This post continues the description of the fuel tank restoration. Refer to petrol tank – 1.

The POR-15 Fuel Tank Repair Kit I purchased contained:
4 litres Cleaner Degreaser
1 litre Metal ready
1 litre Tank Sealer

There’s a fair bit of work involved in using the POR-15 tank sealer products. The first step is to clean the inside of the tank with Cleaner Degreaser. You mix 2 litres of Cleaner Degreaser with one litre of hot water and slosh the mixture around the tank for about 20 minutes before draining it out. It will be quite dirty. After flushing with water, repeat the process with the remaining Cleaner Degreaser and hot water. After flushing again, the water coming out of the tank should be reasonably clear. It was in my case.

I rapidly learned a couple of things in this process. Firstly, a Mk2 tank with 3 litres of fluid in it is pretty heavy … and I’m no spring chicken. Secondly, the duct tape I used to seal the openings worked well initially, but for whatever reason, getting a good seal became more problematic with each step in the process. Possibly this was due to the poor condition of the tank surface. The hardest areas to get a consistent seal were the openings for the tank sender and the bung.

Anyway, I found that I was spending an inordinate amount of time fiddling about with duct tape to ensure a good seal. I needed to think of a better way. To solve the weight issue, I initially tied the tank to a beam in the garage and later to my engine crane.

Sealing openings with duct tape worked well – initially
Interior after cleaning with Cleaner Degreaser

The next step is to apply Metal Ready which is a rust remover and etching agent. The solution needs to get to as many areas of the tank as possible, so more sloshing the fluid back and forth. I then flushed the tank with warm water as per the instructions.

By this stage, I had come up with a Heath Robinson type of arrangement with cargo straps, a metal plate, and cork sanding blocks to keep the stuff inside the tank while all the sloshing around was going on. Despite how it looks, this approach worked well.


Surprisingly effective alternative to duct tape

All the instructions for the tank kit (see below) stress the need for the tank to be “bone dry” before the sealer is added. I used a heat gun as per the instructions.

Drying the tank interior

Tank interior after treatment with Metal Ready

As soon as I was confident the tank was completely dry I sealed the tank holes with my “sanding block and cargo strap” method and added the tank sealer. I rolled the tank slowly through every conceivable angle to “ensure” 100% coverage of the tank interior. Given the positioning of the internal baffles getting 100% coverage is probably aspirational, but I was happy with the results.

Top of tank
Bottom of tank
Bottom of tank

The covering is quite transparent when it’s on thinly, as is the case with the vertical baffles, although by eye I can see that the sealer has covered the interior well. This doesn’t show up very well in the images. I did expect the coating to be a bit thicker. However, the sealer is quite thin, and when I drained the tank and poured the contents back into the can, it was clear that there wasn’t a lot left in the tank.

The round blob in the centre and right-hand image is where I tried to remove some material stuck on the sealer, but I misjudged the strength of the magnetic pick up used. The left image is the top of the tank where any remaining sealer puddles when the tank is inverted to dry.

Next up was painting the tank exterior. I used black POR-15 black paint for this. First I gave the exterior a final clean with Cleaner Degreaser and then applied Metal Ready.

By the time I got to this stage the sealer had well and truly cured, so I wasn’t overly worried about a bit of water getting past the duct tape. I sprayed on the Metal Ready with a spray bottle.

Metal ready applied
Metal ready applied on tank exterior, already looking better than the original rusted surfaces
POR-15 applied
Tank painted. Nice and shiny!

I’m happy with the completed tank. The POR-15 black coating looks great and has transformed the rusty exterior. When you look closely it’s obvious the paint is covering existing rust, but given the location of the tank in the vehicle that’s hardly an issue. I’m hopeful that the sealer and the exterior coating will stand the test of time.


This is a labour-intensive process, so set aside plenty of time. Once you have etched and dried the tank interior you don’t want it sitting around as flash rust can occur if there is any moisture around. I felt I needed to get straight onto adding the sealer as soon as I was confident the tank was completely dry.

The sealer went “off” faster than I expected. As soon as you think all the sealer is out, turn the tank upside down to dry completely for 3 – 5 days. The instructions I had were vague in this area. Luckily I got to it just in time.

Make sure all the threads are clear of sealer.

Every set of instructions I found seemed to be subtly different. The link below is the most comprehensive instructions I found. I wish I had these when I did the job, although to be fair it was only the warning regarding the length of time the sealer should be in the tank that was not clear.

Link to instructions. The kit I purchased didn’t have the mirror or tape included.

I know some of you have already gone through this or similar processes, so I’d love your feedback.