/l for solvent-borne grades, 50 to 150 g/l for water-based grades | ISO 11890-1 difference method for solvent-borne grades above 15 per cent VOC by mass, ISO 11890-2 gas-chromatographic method for water-based grades within its range |
Application
The defining constraint in this market is variety, not severity. A jobbing coater runs many substrates, many part sizes and short runs through one booth, often with no oven, so the products have to be forgiving of a preparation standard that changes from batch to batch and of a rack that is emptied when the next job arrives. The Arcmetal range is built around that: one primer that keys to steel, zinc and aluminium, a single coat route where throughput governs, and a two-component route reserved for the parts that genuinely need it.
Preparation still sets the ceiling. ISO 8501-1 gives the rust grades and the preparation grades used to judge the surface by eye, Sa grades for blast cleaning and St grades for hand and power tool cleaning, and the salt spray window in the table above moves by a factor of two between St 3 and Sa 2 and a half on the same system. Degreasing comes before mechanical cleaning, not after it, because abrading a contaminated surface drives the contamination in. Coating is applied with the substrate at least 3 degrees C above the dew point, otherwise condensed moisture sits under the film. On bare steel, the interval between cleaning and coating is part of the specification: flash rust forms within hours in a humid shop and is most aggressive under the water-based grades, which is why WB 140 is coated onto steel the same day it is prepared.
The selection logic between the three main routes is an economic one as much as a technical one. Air-drying alkyd, Arcmetal AL, is the cheapest way to hold a long colour list in small batches and the easiest to repair, because a scratch is touched in with a brush from the same tin and the repair melts into the surrounding film. Alkyds saponify on zinc and on alkaline surfaces, so they are specified over a primer rather than direct onto galvanising. Direct-to-metal, Arcmetal DT, removes a whole pass from the process: one product, one gun setting, one film, and the part is off the rack sooner, which is worth more than material cost on a shop running twenty short jobs a week, and the DT grades use saponification resistant modified binders so that the same tin can go onto zinc coated work. Two-component, Arcmetal 2K, is specified when the service demands it, for exterior weathering, wash-down, solvent contact or chemical splash, and it is the only route in the range that holds gloss and colour outdoors over years rather than seasons.
Two-component products carry an operational cost that does not appear on the price list. Induction, typically 10 to 30 minutes on the solvent-borne grades, is the time the mixed material needs before it sprays and cures as intended, and skipping it shows up later as soft film and poor resistance. Pot life then runs from the moment of mixing whether the gun is working or not, and it roughly halves for each 10 degrees C rise, so a six hour pot life quoted at 25 degrees C is closer to three hours in a Greater Noida summer shop. The practical consequence is that mixed batches are sized to the session, not to the tin: a shop that mixes five litres for a two litre job discards three litres and cleans the gun in solvent it also pays for. Timing the pot from a clock rather than judging it from the pot is the single change that removes most two-component waste, because a material that is still liquid can already be past the point where it will build film properly.
Water-based finishes work well where the constraint is ventilation, solvent storage, odour or the fire loading of the shop, and where the drying environment can be controlled. They dry by water evaporation, so air movement and relative humidity govern the cycle in a way that solvent-borne material does not: a part that is touch dry in 45 minutes with air over it can still be wet after three hours in a still, humid corner. Wetted parts of pumps, lines and guns have to be corrosion resistant, and stock is protected from frost. Water-based two-component polyurethane adds a second constraint, because the polyisocyanate reacts with water as well as with the resin and that side reaction releases carbon dioxide, which is why film build per coat is held to the stated range and why the end of pot life is not signalled by a viscosity rise. Where those conditions are met, WB 140 covers interior work and WB 270 reaches two-component resistance levels. Where they cannot be met, the honest answer is a solvent-borne grade with the extraction to match.
Film build and recoat discipline govern the rest of the result. Wet film is checked with a comb during application rather than measured as dry film after the fact, because by then the correction costs a pass. Force drying starts with a flash-off at shop temperature before the part goes into warm air, because skinning a film that still holds solvent produces popping and pinholes. Recoat windows are stated on every Technical Data Sheet and they matter most on epoxy: a fully cured epoxy film is washed to remove any amine blush and then abraded before it will accept the next coat, and overcoating a partly cured film outside the window is a common cause of intercoat failure. Air-dried alkyd films go on hardening long after they are touch dry, so stacking, strapping and wrapping are timed against hard dry, not against touch dry.
The boundary against Industrial and Infrastructure Coatings is drawn by where the item lives, not by its chemistry. If the item stays where it was built and is maintained in place, it is an infrastructure job and is specified against an exposure environment and a maintenance interval. If it leaves the shop as a product, it belongs here, and is specified against a batch, a colour reference and a handling time.
Specifying this range
Specifying correctly for a jobbing shop depends on facts about the shop as much as facts about the part. These are the questions Arctic will ask at enquiry, and the answers determine which of the ten grades is quoted.
- What is the substrate, and does it vary between batches? Bare mild steel, hot-dip galvanised, electro-zinc, aluminium, brass or a mixture on the same rack. A mixed rack points to Arcmetal PR 210 as the common primer.
- What preparation can the shop actually achieve? Blast cleaning to ISO 8501-1 Sa 2 and a half, power tool cleaning to St 3, or degreasing and abrading only. This sets the realistic protective life before any product is chosen.
- Where does the finished item spend its life? Interior dry, sheltered exterior, full exterior, regular wash-down, chemical or solvent splash, or coastal exposure. Where a corrosivity category is already named in the enquiry, the ISO 12944-2 categories are the reference used.
- One coat or two, and what total dry film thickness is specified? A single coat route trades total build and a dedicated anti-corrosive layer for a pass saved.
- Is there an oven or warm air, and what temperature can the part tolerate? Assemblies containing plastics, seals, bearings or electronics rule out force drying and point to the air-dry grades.
- How soon must the part be handled, stacked, strapped or packed? Handling time, not touch dry time, is the number that governs the rack, and it is the usual reason to move from AL 160 to AL 290.
- How much mixed material is used in one session? For two-component grades this sets pack size and batch size, and it is the difference between a viable and an expensive two-component process.
- What is the shop temperature range through the year? Pot life shortens in summer heat and epoxy cure slows sharply below 15 degrees C, so both ends of the range matter.
- What are the ventilation, extraction, solvent storage and odour limits? These decide whether the water-based route is a requirement rather than a preference.
- What colour reference and sheen apply? RAL, BS 381C, BS 4800, an IS reference or a customer panel, and matt, satin or gloss. Each colour is recorded against the reference named, so repeat orders are checked against that standard.
- What is the repair and recoat expectation in service? A part that will be touched in by the end user favours alkyd; a part that will never be repainted favours two-component.
- Is a compliance dossier or a declaration required for the end market? These are issued on request against the grades supplied.
Every grade is supplied with a Technical Data Sheet and a Safety Data Sheet naming the system, the preparation it assumes and the recoat window it depends on.
Documents and specification
The Technical Data Sheet, Safety Data Sheet and regulatory declaration for any grade in this range are issued by our laboratory against the substrate and process you are running. Tell us the job and we will specify against it.