Paint removal with Dot-4 brake fluid

So how do you get paint off of motorcycle plastics?

After my efforts with the LC tailpiece earlier this year, using mechanical methods, I spent a happy couple of hours cruising the internet for better ways of reclaiming old Yamaha plastics.

Every single paint stripper I looked at was “bad” for Yamaha plastics, (and probably similarly bad for plastics from other bike manufacturers).
So we are back to the DOT-4 Brake fluid which as far as I know is benign to the plastic, but hopefully deadly to the paint.

I chose a particularly horrible RD250LC side panel for my test piece. It is fundamentally sound with no cracks visible on the back side, but has been covered with many coats of different paints over its 40 year lifespan.
The aim is to cover with dot-4, refreshing daily for a week or two, agitating with a paintbrush, so as not to damage the underlying plastic.

Initially, the technique seemed to be working well on the near millimetre thick paint, but as time went by, less and less of an affect was perceivable.

Eventually, after 3 weeks, (day 21), I gave it a good mechanical scrubbing with a stiff nylon bristled brush, but no more paint came off.

Perhaps it is the nature or type of paint, perhaps it is just too old and cured after 40 odd years. Perhaps I needed to give it more time, but after 3 weeks I had become somewhat disheartened with the experiment.

The black had come off quite well, but it was clearly “only2 a couple of coats. the red paint underneath is clearly made of sterner stuff, and is very thickly applied. I wouldn’t be surprised if it had been brush applied in many coats. Whatever, the DOT-4 just wasn’t shifting it.

In conclusion, it was worth a try, and perhaps with items where paint has been less liberally applied, it may do the job, but for difficult reclamations like this side panel, I don’t think Brake fluid is the panacea I was hoping for.

UPDATE : January 30th 2022. (4 weeks later)

I was tidying the sidepanel away, after it had just sat in the garage over Christmas.
As it was still covered with brake fluid, I was washing it off with hot soapy water and a stiff nylon brush, (in the hope that more paint would come off).
More paint was not removed by brushing, however, I did dig a fingernail into the paint, finding it to be very soft, and amenable to scraping.

I set to, with a nylon scraper, and (Very carefully) with a Stanley blade, with the following results.

So in some circumstances, the DOT-4 solution can work… or at least help.
I have now put the sidepanel back in its washing up bowl, and coated it with more Dot-4, however the underlying paint seems to be a bit tougher than the layers already removed.

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