Boiled Linseed oil is not only for wood, you can take it as rust protection too. It's work very good.
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In the middle ages linseed oil was used as a corrosion inhibitor for armor and weapons (black burn). Used it also in the automotive industry. Today it returns again in classic car circles, in the preservation of historical monuments, and healthy building to this non-toxic type of preservation. The oil forms a water-insoluble link with FE3 +-ions in the rust. In addition, after the bonding, the oil forms a crack-free coating.
Red lead (lead-lead), a classic and highly effective but toxic corrosion and wood preservatives, which both inside and outside was used already by the Phoenicians around 700 BC for preservation of ships is formed by adding Blei(II,IV)-oxid (Pb3O4) to linseed oil. This was the lead toxic and fouling-resistant in the outer layer, and as a fungicide in the Interior. The use of Bleioxids is permitted only with special permission - for example for restorers. Therefore, Eisen(III)-oxid is today used in modern wood and rust protection with Lein?l color instead of toxic Bleioxids. This red Eisenmennige is non-toxic. The moulds and fungal-retardant effect is achieved through the addition of zinc.