Thurmalox 225HD High Build, Air Dry, High Temperature VOC Compliant Coating

Thurmalox 225HD is a two component, corrosion inhibitive, high build, air dry, high temperature, VOC compliant heat resistant coating system for protection of carbon and stainless steel surfaces from atmospheric corrosion and corrosion under insulation. It is an ideal coating to cover steel surfaces with deep profiles, eliminating the problem of pinpoint rusting by covering the peaks with this unique high build coating. Thurmalox 225HD may be top-coated with itself, Thurmalox 230/230C Series, or Thurmalox 260/260C Series.

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SKU: Thurmalox 225HD Categories: ,
  • High build, high solids
  • Self priming, two component
  • Easy to apply by brush, roller or spray
  • VOC compliant – 3.44 lb./gal. (292 g./l.)
  • Withstands temperature of 1000 F (538 C)
  • Air dries
  • Easily topcoated with Dampney Topcoats
  • Protects against weathering and corrosion
Generic TypeModified Silicone Co-Polymer
Mixing Ratio9:1 by volume
ColorLight Gray
Number of Components2
Temperature Resistance Continuous149 – 538 C
350 – 1000 F
Temperature Resistance Intermittent648 C
1200 F
Volume Solids50 percentage
Dry Film Thickness Per Coat4.0 – 5.0 mils (101.6 – 127 microns)
Wet Film Thickness Per Coat8.0 – 10.0 mils (203.2 – 254 microns)
Theoretical Coverage800 sq. ft./gallon 19.7 sq. m./liter (at 1 mil/ 25 microns)
Application Temperature Range50 to 200 F
Flash Point27.2 C
81 F
Viscosity1190 cps
Drying Time to Touch at 50 F (10 C), 50% RH6 hours
Drying Time to Recoat at 50 F (10 C), 50% RH12 hours
Drying Time to Ship at 50 F (10 C), 50% RH48 hours
Drying Time to Touch at 70 F (21 C), 50% RH4 hours
Drying Time to Recoat at 70 F (21 C), 50% RH8 hours
Drying Time to Ship at 70 F (21 C), 50% RH24 hours
Drying Time to Touch at 94 F (34 C), 50% RH Air Dry3 hours
Drying Time to Recoat at 94 F (34 C), 50% RH Air Dry6 hours
Drying Time to Ship at 94 F (34 C), 50% RH Air Dry12 hours
Full Cure17 days
Weight Per Gallon15 lb
Shelf Life1 Year
V.O.C292 GMS/Liter
3.44 LBS
Pot Life8 – 12 hours
Only thin Thurmalox 225HD with Dampney 180 Thinner. Do not thin beyond federal, state and/or local VOC emission regulations.
Note: Use of other thinners not approved by Dampney may hinder product performance and void product warranty.
Clean Up
Thoroughly flush spray equipment and hose immediately after use with Dampney 162 Thinner. Dismantle spray equipment and clean parts, brushes and rollers with Dampney 162 Thinner.
StorageStore in a cool, dry place with temperatures between 50 F and 100 F (10 C and 38 C). Keep container closed when not in use.
Packaging1 gal. kit
5 gal. kits
Note1 Humidity, temperature and coating thickness will affect drying and curing times
Recommended Uses
Application where (1) the benefits and features of Thurmalox 225HD are needed and (2) where federal, state, and/or local authorities require high temperature coatings to be compliant with reduced VOC (volatile organic compound) emissions regulations.

  • Stacks, Breechings, Boiler Casings
  • Manifolds, Mufflers and Exhausts
  • Hot Piping, Process Vessels, Heat Exchangers
  • Refinery Equipment – Heaters, Crackers
  • Furnaces, Kilns, Heat Exchangers
  • Insulated surfaces from 500 F (260 C) to 1000 F (538 C).
    (NOTE: 225HD must be air dried for a minimum of 7 days before insulating)

Not Recommended For

  • Interiors of breechings
  • Interiors of scrubbers


Performance Testing Data
High Temperature Test: ASTMT2485 Method A 1000 F (538 C) – 100% Pass
Abrasion Resistance: ASTM D4060 (Heat Cured) (CS-17 wheel, 500 gm load, 1000 cycles). – 320 mg loss
Abrasion Resistance: ASTM D4060 (Air Dried) (CS-17 wheel, 500 gm load, 1000 cycles). – 370 mg loss
Adhesion: (Air Dried) (ASTM D 4541 Adhesion Elcometer) – 400 psi
Flexibility: ASTM D 522 Mandrel Bend Test
Heat Cured: 6.0 mils DFT-13 % elongation
Ambient Cure: 6.0 mils DFT- 22 % elongation
Salt Fog resistance: ASTM B 117 (6 mils DFT)
Heat Cured: no rust, blisters, cracking & de-lamination and no undercutting – 1500 hours
Ambient Cure: no rust, blisters, cracking, de-lamination and no undercutting – 1000 hours
Surface Preparation
To ensure optimum long term coating system performance, surfaces must be clean, dry and free from dirt, oil, grease, salts, welding flux, mill scale, rust, oxides, old paint, corrosion products, visible contaminants or other foreign matter detrimental to the adhesion of this coating system.
Remove all surface imperfections that will induce premature coating system failure. All sharp edges rounded, rough welds and weld splatter shall be ground smooth.Carbon Steel: Insulated or Uninsulated
Abrasive blast all surfaces to SSPC-SP 10, “Near White Metal Blast” / NACE No. 2, leaving all surfaces with a profile depth of 1.5-3.0 mils (38.1-76.2 microns) after blasting. Care should be taken to select abrasives of a proper mesh size to yield the degree of cleanliness and required profile depth.
If abrasive blasting is not permitted, prepare surface by “Power Tool Cleaning” per SSPC-SP 11, using a “Dynascaler Air Powered Surface Preparation Tool” with 3M Heavy Duty Roto Peen “Bonded Shot” flap assemblies mounted in the tool.

