Angle Grinding Rust

[312 Sprinter]

lol as u grind the metal u are putting heat into it this will cause moisture so the oxidation process will have already started also u will not get rid of it all as it will still be deep in the metal u just wont see it

If the process has already started under the primmer then no

Good grief we have a scientist in our midst.....

There really isn't anything especially difficult about treating rust. Stop oxygen and an electrolyte from getting to the steel and the steel won't rust.

That is why you need a good coat of paint, and it is why the rust will bubble through a badly prepared panel. If it is rusty and pinholed on the side you can't see it'll bubble through. Remove the rust, treat is with a phosphoric acid based rust remover, prime and paint and it won't come back. There is no point at all in cutting out steel that isn't perforated.

 

[312 Sprinter]

It can be top coated using por-15 primer and then the top coat

But I agree it is no good on clean surfaces. It needs to adhere to the rust to seal it in from the atmosphere.

It can, but even then I've had it react. If the OP is going to clean back to bare metal then POR is the wrong choice. As you say it works best straight over rusty metal.

 

[andy clark]

Good grief we have a scientist in our midst.....

There really isn't anything especially difficult about treating rust. Stop oxygen and an electrolyte from getting to the steel and the steel won't rust.

That is why you need a good coat of paint, and it is why the rust will bubble through a badly prepared panel. If it is rusty and pinholed on the side you can't see it'll bubble through. Remove the rust, treat is with a phosphoric acid based rust remover, prime and paint and it won't come back. There is no point at all in cutting out steel that isn't perforated.

lol ok then mate all im saying is why bodge it if the metal has rust in it all u are doing is covering it up u will not get it all out why waste your time covering it up just for it to come back in a few years why do u think when u have a car restored they go to the trouble and expence of fitting new pannels and cutting out all the rust if all u had to do was grind it away and slap abit of anti rust on it then paint it lol and by the way as i have stated if the rust is allready in the metal which it will be then the best primmer and top coat in the world isent going to stop it rusting as the rust is allready there lol

 

[renault12ts]

I don't understand how the rust is in the metal. Rust (oxidisation) is a surface effect caused by moisture and air on bare metal.

 

[312 Sprinter]

lol ok then mate all im saying is why bodge it if the metal has rust in it all u are doing is covering it up u will not get it all out why waste your time covering it up just for it to come back in a few years why do u think when u have a car restored they go to the trouble and expence of fitting new pannels and cutting out all the rust if all u had to do was grind it away and slap abit of anti rust on it then paint it lol and by the way as i have stated if the rust is allready in the metal which it will be then the best primmer and top coat in the world isent going to stop it rusting as the rust is allready there lol

The rust isn't "in" the metal, rust is metal with added oxygen. Either you have a rust hole, which needs to be welded or the panel needs to be replaced, or you have essentially sound metal with some surface corrosion.

A rusty piece of metal won't somehow keep corroding in the absence of oxygen and an electrolyte. If you stop the conditions needed for rusting to take place you've cured the problem.

 

[andy clark]

I don't understand how the rust is in the metal. Rust (oxidisation) is a surface effect caused by moisture and air on bare metal.

And your eyes can see that well that they can see into all the microscopic pits in the metal? as u look at the nice big shiny bit u have rubbed down it will still be in the metal

 

[andy clark]

The rust isn't "in" the metal, rust is metal with added oxygen. Either you have a rust hole, which needs to be welded or the panel needs to be replaced, or you have essentially sound metal with some surface corrosion.

A rusty piece of metal won't somehow keep corroding in the absence of oxygen and an electrolyte. If you stop the conditions needed for rusting to take place you've cured the problem.

lol yep sounds good but dosent last more than a few years!

 

[renault12ts]

And your eyes can see that well that they can see into all the microscopic pits in the metal? as u look at the nice big shiny bit u have rubbed down it will still be in the metal

NO, it wont.

 

[312 Sprinter]

lol yep sounds good but dosent last more than a few years!

Did you learn to spell at the same educational establishment that endowed you with your unique insight into the interaction of oxygen and mild steel perchance?

