304 Stainless signs.....rusting!

[ezduzit]

The shot blasting is the most likely cause of this. Its effect is just the opposite of highly polishing, which is what is done to yacht hardware for best appearance.

Also some imported grades of 300 series stainless exhibit much more problems with rusting.

Electropolishing might be an affordable fix.

[leightrepairs]

304 stainless often turns brown like your signs from materials in the vicinity of it. I think i would clean them and then have them chromed. Just my 2 cents

[Insaneride]

Just my two cents worth; Ive noticed a difference in GERMAN stainless vs India, Pakistan and China stainless. Also, German stainless is non magnetic at least in my xperiance whereas, the others are magnetic.

[montgoc3]

Just my two cents worth; Ive noticed a difference in GERMAN stainless vs India, Pakistan and China stainless. Also, German stainless is non magnetic at least in my xperiance whereas, the others are magnetic.

That typically depends on the grade of stainless. Ex: 400 series vs. 300 series.

[Insaneride]

That typically depends on the grade of stainless. Ex: 400 series vs. 300 series.

I think you just answered Mr Colts question.

[ezduzit]

Even 316 is much more corrosion resistant than 304

[dbotos]

Blast, blow off, acetone rinse, and clear powder coat. A super-durable clear would probably be good since they're outdoors in all kinds of weather:

http://powder365.com/store/index.php...roducts_id=179

[motolife313]

You have posted the same thing in like 5 different threads. I think most of us get it. And this thread is old

[hddnis]

Well, since someone revived the dead thread...

How did Hypertherm fix the signs?

[Northern Sweden Weld]

Should have cut it with water insted. The heat from the plasma depletet the plats of chrome. This is the reson why we use higher grade fillers when welding stainless.

[jimcolt]

If that was the case only the plasma cut edges would have rusted. The signs were reblasted in a shop that only handles stainless. It has been a couple years and they all still look great. No clearcoat.

Cutting with an abrasive waterjet would have made signs with a tighter tolerance, not at all necessary. They still would have needed shot blasting for the desired finish.

Jim Colt Hypertherm

Should have cut it with water insted. The heat from the plasma depletet the plats of chrome. This is the reson why we use higher grade fillers when welding stainless.

[vwguy3]

You have posted the same thing in like 5 different threads. I think most of us get it. And this thread is old

Huh?, the post before yours is from 2013.

[Showdog75]

Huh?, the post before yours is from 2013.

I think the said poster got the boot for trying to push his product.

[hddnis]

If that was the case only the plasma cut edges would have rusted. The signs were reblasted in a shop that only handles stainless. It has been a couple years and they all still look great. No clearcoat.

Cutting with an abrasive waterjet would have made signs with a tighter tolerance, not at all necessary. They still would have needed shot blasting for the desired finish.

Jim Colt Hypertherm

Thanks for the update. I always like learning solutions to problems that have worked for other people.

[vwguy3]

I think the said poster got the boot for trying to push his product.

Well that makes sense.

[jimcolt]

I don't think so....I am the original poster on this thread. Was looking for advice....which I got a couple years ago when it was first posted! Not sure where you see a product being promoted?

Jim Colt

I think the said poster got the boot for trying to push his product.

[VPT]

A rough surface will hold debris. If the signs are outside it is possible that it collected enough junk from rain to rust. With pretty much any metal the smoother the surface the more resistant to "stuff" it is. This is especially true with stainless, if the sign was polished it would resist rust much better.

[Teggy1]

I don't think so....I am the original poster on this thread. Was looking for advice....which I got a couple years ago when it was first posted! Not sure where you see a product being promoted?

Jim Colt

There was a poster posting the same stainless finishing equipment in all kinds of threads. They posted here as well, thus the old thread revival. It appears the administrators removed him and his posts, leaving voids in the conversation.

[Pipeliner]

I think the said poster got the boot for trying to push his product.

Not sure where you see a product being promoted?