Stainless Steel: Insulated or Uninsulated
All surfaces must be clean and dry. Remove all oil, grease, soil, drawing and cutting compounds, and other foreign matter by methods outlined in Steel Structures Painting Council Specification SSPC-SP 1, “Solvent Cleaning”, using Dampney 170 Cleaning Solvent. Prepare all surfaces by using “Starblast” fine grade to achieve a surface profile of 1.52 mils (38.1-50.8 microns) of profile.

Mixing & Application Guidelines
Thurmalox 225HD has a 9:1 mix ratio by volume consisting of a Part A and Part B which must be mixed together before use. The individual components must be mixed separately to disperse the pigments uniformly. Add Part B to Part A and mix thoroughly with a low-speed power mixer for a minimum of 3 minutes or until mixed coating is completely blended and of a uniform color. Do not open containers until ready to use. Keep lid on container when not in use.
Cure Time 70 F (21 C) 50% RH
Thurmalox 225HD will air dry, tack and thumb print free within 4-6 hours. A temperature of 350 F (149 C) must be achieved to cure Thurmalox 225HD before it can be put into wet-dry-wet thermal cycling service.
Application Information
Apply only when air, product and surface temperatures are above 50 F (10 C) and surface temperature is at 5 F (3 C) above dew point. The relative humidity during application and curing should not exceed 80%RH. Thurmalox 225HD can be applied by brush, roller, airless spray or conventional spray. No thinning is necessary for brush, roller or spray application.

Brush/Roller: Extra care should be taken to measure and hold film thickness when applied by brush and roller. This method should only be used when spray method is not available.

Brush: Use a medium china bristle with steel shank and wooden handle. Do not use synthetic-bristled brushes.

Roller: Use a wooden handled roller with a 1/2″ phenolic cored lambs wool roller attached. Roll coating out thoroughly, maintaining a continuous wet edge and uniform appearing paint film.

Airless Spray:
Pump: – 30:1
Operating pressure: – 2500-3000 psi
GPM output: – 3.0 gals per minute
Material hose: – 3/8″ ID
Tip Size: – 0.017″-.023″
Filter Size: – None
It is recommended that Teflon packing be used.

Conventional Spray:
Fluid tip: – 66
Air Cap: – 63P
Atomizing Air: – 50 psi
Fluid hose: – 5/16″ ID
Fluid Pressure: – 15-20 psi

Recommended Systems
Carbon Steel:
1st Coat; Thurmalox 225HD – 4.0-5.0 mils DFT
2nd Coat: Thurmalox 225HD – 4.0-5.0 mils DFT
Total System – 8.0-10.0 mils DFT
Stainless Steel:
1st Coat: Thurmalox 225HD – 4.0-5.0 mils DFT
2nd Coat: Thurmalox 225HD – 4.0-5.0 mils DFT
Total System – 8.0-10.0 mils DFT
Carbon Steel:
1st Coat: Thurmalox 225HD – 4.0-5.0 mils DFT
2nd Coat: Thurmalox 230C or 260C – 2.5-3.0 mils DFT
Total System – 6.5-8.0 mils DFT
Stainless Steel:
1st Coat: Thurmalox 225HD – 4.0-5.0 mils DFT
2nd Coat: Thurmalox 230C or 260C – 2.5-30 mils DFT
Total System – 6.5-8.0 mils DFTNote: Other Thurmalox coating systems can be put over Thurmalox 225HD as a finish coating. When extreme cyclic (fast thermal cycling) conditions are present, consult Dampney Technical Service.
Precautionary Information
WARNING: Flammable Liquid and vapor.
Keep away from heat, sparks and flame. Vapors may cause flash fire. Do not breathe vapors or spray mist. Avoid contact with eyes, skin and clothing. Use only with adequate ventilation during mixing and application.Wear an appropriate, properly fitted organic vapor cartridge type respirator (NIOSH approved) during and after application unless air monitoring demonstrates vapor/mist levels are below application limits. Follow respirator manufacturers directions for respirator use. Wash thoroughly after handling. Wear protective gloves, chemical safety goggles and impervious protective clothing. Use skin cream. In confined spaces it is required to use a positive pressure supplied air-respirator (NIOSH approved) Use explosion-proof lights and electrical equipment. Use only non-sparking tools and equipment. Wear conductive and non-sparking footwear. Make certain that all electrical equipment is grounded. Observe all safety precautions and follow procedures described in OSHA regulations. See MATERIAL SAFETY DATA SHEET (MSDS) for complete precautionary and disposal information.

If instructions and warnings cannot be strictly followed, do not use this product.

For industrial use only.

Dampney protective coating products are expressly warranted to meet application technical and quality specifications. The technical data contained herein are accurate at the date of issuance but are subject to change without prior notification. No warranty of current accuracy is hereby given or implied. User must contact Dampney to verify correctness before ordering. Dampney assumes no responsibility for coverage, performance or injuries resulting from handling or use and LIABILITY, IF ANY, SHALL BE LIMITED TO PRODUCT REPLACEMENT. In no event will Dampney be responsible for consequential damages, except insofar as mandated by law. Dampney DISCLAIMS ALL OTHER WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

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