Day 10 update:
Been somewhat slow this week, owing to a major science conference that's downtown for the week; however, I did make it home in time to spend some quality time on the gas tank. From my Day 7 update, I left off with the insides of the tank cleaned out after a thorough wash with BBs and nuts. The remaining surface rust still needed to come out, which is stage two of the KBS kit: a phosphoric acid/zinc etch. The tank was first allowed to dry after Sunday's efforts. I then fashioned up a little cap out of rubber to seal the inlet:
I then "glued" this down to the inlet with two coats of clear nail polish and let it dry overnight. The first bead was laid down onto the bare metal ring of the inlet, then the second around the edges, forming a complete epoxy seal. Nail polish comes right off with acetone yet is almost completely impervious to mild acids such as phosphoric, which is why I chose to use it. After pouring in all of the phosphoric acid solution, the petcock inlet was sealed in the same manner as when I cleaned the tank... a bit of thick plastic, a strip of rubber to protect the threads, and then a screw-type ring clamp to tighten it down. I then carefully and repetitively rotated that tank around for the better part of 45 minutes to make sure the entire insides were etched. I walked around with the tank in my hands, rotating it steadily, for 5 minutes or so. Then I let it rest for 5 minutes, and repeated.
Once the acid etch was done, I drained it back into the bottle from which it spawned, and thoroughly rinsed the tank with warm water more than 5 times. Filled it all the way up, drained, over and over. The temporary inlet seal was cut off and removed for this process. The last sealant step required a completely bone-dry tank, so I first started drying it with a hair dryer on high. After 20 minutes of cooking the bloody thing, I peered inside with a little flashlight to see if there were any wet spots. There were tons. I really wanted to try and seal it that night, but the instructions were very explicit on being
PATIENT. They even put patient in bold like that. So, I set aside my urge to finish it as soon as possible and let it dry for 24 hours.
Next day, I checked the insides again, and they were thankfully completely dry as far as I could see. I needed to replace the seal again, which meant another delay in letting the epoxy dry, so I first (for good measure) dried the insides again with the hair dryer. I REALLY wanted that sucker to be bone dry. I replaced the rubber seal and nail polished it down again. Let sit another 24 hours.
Now we come to last night. Sealant time! I poured in the entire contents of their silver-colored polyurethane blah bla blah mixture. That stuff smells HORRIBLE. I did this effort on campus in the fume hood, so all those nasty vapors were swept away and I spared both my own health and that of my neighbors/roommates. Sealed up the petcock, then repeated the whole walking around rotating bit for 30 minutes to ensure the coating had covered every square angstrom of the inside of that tank. When I was as confident as I could be that I'd achieved that goal, I let loose the temp seal on the petcock and drained out all that nasty-smelling sealant. This took a long time; the sealant is quite thick, and begins "setting" in like 30 minutes, so I had to work somewhat fast. You're supposed to avoid having puddles or large amounts of excess sealant build-up anywhere inside. So again, I very
patiently rotated the tank into a position to let all the excess sealant gather into the corner by the petcock, then drained it out of said petcock. I repeated this over and over again, for what must have been the better part of 45 minutes, before the sealant stopped flowing out entirely. At that stage, I was hella tired and ready to sleep. I set the tank down flat in the fume hood to let it dry overnight.
Today, I am happy to report the tank looks smashing! Just a reminder, here's before:
and here's after everything is done:
I haven't cleaned up the leftover bits of rubber and nail polish yet, as I'm waiting for the insides to fully cure. Supposedly needs 96 hours before you can put anything back inside the tank. KBS claims this is a permanent solution to all future gas tank corrosion issues, as the steel is now totally coated. Well, at least corrosion from the inside, that is. They warn you not to get any of their sealant on your skin, and to immediately wipe it off any parts you don't want it to permanently attach itself, because that's exactly what will happen if you let it cure. They claim no known solvent will remove it. Sort of like silicone, I suppose. If it gets on your skin, the only course of action is to let time pass. So I wore a lab coat, safety goggles, and acid-proof gloves. Yummy. At any rate, I hope this is the last time anyone, at least in my lifetime, will have to work on the insides of that tank! Now comes the outside... LOL
[EDIT]
Forgot to mention... a bunch of parts came today, woohoo! New tapered steering bearings, throttle push/pull and clutch cables, spark plugs, oil filter, and brake shoes and pads. I placed a second order with BikeBandit recently for new side "500Four" emblems and the steering stem spanner tool. I've already begun building a new wishlist, though: new low-profile fork dust seals from a 500 twin and a replacement alternator cover. Mine has a couple deep gouges in it that I don't think can be worked out. I'll still try, so I haven't ordered it yet.
