- Joined
- Jul 27, 2012
- Messages
- 3,094
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- 445
- Location
- Brisbane - Australia
- My Car
- 1973 Mustang Convertible
Hi to all,
Just wanted to talk about rust in cars, and the the term used - "rust free" some sellers use when selling on their cars. This post is in response to a fellow forum member who was asking about what rust free really means. So i thought i'd post my 2 cent's worth on the subject for everyone's benefit. If you have any thing to say or add as well,further to what i have, please jump in and give your feedback.
In the TRUE use of the term "rust free", that's what it means - zero rust present anywhere on the vehicle. If any rust has been present in any car, and has been correctly and properly and fully removed, then the car can be truely called rust free. Sadly, many sellers use this term rust free rather loosely when describing the condition of their car.
But in reference about surface rust and scaly rust on floor pans and frame rails,and rust leaving gapeing holes in sheet steel, and trying to remove it by sanding it off, etc, then that needs some explaining.
Here's the problem. When rust attacks metal, it penetrates into the metal, depending on how advanced the rust is. That's the problem, because to remove ALL traces of the rust, you have to go into the steel and get it all out. How deep you go depends on how advanced the rust is, and how much it has penetrated into the steel. For example, i have worked on many cars over the years, that had bad, advanced surface rust on the panels. This surface rust was in some cases, so bad, that it had eaten deeply into the steel, and the steel then was badly pitted with the rust. To try and remove this rust, sand blasting was the only method to go with to try and get it all out. Disc sanding alone would not have done the job needed. Assuming then that the sand blasting didn't distort the sheet metal, and you got all the rust out, then fillers would still have to be used to back fill in all the bad pitting of the steel. Not a good way to go really. New panels would be a better option in these type of cases.
When repairers attempt to remove rust from steel,they will choose different methods to try and get it out. Such as disc sanding, stone grinding, sand blasting etc, etc. BUT, what ever method you choose, if you don't COMPLETELY remove it all, you will have ongoing rust issues, and in that case, you can't call your car truely rust free, because there is still rust present in your vehicle, even though you tried to get it all out. A lot of people try and remove as much rust as they can from the steel, but sadly, there will be traces of it still present that they missed. When rust has penetrated deep enough into the steel, it is more wise to replace the corroded section of steel with new steel, than to attempt to remove all rust from the corroded section, as you will never be able to remove all the rust from the steel successfully. Welding new sections of steel to replace corroded rusted out sections is an option in some cases, but you must be very sure to remove any traces of existing rust when going about this kind of work. Mig welding a rust hole is another option to repair rust, but again, be sure to remove any traces of existing rust around or in the repair as well.
When a seller is selling a car that had rust present, but claims that ALL rust has been removed and is now truely rust free, then you are at the seller's mercy. It is very, very hard, almost impossible, to prove that any traces of rust would still be present in the car. You really have to take his or her word for it, that the car had ALL rust completely removed, and is truely rust free, and pray that you won't get any rust issues occurring down the track for you. Repairers, will choose to use rust converters, and paints like epoxy primers to stop any ongoing rust issues from occurring again, but if you didn't completely remove all traces of rust from the steel, then in reality, you don't have a rust free car.
A car buyer can be lucky enough to buy a car that has been so well looked after and cared for and protected, that there is really no rust present on the car to start off with. These cars do exist, but the general rule will be to expect some form of rusting (mild to wild) happening on the car your buying. The trick is obviously to end up buying a car with the smallest amount of rust present on the vehicle, and hope like hell that the seller hasn't carried out dodgy rust repairs and not properly removed all traces of rust from the car. An original car with very minor rust issues, if not any, is the better buying option than a car that has had rust issues, and they have been repaired by previous owners.(Pray that they were done correctly) Unrepaired cars with minor rust issues is the better buying option in some cases. In that sense, you can monitor the repairs to see that the rust is taken care of properly. Also, be aware, that proper and correct rust repairs are very expensive when carried out buy reputable body shops. Try your best to avoid the shonky body shops for rust repairs, as the rectification work won't be carried out properly, and your rust wil be sure to come back later. DIY rust repairs is an option for many to try and save money, but unless you know what you're dong, the job could develop on going problems later. Don't forget about steel body safety issues too with major rusting of a vehicle. Welding, correct and done properly plays a big part in making sure the car ends up being safe and roadworthy when finished. Scott, our Forum tech rep has posted very good advice and help on this subject.
