Author Topic: Rust Removal  (Read 31997 times)

Offline Darren

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Re: Rust Removal
« Reply #25 on: August 25, 2009, 07:08:21 AM »
Interesting John, I know not the answer...

I was thinking that Soda Crystals (Sodium Carbonate Na2CO3 ) is basically a mild relative to Caustic Soda (Sodium Hydroxide NaOH) Both made from common salt (Sodium Chloride NaCI) I believe via an electrolytic process. The process removes the Chloride and adds the Hydrogen from water.

The point is they are all some form of salts and there are many others.

My thinking is that the chemical softens the paints over a period of hours.The hydrogen formed at the cathode surface expands and pushes the paint off under pressure.
Because we have made the part negative no oxygen is formed on the part so even though it's immersed in salts the chemical elements needed to cause corrosion are not present.
This makes the process non invasive to the subject being de-rusted.

However, at the sacrificial positive anodes we have the oposite story. Oxygen is formed on the surface and a rapid evasive process takes place. If you want to rust something quickly and violently then this should do the trick.

It's worth remembering that while the current is kept flowing, your part (as long as it's at negative potential) will come to no harm as it's protected by hydrogen. Switch the current off and the oxygen in the water can now get to your piece and combined with the salts with soon start to attack your subject.


That's how I understand the process.....but I could be wrong as I failed chemistry badly.....
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Offline Darren

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Re: Rust Removal
« Reply #26 on: August 25, 2009, 08:00:52 PM »
Moving on a little I decided that doing half an item and then turning it over was not only taking double the time but also lead to a problem. When the object was turned over the bare side poking out of the mixture rusted at a phenomenal rate. I assume due to the evaporating water from below and and chemicals or gasses present.

The answer seems to be to totally submerge the part. I rigged up another container and used the round barrel to start off the process on the drill main column. As you can see the column is only half in. Therefore I will be rigging up another container tomorrow to do it properly.

Indecently, almost everyone, in the UK at least, has a suitable container for an item around this size. But you'll have to wait and see what I come up with.... :ddb:





So while those two were fermenting ( I hadn't "discovered" the big bucket at this point) I made a start on the drill stand which was in a bit of a sorry state...I'm using a small angle grinder with a flap wheel type disk.
Nothing fancy here just a good clean up ready for painting as I know the stand will get knocked about from experience.



All done, didn't come out too bad in the end



I like to be able move my tools about, esp if I need to make room, but mostly to make cleaning easier. This drill is heavy so I'm putting some wheels on the back of the frame.





The idea is that you can lift the front and all four feet will lift off the floor. It'll still be heavy but at least moveable single-handedly.
The wheels are not here to support anything, it still sits on all four feet.



« Last Edit: August 25, 2009, 08:09:56 PM by Darren »
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Offline John Hill

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Re: Rust Removal
« Reply #27 on: August 25, 2009, 10:19:22 PM »
Whoohoo!  Be careful with your 'drill on wheels' Darren!  If you lift the front it will not have to come up very high before it wants to tip over backwards and you will be hard pressed to stop it!  (Now how would I know about such things?)
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Offline Darren

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Re: Rust Removal
« Reply #28 on: August 26, 2009, 04:43:15 AM »
Thanks for the heads up John....hadn't crossed my mind...... :doh:

It's top heavy init.....umm what to do now as I can see exactly what you mean.......
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Offline Darren

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Re: Rust Removal
« Reply #29 on: August 26, 2009, 05:08:01 AM »
I think the simple answer is to move the wheels further back to alter the balance position and centre of gravity.

I can do that.... :)
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Offline John Hill

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Re: Rust Removal
« Reply #30 on: August 26, 2009, 05:12:37 AM »
Darren, I am sure you will figure something suitable.   I had a close shave with my cut-off saw which was mounted on a similar stand.  I have solved the problem (in my mind  :med:) and will 'one day' fit some sort of socket on the front of the stand so that I can put a long handle (maybe 3 feet of 2" water pipe, or sumfink) which will get me back in control when moving the machine, meanwhile I am very careful!

Did you fabricate the stand? It looks a neat job.

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Offline Darren

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Re: Rust Removal
« Reply #31 on: August 26, 2009, 05:16:52 AM »
Thanks John,

Yes I was thinking a pull out bar would give much more leverage and thus control.
I made the stand about 20yrs ago from what I had laying around, nice and solid... :thumbup:
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Offline Darren

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Re: Rust Removal
« Reply #32 on: August 26, 2009, 08:16:39 AM »
The current status after a good wash, pretty good condidering all the cement that this was covered in .I didn't clean any muck or grease off this time before I started just to see if it could cope. It did......not problem with that at all.. :thumbup:

This was too long for the middle section to fit in the solution



So as I said before I needed a bigger bucket.....so here it is..do you recognise it.... :lol:



To save my good steel bars which so far seem unaffected I purchased some re-bar from the local merchants, but any scrap will do.

