rust treatment?
#18
Drifting
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OP stated he has had the car for 2-3 years. In my experience, that is about the time frame for rust to resurface after a patch job. If there is rust in the rocker panel at the door frame, then is there more hidden rust in the unexpired rock panel? How many "patch repair" areas are in this car from previous ownership or is this a situation where the car became submerged in sea/salt water during its former life?
#19
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OP stated he has had the car for 2-3 years. In my experience, that is about the time frame for rust to resurface after a patch job. If there is rust in the rocker panel at the door frame, then is there more hidden rust in the unexpired rock panel? How many "patch repair" areas are in this car from previous ownership or is this a situation where the car became submerged in sea/salt water during its former life?
I overlooked that and thats a very very good point same exact thing happened with a mercedes 280se i picked up
#20
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There is a big difference between "surface" rust and "destructive" rust. Surface rust can be sanded off, brushed off, or ground off down to good metal that is under the rust.
Destructive rust is so deep that it has often penetrated through the metal or has left pits that are mostly through the metal. Destructive rust normally weakens the metal substantially. Destructive rust can not be gotten rid of except to cut it out and weld in a new piece of fresh metal. Any coating that you apply over the top of destructive rust will not save the metal from eventual total destruction.
If you want to coat the surface in order to save metal from being destroyed by rust, you must not have holes through the metal to the other side. This includes pin holes that go through. The only way to stop rust from occurring is to prevent moisture from getting to the bare metal. Steel/iron will react with moisture in the air to cause iron oxide (rust).
There are several paint products that are made from a moisture curing polyurethane. There are many different formulations of moisture cured polyurethane, and each manufacturer is different. Because the polyurethane reacts with moisture to cure, it will pull the moisture from out of the microscopic pores of the surface rust on steel. This removes the moisture that would normally allow the metal to continue to rust after the surface is coated with paint. Any paint product that does not remove the moisture from the microscopic pores of the metal will eventually have more rust form and cause the paint to blister and bubble away from the surface of the steel.
It is this moisture scavenging process that happens when the polyurethane coating is curing which will stop the rust from continuing to form between the steel and the coating. No other polymer paint coating will do this except moisture cured polyurethanes. It is also important that the rust prevention coating be formulated to stop moisture from migrating through the coating to get to the steel. Any polymer coating can have moisture migrate through it. All paint coatings are polymers, and polymers allow moisture to migrate through them to some degree.
I have used Chassis Saver as a rust coating. It is less expensive than Por 15. It has done an excellent job of stopping the rust and it has not peeled or blistered after many years. The version that I have used is heavily filled with small aluminum flakes. As the coating cures, these aluminum flakes settle and flatten out, which provides a much higher moisture resistant barrier than can be provided by just the polyurethane itself. Por 15 is filled with carbon black particles to try and increase the moisture resistance of the cured coating, but the aluminum flakes do a much better job of preventing moisture migration. These moisture cured polyurethane coatings are very durable and are very scratch resistant and have very good chemical resistance, including salt brine. They will be attacked by the sun's UV rays, which causes the polyurethane to break-down. So they must be top coated if they will be exposed to the sun. Moisture cured polyurethanes are not the same as single or two-part polyurethane paints that are normally cured by a different chemical reaction.
The only problem with moisture cured polyurethane coatings is the fact that they are difficult to apply other paints or coatings over the top of them and obtain good adhesion of the top coat paint. Sanding the surface is the best method of obtaining good adhesion for a paint top coat, but there are other methods as well. I have used Chassis Saver paint as a coating on bare rusted metal. I first remove as much rust as possible with a wire brush on a power tool, then I wipe down the wire brushed surface with a solvent to remove any dust prior to painting on the Chassis Saver paint. After it is cured, I then sand the surface and applied body filler, or primer, or final paint, depending upon my application. It can also be used before applying fiberglass so that you don't develop rust blisters later. Follow the manufacturer's instructions for best results. You do not have to remove all of the rust. Just remove as much as you can using mechanical methods (sanding, grinding, wire brushing, sand blasting) or chemical acid etches. The surface must not have flaky rust that can be removed. The polyurethane coating adheres more by mechanically locking onto the rough metal surface than by other means, so sanding with 60-100 grit or sand blasting is best. These coatings can be applied by brushing, spraying, or pouring onto the metal surface. Several coats can be applied as long as you don't wait too long between coats. Once the coating is mostly cured, no more tackiness, usually a couple of hours, you must wait for it to be fully cured and then sand the surface before applying a new coating. You can fill rough, pin hole cratered steel surfaces by applying multiple coats, then sand it down smooth, and then apply additional coats, repeat until you have a very smooth surface that looks like there never was rusted metal.
