Welding Tips and Tricks

What's the best way to get rust off of 304L stainless steel? Somebody at work cleaned all the welds on a conveyor with a steel wire brush in a drill, and now everything he cleaned is rusted.

I, too, would like to know how best to do this. I encounter this amateur crap all the time. I can usually let it slide, but it looks unprofessional.

Welcome, Mikedjwelding!

Steve S

This is just a wild guess, but a SS wire wheel?

I saw them at the LWS a week or so back, and then winced at the price (as a hobby/amateur welder, ~$45/wheel hurts!)

Hey, "hey_allen", this is an "after the fact" question, where someone has used a carbon-steel or contaminated brush to clean his welds. The rust has accumulated.

How do you clean it, so your repair doesn't look like ass?

Steve S

Mikedjwelding wrote:What's the best way to get rust off of 304L stainless steel? Somebody at work cleaned all the welds on a conveyor with a steel wire brush in a drill, and now everything he cleaned is rusted.

Depending on how much you have to do, and how long it's been there would be good to know. If it's recent then it shouldn't be too difficult to remove. A quick search turned up a solution of 1 tablespoon baking soda with 2 cups water. Or vinegar poured directly on, or lemon juice and baking soda.

I haven't tried these, and I'd presume if the rust has been there awhile more aggressive methods might be needed.

It just happened, we washed it when we were done with it and the next day it was rusted. We need to get it shipped soon and can't afford to waste time trying all kinds of different things and hoping it works, I was hoping someone here had experience in actually getting it out permanently.

http://www.bssa.org.uk/topics.php?article=55 read through this article.

weldin mike 27 wrote:http://www.bssa.org.uk/topics.php?article=55 read through this article.

Good article and website, I'll read thru this as time permits, thanks Mike

YO!!!!!
I've had good dealings with this company.


http://www.lehighvalleyabrasives.com/ab ... -rdm472858

If you've got a lot of money, then use one of these:

http://www.fronius.com/cps/rde/xchg/SID ... ULxDpNqkUM

1 quick wipe, before (LHS) and after (RHS). No rust has ever appeared since.

Mikedjwelding wrote:It just happened, we washed it when we were done with it and the next day it was rusted. We need to get it shipped soon and can't afford to waste time trying all kinds of different things and hoping it works, I was hoping someone here had experience in actually getting it out permanently.

Mikey whined "I was hoping someone here had experience in actually getting it out permanently."

HHiiiiiiyyyyYYYYOOO!!!

1-never use any sanding, grinding or wire wheels, brushes that have ever touched steel.
2-Wire wheeling will embed the steel particles into the SS--and can cause intergranular corrosion, etc.,
besides pissing off everybody. Handling/fabbing SS requires cleaning all, clean work surfaces,
repeated wiping and cleaning.


3-Do not try to sand, wire brush, etc.--those tiny particles away--just makes matters worse

B4 using diluted nitric-
phosphoric acid -H'depot paint dept. $16/gallon
This process, even with the nitric--is to try and remove the steel--not embed it further
gently flood the area, wait a few minutes, try to gently wipe off any rust bloom or smearing
-wipe clean, wash and flood again with phosphoric, let stand, while gently using wet 3M pad to
gently remove more stain---rinse with phosphoric, p-towel wipe, flood again
[I much prefer using the phosphoric to the nitric--for a whole bunch of reasons and if you've never
worked with nitric, then don't ask.]
If some stain has just been removed, the wipe, rinse with phosphoric, right now---you don't want
this steel solution to linger on the SS
for heavier embeded stuff--can use NEW SS toothbrush and very gently brush area, keep towel wiping
and flooding with new acid as soon as some stuff has visually been lifted off.
Repeat, repeat, repeat.
After one's pretty certain that the f'up is corrected then soak or at least wet down and let stand
for 30 min's or longer--something like 10% nitric solution to passivate the cleaned surface...
..or give more time with the phosphoric.
Rinsing with steam distilled water doesn't hurt.
Passivation is not a cure-all for gross contamination, like a whack job using a steel wire wheel---
where's the supervision and training?
--I've used the phosphoric cleaning described above--even with heavily rust stained SS.
I've only had 1 episode in my shop of steel contamination on new SS--and by gawd--I learned
much from that epi$ode--cause by myself, not outside parties. You will, too.

dave powelson wrote:

Mikedjwelding wrote:It just happened, we washed it when we were done with it and the next day it was rusted. We need to get it shipped soon and can't afford to waste time trying all kinds of different things and hoping it works, I was hoping someone here had experience in actually getting it out permanently.

Mikey whined "I was hoping someone here had experience in actually getting it out permanently."

HHiiiiiiyyyyYYYYOOO!!!

1-never use any sanding, grinding or wire wheels, brushes that have ever touched steel.
2-Wire wheeling will embed the steel particles into the SS--and can cause intergranular corrosion, etc.,
besides pissing off everybody. Handling/fabbing SS requires cleaning all, clean work surfaces,
repeated wiping and cleaning.
3-etc.
4-etc.

Bitch, much?

We're hear to help each other, and the question is what to do AFTER the damage is done.

You chose to give us a "week 1" lecture on prevention.

Or should I spell that "weak one".

Steve S

Otto Nobedder wrote:

dave powelson wrote:

Mikedjwelding wrote:It just happened, we washed it when we were done with it and the next day it was rusted. We need to get it shipped soon and can't afford to waste time trying all kinds of different things and hoping it works, I was hoping someone here had experience in actually getting it out permanently.

