Derusting/Degreasing advice

[Dissolve]

Hello,

I have an old pillar drill that needs stripping down and painting. The table and column have quite a bit of surface rust although it's not terribly deep.

I know I could attack the rust with wet and dry, but are their any quick chemical methods or tips for efficiently removing the rust before I get stuck in?

Once it's cleaned up and ready for some paint, what's the best way to strip the old finish off? Again is their a chemical shortcut or just elbow grease?

If I paint over the existing paintwork, what should I use to thoroughly degrease it before?

Thanks

 

[iNewbie]

Have you tried using the 'search' facility. I bet this has been covered before.

 

[carlb40]

For small parts that can fit in a suitable tub, you can use oxalic acid / baking soda vinegar etc to remove rust. To remove previous finishes and rust together - you can use electrolysis

https://www.youtube.com/watch?v=54ADeB6V1rQ

 

[Spindle]

Hi

Use electrolysis for everything - the benefit is that it will remove and neutralise the rust in all of the inaccessible areas and it will not remove any parent metal. Remember to protect electrolised surfaces immediately on removal from the bath or they will develop a fine coat of rust almost before your eyes.

Regards Mick

 

[Dissolve]

Hi

Use electrolysis for everything - the benefit is that it will remove and neutralise the rust in all of the inaccessible areas and it will not remove any parent metal. Remember to protect electrolised surfaces immediately on removal from the bath or they will develop a fine coat of rust almost before your eyes.

Regards Mick

Wow, I've just looked at the youtube videos, I have a couple of questions before I go and start my experiments! Haha

What sort of car battery charger do you need? I can only see automatic battery chargers for sale at places like Argos. Is it essential to find a manual charger? What sort of ampage should I be running at? (Safely) haha

 

[carlb40]

Hi

Use electrolysis for everything - the benefit is that it will remove and neutralise the rust in all of the inaccessible areas and it will not remove any parent metal. Remember to protect electrolised surfaces immediately on removal from the bath or they will develop a fine coat of rust almost before your eyes.

Regards Mick

Wow, I've just looked at the youtube videos, I have a couple of questions before I go and start my experiments! Haha

What sort of car battery charger do you need? I can only see automatic battery chargers for sale at places like Argos. Is it essential to find a manual charger? What sort of ampage should I be running at? (Safely) haha

Any charger will be ok. There are even people who use phone chargers etc. From what i read/ saw last year a lot of people prefered lower amperage chargers. Anyhing that supplies a 12v power will work inc PC power supplies.

 

[Dissolve]

Hi

Use electrolysis for everything - the benefit is that it will remove and neutralise the rust in all of the inaccessible areas and it will not remove any parent metal. Remember to protect electrolised surfaces immediately on removal from the bath or they will develop a fine coat of rust almost before your eyes.

Regards Mick

Wow, I've just looked at the youtube videos, I have a couple of questions before I go and start my experiments! Haha

What sort of car battery charger do you need? I can only see automatic battery chargers for sale at places like Argos. Is it essential to find a manual charger? What sort of ampage should I be running at? (Safely) haha

Any charger will be ok. There are even people who use phone chargers etc. From what i read/ saw last year a lot of people prefered lower amperage chargers. Anyhing that supplies a 12v power will work inc PC power supplies.

Brilliant, just dug up an old car battery charger, it says it's automatic but we'll give it a go and see what's what.

Great! All the videos say to use some american brand washing soda but the nearest thing I can find is soda crystals like this:
http://www.tesco.com/groceries/product/ ... =258133332

think that'll do the trick?

 

[Phil Pascoe]

You can use any soda or table salt, apparently. It just serves to improve the conductivity of the water.

 

[marcros]

I think that if you have a new type battery charger- this may be automatic- you can fool it by putting a battery into the circuit. I had to do this with mine- it wouldn't work by just collecting it to the electrolysis setup. I put charger to battery and battery onto electrodes with jump leads.

 

[Spindle]

Hi

The washing soda you linked is exactly the same, chemically, as the Arm and Hammer brand usually shown in US websites. Although salt will turn the water into an effective electrolyte I wouldn't recommend using it - think of the effect sea water has on iron and steel, any residual left after you've de-rusted will just re-start the corrosion.

With regard to amperage: the current drawn will depend on the surface area of the electrodes and their proximity, (the closer they are together, the more current will be drawn). My battery charger registers about 4 amps for items the size of a brake disc. I use a phone charger for smaller items but need to keep a watch on it initially as it can get quite hot - moving the electrodes further apart serves to regulate the current demand and thus the temperature of the charger.

The ideal tool to remove the converted rust and paint residue is a wire cup brush fitted to an angle grinder.

Finally, try to avoid stainless steel electrodes, they release hexavalent chromium salts, turning the electrolyte an orange yellow colour, they are hazardous chemicals and it's not permissible to dispose of them down the drain or on the garden.

