Disturbing Images. Happy Ending. Electrolysis is Strong Mojo!

[raygreenwood]

[fred g]

"Your tank would have me weighing the time messing with, chemical exposure and where I was going to put waste chemicals when done with outcome dodgy vs cost of new tank. "

Yeah I know, all of that is running through my mind. MEK was not in the New Hampshire hardware or commercial paint stores I went to and they can't order it. I'll try a marine paint store over in Maine today.

First I may try putting it on a hot plate in the driveway and just see what boiling water and detergent do. I have visions of dead birds falling from the sky and my neighbors lawn dying using the MEK method.

Edit: from a Ray Greenwood post below about MEK,
"be careful. Low flash point and not good with static.....and shaking it around builds pressure."
I was not very cautious about static or heat when I used the MEK in the sealed tank and should have been.

Hell no to a Chinese replacement tank. I have plenty of time, little money and no patience left for crummy parts.
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71 Kombi Rusty the 'Afront'

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[WildIdea]

[busdaddy]

If MEK isn't available the paint stripper option is the next best thing.
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[raygreenwood]

A couple of clarifications....so people understand what chemicwl does what.

First....MEK. This is really specific to getting varnish off and melting some of the resins 9n an epoxy or a polyester resin. But its evaporation rate is far too fast to just use it to dakpen something.

In a gas tank you seal it up andcslosh it around. And be careful. Low flash point snd not good with static.....and shaking it qround builds pressure. So once what its going yo dissolve has been softened.....pour it out, rinse with water to remove explosion risk....put in a little water and put in a chain to slosh around and crack off whats been loosened.

But trying to put 12 gallons of MEK in is not a way to go. Expensive. Also just trying to leave the tank at one angle to soak a spot with MEK does not work....becaise within seconds the last spot it was on.....will clash dry and whatever was softened will harden again.

The caustic soda (lye or sodium hydroxide) they use in a gas tank or engine hot tank....will do more good and remove the most crap, grease and varnish.

The acid.....is to dissolve rust. Ray

[busdaddy]

I had suggested MEK since it's what's specified by the manufacturer to remove Randolph #912 sloshing sealer (AKA Bill Hirsch, Red kote), it's not an epoxy, it's solvent based and the trapped fumes from the MEK soften it even if it's not in contact with the liquid.
I have no idea what's in that tank of the OP's, it looks like Randolph/Hirsch/redkote that was applied with no cleaning or prep first in some attempt to glue down the loose garbage in there from here. If it's an epoxy of some sort as you suggest I doubt the MEK will even touch it.
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[raygreenwood]

[fred g]

First of all I would like sincerely thank you all for your support and suggestions on this. I understand my not buying a new Brand X tank from ___ makes little sense to most of you. A: I don't want a Brand X tank, B: I don't do business with ___.

Yesterday I soaked and sloshed with a quart of MEK over a period of 12 hours which removed a little coating from around the edges and rinsed out some tiny specs then came out clear. So, it's epoxy(?). The original long term owner was career Air Force. The lining could be stealth bomber paint for all we know...
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71 Kombi Rusty the 'Afront'

"Buy the ticket, take the ride." H.S Thompson

[busdaddy]

If the MEK came out clear it's likely epoxy, 12 hours should make it come out slightly thickened and milky if it's the solvent based stuff, and any you spill should dry into a sticky residue.

I fully understand your reasoning, from what I've seen of those "new" tanks the OG one is worth saving if you can.
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[fred g]

I found a quart of Jasco paint stripper in the paint locker and sealed it up inside the tank with a can of old bolts. I spun it around end for end side to side to get the bolts moving every few hours. After letting it sit sealed up for 20 hours most of the solvent had escaped and the liner and stripper came out with Tide, TSP and boiling water. Today I did two more rounds of muriatic acid and water washes and this is what it looked like when it was still wet.

There seems to be a factory coating inside the tank and there are traces of the old liner here and there as little clumps and streaks of white paste that are barely attached.

The first picture is the epoxy coating before the stripper went in.

_________________
71 Kombi Rusty the 'Afront'

"Buy the ticket, take the ride." H.S Thompson

[busdaddy]

Wow, that looks way better!, maybe a few more acid treatments will dislodge the remnants?
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[fred g]

Next up: Electrolysis

[fred g]

Guitar Man you ARE the man.

The picture in the above post shows where I picked up again. I did one more acid wash and a thorough rinse and it looked really good then I sprayed Ospho into it once the tank was dry. This made a awful mess with black crusty stuff coming out of the seams. Bad Chemistry.

I followed the instructions from a farm journal.
1/3rd of a cup of Arm&Hammer Washing Soda for every 5 gallons of water,
more soda is NOT better. Dissolve completely in (hot) water. Undissolved powder will retard the process.

I taped up the fill hole with silver 3M HVAC tape, plugged the vent and lower spud and with the tank lying flat filled it through the sender hole. I raised the sender hole side up 1" so the "domed" part of the tank where the vent comes out was submerged.

With a large plastic funnel sitting in the sender hole I slid a piece of rebar through the funnel hole into the tank until it hit the bottom then raised it up 3/4" and clamped it with vice grips (inside the funnel) to keep it from going in deeper. Once the current is applied the reaction creates Oxygen and Hydrogen so creating sparks is a bad idea. Remember the Hindenburg!

I hooked up a battery charger to a car battery and used jumper cables from the battery to the tank using the mid-line flange to attach the ground (remove the paint so you establish a proper connection) and attached the positive cable to the rebar inside the protective funnel. I set the charger to 3 amps and let it cook for a day then changed out the fluid and let it cook another day, and then a third time. It really looked like hell again after that with rust and gunk stuck to the inside that did not flush out with water.

I did another quick series of flushes using about a cup of acid each time rolling the tank around for a minute or so. After that it was perfectly clean. I rinsed it with a quart of distilled water and washing soda to neutralize the acid then let it dry and rust for 48 hours. I used distilled water because something in our chemically enhanced water (courtesy of the US Air Force) may have reacted with the Ospho which does not like water or salts (especially chlorine) which may have created the mess previously.

Tonight I put 4oz. of Ospho in a spray bottle and using a very fine mist gently sprayed Ospho into the openings creating an acid fog inside the tank. I stuck rags in the holes and rolled it around until I heard fluid inside the tank then I turned it on end and let the Ospho run out the fill hole. 4 ounces in 3+ out. I know from experience too much Ospho is not a good thing - get it on, then get it off.

The tank is in great shape inside and out. At some point the fill and vent lines were replaced and I'm guessing the tank was lined at that point to prevent future problems There is some sort of very thin factory coating (galvanizing?) inside and smooth bare steel without any pitting. The rebar looked like a stick the dog had been chewing on. Electrolysis is strong Mojo. Damn, what an ordeal...
_________________
71 Kombi Rusty the 'Afront'

"Buy the ticket, take the ride." H.S Thompson

[busdaddy]

[fred g]

I used a shameful amount of chemicals and 50 gallons of water in the process. Knowing what I know now I would have tracked down another tank or cut this one open media blasted it and had my buddy weld it up.
I tried to be careful with my waste disposal - neutralizing the acids with Borax and diluting it with the wash water, letting the sediment settle and pouring off the neutralized diluted remains to evaporate. As careful as I was with the chemicals they still went everywhere - this was not an Earth friendly venture. The up side is I won't need to mow the lawn again, and on a clear day I can see Mount Washington!

_________________
71 Kombi Rusty the 'Afront'

"Buy the ticket, take the ride." H.S Thompson