Jim, Showdog was referring to "the said poster" that VW was referring to.

Some d-bag scammer posted the same thing on several old threads. The mods removed him and deleted his posts. And now here we are stirring up 3 year old stainless steel dust! And the damn sign will probably start rusting again!! Thanks a lot you scammer guy who got deleted and left us with this to deal with to start off 2017!!!!!!!

We all know you're legit Jim Colt.

[Pipeliner]

There was a poster posting the same stainless finishing equipment in all kinds of threads. They posted here as well, thus the old thread revival. It appears the administrators removed him and his posts, leaving voids in the conversation.

Well thank you Teggy1 for beating me to the punch by 9 minutes and ruining everything I thought so hard on to try to put into words!!!!!!!!!!!!

2017 is just not going to be my year from the looks of it. First the scammer guy confusing every body. And now Teggy1 ruining my post by posting the exact same thing I was going to say!!!!

[edit: I'm really not mad at Teggy1. This whole post was in jest. No one take anything seriously. No hard feelings. Except for the scammer guy. And rust.]

[Teggy1]

Well thank you Teggy1 for beating me to the punch by 9 minutes and ruining everything I thought so hard on to try to put into words!!!!!!!!!!!!

2017 is just not going to be my year from the looks of it. First the scammer guy confusing every body. And now Teggy1 ruining my post by posting the exact same thing I was going to say!!!!

[edit: I'm really not mad at Teggy1. This whole post was in jest. No one take anything seriously. No hard feelings. Except for the scammer guy. And rust.]

No worries man!

I'll try not to do it again.

[motolife313]

That guy push his luck too far. Must be a rookie

[kess]

What is Stainless Steel in few words. (rust problems)

Stainless steel is an alloy of iron which contains at least 10% chromium (Cr).
This addition of chromium defines the unique properties [stainless, corrosion and heat resisting].
The chromium content of the steel allows the formation of an invisible, corrosion-resisting chromium oxide film on the steel surface.
If damaged mechanically or chemically, this film is self-healing, providing that oxygen, even in very small amounts, is present.
A common form of rusting stainless steel is after the stainless steel has been exposed to very high temperatures (400-850°C) or (750-1550°F).
If this happens, sensitization can occur which is where the carbon and the chromium bond together in the stainless steel and form carbides.
These carbides situate themselves at the stainless steel grain boundaries, and the grain boundaries become deficient of chromium.
With lower chromium concentrations at the grain boundaries, the chromium oxide protective film can become discontinuous and start rusting.
The best solution is to polishing the overheated and the nearby areas using suitable abrasive brushes and polishing pastes.
This process is able heal the points of chromium oxide film that they has damaged.
At reality we do a very thin and smooth grinding/cleaning of the carbon carbides (that has come out at the surface from overheating).
So, removing the tiny steel particles we help the chromium oxide film to be able again, to self-healing the stainless steel.

Chemical Composition
Stainless Steel AISI 304

Carbon 0.08% max.
Manganese 2.00% max.
Phosphorus 0.045% max.
Sulfur 0.030% max.
Silicon 1.00% max.
Chromium 18.00-20.00%
Nickel 8.00-10.50%

Chemical Composition
Stainless Steel AISI 316

Carbon 0.08% max.
Manganese 2.00% max.
Phosphorus 0.045% max.
Sulfur 0.030% max.
Silicon 1.00% max.
Chromium 16.00-18.00%
Nickel 10.00-14.00%
Molybdenum 2.00-3.00%

Happy New Year
Bill

[Showdog75]

And?...

[TheBFA]

From what I've heard that sounds legit based on my experiences, getting stainless really hot will burn off some of the chromium content. If you notice, the problem areas are in the heat affected zones where it was cut.

I don't recall all the properties of the different grades of stainless, but in my experience, 304 isn't meant to stay rust free. Its used a lot in exhausts where looks don't really matter. 316 tends to be the most common for cosmetic fixtures.