Helen being the wonderful girl she is brought me a shiny new bag of washing soda from her shopping trip yesterday..this is 1KG at 59 pence.



I used this much this time around, about 100g



Chucked it in the bucket and filled with water.

As another experiment I'm trying a phone charger for the power supply. I didn't cut the end off and bare the wires as this one has another use, but it may be best if a proper connection is made. This one is 5V at 500ma or 0.5 amps if you prefer. Be sure to check the polarity before you connect....!! It's the diagram just above "Made in China" Or if you snip and bare the ends of the wires best check with a meter.



Initially I'm getting 4.8V at 350ma, but the ma may yet go up as the process gets under way. We'll have to wait and see.

A set up like this is perfectly happy outside, so any space in the garden will do, and it does not look unsightly too boot..... :thumbup:



« Last Edit: August 26, 2009, 08:19:25 AM by Darren »
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Offline Stilldrillin

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Re: Rust Removal
« Reply #33 on: August 26, 2009, 12:37:08 PM »
You got me wondering earlier Darren...... I couldn`t think of a larger bucket.......  ::)

How will the solution cope with grass cuttings?  :D

David D

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Still modifying bits of metal... Occasionally, making an improvement!

Offline Jonny

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Re: Rust Removal
« Reply #34 on: August 26, 2009, 01:14:09 PM »
Excellent Darren and Dave cant wait to give it a try. I did mention it at work today which raised some eyebrows, if it goes wrong its £11k to replace.
Thanks.

Offline Andy

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Re: Rust Removal
« Reply #35 on: August 26, 2009, 03:38:49 PM »
This is brilliant Darren. I've been following this with interest. Cheap, easy, not much effort =  :D

When you said about using a larger container that most households have I thought you were going to suggest the bath for a minute...  :bugeye:

The only commercial product that I've had any real success with is Metal Ready. Far too expensive for big jobs though. Used it for de-rusting inside motorcycle fuel tanks.
From probably the smallest, dampest and most untidy workshop in Bradford, West Yorks, England, if not the world..

Offline Darren

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Re: Rust Removal
« Reply #36 on: August 26, 2009, 05:32:52 PM »
Thanks for the feedback guys, as many of you will know this is not a new idea by any means. There are quite a few pages on the net covering this.

This is an interesting one using a towel as Dave BC suggested earlier..http://madmodder.net/index.php?action=post;topic=1651.30;num_replies=35

David D...wot grass cuttings.....we have sheep around here ya know.... :lol:

Jonny, just what is this metal part at 11K......you might want to look up Hydrogen embrittlement before you give this a go. It really doesn't affect our parts, but if you are working with a "critical" part it may. It's not permanent though and can be eliminated my heating the part afterwards. It's to do with the hydrogen forming on the surface of the subject. Some also forms inside the metal and due to the hydrogen expansion it can put pressure on the part. Not to the point of actually breaking it, but it does reduce integrity to a small degree. Like I said it does subside as the hydrogen finds it's way out over time.

For our needs it is of no consequence.

Andy, yep Metal Ready is pretty good I agree. But to do this pillar drill would cost more than the drill is worth.



So a progress report, the contents of the bucket are fermenting nicely  :) The mobile charger is coping fine and the ma rose to 480ma as expected, prob due to the iron content of the water helping conductivity.
But it's a little on the slow side, prob due to the large size of the part and the low ma I guess. So I have changed to a charger giving 1.5A or 1,500ma output tonight and instantly the difference is obvious.






 
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Offline sbwhart

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Re: Rust Removal
« Reply #37 on: August 27, 2009, 01:21:22 AM »
Hi Darren interesting thread  :thumbup:. keen to see how your charger works out with it, I think i may rig a small bath up to do some old tools that could do with a de-rust

Have fun

Stew
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Offline Bluechip

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Re: Rust Removal
« Reply #38 on: August 27, 2009, 04:16:42 AM »
Crikey,this ones going on a bit .. :D

I wonder if my received wisdom to use a current limiter is relevant to the hydrogen embrittlement aspect.

Maybe the effect is much reduced or eliminated by a long soak at a very low current ?

Just a thought.

There are fairly large plastic box things in the DIY sheds from time to time. Cheapish.
The sort used to store toys etc. Focus have 'em anyway, although it's a year or so since I got one.

