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Cleaning methods for pitted metal on a large item

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Ttrees

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Hello folks
Going scrubbing my tablesaw cabinet tonight to get at the last of the deep pitting, before priming.
Been looking at various youtubes with vinegar baths, but not seen any folks
using a wire brush and vinegar for the elbow grease version.
Would vinegar work, or something else, even a little?

If so, what is the best way to neutralise this afterwards, bearing in mind the shops are closed.

Can I prime straight away afterwards?
Thanks
Tom
 

Trevanion

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Depending on how deep is it I would just run it over with a polycarbide wheel or a twisted wire wheel and that's usually enough to shift most of the rust. If you wanted you could then use rust converter over it to help get the primer to stick to it.

I find whilst vinegar does shift the rust, it also tends to make pitting a little worse. But if you're filling it with body filler anyway that doesn't really matter. I think it's neutralizsd with a baking soda/water mix.
 

Jacob

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I'd just brush off anything loose and then paint with linseed oil as a primer, over any remaining rust. Sticks like the proverbial to a blanket. Follow up with linseed paint or any oil paint.
 

Ttrees

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Thanks Trevanion
I have been using a cup wheel on the angle grinder allready, and bought a new aggressive handheld wirebrush
to get down into the pitting.
I was thinking this used with something else that might help, would finish the job off for me.

Not bought any rust converter, nor know anything about it, I'll be proceeding on the cheapest way possible,
as I ended up buying some expensive green aerosol paint in Homebase , as it was the only shop open, and I had to go home with something.

I was worried about vinegar making the problem worse, so did see baking soda mentioned.
I've also read of folk using baking soda to remove rust.

I have a liter of Isopon primer, so was going to just build it up instead of using any filler.
Not sure if I'm going to need more paint, I want to budget for that instead.

Tom
 

SammyQ

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I can vouch for the various permutations of phosphoric acid for getting into deep rust, once brushed out. Jennolite, Vactan(sp?), whatever, they all leave a purply-black stain that's easy to paint over. So far, all that I've treated this way has stayed rust free, including an entire AGS tabletop that I simply washed over with it to survive deep storage for a few months. (Not proud, desperate :oops: ).

Sam
 

ED65

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Ttrees":ih2p777m said:
Been looking at various youtubes with vinegar baths, but not seen any folks
using a wire brush and vinegar for the elbow grease version.
There's at least one (Katz-Moses?) showing scrubbing down using vinegar and he claims the secret is the vinegar, but I can guarantee that the effect is minimal or nowt over doing the same thing with plain water. Do the comparison yourself, see what you think.

Ttrees":ih2p777m said:
...what is the best way to neutralise this afterwards, bearing in mind the shops are closed.
Soap suds.

Wire wheeling is about the only way you'll reliably get rust out of pits. So it's either that or using a rust converter such as Kurust, which I believe is based on a strong tannic acid solution (converts the iron oxide to iron tannate).
 

Bm101

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Heads up on the Kurust.
It's great gear. Fairly pricey but it goes a long way. If you've mixed pva with too much water, that's the consistency. Bubbles up, paint and recoat. I buy cheap makeup brushes from amazon as throwaways. Sorry Turtles. Sorry kids. :oops:


Paint on to internal Meddings hood that was covered in (very thin) surface rust. I was not after restoring this with hours of work to go.

Goes on watery like thin soap solution. Gradually turns blue. Now seems to be the time to keep recoating, keep the brush washing over everything. 2 or 3 coats goes on like nobodies business with no effort.


Dries black and paintable by all reports. Never tried. So far. (hammer)

On stripped and grinded (flap wheels on cast where I wont see the old rust paint and life is too short ) this is what it looked like first for general condition:


On rust free cast iron, it goes shiny and good. Very much like this finish. I ended up blacking this machine but fair play to Kurust. It would be an acceptable finish on cast that was subject to damp.
Bear in mind I this is the unseen underside of a machine that no eye will see. it's lucky it got that much work.


Acceptable finish for a working machine I would hazard. The red bits, are the last of the old paint where I could not get the grinder discs in, not any form of rust btw.
Anyway. Ideas.
Hope it helps Tom.
 

ED65

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Yup, this ^

As Chris says it does go a long way. The wee bottle I started with I'm only just down to the last dregs after years of using it, not just for spot treatments but on the occasional whole plane body, two full coats, before painting.

It is intended to be painted over, the instructions make this plain and if memory serves say that it's compatible with most topcoats but if in doubt to test first.
 

Ttrees

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Thanks folks
Looks like the consensus is that vinegar or a similar thing to produce a chemical reaction,
needs time and is no better for immediate use than the wire brushes on their own.
I didn't bother trying for fear of more corrosion problems, as the lot got flash rusting on all the parts, and needed another go with the wire wheel.

This must have been because it was beside the sea.
The aluminium parts on this machine had what looked like chemical salt deposits...
It was a real PITA to clean out the hollow fence, and webbing on the extension table.

I coated the aluminium with the Isopon primer, hoping this will suffice.
Wondering if there's some sort of method to stop this flash rusting happening again on the aluminium for contact areas such as the extension table?
Like as patina solution, or would working through the grits down to a polish and then waxing be better?, That sounds like the cheapest option.
Thanks
Tom
 

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