# Coating a Refractory-Lined Stack Before the Lining Goes In Coat a refractory-lined stack on the bare internal steel before the refractory goes in, ideally on prefabricated sections in the shop. Weld the anchors, blast the steel, apply a coating such as KilnGard-600SCW around the anchors, inspect it, then line and assemble. In 2026, KilnGard-600SCW was shop-applied to 18 prefabricated sections of an Exxon Canada stack before refractory installation. **Category:** Articles **Written by:** Surjit Gill **Last updated:** Oct 12, 2026 **Source:** https://signals.polylloycoatings.com/articles/refractory-lined-stack-coating --- ## Refractory-Lined Stack Coating: Key Points - Coat a refractory-lined stack on the bare steel before the refractory is installed; once the lining is in, the steel cannot be reached until the next reline. - Coating can go inside an existing stack, on replacement sections on the ground, or on newly manufactured sections before assembly; shop coating of new sections gives the most control. - The working sequence is specify, weld anchors, blast, coat around the anchors, inspect, then line and assemble the sections in the order the project sets, and start up. - KilnGard®-600SCW (600 °C service limit) was applied in the shop in 2026 to the internal steel of 18 prefabricated sections for an Exxon Canada refractory-lined stack, around densely spaced anchors. - The Exxon Canada project is an application-stage reference: it documents placement and coverage, not in-service performance. - A coating behind refractory protects the steel interface; it does not replace the refractory or fix a lining design that lets the shell overheat. Coat a refractory-lined stack on the bare internal steel before the refractory goes in, ideally on prefabricated sections in the shop. Weld the anchors, blast the steel, apply a coating such as KilnGard-600SCW around the anchors, inspect it, then line and assemble. In 2026, KilnGard-600SCW was shop-applied to 18 prefabricated sections of an Exxon Canada stack before refractory installation. ## Why a Refractory-Lined Stack Needs Its Coating Before the Lining Goes In A new refractory-lined stack looks finished the day the last castable is placed, but the steel behind the lining is exactly where it was. If it went in bare, it stays bare for the life of the lining. ### The Steel/Refractory Interface Refractory-lined stack coating is a protective coating applied to the internal steel of a stack before the refractory lining is installed. The coating has to go on first, because once the lining is in place the steel is hidden until the next reline. Heat, permeating process species and thermal cycling can contribute to oxidation and corrosion at the steel/refractory interface; the mechanism is covered in [corrosion behind refractory linings](https://signals.polylloycoatings.com/articles/corrosion-behind-refractory-lining). Stacks are the final stage of the gas path and often run at its lowest temperatures, and linings and insulation hide the steel, so corrosion there can go undetected. ### What the Coating Does and Does Not Do The coating is a barrier on the steel; the refractory still carries the thermal duty. KilnGard-600SCW has a service limit of 600 °C (1,112 °F) at the steel, and it is placed directly on prepared steel beneath the refractory lining. Its bulletin applications go beyond kilns. They include waste incineration furnaces, and ducts, filters and stacks in copper, zinc or lead smelters, in each case on steel beneath refractory. A stack is one more lined vessel where the same logic applies: protect the steel first, then line it. ## Three Stages When Stack Steel Can Be Coated Stack steel can be coated at three stages, according to Polylloy's May 2026 International Cement Review (ICR) article, and the stage decides how much control the applicator has. ### Existing Stacks, Replacement Sections and New Sections Coatings can be applied inside an existing stack as part of maintenance, on replacement sections on the ground, or on newly manufactured sections prior to assembly. For a lined stack, the first route means removing the lining. The steps in this guide cover new and replacement sections, where the coating is planned into fabrication. Unlined and relined stacks are compared in [industrial chimney and stack corrosion options](https://signals.polylloycoatings.com/listicles/industrial-chimney-stack-corrosion). ### Why Shop Coating of New Sections Gives the Most Control In the shop, every section interior is fully accessible, blasting is sheltered and humidity can be controlled. The coating is inspected before anything hides the steel, and none of the work sits on an outage critical path. Polylloy's experience is that the design stage is where the coating is easiest to add; once the fabrication schedule is fixed, it is the step most easily squeezed out. ## How to Coat Prefabricated Stack Sections Before Refractory Installation The seven steps below follow the order the work happens on a prefabricated, refractory-lined stack. ### Specify the Coating with the Stack and Refractory Design (Steps 1-2) 1. Write the coating into the fabrication and refractory specifications at the design stage: grade by steel temperature and gas chemistry, surface preparation, [inspection hold points](https://www.polylloycoatings.com/industrial-inspection-maintenance-services) and who applies. 2. Agree the sequence with the fabricator and the refractory installer. Anchors are welded and all hot work on the section is complete before blasting, so the coating is applied around the anchors, as on the Exxon Canada sections. ### Prepare and Coat Each Section (Steps 3-4) 1. Abrasive blast to SSPC-SP10 / NACE No. 2 near-white, the joint Society for Protective Coatings (SSPC) and NACE International standard, with a profile above 3 mils (75 microns). Keep the steel clean and dry, relative humidity below 90% and the steel 5 °C above the dew point. 2. A certified Polylloy partner applies KilnGard-600SCW, a two-component, water-based nano-ceramic composite, by air spray, roller or brush. The coating goes on the internal steel, around and onto the anchor bases. ### Inspect, Line and Assemble (Steps 5-6) 1. Verify dry film thickness (DFT) and coverage, especially around anchors and at section edges, and repair before the refractory installer starts. This is the last time the steel is visible. 