Here is a bit of technical blurb i pulled off the net on rust. You may find it helpful and interesting.
Rust is the common name for a very common compound, iron oxide. Iron oxide, the chemical Fe2O3, is common because iron combines very readily with oxygen -- so readily, in fact, that pure iron is only rarely found in nature. Iron (or steel) rusting is an example of corrosion -- an electrochemical process involving an anode (a piece of metal that readily gives up electrons), an electrolyte (a liquid that helps electrons move) and a cathode (a piece of metal that readily accepts electrons). When a piece of metal corrodes, the electrolyte helps provide oxygen to the anode. As oxygen combines with the metal, electrons are liberated. When they flow through the electrolyte to the cathode, the metal of the anode disappears, swept away by the electrical flow or converted into metal cations in a form such as rust.
For iron to become iron oxide, three things are required: iron, water and oxygen. Here's what happens when the three get together:
When a drop of water hits an iron object, two things begin to happen almost immediately. First, the water, a good electrolyte, combines with carbon dioxide in the air to form a weak carbonic acid, an even better electrolyte. As the acid is formed and the iron dissolved, some of the water will begin to break down into its component pieces -- hydrogen and oxygen. The free oxygen and dissolved iron bond into iron oxide, in the process freeing electrons. The electrons liberated from the anode portion of the iron flow to the cathode, which may be a piece of a metal less electrically reactive than iron, or another point on the piece of iron itself.
The chemical compounds found in liquids like acid rain, seawater and the salt-loaded spray from snow-belt roads make them better electrolytes than pure water, allowing their presence to speed the process of rusting on iron and other forms of corrosion on other metals.
Hope that helps,
Greg.
Just wanted to talk about rust in cars, and the the term used - "rust free" some sellers use when selling on their cars. This post is in response to a fellow forum member who was asking about what rust free really means. So i thought i'd post my 2 cent's worth on the subject for everyone's benefit. If you have any thing to say or add as well,further to what i have, please jump in and give your feedback.
In the TRUE use of the term "rust free", that's what it means - zero rust present anywhere on the vehicle. If any rust has been present in any car, and has been correctly and properly and fully removed, then the car can be truely called rust free. Sadly, many sellers use this term rust free rather loosely when describing the condition of their car.
But in reference about surface rust and scaly rust on floor pans and frame rails,and rust leaving gapeing holes in sheet steel, and trying to remove it by sanding it off, etc, then that needs some explaining.
Here's the problem. When rust attacks metal, it penetrates into the metal, depending on how advanced the rust is. That's the problem, because to remove ALL traces of the rust, you have to go into the steel and get it all out. How deep you go depends on how advanced the rust is, and how much it has penetrated into the steel. For example, i have worked on many cars over the years, that had bad, advanced surface rust on the panels. This surface rust was in some cases, so bad, that it had eaten deeply into the steel, and the steel then was badly pitted with the rust. To try and remove this rust, sand blasting was the only method to go with to try and get it all out. Disc sanding alone would not have done the job needed. Assuming then that the sand blasting didn't distort the sheet metal, and you got all the rust out, then fillers would still have to be used to back fill in all the bad pitting of the steel. Not a good way to go really. New panels would be a better option in these type of cases.
When repairers attempt to remove rust from steel,they will choose different methods to try and get it out. Such as disc sanding, stone grinding, sand blasting etc, etc. BUT, what ever method you choose, if you don't COMPLETELY remove it all, you will have ongoing rust issues, and in that case, you can't call your car truely rust free, because there is still rust present in your vehicle, even though you tried to get it all out. A lot of people try and remove as much rust as they can from the steel, but sadly, there will be traces of it still present that they missed. When rust has penetrated deep enough into the steel, it is more wise to replace the corroded section of steel with new steel, than to attempt to remove all rust from the corroded section, as you will never be able to remove all the rust from the steel successfully. Welding new sections of steel to replace corroded rusted out sections is an option in some cases, but you must be very sure to remove any traces of existing rust when going about this kind of work. Mig welding a rust hole is another option to repair rust, but again, be sure to remove any traces of existing rust around or in the repair as well.
