WC-1 NG is a specially formulated water-based breathing-type mastic coating for the protection of thermal insulation, or other substrates, in nuclear applications where it is important to minimize the risk of stress corrosion occurring on certain types of steel components. WC-1 NG contains only minimal levels of chlorides, fluorides, oxidizable sulfur, and other leachable contaminants which can cause stress corrosion. WC-1 NG is a heavy-bodied high-build coating which provides excellent topcoat protection while maintaining a very low flame spread classification.

WC-1 NG is a PVA based material which can be applied by trowel, palm or spray to a wet film thickness of 1/8” to yield our recommended dried film thickness of 1/16” (application method must be specified when ordering). Whey dry, WC-1 NG provides a tough, durable, flexible film which offers excellent protection from the elements, other sources of moisture, mechanical abuse and a variety of moderately harsh chemical environments. It will maintain a water-tight seal under intermittent flooding but should not be used where it will be exposed to continual standing water.

WC-1 NG has been fully tested by independent government-approved laboratories for compliance with NRC Reg. Guide 1.36 and MIL-DTL-24244D (SH).

WC-1 NG is a latex emulsion which contains no hazardous substances or solvents. It must be protected from freezing during storage and application. It must be protected from moisture, freezing, oil, grease and foot traffic, until it is thoroughly cured.

Vimasco manufactures under a stringent quality assurance program in accordance with MIL-I-45208 and each batch is tested for compliance with the appropriate standard or specification. Our manufacturing and Quality Assurance procedures are routinely audited by government and private industry inspectors.
We do not include the SDS for these products on our website, these may be obtained by contacting our office at our regular address, phone, fax or e-mail.

Product Information and Data


In accordance with OSHA Standard 29 CFR 1910.12 (Right to Know Law) a Material Safety Data Sheet is available for the product and all Vimasco products.


Vimasco products are designed to meet the needs of specific situations. They are warranted to be effective for their intended uses only. No further warranties are expressed or implied. The methods and condition of application over which we can exercise no control are important factors in the performance of our products. We make specific recommendations for the application and use of all Vimasco products, but we cannot enforce our recommendations upon users; therefore, it is necessary that we state, as a condition of sale of our products, that we will replace or refund the purchase price of any Vimasco product found by our laboratories to be defective, but that we assume no responsibility beyond the purchase price of the materials. No representative of our Company, Distributor or Agent has any authority to change or extend this condition of sale.