What about repaing a leaky or rusted fuel tank once it is empty? They can be very dangerous and may explode causing severe injuries or even death unless proper precutions are taken. Personally, I have over the past 30 to 40 years repaired fuel tanks sucessfully and without danger. The first one I did was for a '37 Buick in 1964, so that was 44 years ago, actually. The whole idea is to make sure the tank is empty; then SECURELY fasten a CONTINIOUS air supply to the tank's filler spout so that any fumes are exited throughout the repair process. This does not allow fumes to bulid and cause an explosion. I have utilized the process dozens of times and it works! Since I haven't had experience on larger type tanks, I wouldn't recommend repairing a huge storage tank of any type or even a semi truck's tank. However, this works well for automobile tanks.

My father was a welder. He always filled gas tanks with water and then welded them while the were filled with water. That insured that there were no way that there were any gas fumes in the tank.

We've talked in other forums about fuel tanks in general, including on aircraft.

Lessons learned with aircraft fuel tanks can easily be thought of and employed when dealing with automotive tanks. Just yesterday, the FAA announced a new requirement for the airliners to fill their fuel tanks with nitrogen as the fuel is depleted, in order to prevent explosions like the one that is blamed for TWA Flight 800.

http://afp.google.com/article/ALeqM5hoWAHm7uDMQji6uWHDOtoWajeN1w

It's called "inerting". The military has done it for years. Actually the vapor/air mix has to be close to right, together with an ignition source for an explosion to occur. Beleive it or not aircraft fuel tanks are filled with electrical components including boost pumps, fuel probes and valves.
Even though it takes a multiple chain of failures and conditions to initiate an explosion Murphy's Law will see that it will eventually happen. Two of the passengers from Flt 800 were from my small home town.........Bob

No amount of inerting will prevent tank explosion following a missile hit. In my opinion, the TWA 800 cover up is one of the greatest shams in the history of the country. Damned if I can figure out the why, either.

Cheers,
JMC

John, I was still "in the buisness" when that happened and followed it closly through trade publications. Something like 90% of the wreckage was recovered from the sea floor. It was a heroic effort in both determination and money. The aircraft was painstakingly reassembled in a hangar at JFK. There is no doubt the ignition originated in the center fuel tank and the force of the expanding gas propagated from inwards outwards. The aircraft then came from together to apart.
There is no cover up, there is no missle, there is no evidence of external penetration, there is nothing but a disaster waiting to happen.
The last I heard the reassembled aircraft was still being used as a teaching tool for accident investigators from around the world. Small comfort............Bob

Two of them were husband and wife dance instructors that taught ballroom dancing to a group of us from our sixth grade class. Very nice folks, just going on vacation...and then gone.

Another reminder that life is often all too short;

Smile, enjoy what you are blessed with, and help someone else enjoy theirs more.

Joe

Bob,

I'm not a conspiracy hound, but I've been in/around aviation and space programs a long time (FAA ATP/ME/SE Land/FE tickets) with over 5500 hours of Navy and civil flight time. I've also been a squadron safety officer and have had mishap investigation training. On this event, I'm a 'determined skeptic'.

There are some things with respect to the TWA 800 investigation/recovery/salvage and aftermath that do not add up to a normal post-accident investigation.

Chief among these:

-- The apparent complete disregard paid to knowledgeable eye witness accounts of the accident. Among these witnesses are an experienced military aircrew in flight at the time and the accounts of four or five other air transport cockpit crews.

-- The rather odd handling of the entire early portion of the investigation.

-- The activation of specialized USN recovery teams who were placed under strict orders of silence

-- Significant thermal, explosive, and balistic damage that clearly points to an intial detonation outside of the CWT at a point forward of the left main wing spar. This resulted in the structural deskinning of the top of the left wing tank by hydraulic shock and inward deformation of major centerwing bulk head structures. Collateral evidence is provided by the record of the angle of attack probe position just priod to aircraft power loss.

