Hello again, just reporting what has been done since my last addition to the photo log in December 14. In March I finally got the time and felt I had read enough about using the POR-15 and Muratic Acid to clean the tank that I could proceed. I had used the tank cleaner twice, one quart each time, and got crud out, but there still looked to be more rust that I expected an etch to be able to deal with. So I practiced cleaning some rusty parts in a little of the acid. I have a mask with Organic Vapors filters which I wore when working with the acid, and goggles.
The acid would turn from clear to bright yellow when it "ate" the rust, then to a dark brown when neutralized with the baking soda. In the process a foam was formed like the head on a beer, only it too was a yellow color like the acid had become. I figured it was neutralized when adding more didn't cause anything to happen. The acid and the foam were both a dark brown color.
My main concern treating the tank were the vapors created while the acid worked and again while neutralizing it with baking soda. The result of the baking soda reaction is CO2 and saltwater, so once neutralized completely I could filter out the big pieces and put the liquid down the drain. How much acid would create so much CO2 at a rate which would exhause acid vapors out of the tank? Since the recommended approach is to add acid to water not water to acid when diluting it, I put a gallon or two of water in the fuel tank, then slowly poured small amounts of acid thru a funnel into the tank using gloves, mask and goggles. I'd shake the tank a bit to mix it all up and repeat.
I did this until I started thinking I had enough acid in the tank to make neutralizing it hard enough. Then I started adding the baking soda. After neutralizing the acid and rinsing the tank, I could see clean spots and rusty spots, so I repeated the treatment. I used a little less than a gallon of Muratic acid in both treatments. And a LOT of baking soda.
After the last treatment the inside of the tank looked like new metal. Perfect! I should have taken a photo of the tank at that stage, because I let it sit for a few days before I could get back to it. The POR-15 instructions said the etch was fine with some light surface rust, in fact better, because there would be more for the sealer to grip. So I didn't worry about the flash rust.
I treated the tank with the etch and after collecting the etch into the original bottle for future use rinsed the tank a few times with water. I dumped out all the water I could and set up a fan blowing air into a funnel that was placed into the fill pipe flange and exhaused out the sending unit hole. I set this assembly out in the hot Florida sun during the days and let it run for several days. I'm pretty sure the tank and all it's crevasses were dry.
There are photos of the tank in the etched state and again after the sealer had dried.
https://plus.google.com/photos/111176050916109003072/albums/6084564272690863585
It wasn't until after etching or maybe after the sealer was poured in that I remembered that I had planned on removing the sending unit so the screws would not be frozen into the threaded holes. Ooops! This is one of the problems with letting too much time pass between steps and not writing the planned steps down. Five of the six screws came out, one required more force than the others. The sixth one twisted off and the screw is still in the tank. I need to get a screw (or maybe a Allen head screws?) and extract the remains of the screw. Worse case if the easy-out doesn't work, I'll re-drill and tap the hole with the screw part in place and hope for the best.
That's where things currently stand. The latest photos are all of the inside of the tank thru the fill tube.
Between March and now - 25-May-15 - I was busy learning to play banjo and fiddle for St Patrick's Day gigs, filling flute and whistle orders, and moving my 89 YO mother back to Ohio. I think I again begin to think about getting that screw out and start putting things back together.
Later,
Carey
