rcx132
Philip
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- Location
- London, UK
This video showed up on my feed so I thought I'd share. It nicely sums up the importance of surface prep, following manufacturer specs and how to get a coating that will last decades. It's all stuff that we here on this forum already know but summed up nicely for anyone new:
I still remember my first 4x4 had a rusty spare wheel carrier. So I followed the age old advice to clean it with a wire brush and paint it with hammerite. That lasted less than three months of road use, and I couldn't understand why, I mean everyone knows to use a wire brush and hammerite, it even says so on the tin. So why did it fail? It took me years to figure it out, but it's simple.
(1) Wire brush does very little. It can also be misleading as it polishes up the rust and makes you think you're back to clean metal. Applying some rust converter quickly discloses the truth as it turns rust blue while true bare metal stays same colour. (2) Hammerite is not fit for purpose and shouldn't be on the market. It lets moisture through. It doesn't stop rust.
I now mainly use media blasting as it removes rust, loose paint, scale (I think?), etches the metal, and roughens it up all at once. It gets into any rust pits and it seems to remove grease as well (due to etching?), but to be sure I might degrease parts before blasting. And then epoxy primer and 2k polyurethane based top coat, the only truly water tight coating.
The only exception I've found is PlastiKote spray. I once applied it to a motorcycle bracket I'd made, and it lasted over five years of daily road use. Metal still needs to be clean though.
I still remember my first 4x4 had a rusty spare wheel carrier. So I followed the age old advice to clean it with a wire brush and paint it with hammerite. That lasted less than three months of road use, and I couldn't understand why, I mean everyone knows to use a wire brush and hammerite, it even says so on the tin. So why did it fail? It took me years to figure it out, but it's simple.
(1) Wire brush does very little. It can also be misleading as it polishes up the rust and makes you think you're back to clean metal. Applying some rust converter quickly discloses the truth as it turns rust blue while true bare metal stays same colour. (2) Hammerite is not fit for purpose and shouldn't be on the market. It lets moisture through. It doesn't stop rust.
I now mainly use media blasting as it removes rust, loose paint, scale (I think?), etches the metal, and roughens it up all at once. It gets into any rust pits and it seems to remove grease as well (due to etching?), but to be sure I might degrease parts before blasting. And then epoxy primer and 2k polyurethane based top coat, the only truly water tight coating.
The only exception I've found is PlastiKote spray. I once applied it to a motorcycle bracket I'd made, and it lasted over five years of daily road use. Metal still needs to be clean though.
