VCT Paper

[pantannojack]

Vapor paper, how does it work? Is it for use only in the fiber boxes? Or may it be used in fabric zippered gun socks?

I got a new M&P came in a plastic bag with foam. What is that?

 

[dfariswheel]

Actual VCI paper gives off fumes that drive out oxygen and moisture and surround the metal with a vapor that prevents rusting.

It will work in fiber, cloth, or cardboard boxes for a SHORT time, but the vapor will escape leaving the gun unprotected.
Manufactures can use these types of boxes because the guns get sold and put into use before the paper looses effectiveness.

To last and provide protection of up to as much as 10 to 15 years the gun has to be sealed in a moisture proof special "hard" plastic bag so the vapor can't exfiltrate and allow in air.
Standard plastic bags will NOT prevent the vapor from escaping or air and moisture to enter.

 

[Alk8944]

Actually it is VPI, Vapor Phase Inhibitor, but popularly you may see it either way. It works best when used in an impermeable closure or some type. The military uses hermetically sealed foil/polyethylene/cloth laminated bags that are heat sealed.

If you find thick paper, usually white, circles that look like small shotgun wads, in packaging they do the same as the VPI paper.

It works like dfarriswheel said.