I thought everyone might be interested in how I used Molasses to de-rust a bonnet.
It may be applicable to members who wish to derust a metal item without resorting to media blasting.
Backstory:
I'm helping my brother restore his Mk1 Austin Healey Sprite.
When he bought the Sprite as a disassembled project, it came with a repoduction fiberglass bonnet. Originally these cars came with a one piece steel bonnet and Brotato
wanted to restore the Sprite with an original steel item - problem being, these are now rare and good bonnets command silly prices.
He found a bonnet on Gumtree in Perth that was a bit sad in condition, but it was complete and fairly unmolested.
It had however been media blasted, given a light coat of Red Oxide then left to rust some 15+ years ago.
He bought it for a few hundred dollars and I had it shipped over.
Now I didn't want to have it Garnet blasted again to remove the rust and risk warping the already thin steel.
Soda blasting was out as it won't effectively remove rust this ingrained, it could also warp the panels and it's an expensive process to have done.
I considered sanding & wire buffing the rust then applying phosphoric acid, but this is laborious and probably won't remove every last spec of rust.
The Molasses bath seemed like the best solution as I had success with this technique before on engine tinware (rocker covers, timing covers etc).
So we unpicked the guards off the centre section of the bonnet - as the T-beading had rusted away and would have to be replaced - as well as the radiator intake ducting etc.
I then went on eBay and bought a cheap 800ltr inflatable pool for about $140, bought 40ltrs of stock feed Molasses, filled the pool up with water and immersed the bonnet in it:
We then mixed in the Molasses covering the part of the bonnet we wanted to de-rust (we are replacing the lower valance as it's beyond repair) :