I have used converter products before. These are normally a weak phosphoric acid solution that causes an iron phosphate to be formed from the iron oxide. In a well controlled manufacturing process, a converter solution will increase the adhesion of paint top coats, but I have not had such good success at my home shop. So I simply do the mechanical abrasion of the rusted surface to remove as much rust as possible and to produce a scratched or rough surface and then use the Chassis Saver. This is much simpler and I have had great success.
Destructive rust is so deep that it has often penetrated through the metal or has left pits that are mostly through the metal. Destructive rust normally weakens the metal substantially. Destructive rust can not be gotten rid of except to cut it out and weld in a new piece of fresh metal. Any coating that you apply over the top of destructive rust will not save the metal from eventual total destruction.
If you want to coat the surface in order to save metal from being destroyed by rust, you must not have holes through the metal to the other side. This includes pin holes that go through. The only way to stop rust from occurring is to prevent moisture from getting to the bare metal. Steel/iron will react with moisture in the air to cause iron oxide (rust).
There are several paint products that are made from a moisture curing polyurethane. There are many different formulations of moisture cured polyurethane, and each manufacturer is different. Because the polyurethane reacts with moisture to cure, it will pull the moisture from out of the microscopic pores of the surface rust on steel. This removes the moisture that would normally allow the metal to continue to rust after the surface is coated with paint. Any paint product that does not remove the moisture from the microscopic pores of the metal will eventually have more rust form and cause the paint to blister and bubble away from the surface of the steel.
It is this moisture scavenging process that happens when the polyurethane coating is curing which will stop the rust from continuing to form between the steel and the coating. No other polymer paint coating will do this except moisture cured polyurethanes. It is also important that the rust prevention coating be formulated to stop moisture from migrating through the coating to get to the steel. Any polymer coating can have moisture migrate through it. All paint coatings are polymers, and polymers allow moisture to migrate through them to some degree.
I have used Chassis Saver as a rust coating. It is less expensive than Por 15. It has done an excellent job of stopping the rust and it has not peeled or blistered after many years. The version that I have used is heavily filled with small aluminum flakes. As the coating cures, these aluminum flakes settle and flatten out, which provides a much higher moisture resistant barrier than can be provided by just the polyurethane itself. Por 15 is filled with carbon black particles to try and increase the moisture resistance of the cured coating, but the aluminum flakes do a much better job of preventing moisture migration. These moisture cured polyurethane coatings are very durable and are very scratch resistant and have very good chemical resistance, including salt brine. They will be attacked by the sun's UV rays, which causes the polyurethane to break-down. So they must be top coated if they will be exposed to the sun. Moisture cured polyurethanes are not the same as single or two-part polyurethane paints that are normally cured by a different chemical reaction.
The only problem with moisture cured polyurethane coatings is the fact that they are difficult to apply other paints or coatings over the top of them and obtain good adhesion of the top coat paint. Sanding the surface is the best method of obtaining good adhesion for a paint top coat, but there are other methods as well. I have used Chassis Saver paint as a coating on bare rusted metal. I first remove as much rust as possible with a wire brush on a power tool, then I wipe down the wire brushed surface with a solvent to remove any dust prior to painting on the Chassis Saver paint. After it is cured, I then sand the surface and applied body filler, or primer, or final paint, depending upon my application. It can also be used before applying fiberglass so that you don't develop rust blisters later. Follow the manufacturer's instructions for best results. You do not have to remove all of the rust. Just remove as much as you can using mechanical methods (sanding, grinding, wire brushing, sand blasting) or chemical acid etches. The surface must not have flaky rust that can be removed. The polyurethane coating adheres more by mechanically locking onto the rough metal surface than by other means, so sanding with 60-100 grit or sand blasting is best. These coatings can be applied by brushing, spraying, or pouring onto the metal surface. Several coats can be applied as long as you don't wait too long between coats. Once the coating is mostly cured, no more tackiness, usually a couple of hours, you must wait for it to be fully cured and then sand the surface before applying a new coating. You can fill rough, pin hole cratered steel surfaces by applying multiple coats, then sand it down smooth, and then apply additional coats, repeat until you have a very smooth surface that looks like there never was rusted metal.
