Rust

Stig posted this in Thepowerofdiesel's project thread but perhaps we can create a seperate thread to address this topic.

RUST is the worst threat any car faces, all steel vehicles will eventually rust away to nothing.
Car manufacturers have absolutely no interest in making a car that doesn't rust.
Some rust is easy to fix and some rust is almost impossible to fix, as Stig has stated

Windshield and door columns are hollow structures and moisture will eventually get into them and start them rusting from the inside out.
The whole area under the back seat is a big hollow space, the front firewall has many hollow spaces as does the area under the windshield


Heres a good example of several problems
-hidden areas you can get at, for example the double layered firewall you can see examples where the engine harness and AC lines enter
or where the air enters the ventilation system from outside. This is a real fucking real real pain in the ass, I have spent many hours trying
to fix this problem and still have leaks.

So lets investigate a little further, I cut open my white coupe to see exactly whats in there and its not pretty



Here we see the problem that sandblasting can't solve unless you start cutting extra access holes, theirs still going to be rust lurking in hollow spaces


Perhaps the best option is to hot tank the whole car, this involves sinking the whole chassis in a tank of acid that will basically strip anything
but steel, paint body filler rust, aluminum.... will all be removed, this will do a good job and I would seriously consider doing it at a cost of close to $2000USD
but they could potentially do more harm than good. I have checked quite extensively into this process and I can't find any company that can dip the chassis
in a coat primer after the rust rermoval, all the companies spray the completed chassis. This means that all those hollow areas like door and windshield columns
have had the paint stripped out of ther inside of them and are now bare metal, this means that you have really made the situation worse their may have been a
bit of rust in the hollow areas before but at least the remainder of the hollow area still have a protective primer on it.
If any of the companies had a tank of primer to dip the car in this would be the best solution but with a spray on primer your probably doing more harm than good

Sandblasting isn't going to get all the rust but it isn't going to strip primer from inaccesable areas either and its far cheaper.
So you really only have 2 choices for removing rust and sandblasting is probably the better choice for most people.

Now that the rust has been removed we have 2 jobs left, we have to replace badly pitted and rusted out areas and we have to protect the new metal.
As Stig has previously stated one big problem is hollow areas in the body and the other big problem is the way all body panels are joined together by
overlapping two pieces of sheet metal by 1/2" or so and spot welding the 2 pieces together. This is just and absolutely horible way to joint the seams
and pretty much guarantees that the spot welded seam is eventually going to rust.

Hollow Areas
As far as I can tell hollow areas rust because they are hollow and contain moist air that can condense on the metal surface. As far as I can tell Toyota
did prime the inner metal surfaces before spot welding parts together but either the spot welding process has compromised the primer in certain areas
or the original aplication of primer was not good enough. Here you can see a spot of rust I had in the roof just in front of the rear hatch, theirs no reason
for this spot of rust except moisture has condensed on the roof and run to the lowest spot where it found a weakness in the metals protection and rusted
through.


you can clearly see that although the inner surface appears to have an olive green primer on it it has not been good enough to prevent the rust in an area that has
absolutely no reason to rust


So how can we protect these hollow or hard to reach areas. I think that I'm going to use expanding foam, in some cases the hollow areas need to run wire harnesses
so I'll run them first and then seal them in place. I remember reading somewhere that filling the rocker panels with foam will strengthen the frame a bit and I know
from owning custom vans in the past that the foam works very well at filling areas and preventing moisture from getting to the metal.

In order to prevent rust you have to prevent moisture and oxygen from coming in contact with bare metal so if I fill hollow areas with foam I will eliminate the air
and moisture needed to create rust and in the event that there is allready a bit of rust started inside a hollow space the foam will seal around it and prevent new moisture
from getting to it.

