Dealing with rust

Rust guide.

It's worth noting that a lot of the time, once rust is in your car, it isn't leaving again so these may only prolong the inevitable.

Rust repair on old sheds really depends on two factors. How early you catch the rust and how structural the rusty piece of car is. The general rules go:

Non structural, early catch = Minor cosmetic repair.
Structural , early catch = Prevent it getting any worse.
Non structural major rust = Major cosmetic repair.
Structural major rust = Major repair.

These repairs need certain tools - if you don't have access to a welder and grinder - don't bother.

Minor cosmetic repairs – for instance a wheel arch that is beginning to bubble.

The best way I have found to deal with this on a nice car is send to a small independant bodyshop and ask them to skim it over, cure and repaint it. Of course on our tramp cars thats a shit idea so here are the basics of doing it yourself.

Dont be a pussy, grab the angle grinder with a nice big wire brush attachment and get trigger happy... no point rubbing it back just a bit if you leave crusty bits it will return. If you make a massive hole in the car then it needed replacing anyway so skip this step and go straight to “major cosmetic repair”.
Nuke the bastard with the grinder till all you can see is solid shiny metal, dont worry about any holes smaller than a 5p but make sure what you have left is solid.
Cure the rust with a treatment (I'm honestly not sure how well this works, but its worth a go as its all exposed) cover everything you can see in the Kurust (or similar) solution and follow the instructions on the damn bottle.
When this has dried/cured etc., get some decent rust resistant primer. I personally use a zinc based one but red oxide is a reasonable one as well. Make sure the area is keyed nicely with a fine sandpaper and is free from shite and cleaned so the grease from your fingers doesnt stop it sticking.
Paint in long, even strokes about 20 cm from the paint work and give it a light coating, dont need to go nuts just make it even.
Apply bodyfiller, and for fucks sake use easysand. Otherwise you will be there for a month of Sundays. Build it up to above the level where you want the paint to be, then sand back to it
Sand this layer down (use a sanding block, it produces much better results and is easier on the fingers). This is the stage where taking some time is important to get a decent finish use a coarse grit sandpaper to sand down to the level then uses a couple of finer grits to smooth it out.
Apply a couple of layers of filler primer. Until all the sanding marks are gone then sand that again with a medium followed by a fine sand paper
Apply correct colour primer, for instance black normally uses a grey primer where is bright colours use a white primer.
Sand between coats with a very fine sandpaper to key it up. Remebering to wash off the dust and finger prints.
Spray the top coat. It it VERY difficult to blend a new paint layer with an old one so try and lose the blend in natural curves on the car, makes the shade difference harder to see, especially in sunlight. And for gods sake spray very light coats and lots of them, heavy coats run and peel.

Minor Rust prevention on structural parts: ie chassis rails.

The first thing to do is assess how far the rust goes, get a wire brush and really set to work on that thing. If you cant make any holes (and do try) then go to the first section and perform steps 1-5.

When you have done that then liberally apply that black gunky underseal in a aerosol can all over everyfuckingthing.

If you do make a hole... well, scroll down, skip onto "Major structural rust repairs".

Major Rust Repairs. Non Structural

There are two ways to go here. You can do it properly or you can bodginate with fibreglass hole filler and fuck loads of body filler, wont work well on a tramp car becaus it willl break up if hit by a cone or delaminting tyre etc. so I won't bother with it.

First up you have to work out what you are dealing with. For instance for a sill repair it is perfectly acceptable to cut the old bit of rust out and weld a plate over the top of it the paint the fuck out of it with underseal.... it won't look pretty, but it works.

To do this:

Cut out ALL the rust, this only work on rust holes less than about 10cm across. Cut out a nice square shape.
Cut a piece of steel about 1-2cm bigger than the hole you have cut in the car, this can be from a piece of repair steel bought from a motorfactors or with an old bit of wing or something, make sure its all cleaned up and and no rust/paint left on it.
Hold it against the hole you have made and make sure you have cleaned all the paint off the car about 3-4cm around the plate, dont worry if the plate is flat and the sill is rounded we will deal with that soon.
Place the lower or upper flat edge of the plate against the car where you think it will sit, push it round the sill just to make sure it will be big enough.
Tack edge of the plate to the car, a couple of big tacks because you will be hitting it with a hammer soon.
Use a hammer to bend the metal plate around the sill until it is flush against the exsiting sill then hold it tightly against the car and put a couple of tack on the other edge to hold it against the car.
Use the hammer to hammer any loose edges flush to the car.
Seam weld all the way around the edge of the plate.
Give it a damn good brushing over with a wire brush wheel on an angle grinfer or flap wheel to make sure the are no shit bits of weld and neaten it up a bit.
Clean it all up really well with a non water based cleaner and mask a big rectangle around the weld.
Spray the fuck out of it with black gunky underseal.

To repair visible bodywork areas:

Again hit it with a flap wheel/wire brush until there is no rust left. And inspect the area holes. Cut out ANY rust left. Now its alot easier to buy a repair panel for a wheel arch than make one if its totally shit (like any thing bigger 4cm hole).
Here is where it starts getting difficult... not really recommended for beginners. Cut out the rust, try to keep to nice easy shapes like squares and rectangles because circles will make it really hard later.
Get a chunk of cornflake packet. Hold it against the the car and cut out a stencil of the hole in the car. Make sure its pretty fucking close will make the cutting in metal and welding a lot easier later.
When the cornflake packet stencil is perfect lay it on the sheet of repair steel and draw around it with a permanent pen/scriber.
Cut out the repair steel perfectly and hold it up against the car to test it. Make any modifications you need to make make sure you trim it so it fits nicely inside the hole, needs to sit flush or will look crap.
Put a tack weld about every few centimetres around the seam. And make sure it all fits nicely without any big gaps because these are a cunt to fill with weld.
Seam weld all around the outside.
Make sure you get good penetration (lol) because if you dont you wont be able to go all over with with a flap wheel and flat it all back without breaking the weld.
When this is done skip to step 4 on the minor rust guide and carry on from there. Remembering to rust proof inside as well as outside!

Major rust repair (structural)

To be honest, if i have got to tell you how to do this you probably shouldn't be attempting it anyway, dont want a strut to collapse or steering mount to come off at speed so probably best you get this done by someone who knows what they are doing or bin the car and start again....

There we go.... I assume no responsibility if you fuck something up or it doesnt turn out well. and this is just how I do things so feel free to correct me if you know a better way!

Guide written by: Gibson.