A PTFE-type fluoropolymer coating creates a very low-energy, low-friction surface: sticky, wet or pasty products barely adhere to it, and most chemicals do not attack it. It is applied in a shop, on a blast-cleaned part that can be removed, then baked in an oven. It solves sticking and friction problems, not severe abrasion or impact, and it is hard to repair in the field.
Fluoropolymers are a family of resins, and PTFE is the best-known member. On industrial equipment they are mostly used to fix a flow or build-up problem: product sticking to chute walls, paste hanging up in a hopper, a roller that fouls, a vessel that takes too long to clean. This guide is for maintenance and production managers who want to know whether this type of coating solves their problem, or whether another family of protective coatings is a better fit. For an overview of the families, see our article on types of industrial coatings.
What properties set a PTFE coating apart?
A PTFE coating stands out for three properties: a surface that wets very poorly, so water, oils and most sticky products bead up instead of spreading; one of the lowest friction coefficients among coating materials; and high chemical inertness. It also tolerates a wide service temperature range and is an electrical insulator.
The family includes several resins with related but different behaviour:
- PTFE. The reference resin for release and low friction. It does not truly melt during baking, which gives thin films, often applied in several coats.
- FEP and PFA. Fluoropolymers that melt and flow during baking. They form more continuous, thicker films that are better suited to chemical contact.
- ETFE and PVDF. Tougher fluoropolymers that resist mechanical rubbing better, at the cost of slightly lower release.
- Reinforced formulations. Fluoropolymers loaded with hard particles or combined with a tougher base coat, to resist wear better.
The right choice depends on the problem to solve. Exact values (maximum temperature, thickness, chemical resistance) come from the technical data sheet of the selected product.
On which equipment is a non-stick coating useful?
A non-stick coating is useful wherever a product sticks, builds up or rubs enough to slow production or force frequent cleaning. The table below summarizes common uses and what to check before choosing.
| Equipment | Problem solved | Point to check |
|---|---|---|
| Transfer chute | Build-up of wet or sticky product | Share of sliding abrasion and impact |
| Hopper and small bin | Arching, erratic flow, residue | Whether it can be removed and oven size |
| Roller and drum | Fouling, product tearing | Contact pressure and friction |
| Vessel and mixer | Long cleaning, cross-contamination | Chemicals and temperature |
| Mould, fixture, baking plate | Difficult release | Thermal cycling |
| Scraper, slide, guide | Friction and wear of conveyed product | Load and speed |
For silos and hoppers, the choice of a flow-promoting lining is covered in our article on silo and hopper linings. For mine chutes exposed to ore, see also conveyor and chute painting: abrasive ore often wears a thin non-stick film before it has paid for itself.
How is a PTFE coating applied in the shop?
A PTFE coating is applied in a shop in four stages: part preparation, primer, fluoropolymer coats and oven baking. Baking is the step that requires a shop, because it needs a high, controlled temperature across the whole part, which a field job cannot provide.
- Removal and inspection. The part is removed, cleaned and inspected. Worn or holed areas are repaired before any coating.
- Degreasing and outgassing. Oils and absorbed contaminants are removed, sometimes by a first pass through the oven, so they do not come back out during baking and blister the film.
- Abrasive blasting. The surface is blast cleaned to the degree set by the specification, often white or near-white metal, with a surface profile suited to the primer. Our abrasive blasting service handles this step.
- Primer, coats and baking. A bonding primer is applied, then the fluoropolymer in one or more coats, each followed by baking as per the data sheet.
The part therefore has to fit in the oven, withstand the baking temperature without distorting and contain no materials that degrade at that temperature (seals, bearings, plastics). These conditions are checked before quoting.
What limits should you know before choosing?
The main limit of a PTFE coating is its low resistance to abrasion and impact: the film is thin and relatively soft, and angular ore or falling lumps wear it quickly. Next come the possible porosity of thin films, the difficulty of field repair and the need to remove the part.
- Abrasion. Under severe sliding abrasion, bonded ceramic, polyurethane or rubber last longer. Our comparison of rubber, ceramic and polyurethane helps decide.
- Impact. Impact zones need a material that absorbs energy; a fluoropolymer does not belong there.
- Porosity. A thin film can contain pores that let a corrosive product reach the steel. In chemical service, continuity is checked with a holiday test, and resins that form a continuous film are preferred.
- Size. Oven size limits part size. Large fixed equipment is treated with another system applied in place.
- Regulation. Fluoropolymers are among the substances monitored by Canadian authorities. The safety data sheet and the client's requirements are checked at the selection stage.
Can a damaged PTFE coating be repaired?
A PTFE coating can rarely be repaired in the field with the same result: a lasting repair means removing the part, stripping the old film, blasting again, then reapplying and rebaking in the shop. Cold-applied touch-up products exist, but they do not reproduce the release or the adhesion of a baked film.
In practice, coating renewal is planned like a wear part: a spare coated part is prepared ahead of time and installed during a shutdown, while the worn part goes back to the shop. This rotation avoids keeping the equipment down for the treatment time. Wear that keeps coming back at the same spot often points to a mechanism that was misread, such as impact or sliding abrasion, which needs a different solution in that zone.
Which checks validate a PTFE coating?
A PTFE coating is validated by checks at each stage: cleanliness and profile before the primer, thickness after each coat, film continuity and adhesion on the part or on a test panel. These are the checks of any quality coating, adapted to a thin, baked film.
- Preparation. Cleanliness to SSPC-SP 5 or SP 10 and a measured profile, for example to ASTM D4417.
- Thickness. Non-destructive measurement, sampling plan to SSPC-PA 2 and the range on the data sheet.
- Continuity. Holiday detection to a method such as ASTM D5162, when the service requires it.
- Adhesion. Cross-cut or pull-off testing (ASTM D3359 or ASTM D4541) on a panel prepared with the part.
Our coating inspection service can document these checks and hand over a record that stays with the part.
When is another coating a better choice?
Another coating is a better choice when the main problem is abrasion, impact, chemical immersion over a large area, or equipment that cannot be removed. A fluoropolymer remains the right choice for a removable part where the product sticks and rubs without heavy abrasion.
For a fixed process vessel, a novolac epoxy or vinyl ester lining applied in place, described in our article on process vessel corrosion protection, is often more realistic. For a mine chute, a bonded wear liner or an elastomer works better. A diagnosis of the equipment, the product and the wear mode settles the question before you spend.
Frequently asked questions
Does a PTFE coating withstand heat?
Yes, over a wide but limited temperature range. The maximum service temperature depends on the resin and the primer and is stated on the data sheet of the selected product.
Can a PTFE coating be applied in place, without removal?
Not a true baked PTFE coating. Baking requires an oven. In place, a cold-curing low-friction coating is applied instead, with lower release performance.
Does a PTFE coating protect steel against corrosion?
It helps, but a thin film can be porous. In corrosive service, choose a resin that forms a continuous film, apply enough thickness and check continuity.
How long does a PTFE coating last on a chute?
It depends mainly on how abrasive the product is and on the zone. Without severe abrasion it lasts a long time; under abrasive ore it wears quickly. An inspection after the first service period sets the replacement interval.
Our crews and qualified subcontractors treat removable parts in the shop and fixed equipment in place, working from LaSalle, including in Montreal and Ontario. Send photos, part dimensions, the product in contact and the service temperature through the quote request: pricing on consultation, reply within 24 business hours.
Hicham M, P Eng, PMP
Engineer and project manager (PMP) at Induscoat. Over 16 years of experience in industrial coatings, composite repairs and wear protection on mining, energy and petrochemical sites in Canada and internationally.