Spot Welds
The only solution to this is to solidly weld all exterior seams, and ideally solidly weld all interior seams as well

Protection
Once all the metal works done its time to protect the metal so I'd start with a few coats of primer and then either use a truck bed liner for things like the interior floor/ trunk
area and for things like the rear wheel wells I'd use a creeping penetrant like Rust Check Coat and Protect which is going to go on like a gel


POR15
Paint Over Rust is probably the best know and most expensive chemical that claims it will neutralize rust. It does seem to do a good job but has some problems
- it is UV semsitive so it can't be exposed to light, which means you have to put some other coating over it to protect it from sunlight.
- POR15 will not allow other products to adhere to it so you will have to use another product to etch the POR15 before you can paint over it.
- I know Mafix did the underneath of Nemisis with POR15 so perhaps he'll comment on how well it has held up. I have used it to on such things as a ST165 rear differential
so the next time I get to check on it I'll let you know how it has handled the last 3 years

In the end I don't think we'll ever eliminate all the rust from a 20+ year old car but we can eliminate most of it and hopefully seal any remaining rust to prevent it from getting
any worse

 

I think sand will get in even if you do seal all the holes, don't ask me how but trust me I've sandblasted enough parts to know the sand will go absolutely everywhere so
if your going to sandblast one of these rotiseries will be a big help in getting all of the sand out

 

POR15 is a good product as I've said I have used it and as you say it is a PITA having to first treat it with marine clear and metal ready before applying the POR15 and the having to use the self etching
primer if you want to apply other paint over it.


In the following picture the rear diff and crossmember have been covered in POR15 the 3 piece driveshaft has multiple layers
of tremclad (rustoleum) paint and 3 layers of clearcoat. Both have held up well so you don't need really espensive products to
get good protection you just need a thick enough covering. In another couple of months I'll get updated pictures to see how
their doing.



The only way any of these items is going to rust in the future is if the paint/POR15 covering is compromised by abrasion or
chipping so routine inspections and a scratch and chip repair container of clearcoat to reseal any problem areas should keep
things looking good



I suggest you look into a newer product called Rust Bullet
http://www.rustbullet.com/aboutus.asp

No pre products like marine clear and metal ready are needed just remove loose rust and paint this stuff on
it can even be covered with other products without the need of an etching primer as long as you apply the
final covering withing a couple days of applying Rust Bullet

Another product you may consider is called SKYCO OSPHO

http://www.ospho.com/

This product contains acidic chemicals that

 

Nice idea costs a couple hundred bucks up here in Canada for an automotive system but I have my doubts about its effectiveness.

Electronic Rust Protection

http://counteractrust.com

Marine industries use an electronic system to counter act rust on ocean going ships but that system requires the attachment of
zinc plates to the ships hull under the waterline. The system causes the zinc plates to corrode before the steel hull does and it
is effective at protecting the hull of the ship below the waterline but look at the upper structure of the ship and its rusting away
so the ship based design only works for metal submersed in water and has no rust preventative effect on the part of the ship
above the waterline.

The automotive system has no zinc strip and the vehicle is hopefully not immersed in water so I think their counting on people
knowing that the marine industry uses an electrical system to prevent rust but I don't think the automotive system has any value

So thats my opinion and you must note it is only an opinion as I have not actually used the system as I think its a waste of $200

 

I'm going to do a series of posts on the steps I think the home mechanic could use to do
an excellent job of protecting their vehicle from rust. The best first step by far is a
chemical stripping which is a 2 part process. The first step is to submerge the body in a
tank of Sodium hydroxide which removes paint and grease. The second step is to submerge
the body in a tank of Phosphoric acid, this will neatralize the Sodium hydroxide and will
remove/convert the rust and etch the metal. It is impractical to get a tank big enough
to do the body but it may be considered for smaller parts like engine cross members, sunroof
control arms.....

Sodium hydroxide
Sodium hydroxide (NaOH), also known as lye and caustic soda is the product used in the first tank
of a chemical dip process, this part of the process removes paint and grease. This process is most
effective when the chemical solution is heated. Home based shops often use a 55 gallon oil drum
with a propane heater underneath. You may also find this setup at radiator repair shops so you
may be able to work a deal with them for parts that fit in their tank


Health Considerations
Solid sodium hydroxide or solutions of sodium hydroxide may cause chemical burns, permanent injury
or scarring if it contacts unprotected human, or other animal, tissue. It may cause blindness if it
contacts the eye. Protective equipment such as rubber gloves, safety clothing and eye protection
should always be used when handling the material or its solutions.

Tissue digestionIn a similar fashion, sodium hydroxide is used to digest tissues, such as in a process
that was used with farm animals at one time. This process involved placing a carcass into a sealed
chamber, then adding a mixture of sodium hydroxide and water (which breaks the chemical bonds that keep
the flesh intact). This eventually turns the body into a coffee-like liquid, and the only solid that
remains are bone hulls, which could be crushed between one's fingertips. Sodium hydroxide is frequently
used in the process of decomposing roadkill dumped in landfills by animal disposal contractors.