I have used converter products before. These are normally a weak phosphoric acid solution that causes an iron phosphate to be formed from the iron oxide. In a well controlled manufacturing process, a converter solution will increase the adhesion of paint top coats, but I have not had such good success at my home shop. So I simply do the mechanical abrasion of the rusted surface to remove as much rust as possible and to produce a scratched or rough surface and then use the Chassis Saver. This is much simpler and I have had great success.
#22
Advanced
Thread Starter
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OP stated he has had the car for 2-3 years. In my experience, that is about the time frame for rust to resurface after a patch job. If there is rust in the rocker panel at the door frame, then is there more hidden rust in the unexpired rock panel? How many "patch repair" areas are in this car from previous ownership or is this a situation where the car became submerged in sea/salt water during its former life?
#23
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i have a restoration shop in south florida.
Where i see these holes i know that there are many other area of rust that you cannot see.
Getting into this job can open up a can of worms. You might not want to do what needs to be done.
Be prepared to spend money to make it right.
1988 coupes Have gone up in value so dont be afraid to save the car if you can.
Id pull the interior and see what you have inside and outside.
I use restoration design for all my panel needs.
Where i see these holes i know that there are many other area of rust that you cannot see.
Getting into this job can open up a can of worms. You might not want to do what needs to be done.
Be prepared to spend money to make it right.
1988 coupes Have gone up in value so dont be afraid to save the car if you can.
Id pull the interior and see what you have inside and outside.
I use restoration design for all my panel needs.
Last edited by tcsracing1; 02-08-2019 at 07:49 PM.
#24
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i have a restoration shop in south florida.
Where i see these holes i know that there are many other area of rust that you cannot see.
Getting into this job can open up a can of worms. You might not want to do what needs to be done.
Be prepared to spend money to make it right.
1988 coupes Have gone up in value so dont be afraid to save the car if you can.
Id pull the interior and see what you have inside and outside.
I use restoration design for all my panel needs.
Where i see these holes i know that there are many other area of rust that you cannot see.
Getting into this job can open up a can of worms. You might not want to do what needs to be done.
Be prepared to spend money to make it right.
1988 coupes Have gone up in value so dont be afraid to save the car if you can.
Id pull the interior and see what you have inside and outside.
I use restoration design for all my panel needs.
im with you on that thats exactly what i said, pull the interior first then decide
#25
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Hello Everyone,
I hope this message finds you all in good health and high spirits. Recently, I came across two products, OSPHO and Rust Converter, that claim to possess remarkable capabilities in transforming rust and restoring metal surfaces. However, I now find myself in a quandary and would sincerely appreciate your advice on this matter.
If any of you have had the opportunity to utilize either OSPHO or Rust Converter, I would be extremely grateful to hear about the outcomes you experienced. Specifically, I am keen to learn which product proved to be more effective in effectively transforming rust and providing long-lasting protection for metal surfaces.
Your invaluable experiences and recommendations will play an instrumental role in guiding my decision-making process. I extend my heartfelt gratitude to each and every one of you in advance for your kind assistance.
Warm regards,
I hope this message finds you all in good health and high spirits. Recently, I came across two products, OSPHO and Rust Converter, that claim to possess remarkable capabilities in transforming rust and restoring metal surfaces. However, I now find myself in a quandary and would sincerely appreciate your advice on this matter.
If any of you have had the opportunity to utilize either OSPHO or Rust Converter, I would be extremely grateful to hear about the outcomes you experienced. Specifically, I am keen to learn which product proved to be more effective in effectively transforming rust and providing long-lasting protection for metal surfaces.
Your invaluable experiences and recommendations will play an instrumental role in guiding my decision-making process. I extend my heartfelt gratitude to each and every one of you in advance for your kind assistance.
Warm regards,