its been years since ive had to remove rust. Loads of ways, loads of old wives tales - however what is the best proven method?

Some small parts may do with electrolsysis, however what about big parts (like mini shells and subframes)?

Shot blasting and acid dip is out iof the questions as the parts arent that bad. Is it right that if i remove the rough bits with the angry tool, the paint with good quality stuff - as long as air doesnt hit the metal it wont rust any more? Or does the rust need to be converted first.

Is POR15 the best paint for unseen parts? Or is hammerite still recommended? Ive used chassis enamel before but it seemed to rust again after a couple of years use.

If you're not in a major rush and are of strong constitution, soaking in malt vinegar works really well.

I did some of my donor parts - soaked for about a week and gave them a cleaning with an old toothbrush occassionally. Once finished I washed thoroughly in clean water and then stuck the parts in my gas BBQ to draw al of the water out of the porous castings then a quick going over with a wire brush to finish.

Worked a treat and despite not treating or painting some parts, theylve still not rusted very much at all more than 2 years on.

Bloody stinks though, and to do a subframe you'd need a bloody big tank and plenty of vinegar (it's very cheap though!). I guess a plywood box lined with pond liner would do the trick nicely, with a lid held down by brick as far away from the house as possible and down wind!

ETA

For the body shell you could always get one of the light duty sand blasters like the ones bodyshops use. My mate used to work at a BMW bodyshop and that's what they used to sort out rusty stone chips and the like - very light pressure (well, enough to hurt without breaking the skin on your arms IIRC )

[Edited on 5/8/09 by StevieB]

home made electrolysis bin! no need to wait for a week, just leave it running over night

Ive not done electrolysis before, may need to dabble. With any luck Coozer will have some kit i can try.

Ill probs use wire wheel in angry grinder under the body to get the floor clean before painting.

I wonder if my kit car build trestles will be man enough to hold a mini up

Oxalic acid gel works fairly well.
I bought some from R&D Laboratories (Google Mistral Cleaning). They post, no problem.

oxalic acid is the active indgredient in products to remove tanin stains in oak worktops.

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Originally posted by DarrenW
oxalic acid is the active indgredient in products to remove tanin stains in oak worktops.

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Originally posted by mookaloid

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Originally posted by DarrenW
oxalic acid is the active indgredient in products to remove tanin stains in oak worktops.

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and how would you be knowing that then?

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Oxalic acid is the toxic component in rhubarb leaves.

Presumably to meet the £250 budget you could derust with crushed rhubarb leaves!

Matt

Something that has worked very well for me, including derusting brake drums to where they look like new, is to mix a solution of one part of molasses to ten parts of water. Leave the parts in for a week or so, and hose/scrub off the rust. The solution is cheap and if you need to do big parts, dig a hole and drop in some six ml poly to make your tank.
It truly is amazing and no problem getting rid of the stuff afterwards. Just chuck it on the lawn. I have kept mine going for three months, although it was pretty rank by then. The solution will not dissolve paint or grease, so you gotta take that off first.

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Originally posted by Gunner1
Something that has worked very well for me, including derusting brake drums to where they look like new, is to mix a solution of one part of molasses to ten parts of water. Leave the parts in for a week or so, and hose/scrub off the rust. The solution is cheap and if you need to do big parts, dig a hole and drop in some six ml poly to make your tank.
It truly is amazing and no problem getting rid of the stuff afterwards. Just chuck it on the lawn. I have kept mine going for three months, although it was pretty rank by then. The solution will not dissolve paint or grease, so you gotta take that off first.

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Some good ideas so far.

Molasses - i need to ask - what is it?

Lets assume i pull the rear subframe out of the mini. This reveales the boot floor that was replaced 2 years ago so in fairly good nick. I want to wire brush and paint. What would you use to derust some areas? (stuff that can be left on and wont need to be washed off).
What would you use to paint it? I was thinking several coats of black hammerite / smoothrite followed by stone chip or underbody schutz before refitting the subframe. How does that sound?

I seem to recall the trick is preventing oxygen and dampness getting to any bare or already rusted steel. Does the rusted surface have to have rust converter applied first?

Ive used cheapo chassis black paint before but didnt seem to do a good job. Dont want to use POR15 as ive heard you have to be careful to apply exactly right or it wont work, and i dont have the budget for it.

(BTW - the shell is quite solid so localised rust looks like surface corrosion only).

Went to local bodyshop today. Bought some zinc rich red oxide primer and chassis black paint. Hopefully a few coats of each will hold further surface rust back.

Got covered in red dust using the tool. I hate those things - was picking steel shrapnel out of legs for ages

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Originally posted by DarrenW
Got covered in red dust using the tool. I hate those things - was picking steel shrapnel out of legs for ages

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Originally posted by David Jenkins

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Originally posted by DarrenW
Got covered in red dust using the tool. I hate those things - was picking steel shrapnel out of legs for ages

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I usually wear my leather welding apron - got fed up with little red puncture wounds all over my legs!

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Short-arse!