removing rust and stopping it from returning.

[Ben Up North]

Not really specific to off-roading or Subarus, but anyone got any tips on removing rust and stopping it from returning?

I've separated the sunroof on the SVX from the frame and it has some(!) surface(!) rust, but is not too bad to rejuvenate.

When cleaning it off, how far do I need to go? do these rust converter products work well enough, thut I can just brush off the most of it then coat?

Is a rust inhibiting / 2 in 1 paint any better/worse than dedicated primer & paint?

Should I be asking these questions somewhere else?!

 

[Beachworm]

In my experience of restoring old cars I have found that the only sure way to remove rust and prevent it returning in the long run is to remove any rusted panels and replace them with new ones.

In your case, seeing it's the roof panel and given the age of the SVX that would not be a practical solution. If the metal is generally sound and the rust is superficial, sand it back to bright metal and coat with primer and sealer immediately.

If the rust is more entrenched but there are no holes evident after the flakes have been chipped away, and you do not want to go to the trouble of cutting out the affected areas and welding in new metal, you can get a reasonable result using any of the products that are based on phosphoric acid. This reacts with the iron oxide and produces a non-rusting compound. In some cases you will find they contain a PVA solution that forms a protective, sealing coat that you can prime straight over.

 

[Rally]

Ah, the joys of living in humid, salty air. Maybe move to Tennant Creek? ��

 

[scalman]

But something about welding is you overheat that area around and later it want to rust mainly on that welding. And you cant do anything underneath panel when you welded new on top.
Those rust converters or paints on rust can help some somewhere is not visiable. I think mostly you cant do much abouy rust in general its just there .done. You can hide it from eyes but to stop it its sometimes just not possible.
Even for small rust lets say you cut that area off and you weld new peace on top. All is fine but guess where first rust will came out.. on weld. Its hard to protect it.

 

[Ben Up North]

Ah, the joys of living in humid, salty air. Maybe move to Tennant Creek? ��

:lol: Too true. This baby's solid apart from the sunroof.

I don't think I'd ever buy another car with a sunroof though.
Unless it was another svx with a decent sunrood and the rest destroyed.

 

[Ben Up North]

In my experience of restoring old cars I have found that the only sure way to remove rust and prevent it returning in the long run is to remove any rusted panels and replace them with new ones.

In your case, seeing it's the roof panel and given the age of the SVX that would not be a practical solution. If the metal is generally sound and the rust is superficial, sand it back to bright metal and coat with primer and sealer immediately.

If the rust is more entrenched but there are no holes evident after the flakes have been chipped away, and you do not want to go to the trouble of cutting out the affected areas and welding in new metal, you can get a reasonable result using any of the products that are based on phosphoric acid. This reacts with the iron oxide and produces a non-rusting compound. In some cases you will find they contain a PVA solution that forms a protective, sealing coat that you can prime straight over.

Thanks or the info!

So you've played this game before! One of my clients has just rejuvenated an old ford truck (40's/50s). certainly not restore thoughd, this thing iis about an inch away from being a Hot Rod. pretty cool though.

I've used a phosphoric soution on the sunroof no PVA in it though. fortunately none of the spots on the sunroof are visible once it's re-assembled.

If the replacement frame isn't up to scratch, will be looking around to find some-one good enough to fabricate something. will be expensive, but better than 'welding' in the sunroof with a heap of bog or summat, which is the only other option.

 

[Beachworm]

Apart from all the company lease cars I've had I can't remember one that I didn't fix some kind of rust in. I learned a lot (mainly what not to do) from a friend who owned a panel beating business where I rebuilt a Mazda 323 Turbo that my son wrote off. I did some free work for him to repay the favour and it put me off buying used cars from car yards. Some rust repairs I did to his specifications on a Landcruiser wouldn't have lasted much longer than the warranty.

 

[ABFoz]

I have been looking at different sections and completely overlooked this.

Lanolin is good in preventing rust.


Perform a proper underwash first as washing is still the best way to prevent corrosion from building up. When completely dry, Remove the rust using steel brush, sandpaper or whatever until good metal is seen. Paint prep and then primer the metal surfaces. When completely dried, do an underwash and dry again on a dry day. Then use lanolin and a rag.

OZ has Lanotec HP. That has 2x more lanolin that the General Purpose one. That and a rag as a thick coat can mess with the cleaning later on. Make sure that the crevices are all completely covered. Then you can play in mud, sand, snow or have some fun at the beach.

The same can be used in places where the roads are salted during winter. Cheers.

 

[Beachworm]

The lanolin compounds work well for underbody protection but you can't paint over them unfortunately.

 

[ABFoz]

Yes, lanolin is after removing rust and at least a coat of primer. The rust removal must be spot on, though.


Sorry about the colloquial phrasing. I have already edited the post. Cheers.

 

[Lockheed]

I use phosphoric acid and have done for years , when I mention it on other forums it falls on deaf ears . I find this annoying as I have given them an answer to a question regarding rust .
I call these people Askholes people who ask for advice and then do the exact opposite ..

 

[Lockheed]

Here is something a bit more serious for any one that's interested .
the following images are of my own car and the repair is hidden behind trim but I knew if it wasn't addressed it would get worse .

Rear arches:

 

[Kevin]

That's a great job @Lockheed - makes me want to go and check my arches now!

 

[ABFoz]

Thanks for sharing, @Lockheed. It looks as though rust has been properly removed in your examples.

 

[Ben Up North]

@Lockheed That seems to do the job excellently! How well does eat other stuff (i.e does it destroy paint etc)?
How long do you leave it on for?
What do you clean it off with?
What personal protection is required?

 

[Kevin]

What personal protection is required?

Life & accident insurance

 

[Lockheed]

@Lockheed That seems to do the job excellently! How well does eat other stuff (i.e does it destroy paint etc)?
How long do you leave it on for?
What do you clean it off with?
What personal protection is required?

Hi Ben.
I am going answer in order of importance .
So this is 85% phosphoric acid so every care should be taken( as you know) gloves , glasses as a minimum . that being said phosphoric acid is not a strong acid at least when you compare it to say Nitric acid.
I leave it on for as long as it takes (on sheet steel body panels ) it strips the steel and converts rust . but what I also do is to let it do its work then remove it with wire wheel then repeat, you can leave it on over night should you wish.
As said before you clean it off with a wire wheel , you can also use boiling water which neutralises the acid and dries it .
Does it destroy paint ? certainly doesn't destroy 2k factory paint ( I don't know about water based paint) . It can destroy aluminium and shouldn't be used on stuff like coil springs (as far as I have read )

It is also great for rusty stone chips , I drip it down a stainless steel skewer to leave a single drop on the chipped paint then after 30 mins agitate the steel under drop of acid with the skewer (acid has high surface tension) and leave for another 30mins then soak up with a cotton bud and it will leave bright shiny metal.

I should probably ad a disclaimer here and say it does hurt if you get it on your skin , wash it off quick and don't breath in the vapour.

As an interesting side note, if you wear a full face mask you can watch it bubbling away on the rust . ( I like that kind of thing)