Thurmalox 70 Air Dry Silicone Coating for Stainless Steel

Prevents Stress Corrosion Cracking Heat Resistant to 1000 F

Thurmalox 70 is an air drying, silicone based heat resistant coating for metal that protects thermally insulated austenitic stainless steel from chloride induced stress corrosion cracking. Thurmalox 70 withstands temperatures to 1000 F (538 C) with peaks to 1100 F (593 C). It is formulated to contain the minimum amounts of attainable chlorides, halides, sulfides, nitrates and metals that induce external stress corrosion cracking. Every batch of Thurmalox 70 is tested by an independent laboratory for leachable chloride content.

This silicone coating for metal is formulated to meet the currently accepted practice for selection of protective coatings for stainless steel surfaces under thermal insulation as set forth in NACE Technical Committee Report 6H189 “A State-of-the-Art Report of Protective Coatings for Carbon Steel and Austenitic Stainless Steel Surfaces Under Thermal Insulation”.

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SKU: Thurmalox 70 Category:
  • Air Dries, easy to apply system
  • High temperature silicone coating – Withstands continuous temperature of 1000 F (538 C) with peaks to 1100 F (593 C).
  • Free of heavy metal pigments.
  • Does not contribute to weld embrittlement of stainless steel welds.
  • Prevents wet chlorides from the atmosphere or process operations from coming into contact with stainless steel surfaces.
  • Excellent bond to stainless steel without need to abrasive blast (see Surface Preparation).
  • Prevents insulation, which may contain chlorides, from coming into contact with stainless steel surfaces.
Generic TypeSilicone
Temperature Resistance Continuous538 C
1000 F
Temperature Resistance Intermittent593 C
1100 F
Volume Solids17 percentage
Dry Film Thickness Per Coat1.5 – 2.0 mils (37 – 50 microns)
Wet Film Thickness Per Coat8.5 – 10.5 mils (200 – 250 microns)
Theoretical Coverage Per Gallon276 mil. sq. ft.
6.7 sq. m. at 25 microns per liter
Application Temperature at 50Percent RH10 to 50 C
50 to 120 F
Drying Time to Touch at 50 F (10 C) 50Percent RH1 hour
Drying Time to Recoat at 50 F (10 C) 50Percent RH12 hours
Drying Time to Ship at 50 F (10 C) 50Percent RH48 hours
Drying Time to Touch at 70 F (21 C) 50Percent RH30 minutes
Drying Time to Recoat at 70 F (21 C) 50Percent RH8 hours
Drying Time to Ship at 70 F (21 C) 50Percent RH24 hours
Full Cure130 minutes at 350 F (177 C)
Weight Per Gallon8.6 lb
Flash Point7 C
45 F
Shelf Life1 Year
V.O.C5.96 LBS/gal.
715 GMS/Liter
ThinningFormulated for use as supplied. Do not thin.
Clean Up
Thoroughly flush spray equipment and hoses immediately after use with Dampney 100 Thinner. Dismantle spray equipment and clean parts, brushes and rollers with Dampney 100 Thinner.
StorageStore in cool, dry place with temperature between 50 F and 100 F (10 C and 38 C). Keep container closed when not in use.
Note1 See Dry Time section
Recommended Uses
  • Insulated stainless steel piping, vessels and equipment.
  • Nuclear power facilities where a high temperature coating for insulated stainless steel with minimum amounts of chlorides, other halides, nitrates, sulfides and metals is needed.

Not Recommended For

  • Immersion service
  • Interiors of stacks, breechings and scrubbers
  • Uninsulated surfaces
Surface Preparation
Stainless Steel
1. 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”.
3. For large surface areas, steam clean with an alkaline detergent, follow by a steam or fresh water wash to remove detrimental residues.
4. For small surface areas, solvent wipe with Dampney 170 Thinner, a chloride free solvent, using proper procedures and precautions to minimize hazards.
Application Equipment
Conventional spray is the recommended method of application. However, Thurmalox 70 may also be applied by airless spray, brush or roller. Do not apply Thurmalox 70 in heavier films than specified since blistering may occur.

Conventional Spray:
Spray gun – DeVilbiss MBC-510
Fluid tip – AV115-FX (0.042″ tip)
Air cap – 704
Fluid hose – 3/8″ ID – Smaller hose diam. or length over 25 ft. may require increased pressure.
Air hose – 5/16″ ID
Atomizing pressure – 40-45 psi

Airless Spray:
Spray gun – Graco 205-591, 208-663
Fluid tips – 163-614, 163-616 (12″ fan)
Pump – Graco Bulldog 30:1
Fluid hose – 3/8″ ID
Air pressure to pump – 65-80 psi

Use only wooden-handled brush with short China bristles. Do not use synthetic-bristled brushes. Do not flood surface with coating. Brush out thoroughly, maintaining a continuous wet edge and uniform appearing paint film.

Use only wooden-handled roller with phenolic shank and core, and 1/4-3/8″ nap. Do not flood surface with coating. Roll out excess coating on a suitable, screened surface. Then roll out thoroughly, maintaining a continuous wet edge and uniform appearing paint film.

Dry Time 70 F (21 C) 50Percent RH
Thurmalox 70 will air dry tack and thumb print free within 1/2 to 1 hour. Allow 8 hours dry time between coats. Allow 24 hours dry time prior to shipping and handling if coating is not heat cured. Stainless steel surfaces coated with Thurmalox 70 in the air dried state can be handled and shipped prior to a heat cure as long as shipping and handling procedures for thin filmed systems are followed. Avoid mechanical abrasion during shipping and handling. Higher temperatures will reduce tack free, recoat and shipping times. Allow one hour solvent flash off period before heat curing or placing into service. Optimum film properties require a heat cure of 350 F (177 C) for 30 minutes. Equipment protected with the Thurmalox 70 in the air-dried state will heat cure when placed into 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 with adequate ventilation during mixing and application. Wear an appropriate, properly fitted organic vapor cartridge-type respirator (NIOSH/MSHA approved) during and after application unless air monitoring demonstrates vapor/mist levels are below applicable 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/MSHA approved). Use explosion-proof lights and electrical equipment. Use only nonsparking tools and equipment. Wear conductive and nonsparking footwear. Make certain 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 applicable 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.
Mixing and Application Guidelines
Redisperse any settled-out pigments by stirring with a paint paddle followed by thorough mixing to a uniform consistency with an explosion-proof or air-driven power mixer. Do not open containers until ready to use. Keep lid on container when not in use.Application Guidelines
Surface temperature must be at least 5 F (3 C) above dew point. For optimum protection apply two coats of Thurmalox 70 to a dry film thickness of 1.5-2.0 mils (37- 50 microns) per coat. Total recommended dry film thickness is 3.0-4.0 mils (75-100 microns).

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