Otter LRC CM4647296 comes home

[Jordan Baker]

Removed the ends of the fuel tank. At first I tried melting the solder out and uncrimping the edge. It wasn’t working too well and was making a mess of the edge. I ended up using the flap disk in the grinder and simply took the top of the fold off. This went very quick and I was able to remove the end panels. They will get formed back into shape. As suspected the internal baffles were popped from a few tank walls. I will remove them as well. This will give me the access I need to get the rest of the tank cleaned up. This will also let me work on getting the side walls of the tank back into shape. I also removed the senders and the pickup tubes.

[Jordan Baker]

Lastly I found some kind of screened filter loose inside the one tank. Not sure if it’s original but more research is required.

[David Dunlop]

Not exactly a ‘Holy Grail’ but quite a surprise inside the tank.

It looks far too course to be a fuel filter in the conventional sense, but it looks like it might slip into the throat of the filler pipes to catch larger objects. If filling these tanks was an awkward task in a confined space, the filler caps might have had chains fitted to prevent their loss into an inaccessible place. One would also not want to lose one of those chains into a fuel tank, so those screens might have been used to prevent important stuff from falling into the tanks for all eternity.

Another long shot.

Back in the 70’s, I worked up in Yukon doing geology, using helicopters in remote areas. We had a string of 45 gallon drum fuel cashes strung up the Richardson Mountains to give the pilots the range and endurance they needed to move us about. Part of the kit they carried for refuelling was a chamois and a large hand fuel pump for the drums. They would wet the chamois and give it a good ring out and line their fuel funnel with it before pumping the fuel in. For some reason, the chamois let the fuel through but stopped any water from getting into the helicopter fuel tanks. It also stopped sediment passing through.

Maybe that screen served a similar purpose when used with a petrol can and flex hose fitting...?


David

[Jordan Baker]

The end plates and baffles were removed and straightened up.

[Jordan Baker]

The tank looks quite decent inside. There is one spot to patch up, but otherwise it’s quite solid. It will be a bit of work getting the creases out and everything back into shape.

I’m contemplating buying a kids wading pool to make up a dipping tank to chemically clean up the tank. I figured one side can soak at a time and it can just be rotated.

[Jordan Baker]

Not much to report. But I’m trying out a citric acid bath on the fuel tank. I had a large plastic drum that I filled with about 40 gallons of water. Into this I mixed in 10lbs of citric acid. I bought a bag from Amazon. I had been reading about home versions of Evaporust and the citric acid was deemed to be overall pretty mild.

I was able to submerge about half the tank at a time. This is the result after soaking since Sunday night. At first it didn’t look like any changes were taking place. But after power washing, wow it cleaned almost all the rust right up. Tonight I added a much larger fish tank heater (rated for 90 gallon) tank. The dip is supposed to work better when it’s warmer.

[Jordan Baker]

Pretty happy with how this tank cleaned up in the citric acid bath over the past week. Power washing it out really gets it cleaned up and flushes out the gunk. Next up will be stripping the remaining paint off. Then soldering up the pin holes.