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-   -   Ask a corrosion technician anything... (http://forum.e46fanatics.com/showthread.php?t=828150)

Jmanscotch 03-07-2011 09:53 PM

Ask a corrosion technician anything...
 
Inspired by "sitting in hotel room all week" boredom and the recent "ask a" threads, here is my lame version. Plus, I know you all have some hardcore questions on the world of rust, so ask away. :rolleyes:

Credentials:

- Corrosion Technology Degree
- 4.5 years field experience with a top 150 engineering firm
- Good at guessing

Our main focus is the regulated fuel/oil/natural gas infrastructure, but I can offer a half-assed guess on most topics.

Breyton-BMW 03-07-2011 10:11 PM

Do those salt cleaning agents like salt away or salt terminator really work? I heard somewhere they are just dish washing liquid or close to it. Can I just use that instead?

JonJon 03-07-2011 10:12 PM

Could thermite "corrode" steel cored beams in a skyscraper?

:eeps:

JJR4884 03-07-2011 10:13 PM

Quote:

Originally Posted by JonJon (Post 12895262)
Could thermite "corrode" steel cored beams in a skyscraper?

:eeps:

damnit you stole my question

I*do*Werke 03-07-2011 10:18 PM

When will my e30 rust to hell? There is no rust on the body... yet (knocks on wood)

Jmanscotch 03-07-2011 10:22 PM

From Salt Away: "Salt-Away is used to dissolve and remove salt from any surface. It is water based, non-hazardous and biodegradable. It protects metals from corrosion by removing the salt that promotes corrosion. It also contains rust inhibitors that help protect the surface once the salt has been removed."

A) The presence of salt does increase pH and coupled with soil/etc buildup will corrode a vehicle.
B) The Salt Away is "water based" yet goes on to claim that water will not wash away salt (which it will, salt is a naturally adhesive material). They then claim that while being non-hazardous, it can break down the salt (which is not believable, to break down salt you will need something equally aggressive and therefore likely hazardous and not belonging near your cars finish). They also claim it contains rust inhibitors...which it may, but those will not stay as deposits long before they are too washed away.
C) Your best bet is to wash your car weekly/bi-weekly during winter. Take it to one of those automated car washes that has an underbody rinse. When winter is up (and it has rained enough to wash lingering salt off the roadways) wash your car very well and make sure you get in tight areas where salt/dirt deposits exist and get missed by a quick once-through wash. A good coat of wax before winter will offer a good non-conductive interface between the two and go a long way.

Jmanscotch 03-07-2011 10:24 PM

Quote:

Originally Posted by JonJon (Post 12895262)
Could thermite "corrode" steel cored beams in a skyscraper?

:eeps:

Thermite is an oxidizer, so yes. :eeps:

Breyton-BMW 03-07-2011 10:24 PM

I was thinking using it on salt used boats but I think the same thing applies. Thanks.

Jmanscotch 03-07-2011 10:25 PM

Quote:

Originally Posted by I*do*Werke (Post 12895278)
When will my e30 rust to hell? There is no rust on the body... yet (knocks on wood)

If you continue to maintain the surface with a good cleanse and wax thus keeping it from ever being exposed to contaimanents....it will never rust.

I*do*Werke 03-07-2011 10:25 PM

thanks! one more question, would spraying water on the underside of my car help remove the salt or would it be counterproductive because the water also is a catalyst for rust?

Jmanscotch 03-07-2011 10:26 PM

Quote:

Originally Posted by Breyton-BMW (Post 12895301)
I was thinking using it on salt used boats but I think the same thing applies. Thanks.

You can protect a boat exterior by attaching an anode. The water becomes the electrolyte in the chemical reaction and any portion of the boat submerged in water will receive what we call "Cathodic protection".

Jmanscotch 03-07-2011 10:28 PM

Quote:

Originally Posted by I*do*Werke (Post 12895309)
thanks! one more question, would spraying water on the underside of my car help remove the salt or would it be counterproductive because the water also is a catalyst for rust?

It will help remove the salt. There is a tricky line where removing salt and introducing a electrolyte (said water) could seem counterproductive. Fact is, the water will splash out, evap, etc sooner than the salt will bounce/fall out and therefore is still a better bet to wash often.

Plus, fairly clean water (free of too many contaminents) is a lot less corrosive than salt. A reason to sometimes visit the newer (read; uses filters, newer pipes, etc) carwash versus the old, rundown cheap one.

k2pilot 03-07-2011 10:36 PM

is there any reduced lifespan/risk when having homes with rusted outer panels?

Like these,
http://farm3.static.flickr.com/2642/...1da711de_b.jpg

http://www.trendir.com/house-design/...ig-house-1.jpg

I'm a fan of the look and style, but am concerned that over time the integrity of the structures may deteriorate.

question 1b) is there any way to seal in the rust with a sort of clear coat? And if something of this sort were done, would it cease the corrosion/oxidation? Or would the already corroded layer continue to eat away at the surface below?

