How to rust protect your subfloor.

When converting a camper van, there are many areas to consider and many, many things to do. But the first and most important part is the preparation. Avoiding the preparation stages will result in some costly damages in the future and a much more fiddly job (as the van will be fully kitted out).

One of these phases is rust protection.

What is rust?

Rust is the general name for when different alloys containing iron begin to oxidise. They are typically a red/brown/orange bubbly patch on the metalwork. We had quite a lot on the step leading into our van.

You may have seen them on the main walking areas of the vans floor. You may also see more rust spots between the joints of any existing flooring in the van as any water that would’ve seeped through may have been sat for a while and therefore oxidised and started to rust.

How to treat rust?

Depending on how bad the rust is there are a couple of ways to treat it. If the rust is bad enough that you can poke your finger through it and it crumbles away then unfortunately, this is going to need replacing by someone with welding experience. However, if the rust is only on the surface level then you can treat the rust in a three-step process, 1. neutralisation, 2. priming, 3. painting.

On our van, we didn’t have any serious rust issues, only those on the surface, especially the door-way as mentioned above. We decided to use Hammerite as the brand of choice to follow the three-step process.

This blog and this post represent our experience of building a camper van and protecting / preventing future rust. We have detailed all the steps that we took to install and aim to include all the small details that you won’t find anywhere else (as that’s the part that confuses us). If you want to read more about why we are doing this please read more about us.

Identifying areas of rust

As we have mentioned, the first and most important stage is making sure that you identify the areas that need protecting and protect them before you begin covering everything up. This guide will take you through the process of identifying the areas of rust. However, this guide will not take you through welding and repairing extreme rust damage as this will need to be a professionally done job, or a mammoth task if you wish to undertake it yourself.

The easiest way to identify the areas of rust is to go around the van and look for anywhere that it is visibly obvious. The main areas that we found rust in our van were:

• Entry and exist ways to the van 
• Any small dimple holes (looked like screw locations but there were no screws)
• On the edge of any sheet metal

Once you have identified all the areas make a note of where they are so that you don’t miss any. This could be through taking a photograph and circling every area, recording a walk around video or just simply remembering. Try to be quite meticulous so that you don’t face the same annoyance that we did, we found ourselves still finding spots even in the topcoat phase and having to start again. You can see how many spots we found from all the red (primer) in the photograph.

Whilst you are taking a look around, make sure to check out where the outside panels connect to the van. Each clip is a potential entry point for water ingress and should be addressed early on. You can read more about how we did this here (coming soon!).

Preparation

To prepare the rust spots for painting you first need to remove the surface level rust and take them back to bare metal. To do this we used a set of metal wire drill brushes, a mask and some goggles (always be protected!).

With very light pressure spin the metal drill bit on the rust spot and you will see the bare metal begin to show through. You will need to go through the rust and paint before you will see the bare metal, but you will know when you do.

As you can see we took the rust back to the bare metal. We ended up going slightly wider than where the rust ended to make sure that we got it all. It meant a little more effort in the later stages but it put our minds at ease for the future of our van.

We also found that when removing some of the previous flooring (between the two beams in the photographs), we had taken the paint back to bare metal so would also protect there too.

Applying Kurust to rust spots

As we have mentioned, the next phase is applying Kurust. 

What is Kurust?

Kurust is a product by Hammerite. It neutralises the now cleaned rust spots to a solid foundation that can be built upon. It prevents rust from re-occuring and is the perfect first step to prevent rust in the future.

How to apply Kurust?

Once the rust has been removed and is back to bare metal you simply brush on some Kurust onto the areas and wait for 15-20 minutes or so for the solution to turn black. This indicates that the solution is working and chemically reacting with the metal to do it’s function.

The solution is similar to a thinner, runnier PVA glue. We weren’t too sure how much to apply to the area so applied enough that we could see them milky white texture on the spots, but not too thick that the spot turned white with the mixture.

Once the liquid has gone black you know it is working correctly. After this point we can move onto the next stage. We left the Kurust overnight so that we knew it was definitely set by the time we can around to the next step.

Priming the rust 

With each of the rust spots neutralised we can now move onto priming our van’s rust spots. For this we used Hammerite Red Oxide, which can be used without the previous Kurust step, but there’s no harm is using both. 

This step is really simple and just required the red oxide to be painted onto the surface. You want to aim to paint the rust spot and some of the painted surfaces around it. This will allow the paint to entirely cover the area. You can do as many coats as you wish, we decided one thick coat of this, along with one top coat would be enough to satisfy us.

As you can see we may have gone a little overkill with our red oxide primer. But because the front step was in really bad condition we wanted to make sure that everywhere was covered. There is no harm in covering more area, but there is in covering less!

Painting and protecting

With the Kurust and priming done, it was now time to place the top coat onto the floor. This steps is very similar to the previous one, you paint over the red oxide and spread the paint slightly further to encapsulate it. Hammerite recommends two coats of top coat but as we had done all three stages of protection, we were happy with just one.

The only lesson that we learnt from doing this was to make sure that you identify all areas before starting. Although not devastating if you don’t, we quite often found ourselves finding more spots when we were painting the red oxide primer / top coat. This meant having to start the whole process again for that new area which meant more waiting around!