Rust Removal and Preparation [Exocet Build Guide]

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====== Rust Removal and Preparation ======

To keep your build cost friendly you will be reusing a lot of parts from your donor car, of which most will have seen thousands of miles in all weather and are probably not looking their best. For items such as wishbones you can of course buy new however this method gets expensive quickly, so here we will cover on the typical ways for getting those rusty parts back to a "new" condition.

There are two main methods of restoring your old parts depending on your budget which we'll cover below. One is slower but more cost effective, one is faster but costs more.

It is worth considering that for suspension parts, depending on the condition you may need to replace bushes, mounts etc so it is a good idea to press the old ones out before restoring the parts.

=== Wire Wheel & Paint ===

If you have a lot of time but a smaller budget then this is the way to go. You will need some tools, namely a drill and an angle grinder.

**__Aluminium Parts__**

Aluminium is quite a soft metal and as such it is very easy to remove a lot of material very quickly. Brass wire wheels are ideal for cleaning this type of metal and attachments for a normal drill can be purchased very cheaply. A battery drill on its highest gear and in "drill" mode will make quick work of dirty aluminium and bring it back to a clear silver look. 

A bench grinder would be very useful at this stage of the build and can be picked up new for quite cheap, these usually come with a large brass wire wheel that will make quick work of most parts cleaning.

Once the thicker dirt is removed it is a good idea to use a degreaser to get it sparkling. The go to options are "Gunk Off" and "No Nonsense Heavy Duty", use a normal paint brush to agitate the dirt, leave it to dwell for 5 minutes and then agitate again and rinse off with a hose should get most parts back to a new condition.

It is not recommended to use flap wheels or steel wire wheels on aluminium.

**__Steel Parts__**

For most builders you will likely have a Mk1, Mk2 or 2.5 in which case all of the suspension is made of steel and likely very rusty. While you can use a brass wheel on a drill, this will take a long time and won't remove 100% of the rust in all cases so something more aggressive will speed things up. Steel wire wheel attachments for an angle grinder will be the fastest way of removing old rusty metal, leaving mostly clean metal behind. 

Once you have removed the old rust with a wire wheel then you should be left with what looks like clean metal, however you may find that the metal is pitted (tiny dimples in it) and this will hide rust where you can't grind it. Give the part a clean off with a towel (or paint prep wipes work great) and then coat in a rust converter/inhibitor such as Hammerite Kurust or Bilt Hamber Deox; depending on the product it usually takes a few hours for the converter to do its job. 

Instead of converter, you may also want to consider using acid. You can simply remove any thick / flaky rust from a part and then give it a rust bath for a few hours, clean off and then paint. Acid is more expensive than a wire wheel and on smaller parts, can eat away more material. 

Now that you have clean metal you will need to protect it, there are two options here however it is worth noting that neither are going to be as long lasting as powder coating or galvanising. Products such as Hammerite metal paint work fine, but will chip or scratch easily which will lead to rust. Depending on the part you could also paint it in the same manner as bodywork. Red Oxide primer is ideal for steel parts, a few light coats to cover the base metal and you can then use any automotive spray paint for a colour coat, and then it would be best to give it 2-3 clear coats using a 2K lacquer. 

=== Blasting & Coating ===

If your budget allows then this is the best way to make your old parts look good again and most importantly, you will get a longer lasting finish. There are three common types of coating: Powder Coating, Anodising, and Galvanising. Which you use will depend on your budget and whether you are bothered about the aesthetics of the car, however each if done professionally should outlast the car.

**__Aluminium Parts__**

While you can get aluminium parts shot blasted, this can sometimes be too abrasive and leave the surface pitted, as such it is normally recommended to get aluminium parts vapour blasted to get them back to a new state. This is generally enough for most people and you would refit it to the car, however over time the aluminium will again grow dull. The solution to this is Anodizing, this uses electricity to create a coating over the top of the aluminium part and can usually be done in a wide variety of colours. 

**__Steel Parts__**

Generally the most time and cost effective way to restore steel parts is through shot blasting and powder coating. This if done correctly can remove near to 100% of rust from a part and because the powder coat is essentially a layer of plastic-type powder melted over the part it keeps it away from any weathering and stops it rusting again. Powder coat can also be done in almost any colour and you can quote a RAL code to your coated if you wanted parts to match your frame. 
The down side to powder coat is that especially on parts in the wheel wells, it can be susceptible to chipping which can mean water gets in and causes rust. You can of course help prevent this by protecting the powder coat with something like a ceramic coating.

The other option which will give the best longevity to the part is hot acid dipping and galvanising. This is usually a little bit more expensive than powder coating however because the part is dipped in hot acid, it does guarantee that there is no rust left on it. Galvanising is also one of the most weather hardy coatings you can get on a part. (For example, the metal barriers on a motorway are galvanised and you don't often see them rusting). You can also get coating to go over galvanisation so that it can be painted like a normal part should you want it to colour match the frame / bodywork. 


=== Bolts & Fixings ===

You will find a lot of the bolts you remove are a specific size, length, grade and thread which can in some cases make them difficult to replace without costs going through the roof. The solution to this is of course to re-use the bolt however some may not be in the best condition and require a good wire wheeling.

If you need to reuse a bolt then it is worth considering that by wire wheeling the bolt you will remove any coating or plating it may have had to prevent rust. 

The threads on a lot of bolts will probably be quite rusted and as such will have made it difficult to remove them from the donor skate. Wire wheel can remove the thick of the rust however you may sometimes find that you'll need to run a die down the bolt if the threads have become distorted when removing or using a tap for threaded holes and nuts.

Once you've got a clean bolt, it's only going to rust again. It is recommended to coat the bolt, black oxide kits can usually be found online for under £50 and should provide the bolt with enough protection to prevent it from rusting for years to come, without adding too much thickness to the bolts thickness/threads. It's out of the scope here for doing a full hot chemical process but most builders either choose the costly option of new bolts, or alternatively clean up the bolt ones and use a safer method like black oxide to protect the metal, painting bolts isn't generally recommended.

For other generic parts of the build its often easier to buy new bolts off the shelf, just make sure you get the correct grade as you need a minimum for certain parts like the steering column and the seats / harnesses etc. Generic bolts can be found cheap online in bulk either from eBay sellers or places like https://www.orbitalfasteners.co.uk/

You will probably need a range of sizes along with new nuts to suit. Button heads can offer a nice finish when it's something on show.

Depending on the application it is always a good idea to give the bolt a bit of copper grease before refitting, this can in some cases also help ensure you get the correct torque spec. Note: If a bolt requires Loctite then don't grease it.