Bitch, much?

We're hear to help each other, and the question is what to do AFTER the damage is done.

You chose to give us a "week 1" lecture on prevention.

Or should I spell that "weak one".

Steve S

I chose to give a fairly detailed rundown on dealing with the problem.

From the OP's description--it's obvious that preventing the problem is equally important.

dave powelson wrote:...
I chose to give a fairly detailed rundown on dealing with the problem.

From the OP's description--it's obvious that preventing the problem is equally important.

Fair enough.

I read it as, "What now?" and saw no advice on solving the problem at hand. So he has all your prevention advice, and the same problem.

Steve S

Otto Nobedder wrote:

dave powelson wrote:...
I chose to give a fairly detailed rundown on dealing with the problem.

From the OP's description--it's obvious that preventing the problem is equally important.

Fair enough.

I read it as, "What now?" and saw no advice on solving the problem at hand. So he has all your prevention advice, and the same problem.

Steve S

HuH? See partial repost copy below---it's ALL ABOUT solving the problem at hand.

3-Do not try to sand, wire brush, etc.--those tiny particles away--just makes matters worse

B4 using diluted nitric-
phosphoric acid -H'depot paint dept. $16/gallon
This process, even with the nitric--is to try and remove the steel--not embed it further
gently flood the area, wait a few minutes, try to gently wipe off any rust bloom or smearing
-wipe clean, wash and flood again with phosphoric, let stand, while gently using wet 3M pad to
gently remove more stain---rinse with phosphoric, p-towel wipe, flood again
[I much prefer using the phosphoric to the nitric--for a whole bunch of reasons and if you've never
worked with nitric, then don't ask.]
If some stain has just been removed, the wipe, rinse with phosphoric, right now---you don't want
this steel solution to linger on the SS
for heavier embeded stuff--can use NEW SS toothbrush and very gently brush area, keep towel wiping
and flooding with new acid as soon as some stuff has visually been lifted off.
Repeat, repeat, repeat.
After one's pretty certain that the f'up is corrected then soak or at least wet down and let stand
for 30 min's or longer--something like 10% nitric solution to passivate the cleaned surface...
..or give more time with the phosphoric.
Rinsing with steam distilled water doesn't hurt.
Passivation is not a cure-all for gross contamination, like a whack job using a steel wire wheel---
where's the supervision and training?
--I've used the phosphoric cleaning described above--even with heavily rust stained SS.
I've only had 1 episode in my shop of steel contamination on new SS--and by gawd--I learned
much from that epi$ode--cause by myself, not outside parties. You will, too.

Dave,

I apologize.

I responded to your post based solely on the first paragraph.

Steve S

Otto Nobedder wrote:
Or should I spell that "weak one".

Steve S

I see what you did there Steve

I would usually hit it with pickling paste, as already mentioned here. However pickling agents tends to raise surface roughness. So further sanding may be needed after pickling, it depends... Passivation will occur by itself. Film takes around 3 days to get into it's full strength, just to make sure part will have that time before it is introduced to harsh atmosphere.

If those rust pits are gone really deep then I would remove surface depth with sanding and after that hit it with pickling paste. Just to make sure you get those last iron particles etc. out of the steel. Sanding helps because, there is maximum time that pickling acids are allowed to be on the surface. Keep it too long on the steel and you end up with intergranular corrosion etc.

You can also buy heavy duty stainless steel cleaner solvents, which are made to remove iron and other particles. Works really well! Avesta does sell those here in Europe.

@Trackranger:
We have magic cleaner at work too, but never thought it could be used to remove rust. Got to make a test run some day

Note of interest. I sat in on a quick technical discussion on using ss wire wheels to clean ss material verses a carbon wire wheel. They claim, and I am highly inclined to believe them since they are in the food, beverage and dairy industry as well as toxic gasses, that a ss wire when will induce rusting due to the overlapping of the ss from the wire action leaving "pockets" that allow rust to form. Or something like that. I want to try it myself but don't have virgin pipe right now.
-Jonathan

Well, all good information for me, since I had thought that a SS wheel would be useful to knock the rust and hopefully the remaining non-SS off of the surface.

As for my experience, I typically have been working with various carbon steel variants, not on SS, so I have to work on immediately surface protecting them to prevent rust. Depending on the task, either priming and painting, or occasionally waxing the surface, as the end use dictates.

It's always interesting to see the input of everyone's experiences in the different industries, and to try to learn from others experiences, since I doubt that I'll be in the locations to learn them in person unless I find the issue the hard way!

hey_allen wrote:Well, all good information for me, since I had thought that a SS wheel would be useful to knock the rust and hopefully the remaining non-SS off of the surface.

As for my experience, I typically have been working with various carbon steel variants, not on SS, so I have to work on immediately surface protecting them to prevent rust. Depending on the task, either priming and painting, or occasionally waxing the surface, as the end use dictates.

It's always interesting to see the input of everyone's experiences in the different industries, and to try to learn from others experiences, since I doubt that I'll be in the locations to learn them in person unless I find the issue the hard way!

I agree
We do a lot of 316L pipe for the RO industry, after fabrication the pipe spools are electropolished to enhance the corrosion resistance (remove any surface contaminates). Electropolishing is a higher form of passivation.
This shop has some of the largest tanks in the southeast http://www.all-bright.com/