lasercowboy
Chemically speaking, vinegar (acetic acid) should accelerate rust if it does anything. Rust occurs when the surface of the iron oxidises, and in general, acids act as/create oxidants.
A good call is something based on phosphoric acid. This is because the phosphoric acid induces the formation of very hard, passivating and insoluble iron phosphate on the surface of the metal. The phosphate is also a kind of dark grey/black colour which is rather appealing. No matter what people tell you, don't use coke, just because it contains phosphoric acid. The concentration is low, and the concentration of other stuff (namely sugars) is high, and these will cause you problems.
You can buy phosphoric acid from the internet, typical chemical suppliers, or you can find it in some strong cleaning products, like certain kettle cleaners/descalers. It's also in some of the commercial rust converters, but I've never found them remotely as effective as the pure stuff. I think there's also a reactive phosphate in POR15, which is why it's so good at stopping rust.
Normal safety protocols apply: although phosphoric acid is much less aggressive than other strong acids (like battery acid, for example), you still don't want it on your skin or - gods forbid - in your eyes. Decent nitrile gloves and eye protection are a must!
Angus242164
Various rust converter products are available from automotive paint shops, I bought a spray bottle of something based on phosphoric acid a while ago, haven't used it yet though.
Giles
I've had great joy with POR 15 to kill rust.
bigal
Thanks. Input appreciated.
POR15 final stage is quite permanent right? I want the rust gone and hope to use some kind of waxy type sealer (as museums I hear use) to prevent further corrosion. This means I'm not adding a permanent layer and destroying the originality if you know what I mean.
I wonder if the POR15 metal prep will do the trick?
Going to watch some phosphoric acid rust conversion vids now.
1971_144GL
I'm short of time, so in shorthand:
There are much better recipes than many of the auto shop concoctions that are an amazing price relative to the active chemistry.
Up to 10% v/v orthophosphoric is good with a suitable wetting agent. Higher concentration is not better. Avoid HCl or sulphur containing acid, bad news for preservation.
Preferably wash with a sequestering agent to remove chlorine and other mobile ions. Tannic acid correctly applied does well, goes black and will not harm most plaint. Make it up to 5% w/v and 10% alcohol. Several coats a day a part and leave for at least a week.
Mivrocrystalline wax can work for your goal. But it is a pain. I like Dinitrol av 100 thinned by 30% white spirit, excellent clear and stable wax like finish. It's chemistry is water displacing and it remains soluble, so very effective. Very easy to apply.
Por15 is perhaps best described as a cyanoacrylate, it is catalysed by the water in the metal surface microstructure and air forming a very effective barrier layer corrosion inhibition system. Pretty much permanent, but can be abraded off.
And remember that rust in itself does not create rust, lots of rusty things will last indefinitely. But active corrosion and it's rate is a whole other story for another time.
Giles
Phew, I'm glad that was shorthand. It all gets pretty technical when physics comes into the equation. Nice explanation.
Oppolock
I have had good results with Molasses on Sub frames and heavy structure in the past but I wouldn't use it on panels unless you were prepared to lose the tin.
Its a dip and check process and can take a few weeks to yield good results but it does do a very nice job.
The other method I get good results with is soda blasting using the cheapy sand blast guns with the top load reservoirs using either Bicarb beads or 20kg bags of Bi Carb powder, it uses low pressure and will remove surface rust while leaving paint intact with careful use.
Excellent on Alloy wheels too.
bigal
erm.. the lemon was useless.
Time to break out the right acids for the task. Thanks for the advice @1971_144GL
I'll get back to this once my Volvo's are in a happy place.. they both need attention as a priority. 145 nearly back together. XC90 is making some awful power steering whines and unusual noises. Why don't I just own a modern Camry!
sucksqueezebangblow
Because you have a soul?
