Rusty Frame.

[Bruce Day]

Phosphoric acids used in metal cleaning solvents and etchants can, if left on and not thoroughly washed off, cause a fast growing surface bloom of yellow FeO2. But, I don't see how you could color case harden or blue with solvents left on the metal surface.

Yes, annealing alters surface molecular structure, I assume by spacing the surface molecules further apart. It has to, because the surface is softer, but I don't know how.

[Austin W Hogan]

Eric ; RIG is back on the shelf in a different jar, at Jr Welch's in Lebanon NH; I am sure that it is available at an increasing number of shops.

Adding to Mark's comment; Oranges, lemons and grapefruit are extremely corrosive to many kinds of iron; coca cola and other carbonated beveridges are not far behind. Newsprint and kraft paper may be in the right environment.

I have seen guns develope stalactites of corrosion at a spot. I think that these , plus the soft yellow /brown that appears on twist barrels, is fungus/bacteria related. Bruce probably had hours of training on prevention of strainer clogging fungus growing in jet fuel. Most oils promote bacterial /fungus growth. The trick is to find an additive prohibits fungus growth, but does not dissolve blue.

Best, Austin