Thread: Safe rust removal +/- recoating jointer rebuild

There are a zillion ways to remove the rust but the most reliable certain long term methods starts by disassembling the pieces and using either electrolysis or soaking in what is know as a chelating agent (eg a mild organic acid like citric acid or vinegar, or molasses[very slow and smelly], or tannic acid). These acids will remove the rust but won't dissolve the metal even if you accidentally leave the parts soaking for months. This is the best way of getting rid of rust inside crevices and threads.

"Rust off" is basically phosphoric acid (PA) which works better if you soak the parts in it but you cannot leave the parts it in PA for for too long. PA converts rust to Iron Phosphate which means it leaves a blue black coating on the rusted part as thick as the rust unless you rub it off but then you run the rust of it re-rusting. In your first picture the black bits you see in those small pits are iron phosphate.
I've tested PA and the unwashed/unpainted PA coating typically lasts 2-4 weeks outside but under cover (typical shed environment) before it starts re-rusting. Some testing details here Backyard Phosphating. It should last longer inside under a more stable temp/humidity environment but testing that is much more difficult and would take a long longer.

When you remove the parts from any rust removal agent do not wash them in water or they will start to rust again very quickly but air dry them with a compressor making sure you blow out all the crevices etc. The remaining layer acts as a short or long term anti-rust coating. However I do try to prime and paint directly. I usually use a spray can that does both. Etch primer should not be required.

If you decide you don't want to paint, apply a light application of oil or wax immediately, and then every month on so will minimise rust.

The most impressive chelating agent I have used to remove rust and leave a long lasting rust resistant coating is oxalic acid however, it does leaves a thin yellow coating on the metal - but that can easily be painted over. I did a bunch of experiments on this and other acids last year. This stuff is commonly used in industry. It is "mildly"poisonous and she needs handling with care.
Details here Solubility of mild steel in various rust removal acids. - Page 2

For parts that have to rub on each other, regular oiling or waxing is one method to reduce rust uptake. Ordinary gun blue is a tad fragile for tools that have to rub on each other and will wear away too easily. There is a bluing method called fume bluing that is more robust but it is a long winded task and requires exposing the parts to strong acids and boiling the parts in distilled water. I have posted a couple of threads about this in the MW forums, here is one More metal bluing.

On the TS table I would just use some steel wool to get the bulk off, and then maybe make up a little dam around the patch with some plasticine and fillet with vinegar and let it soak overnight to get rid of any rust in any pits. Then use oil or wax on a regular basis.

Hope that helps

I may have a go at the peroxide bluing method you describe, Bob. I only have 3%, so it may be a little long-winded, but worth a try. It can brew while I potter around with other things.

I acquired a bandsaw with a rusty table and a Emco Rex 2000 jointer thicknesser in very poor condition which i successfully rejuvenated using a 1/7 vinegar/water mix. it was slow but removed all the rust.