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Car Rust

architect

Super User
This is a metal question but putting it here since it feels off-topic.

What's the best way to deal with this kind of rusting on a 20-year-old car? I've read all sorts of different methods from rust converter to fluid film, but want to check with the brain-hive here.

I don't really care to restore perfectly. I'm just looking to slow down and delay the rusting so it looks somewhat "respectable" for the family until the car explodes. My partner is pointing out skeleton cars around us and worried our car will look like them...

The first picture showed the rusting contained within the hard edge because I had masked, sanded, and primed these spots a few years ago. But the rust seems to have come to worsen in these areas?

What's the best path with the least time-consuming and skill required? I'm leaning towards just hand brushing some fluid film into these areas :eek::p


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You are behind the 8 Ball on this one. It will only continue to get worse. Fluid film may have helped pre rust, with regular car washes making sure you get into the nooks and crannies.

But if you really want to stop in from getting worse you need to grind away all the rust and post treat with a rust converter.
 
I should have tacked this when it first appeared but had other priorities. I think the rust from the inner side is also coming through and not just the exterior side.

It wasn't looking this bad, but this past winter and all the salting just accelerated this quicker than I had imagined. My previous attempt of sanding and priming held up until recently...

I understand there are no miracles here, so just want the best approach given the circumstance and situation.
 
I should have tacked this when it first appeared but had other priorities. I think the rust from the inner side is also coming through and not just the exterior side.

It wasn't looking this bad, but this past winter and all the salting just accelerated this quicker than I had imagined. My previous attempt of sanding and priming held up until recently...

I understand there are no miracles here, so just want the best approach given the circumstance and situation.

Yup. But it's too late now. Most of what happens is from the inside out. Outside in is actually rare unless there is damage. It just looks like it's outside in. But it's really inside out. The worst spots are seams and places where road dirt can get trapped and hold water - often with salt.

As Jayham said, you need to cut and grind away all the existing corrosion back to good metal and repair it properly.

It's not cheap and it's not easy. But it will only spread faster and faster left to it's own.
 
You could fix it right to look 85% with a mig welder (if you have one, if not, well this option is obviously much less attractive) a few dollars in sheet metal a little filler, primer, and color matched paint.

Or you could probably do just about anything else, spend more money, and have worse results. Fluid film/paint etc are expensive so the least amount of applications needed the better.

How long do you expect/hope to keep driving the vehicle? Perhaps the more important question
 
So barring cutting out the rust and doing it properly, is there anything that can be done to slow the existing deterioration is what I'm looking to do. I understand there is no saving it without going about it "the right way", but this isn't a vintage collectors car so not something I'm interested in investing time into. The rest of the car is already going in different ways.
 
You could fix it right to look 85% with a mig welder (if you have one, if not, well this option is obviously much less attractive) a few dollars in sheet metal a little filler, primer, and color matched paint.

Or you could probably do just about anything else, spend more money, and have worse results. Fluid film/paint etc are expensive so the least amount of applications needed the better.

How long do you expect/hope to keep driving the vehicle? Perhaps the more important question
Posted just after you.

I'm driving it until the repairs to keep it going no longer makes sense financially, and I'm getting close with this Subaru Forester. Maybe 5 years left? But I'm not sure and not much knowhow in cars.

Will probably get another car in a few years and let this wagon be the beater work car that the family doesn't have to look at.
 
But it will only spread faster and faster left to it's own
So will "dry" rust really spread? My theory (based on lack of science but not total ignorance) is that rust continues to spread once it's started because the rust pockets really hold moisture, dirt and salt which causes the rust. I think if you could keep the rust areas protected from moisture and salt then there would be no spread. I feel the oil sprays are very helpful in that regard. I do agree that in most cases rust will continue to spread because the conditions that caused it is the first place are still present. So if you can't remove the rust down to bare metal and repaint then I think the oil sprays are the best solution to prevent further rusting.
 
So will "dry" rust really spread? My theory (based on lack of science but not total ignorance) is that rust continues to spread once it's started because the rust pockets really hold moisture, dirt and salt which causes the rust. I think if you could keep the rust areas protected from moisture and salt then there would be no spread. I feel the oil sprays are very helpful in that regard. I do agree that in most cases rust will continue to spread because the conditions that caused it is the first place are still present. So if you can't remove the rust down to bare metal and repaint then I think the oil sprays are the best solution to prevent further rusting.
This is what I was told also elsewhere online and why I'm considering throwing on some fluid film or similar. But asking here as well since there doesn't seem to a clear consensus.
 
This is what I was told also elsewhere online and why I'm considering throwing on some fluid film or similar. But asking here as well since there doesn't seem to a clear consensus.
Any oil is better than nothing but in my experience the fluid film stuff hangs on and lasts better. It is more expensive and I don't always buy it but I prefer it.

I have a 16 year old Toyota van with nearly 350000 kms on it and a 18 year GMC pickup (which are notorious for bad rust spots) and both vehicles have ZERO rust on them. I am rather particular about keeping them clean however.
 