When a seller is selling a car that had rust present, but claims that ALL rust has been removed and is now truely rust free, then you are at the seller's mercy. It is very, very hard, almost impossible, to prove that any traces of rust would still be present in the car. You really have to take his or her word for it, that the car had ALL rust completely removed, and is truely rust free, and pray that you won't get any rust issues occurring down the track for you. Repairers, will choose to use rust converters, and paints like epoxy primers to stop any ongoing rust issues from occurring again, but if you didn't completely remove all traces of rust from the steel, then in reality, you don't have a rust free car.
A car buyer can be lucky enough to buy a car that has been so well looked after and cared for and protected, that there is really no rust present on the car to start off with. These cars do exist, but the general rule will be to expect some form of rusting (mild to wild) happening on the car your buying. The trick is obviously to end up buying a car with the smallest amount of rust present on the vehicle, and hope like hell that the seller hasn't carried out dodgy rust repairs and not properly removed all traces of rust from the car. An original car with very minor rust issues, if not any, is the better buying option than a car that has had rust issues, and they have been repaired by previous owners.(Pray that they were done correctly) Unrepaired cars with minor rust issues is the better buying option in some cases. In that sense, you can monitor the repairs to see that the rust is taken care of properly. Also, be aware, that proper and correct rust repairs are very expensive when carried out buy reputable body shops. Try your best to avoid the shonky body shops for rust repairs, as the rectification work won't be carried out properly, and your rust wil be sure to come back later. DIY rust repairs is an option for many to try and save money, but unless you know what you're dong, the job could develop on going problems later. Don't forget about steel body safety issues too with major rusting of a vehicle. Welding, correct and done properly plays a big part in making sure the car ends up being safe and roadworthy when finished. Scott, our Forum tech rep has posted very good advice and help on this subject.
Here is a bit of technical blurb i pulled off the net on rust. You may find it helpful and interesting.
Rust is the common name for a very common compound, iron oxide. Iron oxide, the chemical Fe2O3, is common because iron combines very readily with oxygen -- so readily, in fact, that pure iron is only rarely found in nature. Iron (or steel) rusting is an example of corrosion -- an electrochemical process involving an anode (a piece of metal that readily gives up electrons), an electrolyte (a liquid that helps electrons move) and a cathode (a piece of metal that readily accepts electrons). When a piece of metal corrodes, the electrolyte helps provide oxygen to the anode. As oxygen combines with the metal, electrons are liberated. When they flow through the electrolyte to the cathode, the metal of the anode disappears, swept away by the electrical flow or converted into metal cations in a form such as rust.
For iron to become iron oxide, three things are required: iron, water and oxygen. Here's what happens when the three get together:
When a drop of water hits an iron object, two things begin to happen almost immediately. First, the water, a good electrolyte, combines with carbon dioxide in the air to form a weak carbonic acid, an even better electrolyte. As the acid is formed and the iron dissolved, some of the water will begin to break down into its component pieces -- hydrogen and oxygen. The free oxygen and dissolved iron bond into iron oxide, in the process freeing electrons. The electrons liberated from the anode portion of the iron flow to the cathode, which may be a piece of a metal less electrically reactive than iron, or another point on the piece of iron itself.
The chemical compounds found in liquids like acid rain, seawater and the salt-loaded spray from snow-belt roads make them better electrolytes than pure water, allowing their presence to speed the process of rusting on iron and other forms of corrosion on other metals.
Hope that helps,
Greg.
Ones again you have given us all and update on this subject [THUMBS UP SIGN][sMILING FACE WITH SMILING EYES] Well I guess there is so many people who have not been doing it right. Rust is something that Wee all come across regarding our old Cars. Well I have some Rust in my own Mustang. Some that I have to look at before spring break! Well I live in a Country where this is a big problem. So it's not better of the fact it has been in My Country from day one.... But I guess I still am proud of the fact it has been here since it left the State of America 
