A genset paint system decides how long the steel lasts, and the coat schedule matters more than the colour. Compare the surface preparation, the coat thickness and the stripe coat against the site before you accept an offer. Tesla Power writes the schedule by coat; send the site data to the technical desk and we confirm the system.
- Ask for the preparation grade, because paint on a dusty panel is a film with no key.
- Check the coat schedule by thickness rather than by the number of coats.
- Look at the stripe coat on the edges and the welds, where corrosion starts.
- Ask what the site will wash the shell with, since a solvent takes the topcoat with it.
What does a genset paint system have to resist?
It has to resist salt, sun, fuel and the water a site throws at a shell during washing. Salt attacks the edges and the welds, sun breaks down the topcoat on a horizontal panel, and fuel finds every place the film is thin. A system chosen for one of those three fails on the other two.
The site conditions decide the system more than the colour does. A shell in a dry inland yard needs three coats and a shell on a coast needs four, with a stripe on every edge. Ask the buyer for the distance to the sea and the washing routine. Tesla Power writes those two answers on the paint specification, because they change the schedule. A shell that is washed weekly with fresh water is a different case from one washed twice a year with a solvent.
Which surface preparation is needed?
Shot blasting to a near white grade is the preparation that gives a coating a key, and a wire brush is not a substitute for it. A panel blasted and painted the same day holds a film for years, and a panel that sits overnight collects a flash of rust that the first coat cannot cover. Ask for the grade and the time between blast and prime, where 4 h is a common limit.
The cut edges and the welds are the places where preparation is skipped, because they are slow to blast. An edge with a 2 mm radius rather than a sharp arris takes a film better, and a weld that is ground smooth takes a stripe coat without a bridge. Ask for the edge treatment on the drawing. Tesla Power Equipment grinds the louvre edges before the blast rather than after it, because a ground edge that is already primed has to be spot primed again.
| Item | Typical figure | Note |
|---|---|---|
| Preparation | Near white blast | Primed the same day |
| Standard system | 3 coats, 240 microns | Dry film, total |
| Coastal system | 4 coats, 300 microns | With a stripe on every edge |
| Stripe coat | Brush applied first | Edges, welds and bolt heads |
How many coats are needed?
A standard system is a primer, an intermediate coat and a topcoat, and the three together reach about 240 microns of dry film. A coastal system adds a fourth coat and reaches about 300 microns. The number of coats matters less than the total thickness, and a thick single coat is a coat that fails at the edges.
Each coat has a window in which the next one bonds, and a coat left too long has to be abraded before the next goes on. That window is why a paint shop schedules the coats rather than leaving them to the painter. Ask for the recoat window in hours and the shop temperature it assumes. A coat applied outside the window is a coat that delaminates in a year. A shop that sprays all three coats in one shift is a shop that is outside the window on at least one of them.
What is a stripe coat for?
A stripe coat is a brush applied coat on the edges, the welds and the bolt heads, put on before the main coat reaches them. Spray reaches a flat panel at the specified thickness and reaches an edge at about a third of it. The stripe is what brings the edge up to the panel figure.
A stripe coat adds about 50% to the film on an edge, and on a shell where 5% of the area is edge that is where the life comes from: 240 microns x 1.5 = 360 microns, and an inspector who accepts 80% of the spec there is accepting 192 microns. Ask whether the stripe is a separate step or the same spray pass. Tesla Power stripes every louvre and door edge before the topcoat, and the stripe is brushed rather than sprayed so the edge is wet through.
How is the film thickness checked?
A magnetic gauge reads the dry film on steel, and the reading is a set of spot measurements rather than one number. The specification gives a nominal figure and a minimum, and the minimum is what matters on an edge. A shell reported at the nominal figure with no minimum is a shell that has thin spots nobody has measured. Ask for the minimum as a percentage of the nominal figure rather than as a separate number.
The gauge also reads high on a rough surface, so the measurements are taken on a smooth reference area or corrected for the profile. Ask for the number of readings and where they were taken. Tesla Power Equipment records five readings per panel on the inspection sheet, and a panel below the minimum is repainted rather than touched up.
What damages the coating on site?
The lifting slings, the fork lift and the site boots do more damage than the weather in the first month. A shell that is landed on gravel loses the film along the bottom rail, and that is where the rust starts a year later. Touch up the rail before the shell goes into service rather than at the first inspection, because the rail is the first place a shell shows rust and the last place anyone looks.
Washing with a solvent takes the topcoat with it, and a site that washes with diesel is a site that strips the shell. Ask what the site uses and match the topcoat to it. Yangzhou Tesla Power supplies a touch up kit with the shell, because a shell that arrives with a tin of the right paint is a shell that gets repaired.
What does the offer need to state?
The offer should give the preparation grade, the coat schedule by thickness, the stripe coat, the recoat window and the touch up kit. Five items on one line let a buyer check the system against the site without reading a specification, and a schedule quoted as three coats with no thickness tells a buyer nothing at all. Ask for the total dry film thickness as well as the figure for each coat, since 240 microns is the figure a three coat system has to reach.
The wording on the offer matters too. Chinese genset paint suppliers often quote a colour and a coat count with no thickness, and a genset paint system manufacturers page can show a schedule the shop does not follow. Ask for genset paint system for a coastal site, genset paint for the louvre edges and genset in a wet climate as three separate cases. Tesla Power prints the five items on the paint card.
What does the handover file record?
The file carries the preparation grade, the coat schedule, the measured thickness, the touch up colour and the date of painting. One page covers the system when those five items sit under the shell serial number. Add the conformity assessment for the paint system when the coating is part of a permit package and the finish is specified by the buyer.
Hand the page to the technician who will touch up the shell rather than to the buyer who placed the order. the Yangzhou factory describes the blast bay and the paint shop, the commissioning notes lists the shells that ship with a four coat system, the build range explains how the thickness is measured, the 1000kW container build shows the frame that matches the duty, the ISO 8528-1 duty definitions sets the corrosion category the system was chosen for, and the NFPA 110 maintenance routine covers the coating standard behind the schedule.
Frequently asked questions about genset paint systems
It can be touched up on site and it cannot be repainted to the original schedule without a blast, because a new coat on a chalked topcoat does not bond. Plan the touch up and keep the colour record. A full repaint belongs in a workshop with the shell stripped.
The edge is where the film is thinnest and where the water sits, so it fails first on every shell. A stripe coat and a rounded edge move the failure back by years. Ask for the edge treatment before changing the paint.
Galvanising protects a cut edge that paint cannot reach, and it cannot be painted to the same finish without a suitable primer. A galvanised shell in a coastal yard is often the cheaper answer over twenty years. Ask for the coating thickness in microns either way.
Three coats at 240 microns in a dry yard last about ten years, and the same system on a coast lasts about five. The edge figure decides which of those two the site gets. Ask for the warranty in years and the thickness it assumes.
It matters for heat rather than for corrosion, because a dark topcoat runs hotter in the sun and a hotter panel ages faster. A light topcoat on a canopy in a hot yard is worth a few degrees inside. Ask for the colour and the surface temperature the shop measured.
The topcoat in the right colour, a small brush, a scraper and the preparation grade in a pen. A kit with the wrong colour is worse than no kit, because a patch that does not match gets painted over twice. Tesla Power puts the batch number on the kit so the colour can be matched later.