So if you can't remove the rust down to bare metal and repaint then I think the oil sprays are the best solution to prevent further rusting.

The theory suggests that is true. And there may be instances where it works quite well. But good performance hasn't been my experience. It doesn't even work on rusty tools. At best, it seems to stop rust on a surface for a short time, but rust is actually a chemical process that can continue to progress even in the presence of oil. Once a metal is rusted, the corrosion can continue even without water and salt because the water and salt molecules necessary to support galvanic corrosion are now present in the rust itself.

I wouldn't hesitate to apply a thin waxy oil to try and slow things down. But it's hard to apply such oils under existing rust without first removing the rust. If the rust has been removed, why not fix it properly. The rust is seldom located where its easy to fix. It's usually worst at and inside joints, inside folds, inside structures, and behind shields.

I think it's also important to know that the sheet metal of a vehicle is a part of its safety design. The metal is damaged and crumpled in the process of absorbing energy which helps protect occupants. If they felt so inclined, an authority could give you a ticket for driving a rusted vehicle.
 
f the rust has been removed, why not fix it properly. The rust is seldom located where its easy to fix. It's usually worst at and inside joints, inside folds, inside structures, and behind shields.

I might be losing half my car if I have to take off all the rust properly :eek: :(

To your and other points earlier, I think my car is a goner and too little too late...

I'm just trying to slow things a bit down and looking for good return on whatever labour I put into it.

At this point I figure something (oil? rust converter?) is better than nothing? I'm not retired (!) so I got other things I need to be spending my time on.
 
Any oil is better than nothing but in my experience the fluid film stuff hangs on and lasts better. It is more expensive and I don't always buy it but I prefer it.

I have a 16 year old Toyota van with nearly 350000 kms on it and a 18 year GMC pickup (which are notorious for bad rust spots) and both vehicles have ZERO rust on them. I am rather particular about keeping them clean however.

I will definitely be taking care of my next car well and hope for it to be clean for a long time! I'm like the 3rd owner of this car and it was never been in perfect shape. How often and what product do you oil your car with if not fluid film? I know some folks also take it to their local Krown dealer which I heard was okay.
 
If you have a decent air compressor you could get a little spot blaster from princess auto or Canadian Tire.

Blast away the rust, hit it with rust converter, zinc chromate primer & paint. Once the paints cured spray it with fluid film from the back

If you just want cheap take a gallon of used motor oil & melt a few toilet wax rings into it, apply as needed
 
I will definitely be taking care of my next car well and hope for it to be clean for a long time! I'm like the 3rd owner of this car and it was never been in perfect shape. How often and what product do you oil your car with if not fluid film? I know some folks also take it to their local Krown dealer which I heard was okay.
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Here is what I have on my shelf now. I've used alot of "Rust Check" brand stuff as it seemed to be on sale more often. The "Rust Cure" I've never used before but it too was on sale at Peavey Mart the other day.
I suggest washing crevices, folds and underneath REALLY well and allow to dry before spraying on any oil. Dust and dirt hold moisture and salt and it's important to clean that off as often as you can. I like to get vehicles really clean underneath in the fall and then apply oil for the winter salt season. I will also reapply in wheel wells in winter after a car wash if I washed up underneath reasonably well. The Fluid Film stuff seems to cling on better and not as likely to wash off easily. Try avoiding spraying any rubber bushings etc. with oil as it can soften it.
 
I don't know how applicable it might be here but ages ago I used Loctite Extend Rust Treatment. Quite an amazing product.
My new-to-me 2008 F150 has surface rust on a lost of the undercarriage and I'm tempted to get a couple of bottles and spray the underside of the whole truck.
 
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Cars are disposable , more so in the rust belt , I realized this at some point , probably when I started driving 140 km / day to get to work .

I used to try and keep on top of the rust when it became a problem and have restored a number of vehicles , 3 of them were frame off restorations .

I've spent untold amounts of money on this , bought many fenders , patched many panels , welding , grinding sanding , priming and on and on ......
Hours & hours of labour fixing up several vehicles , call it what you want , a hobby , a " lifestyle "............ at the end of the day , reality is , rust never sleeps , it will return , it will get worse .
 
I detest working on car rust, whatever you see it's almost always 10x worse, from the inside out in most cases.

We have had great success with Krown rust. At their Mississauga location they had pictures of a pristine 72? Datsun in their show-off pictures. Those things would rust in the Arizona desert. Best time to spray is summer so it creeps into all the folds before the salt shows up.

Not a fan of the Ziebart stuff, once the rust starts under that goop, it will eat the car before you can see it.
 
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ages ago I used Loctite Extend Rust Treatment.
I wouldn't bother, they have drastically changed the formula and it didn't work worth a sh_t on my Tacoma. I cleaned the frame but as the instructions say "leave a little rust". Two days later the rust was breaking thru, I haven't gone under the truck lately but I'll guess the rust is still coming thru. This was two years ago.
YMMV

 
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