Chemical burn caused by exposure to a less than 10% sodium hydroxide solution photographed 44 hours after exposure


Cleaning agent
Sodium hydroxide is frequently used as an industrial cleaning agent where it is often called "caustic".
It is added to water, heated, and then used to clean the process equipment, storage tanks, etc. It can
dissolve grease, oils, fats and protein based deposits. It is also used for cleaning waste discharge
pipes under sinks and drains in domestic properties. Surfactants can be added to the sodium hydroxide
solution in order to stabilize dissolved substances and thus prevent redeposition. A sodium hydroxide
soak solution is used as a powerful degreaser on stainless steel and glass bakeware. It is also a common
ingredient in oven cleaners.

A common use of sodium hydroxide is in the production of parts washer detergents. Parts washer detergents
based on sodium hydroxide are some of the most aggressive parts washer cleaning chemicals. The sodium
hydroxide based detergent include surfactants, rust inhibitors and defoamers. A parts washer heats water
and the detergent in a closed cabinet and then sprays the heated sodium hydroxide and hot water at pressure
against dirty parts for degreasing applications. Sodium hydroxide used in this manner replaced many solvent
based systems in the early 1990s when trichloroethane was outlawed by the Montreal Protocol.

Water and sodium hydroxide detergent based parts washers are considered to be an environmental improvement
over the solvent based cleaning methods.

Problems
In addition to the serious health risks involved with sodium hydroxide it must be remembered that this process
strips paint and degreases so if you want re paint the metal you must neutralize the sodium hydroxide as it
has leached into seams and could leak out in the future destroying your new paint job. sodium hydroxide is a
base so we need to give the metal a good acid trip. Phosphoric acid will neutralize the sodium hydroxide and
it will also disolve rust and etch the bare metal. I'll discuss Phosphoric acid more in my next post.

Sodium hydroxide is not good for all metals aluminum and other pot metals will be eaten away by Sodium hydroxide
a good rule to follow is if a magnet won't stick to it don't put it in Sodium hydroxide

A lot of this info is from wikipedia you can get more info here http://en.wikipedia.org/wiki/Sodium_hydroxide

 

Phosphoric acid
Phosphoric acid is the liquid used in the second tank of the chemical dipping process
it is designed to neutralize the Sodium hydroxide used in the first step and is also
designed to neutralize/convert existing rust and etch the metal in preparation for
the addition of primer. The Phosphoric acid will also provide a minimal level of
protection to the dipped metal against the formation of new rust. This process is done
at room temperature and does not require the heating of the liquid.


Rust removal
Phosphoric acid may be used as a "rust converter", by direct application to rusted iron,
steel tools, or surfaces. The phosphoric acid converts reddish-brown iron(III) oxide,
Fe2O3 (rust) to black ferric phosphate, FePO4.

"Rust converter" is sometimes a greenish liquid suitable for dipping (in the same sort of
acid bath as is used for pickling metal), but it is more often formulated as a gel, commonly
called naval jelly. It is sometimes sold under other names, such as "rust remover" or
"rust killer". As a thick gel, it may be applied to sloping, vertical, or even overhead surfaces.

After treatment, the black ferric-phosphate coating can be scrubbed off, leaving a fresh metal
surface. Multiple applications of phosphoric acid may be required to remove all rust. The black
phosphate coating can also be left in place, where it will provide moderate further corrosion
resistance

Health Considerations
You would think that with a name like Phosphoric acid that this stuff would be nasty stuff
but you may have heard people say just poor some Coca Cola on that rusty part and sure enough
Phosphoric acid is an ingredient in most Cola's so unlike Sodium hydroxide this stuff is pretty
safe to use. I would still follow the cautions of Sodium hydroxide and use protective equipment
such as rubber gloves, safety clothing and eye protection.

