Natrex™ Frequently Asked Questions

What type of safety precautions need to be taken?

Natrex products are flammable and as such should be used with appropriate care. They should be used in a well-ventilated area and isolated from any source of ignition. Natrex products are incompatible with oxidizing agents and strong acids. The sodium in Natrex will react on contact with water to form sodium hydroxide, which can cause chemical burns.

The personal protective equipment needed while using Natrex includes goggles or face shields, neoprene gloves, and polyethylene or rubber apron. Natrex should be used only with adequate ventilation such as a chemical fume hood. Use a NIOSH approved respirator with cartridge specific for organic vapors or supplied air breathing apparatus if adequate ventilation is not provided. Work should always be performed in close proximity to a full body safety shower and an eye wash station.

Use a dry chemical fire extinguisher to fight fires. Refer to the material safety data sheets (MSDS) for further information.

How long does it take for Natrex to react with my part?

Successful etching hinges on getting enough active Natrex to the surfaces to be etched. Because of this, contact time depends on several factors: the shape of the part (wire, sheet with or without holes, irregular shape), its intricacy, the material it is made of and, if there are holes, how large they are. Wires may require as little as 5 to 10 seconds, while circuit boards may need 60 to 90 seconds or more. For clean, flat surfaces with good agitation in the etchant bath, the reaction occurs very rapidly.

How can I tell if my part has been etched properly?

Visible confirmation that etching has occurred is possible. Teflon and Fluon grades of PTFE quickly give a tan to brown color. Other materials take longer to develop the color change, while still others may be etched but not evidence a color change. For materials where no color change takes place, set a drop of water on the part. If the water spreads out over the surface, it has been etched. Etching decreases the surface tension of fluoropolymers and allows them to become wettable. Drops that remain spherical indicate that the surface has not been etched.

What type of precautions do I need to take with an etched surface?

Several conditions can have adverse effects on etched materials. Scratching can remove the carbon-based film that anchors the adhesive, making bonding difficult. Exposure to UV radiation (sunlight) gradually degrades the film. Strong acids have varied effects: HNO3 and HClO4 will bleach the carbon layer and eventually remove it, H2SO4 darkens the film but will not destroy it and HCl has no effect. Extended storage times or high temperatures do not adversely affect the film. Store etched parts so that they are protected from UV radiation, contamination and scratches.

How should Natrex be stored?

Opened containers with some etchant remaining inside should be blanketed with inert gas (either nitrogen or argon) then capped securely and stored frozen or refrigerated. Blanketing with inert gas displaces oxygen from the airspace above the etchant to prolong shelf life. Any air left in the container will degrade the etchant. Do not use carbon dioxide to displace air in the container as it reacts with the etchant.

Opened containers with no etchant remaining should be disposed of as directed in the Disposal section.

Unopened containers should be stored below 32F. or used immediately upon arrival. If an unopened can is inadvertently left in a warm place, chill in a refrigerator to cool. Remove the cap and inner seal, opening slowly away from the technician to allow release of built-up pressure. Use etchant immediately. Rapid degradation of etchant is possible above 100F.

How do I dispose of Natrex Products?

Natrex25, Natrex19 and Natrex VisReduce are flammable and corrosive. Natrex HighFP is combustible and corrosive. Dispose of these products as hazardous waste according to applicable federal, state and local regulations. Please avoid contamination of soil, drains and water.

Residual product may be present in empty containers. Do not pressurize, cut, weld, braze, solder, drill, grind or expose container to heat, sparks, flames, static electricity or other sources of ignition. Do not reuse containers for food, clothing or products for human or animal consumption.

Inquire about recycling opportunities to reduce your waste disposal cost and reporting.


Fulcrum Chemicals USA Inc.
P.O. Box 28, Lincoln University, PA 19352
Phone: 610-998-0656   Fax: 610-998-0872

Website design by: WebWand Web Design