Jmanscotch 03-07-2011 10:46 PM

Quote:

Originally Posted by k2pilot (Post 12895358)
is there any reduced lifespan/risk when having homes with rusted outer panels?

I'm a fan of the look and style, but am concerned that over time the integrity of the structures may deteriorate.

question 1b) is there any way to seal in the rust with a sort of clear coat? And if something of this sort were done, would it cease the corrosion/oxidation? Or would the already corroded layer continue to eat away at the surface below?

Yes, the rusted exterior is shortening the life span of said panels.

Providing a clear coat over the panels will prevent oxygen from contacting the surface...thus preventing oxidation (besides what small air bubbles exist under/in the coating, never going to get it perfect). There is still contaminants on the surface though and therefore corrosion will occur (corrosion occurs on different levels and different forms). To remove all said contaminant, you would have to remove all of the rust and strip back to bare metal...so it is a lose lose situation. To be fair, the corrosion rate in that situation would be a good bit slower than normal (if coated) and totally worth the cost to own...sweet freaking houses! To be real, I can't see it being any more work/money to maintain a house like that versus a wooden structure, both have their weaknesses and required upkeep. A house like that (here comes some guessing) would likely last 50-60 years before corrosion became a dangerous (loss of structural integrity) situation.

k2pilot 03-07-2011 10:49 PM

Quote:

Originally Posted by Jmanscotch (Post 12895390)
Yes, the rusted exterior is shortening the life span of said panels.

Providing a clear coat over the panels will prevent oxygen from contacting the surface...thus preventing oxidation (besides what small air bubbles exist under/in the coating, never going to get it perfect). There is still contaminants on the surface though and therefore corrosion will occur (corrosion occurs on different levels and different forms). To remove all said contaminant, you would have to remove all of the rust and strip back to bare metal...so it is a lose lose situation.

Figured as much... I guess all main components would have to be galvanized, and maybe make all the "rusted" panels purely cosmetic and interchangeable.


What would you advise as the best metal for a main housing structure that would be low maintenance and long life-span, in terms of corrosion?

Breyton-BMW 03-07-2011 10:52 PM

Quote:

Originally Posted by Jmanscotch (Post 12895315)
You can protect a boat exterior by attaching an anode. The water becomes the electrolyte in the chemical reaction and any portion of the boat submerged in water will receive what we call "Cathodic protection".

I got some type on zinc anode in there already.:thumbup:

Jmanscotch 03-07-2011 11:00 PM

To offer some insight to the theory of corrosion:

When we mine metals out of the earth, we unearth them in their naturally occuring form: What we know as looking like rust.

We take that "rust" and melt it down, compress it and form it into a mold of what it is being used for. ie piping, sheets/panels, body panels, etc.

Energy is used during the refinement process, taking it from its naturally occuring state and making it into something. That energy is basically stored in the objects current form. When you then take that object and place it back into mother nature, she sees the manipulated object with its high energy level and she sees its surroundings (which for these purposes are unmolested) as naturally occuring and thus having a "nuetral" energy level. This creates an imbalance, which is not a well accept thing in mother nature as we know.

What then happens is mother nature (through chemical reactions) allows energy (ions, or something....smoked/drank too much in college to remember details) to flow from the high energy object into the lower energy object in an attempt to balance everything. This transfer of energy reverts the high energy object back to its original state by releasing the energy we introduced into it by refining it...aka "rusting".

The best way (in terms of what we seem to be speaking of mostly here) to combat that is to introduce a non-conductive layer between the object that has a high level of stored enegry and that object that has the lower (nuetral) energy level...if they don't "see" eachother, then they cannot tell there is an imbalance and therefore no reaction will occur.

Bemwe_03i 03-07-2011 11:01 PM

I got couple of rust spots (< than 1mm) from rock chips in the a pillar, will cleaning these the applying paint over it solve the problem?
Also when i wash my car i apply a coat of spray on wax does this do anything good? Usually in the areas where its in contact with water.

farmdog 03-07-2011 11:03 PM

Great answers.....you really know your chit.
Well done.

Jmanscotch 03-07-2011 11:03 PM

Quote:

Originally Posted by Breyton-BMW (Post 12895408)
I got some type on zinc anode in there already.:thumbup:

A properly applied coating (rugged paint) in combination with anodes is going to do you right. Like mentioned, the only areas of the boat that are going to rust/corrode are the areas where bare metal is in contact with the elements. A good coating takes care of most of that, but there will always be defects in the application of the coating and the anode protects those exposed areas only, the less you have, the more efficiently the anodes work and the longer life they have.

You will still have exposure to atmospheric corrosion, which can really only be managed by a good coating.


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