Wednesday, 3 September 2014

Vinegar, rinse, blast, paint, repeat...

After a lot of experimenting I have finally settled on a method for taking rusty components and transforming them back to good-as-new. It all starts a lot of vinegar, citric acid powder and a Bristol City council recycling bin:


I came across this method after reading through an amazing build thread over on Volkszone, so full credit to Andy Sweeney (aka: Last Triumph) for originally sharing this idea.  Basically, once the vinegar and citric powder have been mixed, you simply submerge the dirty components in the acid bath as they are, close up the bin lid and wait. Over the course of a week or so the solution dissolves the grease, dirt and much of the rust. 

A word of warning in case anyone reading is considering doing this; the vinegar bath should be used on components that do not have a structural purpose. This is due to potential embritllement, which could compromise the integrity of such parts. So, no suspension, steering boxes etc!

The results straight out of the bath are impressive... Here is a before shot:


After:


However, when I put a second batch of components in the vinegar solution I unintentionally left them in a bit too long (summer is full of distractions and tangents!). When I pulled them out I was baffled to find that they were covered in a stubborn residue like a coral reef:




I am unsure if this is the result of the sediment from the previous components that were cleaned or simply what happens when you leave metal parts submerged for too long. I guess another possibility is that the citric acid powder and vinegar somehow breaks down or alters over time?

Unexpected coral reef cultivation aside, the parts are then rinsed in water and any loose dirt is cleaned off with petrol and a toothbrush or wirebrush:


The parts then go into the blast cabinet and without that stubborn coating of several decades worth of accumulated crap encasing everything, it only takes a minimal amount of time before they are done. Not only does this process remove the last traces of rust, but also provides a perfect key to the surface ready for paint:


Its then a case of masking (if required), mixing up some Mastic 121 and painting it on using a regular brush:

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