Regards Mick

 

[Dissolve]

Fantastic. I have it working right now. Its a big plastic storage tub with steel rods cable tied into the corners which has copper wire connecting them above the water level.

The battery charger is hooked up with positive to the steel rod's and my drill table is suspended by some galvanised steel garden wire. 30 mins in and I'm getting lots of tiny white bubbles on the sides of the table but not a lot else. Does that sound about right?

 

[tool-me-up]

Add more soda or salt or what ever you used to make the solution. Alternatively up the amps / voltage. Sounds a little slow - I usually get tiny white bubbles in around 5 minutes, in half an hour I have a murky brown solution with a lot of brown/ orange froth on top. Overnight I have accidentally started to erode the part being cleaned resulting in a pitted surface.

Just out of interest because you sound like your enjoying this - once finished and you have a murky brown tub of horrible water - swap the drill for a clean piece of bare steel (scrap ) and change direction of current.

I often wondered if you could plate with a setup like this......

 

[carlb40]

Fantastic. I have it working right now. Its a big plastic storage tub with steel rods cable tied into the corners which has copper wire connecting them above the water level.

The battery charger is hooked up with positive to the steel rod's and my drill table is suspended by some galvanised steel garden wire. 30 mins in and I'm getting lots of tiny white bubbles on the sides of the table but not a lot else. Does that sound about right?

Yeah sounds about right, it does take a few hours or more for it to work on the item being stripped.

 

[graduate_owner]

From what I've read, a battery used in conjunction with the battery charger (i.e. in parallel) helps to stabilise the current because some battery chargers don't give a very accurate DC output.
Also, never use stainless steel for the sacrificial electrode because you can get toxic fumes and a toxic residue in solution from the Chromium in the s/s.

K

 

[Spindle]

Hi

Sounds good, do you know what current is being drawn?

You could move the electrodes closer to the drill table and also make sure you have good connectivity between the charger and the electrodes, otherwise just let it run. I'd give it 24 hours then have a look, by then you should see all the rust converted to a black mess, you'll be able to push it off with a steel rule but as I said if you've got a cup brush on an angle grinder it will make very short work of it.

If you're not going to paint it immediately I'd spray it with WD40 or some other water dispersant or dry it in an oven / airing cupboard and keep it warm until you do.

Regards Mick

 

[Spindle]

Add more soda or salt or what ever you used to make the solution. Alternatively up the amps / voltage. Sounds a little slow - I usually get tiny white bubbles in around 5 minutes, in half an hour I have a murky brown solution with a lot of brown/ orange froth on top. Overnight I have accidentally started to erode the part being cleaned resulting in a pitted surface.

Hi

Sorry but:

As far as I am aware you can't up the amps' - the circuit will draw what ever current it requires, this will be dependant on the area and proximity of the electrodes.

Adding more soda is just a waste of soda.

The reaction does not interfere with the parent metal - I have had components under electrolysis for over a week, (I forgot about it), and there was no damage to the parent metal.

Regards Mick

 

[Dissolve]

Great, no idea what amperage it's running at. It's a halfords own "suitable for engines up to 1800cc" haha I'm storied it's working at all to be honest!

It has a slow and a fast setting, could I try flipping it onto fast without causing any upset? Or is it best left on slow?

I have very very slightly Browning of one corner on the surface of the water but I could definitely move the electrodes closer towards the center so I'll probably do that after a few more hours and look at the results.

 

[Spindle]

Hi

Moving the electrodes closer should result in an almost instant increase in the rate of gas formation - if you can move them to about an inch from the table you should see a steady stream of bubbles, the brown scum will follow. I'd try this first rather than switch to fast charge.

Regards Mick

 

[tool-me-up]

Add more soda or salt or what ever you used to make the solution. Alternatively up the amps / voltage. Sounds a little slow - I usually get tiny white bubbles in around 5 minutes, in half an hour I have a murky brown solution with a lot of brown/ orange froth on top. Overnight I have accidentally started to erode the part being cleaned resulting in a pitted surface.

Hi

Sorry but:

As far as I am aware you can't up the amps' - the circuit will draw what ever current it requires, this will be dependant on the area and proximity of the electrodes.

Adding more soda is just a waste of soda.

The reaction does not interfere with the parent metal - I have had components under electrolysis for over a week, (I forgot about it), and there was no damage to the parent metal.

Regards Mick

more soda just serves to increase the conductivity of the solution - this helps it along a little faster. The better it conducts in theory the more amps it will draw but this is probably not noticeable amount.

Depends what you are using, with a manual car charger I can up the amps or voltage them by selecting boost charge and / or 12v - 24v mode - I have damaged items using this method - look up electro-etching at home or similar on google - you can eat the surface off the metal.

 

[Spindle]

Hi

Electro etching differs from electrolytic rust removal in that the item to be etched is attached to the positive electrode and the electrolyte is a salt of the metal to be etched.

Washing soda is sodium carbonate, if you want to etch iron or steel you would use ferrous sulphate.

Regards Mick