Rust Removal

VW Beetle Restoration Project, Jan-2015

I’d heard about using citric acid for rust removal so decided to give it a go. Bought a 950g bag for about £5:

The first items to be de-rusted were the rear brake drum backplates. You can get an idea of how rusty they were from this pic:

I made up the solution using 2 cupfuls of the acid granules (about 400g) to about 3 litres of hot water and submerged the backplates after giving them a good wire brushing to remove as much rust as I could and degreasing with thinners:

Every couple of hours I lifted the backplates out and gave them a scrub with an old toothbrush. Just a couple of hours later, the solution was turning brown, presumably due to dissolved rust.

The next day, after about 18 hours soaking, I lifted them out and washed them under the tap:

I was pretty disappointed as they didn’t look that much better than when they went in. However, I gave them another wire brushing and the dark residue lifted off easily to reveal nice clean metal with only some light rust remaining:

I was quite pleased as this is about the best results I’ve ever had from ANY rust remover I’ve used in the past. The remaining rust you can see in the photo was removed with some coarse sandpaper and after another wipe with thinners they were ready to paint.

I’d recommend you give citric acid a go – it’s cheap and effective although it takes a long time to work. And, after all, its only lemon juice so its not going to kill your pets!