Phosphoric acid is easilly available at home depot and other building centers. It is normally
sold as a concrete & stone cleaner


So even if you don't want to deal with Sodium hydroxide you may want to consider useing
Phosphoric acid

Once again some of the info was taken from wikipedia http://en.wikipedia.org/wiki/Phosphoric_acid

The metal dipping process referenced is by a company called Metalworks Paint & Rust Removal
http://www.metaldipping.com/index.php the price for one of our 4th gen Celica's would be $1600-$1700 US

 

Interesting but just to clarify the Molasses would replace the Phosphoric Acid as a rust converter Molasses does not strip paint or degrease the part like Sodium hydroxide

 

If you can't afford or just dont want to use chemical stripping then your
going to have to resort to some sort of mechanical removal. Options would
include

-media blasting
-Needle Scaling
-grinding/wire wheels
-replacement metal

Media Blasting
Media Blasting involves shooting some sort of abrasive at the metal. Abrasives
include sand, coal, baking soda, dry ice. Sand is probably the most practical
for the home mechanic. The biggest expense is going to be the purchase of a
compressor but a home garage should allready have 1. The bigger the compressor
the better, 2 or more compressors may be linked together to get a higher air
flow rate. Sand can be screened and re used.
Media blasting will get into a lot of area's other forms of mechanical rust
removal can't reach. Commercial media blasting of sand can produce enough heat
to warp body panels but home setups don't have to worry about warping body panels


Needle Scaling
If you have a compressor and an air chisel a handy attachment you can get is
called a needle scaler. It attaches to your air chisel and works like a jack
hammer with multiple heads to chip away big flakes of rust


Grinding/Wire Wheels
If you can't Media Blast then your stuck grinding away really badly rusted areas
and useing wire wheels to remove surface rust. These tools can quite quickly
build up alot of heat so you have to be careful not to warp body panels.

Replacement Metal
It is allways best to replace metal whenever possible. In this case the whole rocker
panel and about 2" of the rear fender have been cut out and replaced with new metal.
I have no real experience with metal working so I prefer to use alot of smaller pieces
since their easier to shape than 1 large piece of metal.


Disadvantages
The disadvantages of mechanical rust removal include it being a relatively dirty
process, the possibility of warping body panels due to heat buildup, and the inability
to remove rust from areas the tools can't reach.

Metal Preservation
No matter which of these metods you use I would still use a paint brush or spray gun
to aply some Phosporic Acid to the metal after the mechanical rust removal is complete
to convert any rust the mechanical process couldn't reach and to etch the metal for
better adhesion of future coverings

 

I welded it, really no option all 25 year old vehicles around here are going to have alot of rust

Now that we've gotten rid of the rust or at least all that we can reasonably get at it's time to protect
from future rust. Here's an example from my All Trac of the bottom windshield trim that was repaired
about 4 years ago




After sandblasting and some chemical rust treatment and then some bondo




Then a layer of primer, 3 layers of black, some different colors and finally a couple
layers of clear and 4 years later and theirs no signs of new rust








So we really can save a piece of rusted metal if we try. I do believe alot of my sucess is in useing
mutiple coats of paint. I think if I had of just gave it 1 coat of black the rust would have been back
the next year but I have at least 6 layers of coverage. 1 layer of primer, 3 layers of black and 2
layers of clear, and this is just ordinary Tremclad (rustoleum) paint so you don't have to spend alot
of money on specialty paints.

I do believe that having your car rustproofed by somebody like ziebart is a good investment but they
only do the bottom of the car like rocker panels and inside fender and door panels but don't bother to
do things like windshield frames and other upper areas of the vehicle so I have done alot of searching
and have found a place that sells the equipement necessary to apply your own rust protection.

http://raybuck.com/c-54857-undercoat-rustproofing.html

Theirs probably other places that sell the stuff eastwood does to but this place has 1 attachment that
I can't find anywhere else that I think is the most critical piece. It's a 30" fogging nozzle. Only $13.50
but all the other nozzles only spray in a specific direction.


Their gun is a bit expensive $69.50 but not overly so but you can probably find an undercoating gun
for $30 or less, I may be able to convert 1 of my sand blasting guns, it's basically the same principle
except instead of shooting sand it would suck up undercoating and shoot it.


and you can also get undercoating


and inner panel coating


although the liquids you can probably source locally to save shipping

The other thing that would be nice to have is an inspection camera you can get this 1 at walmart for
a couple hundred bucks


I did some more searching and for $30 you can get this setup on ebay, plugs right into your USB port
so you'll get a much bigger screen




so being the cheapskate I am I have this one ordered



I think now you have the ability to do a better job by yourself that you will get at 99% of the profesional shops