2. Install the refractory over the coated steel and assemble the sections, following the project's fabrication plan for which comes first. Plan how field weld joints between sections will be prepared and protected, and confirm the method with Polylloy. ### Start Up (Step 7) 1. Final heat cured activation is completed during stack start-up using process heat. The refractory supplier's own dry-out requirements still apply. ## Exxon Canada Refractory-Lined Stack: KilnGard-600SCW on 18 Prefabricated Sections The Exxon Canada stack is the worked example for the sequence above, documented in Polylloy's 2026 company profile. ### Project Scope KilnGard-600SCW was applied to the internal steel surfaces of 18 prefabricated stack sections for a refractory-lined Exxon Canada stack project. It was installed directly on prepared steel beneath the refractory lining, including around the densely spaced refractory anchors. ### Application Stage Photographs document the coated sections during shop application in June 2026, before refractory installation and final stack assembly. The technical objective is a protective barrier at the steel/refractory interface, where heat, permeating process species and cycling can contribute to oxidation and corrosion. ### What the Reference Shows and Does Not Show The Exxon Canada project is an application-stage case study. The photographs verify placement and coverage on the sections, and no long-term in-service performance claim is made. For a project engineer, the useful lesson is the sequence rather than a result. The sections were coated in the shop, around anchors that were already in place, before the refractory and before assembly, which is the route described in the steps above. ## Who Does What on a Refractory-Lined Stack Coating Project A refractory-lined stack coating project involves four parties, and the coating only works if their sequence holds. ### Roles Each party owns one part of the work: - Engineering, procurement and construction (EPC) contractor or owner's engineer: writes the specification and hold points. - Stack fabricator: anchors, welding and section handling. - Certified application partner: blasting and coating. - Refractory installer: lining over the coated steel. Polylloy formulates and supplies KilnGard-600SCW, specifies the system, trains the applicator and supervises; partners apply, across a network of 15 partners in 22 countries. How partners are selected is covered in [industrial coating contractors and application partners](https://signals.polylloycoatings.com/articles/industrial-coating-contractors). ### Handover Points Two handovers matter most: coating inspection sign-off before lining starts, and protection of coated sections during lifting and transport. Write both into the inspection and test plan as hold points, so the refractory installer does not start on a section the coating inspector has not released. Agree in advance who records film thickness and coverage, who approves repairs, and who signs the release. On a project with many sections, a simple per-section record keeps the sequence clear for everyone. ## Limits of Coating Steel Behind a Refractory-Lined Stack Coating steel behind a refractory-lined stack protects the interface, but it has firm limits that belong in the specification. ### What a Coating Behind Refractory Cannot Do A coating behind refractory cannot correct design, sequencing or preparation problems: - It does not replace the refractory or correct a lining design that lets the steel run above 600 °C, and KilnGard-600SCW is not immersion-rated. - Weld spatter, grinding or anchor work after coating damages the film, so all hot work is sequenced first. - Surface preparation is critical: a fabricator who cannot blast to SSPC-SP10, or a site that cannot reach start-up heat, is not a fit. - Grade choice is per project, and Polylloy's technical team reviews each stack duty. Stacks without refractory are a different selection, such as [StackGard®-255SQW](https://www.polylloycoatings.com/stackgard). Grades for hotter steel are compared in [high temperature coatings above 400 °C](https://signals.polylloycoatings.com/listicles/high-temperature-coatings-400c), and the full grade is described under [KilnGard coatings beneath refractory](https://www.polylloycoatings.com/kilngard). ## Deciding Whether to Specify a Coating for Your Refractory-Lined Stack Four questions settle most specifications: - Is the stack new, or are sections being replaced? - Can coating fit the fabrication schedule before the refractory goes in? - What steel temperature and gas chemistry sit behind the lining? - Who will inspect the coating before lining? To book a Coating Performance Review, [request a coating evaluation](https://www.polylloycoatings.com/contact) with stack drawings or section count, coated area, operating conditions, refractory type, fabrication location and schedule. ### FAQs **Should the Steel Behind a Refractory-Lined Stack Be Coated?** Yes, where heat, permeating process species and thermal cycling can attack the steel/refractory interface. The coating must go on before the refractory, because the lining hides the steel until the next reline. KilnGard-600SCW, rated to 600 °C, is one coating designed for steel protected beneath refractory, including stacks. **Can Stack Sections Be Coated Before They Are Assembled?** Yes. Coatings can be applied to newly manufactured stack sections before assembly, to replacement sections on the ground, or inside an existing stack. For a refractory-lined stack, coating each prefabricated section in the shop, after the anchors are welded and before the lining is installed, gives full access and controlled conditions. **Do Refractory Anchors Need to Be Welded Before the Coating is Applied?** Yes. Finish all welding and hot work on a section first, then blast and coat around the anchors, because welding after coating damages the film. On the Exxon Canada stack, KilnGard-600SCW was applied directly on the prepared steel around densely spaced refractory anchors before the refractory lining was installed. **What Was Coated on the Exxon Canada Stack?** The internal steel surfaces of 18 prefabricated sections for a refractory-lined Exxon Canada stack, coated with KilnGard-600SCW in the shop in June 2026 before refractory installation and final assembly. It is an application-stage reference: photographs verify placement and coverage, and no long-term in-service performance claim is made yet. **How is a Coating Under Refractory Cured in a New Stack?** Final heat cured activation is completed during stack start-up using process heat, so activation is planned into the first start-up rather than done in the shop. The refractory supplier's own dry-out requirements still apply. Project-specific application instructions come from Polylloy and its certified application partner for each stack. **Who Applies the Coating on Prefabricated Stack Sections?** A certified Polylloy application partner applies it, for shop work at the fabricator's shop or another covered area. Polylloy formulates and supplies the coating, specifies the system, trains the applicator and supervises. The fabricator handles anchors and welding, and the refractory installer lines the sections only after the coating inspection is signed off.