If everyone has a go at this the price of washing soda is going to jump in a bit, world shortage imminent ..  :D

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Offline Darren

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Re: Rust Removal
« Reply #39 on: August 28, 2009, 05:17:43 PM »
Stew,

Considering the main column casting has already been done once, and then put into this fresh solution then I believe the little phone charger is doing a grand job.. :thumbup:



However, the first charger I tried died after about 8hrs, the second is sill going strong after almost 30hrs. (I'm not ready to take it out just yet so I'm leaving it in there)
The difference between the chargers is that the one that died was an unregulated type, and the current one has a  regulated output. (This means it can't overload itself and thus burn out) This gets back to what David BC advised earlier with adding a car headlamp bulb in series to limit the current.  :thumbup:

In the other vat I removed and washed down the baseplate....one thing I have noticed about bare cast iron is that rust forms instantly without protection.



So I dried it with a powerful electric paint stripper, got my paint ready, wiped it over with some white spirit which removed the flash rust and painted it. I used poly floor paint with a touch of white spirit to thin it slightly to help with brush marks. You have to get on with it as floor paint dries pretty quickly.



This is just the first coat, it will have another tomorrow.


Onto the stand.
I wanted to reposition the wheels further back so fabricated some brackets on the mill.



Welded them in place and at the same time added a middle shelf from some old bed iron and a handle on the front to make moving it about easier and safer. All parts were de-rusted.
It may be interesting to note that the smaller parts took only an hour or so to de-rust.

The stand was then given it's first coat of paint with a small roller.



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Offline Stilldrillin

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Re: Rust Removal
« Reply #40 on: August 29, 2009, 02:16:36 AM »
By `ek Darren....... 

That stand looks great! Right proffessional......  :clap:

Not too sure of that bin of tomato summator other........  :lol: :lol:

David D
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Offline John Hill

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Re: Rust Removal
« Reply #41 on: August 29, 2009, 05:26:39 AM »
Looks good Darren,  if you have a moment would you please knock up another and send it over for my chop saw?

Ta muchly! :med:
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Offline Darren

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Re: Rust Removal
« Reply #42 on: August 29, 2009, 11:40:31 AM »
First thing in the morning John.... :thumbup:
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Offline Darren

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Re: Rust Removal
« Reply #43 on: August 29, 2009, 05:27:54 PM »
Well this is how the column turned out



Nice to see the detail unharmed



And the other side, note the brass plate was also unharmed, just looks polished up but no harm has come to the raised lettering at all



So now we have it clean better slap some paint on it....



Shall I detail ....?




The base plate and stand were also given their second coat of paint today...while I had the brush out..... :dremel:
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Offline sbwhart

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Re: Rust Removal
« Reply #44 on: August 29, 2009, 05:34:15 PM »
Darren thats brilliant

Cleaned up great
 :clap: :clap: :clap: :clap: :clap: :clap: :clap:

Stew
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Re: Rust Removal
« Reply #45 on: August 29, 2009, 05:50:46 PM »
Darren,

I hope you aren't going to be painting your floor with the same paint.

I can imagine you walking round and bumping into all the camouflaged machinery.  :lol:


Bogs

Offline Darren

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Re: Rust Removal
« Reply #46 on: August 29, 2009, 06:03:07 PM »
Very good John, very good.... :clap:

it'd be like one of those modern white rooms........ :doh:


Talking of which, it almost got pained white, the paint is here.....I never was very good a making decisions....I still might yet....... :scratch:


Stew, the nicest thing about all this is just how little effort it all takes. The old way was such a pain most tools just got a cover up inc chips, chunks, rust an' all.
Add the fact that the whole process inc paint will cost about £10 or less, then it's a no brainer....

I painted my lathe with floor paint, comes in quite a few colours, it's tough (just think of the punishment it gets on the floor) It paints easily. I just brush it on and then run a small roller over it to give a nice finish. Lastly you don't need a hundred brushes or rollers as they keep/wash in white spirit till next time they are needed.



Shall I paint it white........ :bang:
« Last Edit: August 29, 2009, 06:07:38 PM by Darren »
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Offline John Hill

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Re: Rust Removal
« Reply #47 on: August 29, 2009, 08:49:48 PM »


I painted my lathe with floor paint...........

Eh what?  YOU PAINTED YOUR LATHE?  I Turtle Wax mine after every use... :med:
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Offline Darren

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Re: Rust Removal
« Reply #48 on: August 30, 2009, 05:59:49 AM »


Eh what?  YOU PAINTED YOUR LATHE? 

Er yes, isn't yours painted..... :doh:
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Offline Stilldrillin

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Re: Rust Removal
« Reply #49 on: August 30, 2009, 06:09:48 AM »


Eh what?  YOU PAINTED YOUR LATHE? 

Er yes, isn't yours painted..... :doh:

Mine still is....... In a few places!  :D
Still drilling holes... Sometimes, in the right place!

Still modifying bits of metal... Occasionally, making an improvement!