 

[andy clark]

NO, it wont.

lol and i take it your talking from abody shop back ground each to there own mate im not fussed just telling u my view on how its done properly lol u get what u pay for in life if u can do as good a job on your drive with the bits u get from halfords and a dremal multi or a grinder to rub it down and remove all traces of rust ( good point it sits on the surface but that surface would look like a mountian pass if u looked at it under a microscope ) then go for it u will save a lot of money by the way ring up somewhere that dose paint cars and ask them if u rub my rust down then paint the car will u warrent the pannel againts rust after!

 

[andy clark]

Did you learn to spell at the same educational establishment that endowed you with your unique insight into the interaction of oxygen and mild steel perchance?

No mate i carnt spell thats why i have spent 17 years working in workshops and bodyshops getting dirty around cars and trucks lol i take it you are a teacher or an under cover teacher then! ill give u that one fair play u can spell better u are the better man lol

 

[stwat]

No mate i carnt spell thats why i have spent 17 years working in workshops and bodyshops getting dirty around cars and trucks lol i take it you are a teacher or an under cover teacher then! ill give u that one fair play u can spell better u are the better man lol

Y r u posting in txt spk?

 

[andy clark]

Y r u posting in txt spk?

Are you not reading text lol dont know mate ill stop it

 

[312 Sprinter]

No mate i carnt spell thats why i have spend 17 years working in workshops and bodyshops around cars and trucks lol i take it you are a teacher or an under cover teacher then! ill give u that one fair play u can spell better u are the better man lol

It is a bit unfortunate that in 17 years you don't seem to have gained a basic theoretical understanding of what rust actually is and how it forms. Certainly if your craft is bodywork you shouldn't be posting the complete and utter nonsense that you are.

Rust isn't in the metal, oxygen reacts with the metal and oxidises it, oxidised metal is.... RUST. Mild steel doesn't want to be mild steel, it wants to revert to its natural state before the ore was mined and smelted and made into sheets. To do that it needs to be coated, with paint, or galvanising, or anti rust wax or preferably a combination of several of those.

If the steel is still solid and not perforated, and the rust is removed, either mechanically or chemically and then painted there is no reason why the rust should reappear. Well actually there is a reason and that is poor workmanship. It is time consuming, it is rarely done properly, but if it is done properly it lasts, in fact it lasts pretty much indefinitely.

It is why we'll spend lots of money to take a bodyshell from this

To this by having the whole thing acid dipped.

There is no reason why someone can't achieve that on a localised scale by abrading the rust and treating it with a good quality phosphoric acid based rust killer. For components molasses can be used to do the same thing.

 

[andy clark]

i carnt be ased anymore u do it your way do u give warrenty on pannels that were rusty that you have rubbed down? if you do then you must be the only one because i dont no of any because it will come back! and im not saying that its in the metal as such im saying its where you cannot see with your eye it may look clean but there will still be rust there in the metal is just a term stop being such a k**b about it

 

[stwat]

Are you not reading text lol dont know mate ill stop it

Well edited!! But u r still using txt spk so u r.

So ******* annoying when you have a qwertyy keyboard right in front of you.

 

[Nasco12]

i thinc sumwunz about to get band

 

[nick mercedes]

Ive never done this before, any tips?

Once the weather improves I think I will have a go at removing my wings and using an Angle Grinder on them.

Ive never done this before, any tips?

Pack of these:

Alox Fibre Disc 115mm 24 Grit Pack of 10 - Screwfix.com, Where the Trade Buys

One of these:

Tool-Net 115mm Rubber Backing Pad - Power Tool Accessories, For - Grinders & Disc Cutters, Backing Pads

And one of these:

WSAG550 4 1/2" Angle Grinder: Amazon.co.uk: DIY & Tools

 

[andy clark]

How on earth are u going to get the same results at home as acid dipping lol and looking at them pics the rust on that bulk head is minor surface rust there is not any damage to the metal or any signs of the rust eating into the metal and damageing / pitting it not really and good example of trying to save a pannel that has had bad rust on it and going by how rusty mercs can get a front wing / wheel arch will be alot worse than that!

 

[renault12ts]

So, Andy, surface rust can be treated successfully?