The use of polyester fiberglass reinforced laminations for the repair and rehabilitation of existing tank interiors and bottoms has become widely accepted as a practical, economical method of combating corrosion and chemical attack. When repairs are made with polyester-fiberglass reinforced laminations, there is less down time for tank maintenance and the replacement of tank bottoms is eliminated.

Wil-Cor, Inc. Tank Maintenance Services:

  • Tank inspection and recommendations for repair
  • Installation of resin reinforced lining to tank bottom and/or tank interior
  • Testing of completed work
  • Interior tank coating for corrosion and product protection
  • Exterior tank or vessel restoration for structural repair – Contact Armor Plate, Inc.

General Specifications for Fiberglass Reinforced Polyester

Steel Tank Lining

Preliminary Site Preparation

Cleaning of Tank – Tank shall be disconnected, commercially cleaned, and gas levels brought below explosive limits by the customer or others before turning custody of the tank over to the contractor. The contractor will be required to work through the manholes and clean out door, but will not be required to replace covers upon completion of the work.


  • 1Reinforcement – 1.5 oz./sq.ft. fiberglass chopped strand mat with resin binder.
  • 2Nexus or C-Veil for extra corrosion resistance shall be used.
  • 3Polyester Resin System
    • aArmor Plate 600 (Isophthalic)
    • bArmor Plate 700 and Armor Plate 770 (Vinyl Esters)
    • cArmor Plate 800 and Armor Plate 800F (Bisphenol)
    • dArmor Plate 621, 721, 781 and 821 (Isophthalic, Vinyl-Ester, Bispheno – Flake Glass Filled)
  • 4Primer – Same resin as lining. (Armor Plate 784, depending on corrosive environment)
  • 5Putty – Armor Plate 840
  • 6All nozzles under six (6) inches shall have Armor Plate 770 FRP Sleeves inserted.

Quality Control

  • 1All material is to be in new, labeled containers, with lot numbers and MSDS available for customer review
  • 2Temperature and moisture conditions are to be monitored daily.
  • 3Barcol hardness tests and Holiday checks are to be made on final layers of laminate.

Application of Materials


During application of resin, Contractor shall keep all surfaces free of contamination and all work shall cease when the tank becomes wet from sweating or rain, and when the dewpoint is within 5 degrees of the ambient temperature.


  • 1All sandblasted surfaces shall be resin primed the same day they are cleaned. Corrosive environments require priming within four hours. Do not allow primer to cure more than seven (7) days without consulting the manufacturer.
  • 2Priming shall be applied with long nap rollers in sufficient thickness to prevent surface corrosion prior to application of laminated coating


Use the following technique to apply 6 to 8 layers of 1.5 oz. fiberglass mat saturated with resin.

  • 1Apply 2 layers of mat, each layer being 2″ larger than the hole under repair. Saturate the mat with resin. Roll out air bubbles with a serrated roller
  • 2Repeat step 1 until 6 to 8 laminates are applied. Each layer of mat should be 2 inches larger than the previous layer. Rule of Thumb – When the thickness of the fiberglass laminates exceeds the thickness of the steel, the patch is stronger than the steel


  • 1All irregular surfaces, sharp corners, rivet heads, weld seams, etc. shall be made smooth with resin blended into putty consistency. (Armor Plate 840)
  • 2Putty shall be applied to provide a smooth surface for the application of the reinforcement and Armor Plate resins, and to fill all recesses that would contribute to pinholes and air pockets in the laminate.
  • 3In riveted or bolted tanks, urethane foam may be used instead of putty.
  • 4Nozzles shall be lined with a FRP sleeve.


  • 1Stationary roof support columns in crude oil service shall be sandblasted up 12″ – 24″ (as specified) from the tank floor and coated with resin. Columns shall have fiberglass reinforcement extended 4″ up on columns. Chemical tanks shall have all interior surfaces lined or Armor Flaked.
  • 2Floating roof support columns shall be raised sufficiently to clean and coat underneath with resin. A previously sandblasted and resin coated metal plate shall be placed underneath support columns and embedded in wet resin.
  • 3These metal plates are to be of sufficient size to extend 6″ beyond the support columns in all directions.
  • 4Bottom lining is to extend a minimum of 3″ onto metal plates.
  • 5Metal plates shall be furnished to the contractor by others.
  • 6New tanks shall have structural roof support members on the exterior. Special steel shall be specified for the tank to be lined. Suggested specification is America Steel A285C.


  • 1Armor Plate primer resin without reinforcement shall be applied 6″ up on shell of tank above laminate. (See the diagramed examples below.)
  • 2Each layer of fiberglass mat shall be embedded into a previously applied coat of Armor Plate resin. A serrated roller shall be used to work the mat until it is completely saturated and free of air pockets and wrinkles. Each application of the fiberglass reinforcement shall extend up the shell of the tank 18″ to 24″.
  • 3When additional structural integrity of tank walls is required, apply additional laminates. Fiberglass cloth shall be used with epoxy lamination. An additional two to four (2-4) laminates are required under discharge pipes and agitators.
  • 4Extra corrosion resistant Nexus Cloth or C-Veil shall be applied when an extra corrosion barrier is required. Some wrinkling in Nexus or C-Veil laminates may occur. These should be sanded away and re-coated. (Note: Selection of Nexus Cloth or C-Veil will be determined by the chemical contents of the vessel.)

NOTE: Contact your Wil-Cor Representative for information on coating the edges of angles.


  • 1After priming and puttying all irregular surfaces, apply one (1) laminate of 1.5 oz. fiberglass mat to all weld seams, nozzles and manways.
  • 2Apply using a spray or roller. Apply in 5 to 10 mil coatings (white or gray), overlapping to attain an overall coating thickness of 20 mils.
  • 3Repeat step 2, using the opposite color of the first coat, until a total thickness of 40 mils is attained. Holiday check the coating.
  • 4Apply a top coat with 5% wax additive. For extra corrosion resistance, apply one top coat without wax and a second top coat with wax.
  • 5DO NOT EVEN THINK OF THINNING THIS ARMOR FLAKE PRODUCT WITH A SOLVENT! This with the resin is used for priming to attain a better spray consistency.


  • 1All irregular or rough edges of the fiberglass reinforcement shall be smooth prior to application of the top coat.
  • 2The top coating of Armor Plate resin with wax additive added may be applied to the laminated surfaces by brush, roller, or spray
  • 3The laminated surface shall be closely inspected and any exposed fibers or areas showing roughness from the weave of the fiberglass shall be re-coated. Re-coating shall be continued until all exposed fibers are completely covered with Armor Plate resin.


After a suitable curing period, Contractor shall furnish a spark type holiday detector and shall “jeep” the entire area coated hereunder using a minimum of 16,000 volts and a maximum of 18,000 volts for 50-60 mils polyester liner. Minimum thickness shall be 40-50 mils on walls and 65-70 mils on floor. The Company shall have the option of testing laminations for thickness gauge. C-Veil or Nexus increases the thickness 5-10 mils.

Cleaning of Premises

After completion of the work to be performed hereunder, Contractor shall clean the premises of surplus materials, tools, and debris resulting from his operations thereon to the satisfaction of Inspector.