Can this rust be treated
- Thread starter brainhax
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You can stop any rust by treating the surface with phosphoric acid; I spray it on from a misting bottle and let it dry.
The acid converts the iron oxide into iron phosphate, which is inert. It is a very mild acid, but you should use nitrile or similar gloves to protect your skin. A quick rinse under tap water will take care of any acid which gets onto your skin. Don't store the acid in a plastic container not intended for it; you'll have a mess on your hands next day. Also, do not store acid in plastic containers near any metal you do not want rusted. The acid molecules will leak through the plastic cap seal and once airborne will eat any metal it contacts.
You can prevent rust on bare metal by washing with sodium hydroxide; we call that lye in the upper half of the world. A scrub with alumina powder will remove any scale and the bare metal will be rust–proof for years.
I'd recommend a stiff steel brush to remove any loose material. The acid will only treat the upper few molecules on the surface, so you want that rust surface to be as thin as you can get it. Once the iron phosphate occurs, you will not get to any rust beneath it. This process is not good for thick rust. For that you'll need to sand or ice blast, or use an air powered needle scaler, followed by the acid wash.
The long term solution, as I'm sure you recognize, is to cut out the affected metal and weld in new sheet steel.
The acid converts the iron oxide into iron phosphate, which is inert. It is a very mild acid, but you should use nitrile or similar gloves to protect your skin. A quick rinse under tap water will take care of any acid which gets onto your skin. Don't store the acid in a plastic container not intended for it; you'll have a mess on your hands next day. Also, do not store acid in plastic containers near any metal you do not want rusted. The acid molecules will leak through the plastic cap seal and once airborne will eat any metal it contacts.
You can prevent rust on bare metal by washing with sodium hydroxide; we call that lye in the upper half of the world. A scrub with alumina powder will remove any scale and the bare metal will be rust–proof for years.
I'd recommend a stiff steel brush to remove any loose material. The acid will only treat the upper few molecules on the surface, so you want that rust surface to be as thin as you can get it. Once the iron phosphate occurs, you will not get to any rust beneath it. This process is not good for thick rust. For that you'll need to sand or ice blast, or use an air powered needle scaler, followed by the acid wash.
The long term solution, as I'm sure you recognize, is to cut out the affected metal and weld in new sheet steel.