To ensure that the POR-15 sealer would work properly, the tank had to be as clean as possible and all of the loose rust removed. It should be stated right away that the shape of the gas tank limits the view inside to about 40% of the tank. Since seeing most of the tank is impossible, actually being able to reach in and clean it is out of the question. (Insert Mission: Impossible theme music here) My mission, which I chose to accept, was to somehow remove two decades worth of rust without being able to touch the surface I was cleaning. Furthermore, I could not see the surface to tell if it was clean or not. My patience self-destructed.
To get an idea of the tanks configuration, it is about ten inches wide across the top and nine inches tall. The center of the bottom of the tank is raised up to within in an inch of the top to form sort of an inverted “U” shape. This is so the tank will hang over the upper bar of the frame when it is on the bike. When filled, most of the fuel is contained in the sides of the tank. On the bottom there are two spigots, one on each side, that are directly connected by a fuel line to allow fuel to flow from one side to the side which has the outlet to the petcock. The fill hole is located on top and to one side of the tank, which allows you to see into most of that side of the tank. Unfortunately, the raised portion of the tank blocks the view of the other side, proof that whoever designed this tank never had to clean the damn thing.
The tank was so rusty that I was a little apprehensive about using the POR-15 stuff right away. Each stage has to work completely or the sealer won’t stick and you are out $35 and back to square one. So I decided to try to do a preliminary cleaning job before trying the POR-15. At the local hardware store I found a bottle of some stuff called “Naval Jelly”, which is a rust-remover / primer for painting metal surfaces. I dumped the entire bottle of the pink jelly (it lives up to its name) in the tank, sloshed it around a bit, let it sit for 20 minutes and rinsed it out with water. It was amazing! Except for some of the really heavy rust deposits, the inside of the tank was perfectly clean.
The problem with most serious rust removers is that unless you paint the metal right away you will get a new rust coating, or flash rust, once the tank dries. This is exactly what I found when I went out to look at the tank the next morning. But I wasn’t worried since I had already decided to buy another bottle to try and get the heavy rust chunks. I figured that would take care of the flash rust as well, which it did. However, the heavy deposits were still there.
After the second attempt, I decided to go ahead with the POR-15 and see if that would do the trick. If not, the package claimed that the metal etcher would allow the sealer to stick to any rust still in the tank, so no worries. Because of my pre-cleaning job, the cleaner degreaser didn’t seem to do much except instantly dull the finish on the tank where I spilled it when dumping it in. So the next step was the surface prep/rust remover, which didn’t have any more success than the Naval Jelly.
Once the etcher was done, the tank had to be thoroughly rinsed with water then completely dried before applying the sealer. Several warnings on the package stressed this point. This was also backed up by the guy at the POR-15 company I talked to when I called to see if the little bit of the etching solution I splashed in my eye would make me go blind. Always wear your safety goggles!! Anyway, they recommend using a hair dryer or some other device to force dry air into the tank to help with drying. So after a commando raid to procure my girlfriend’s hair dryer, I slipped back into the garage to commence drying. This took a long time.
Once the tank was dry, flash rust appeared again but I pretended not to notice. I plugged up the two little spigots on the tank with cotton swabs to keep them from getting clogged with the sealer. Then I dumped in the tank sealer, which resembles paint (actually, it is paint), sloshed it around a bit to cover all the surfaces in the tank, and then allowed the tank to “drain thoroughly” via the petcock outlet on the bottom of the tank.
Quickly I realized that my plugs were only helping to keep the spigot tubes filled with sealer, which would then dry and plug the spigots completely. Since this was exactly what I was trying to avoid, I decided to remove the plugs and let the sealant drain out. I was rewarded with a spectacular mess. My solution was to jam an old T-shirt under the tank to soak up the excess sealer. It worked excellently.
The next morning, I also found up that my T-shirt idea was also a wonderful way to plug up one of the spigots again. It seems that the one thing I figured correctly was that if the sealant was allowed to pool in the spigots, it would dry and harden into a horrible clog. A good part of that day was spent trying to clear the spigot, a venture in which I was somewhat successful. I like to think that the colorful language that spewed from my mouth was enough to simply frighten the clog out, but perhaps the stiff plastic zip-tie I repeatedly jammed into the spigot helped as well.
*** Pay Attention!! The next paragraph contains all the stuff you should learn from my mistakes!! ***
When cleaning the tank, I wouldn’t worry so much about the rust spots, as long as all of the loose stuff is out. The Naval Jelly was probably not necessary, although it was a lot of fun to slop around and the fumes were top notch! In retrospect, once I dumped in the tank sealer, I should have turned the tank upside down to drain. That would have kept the sealer from filling up the spigots. I have a feeling that while trying to clear the clog, I probably damaged the sealer inside the tank. So now it will begin to peel and flow through the fuel systems, in which case I will have to clean the tank again next year. Luckily, I'll be a little wiser next time around.