-- Recovery ops that were at odds with the debis field locations

-- Ground eye witness accounts from multiple vantage points that, without apparent previous knowledge, clearly describe the launch and flight charateristics of a tier two man portable air defense system (MANPADS) missile (e.g. US Stinger, Soviet SA-14 (Strela), Chinese FN-6). TWA 800 was well within the envelope for both the Stinger and the Strela. Eye witness accounts clearly describe the booster/sustainer motor staging and burn. Nobody who sees/hears a MANPAD launch, even from five miles or more away is going to mistake it with fireworks.

-- The seizing of hundreds of autopsy artifacts (shrapnel) that were with held from the NTSB and the coronor

-- Widespread explosives contamination of the wreckage.

But these are my thoughts. I invite your attention to www.twa800.com, a website created by CDR Bill Donaldson (deceased), for a fairly exhaustive compilation of TWA 800 data.

I honestly don't think we've been given the true story. I'm all in favor of inerting fuel tanks, but like AGW, let's make sure we're not making a correct decision for the wrong reasons and/or manipulated facts and data.

Cheers,
JMC

John I certainly respect your credentials. Since neither one of us probably don't, and never will, know the complete and true story I'll just say I feel for the pax and especially the crew. God speed to them all.........Bob

Concur.
JMC

I've heard of filling tanks with water when being welded, but it seems to me that the water would hinder making a good weld-or solder job. I've proven the moving air supply to be safe and effective, with the added bonus of being able to weld with MIG or open flame without the water.

Heavy air purging is what I do. I Probably over do it by purging for hours but I'd much rather err on the safe side......Bob

I've tried the water fill method. It is practically impossible to gas weld (braze) or solder a water filled tank because the water draws the heat away too fast.

Best method I used was to wash out the tank with detergent thoroughly.

Today I would simply buy a new tank. If a new tank was not available I would take the old tank to a rad shop for repair.

I have used the water filled tank method for welding and have found it very safe. The way I do it is to first wash out the tank with a strong detergent to remove all liquid gas,then fill the tank with water and have the hole to be welded on the very top of the tank so that all air can escape.
Then let out a very little bit of water so that it is not touching the weld area and procede. Some small flames will come out but it cannot explode as there is no collection of explosive fumes inside.
I make sure that the waste water is not pooling around Me on the ground. That will have gas floating on it and would burn. (but not explode)

Of course, I it all outside in an open area and never weld a rotted tank, only a small puntured one.

I have also filled a tank with water and sand blasted the hole area and fiberglassed it.

This is just my opinion and not a suggestion to do it!

You raise an important point, Roger. Sandblasting can cause a static electricity spark, especially in cold dry air. A gas tank should be inerted before sandblating too........Bob

Remember, clean all of your rubber parts with gasoline before adhering them to the body! LOL!

A couple of the tanks I repaired had holes all over the bottom side. After flushing out all the rotten fuel residue, and applying the air supply to the tank, I was able to sand the entire bottom clean and solder (propane torch) all the many, many, tiny holes that had rusted through the tank. It worked well! No leaks!

Re; wk's_olds

What you did was to probably lower the explosive limits of the air/fuel ratio to below an explosive condition and maintain a positive air pressure that kept the flame out of the tank.

It did not explode as you are here to tell about it, but you could have caused the tank air/fule/pressure mixture to a stage that would have been a supper bomb.

You lucked out!

Interesting discussion....

I agree with "inerting" the tank and offer this example.

Many years ago, we had an old "roughneck" well driller who welded a puncture in the gasoline tank on our water well drilling rig. He claimed he had done it several times in the Texas oil patch. Our foreman allowed him to do it only if he parked the rig at the end of the pipe yard away from anything flammable.

The process was simple... He ran a big hose from the exhaust pipe into the fuel filler and ran the truck for 20 minutes before he fired up the ark welder and welded the tank without draining the gasoline!

He effectively enerted the tank before welding without filling the tank with anything that would interfere with the welding process. I do not recommend this, but it shure was effective.

I use a similar system to gently pressurize the gas tank with exhaust in my 13 buick. I can pull long hills without running out of gas when the gas level gets below the carburator. The best thing about it is that there are no moving parts, no electric fuel pump, and it actually makes the tank under the front seat much safer.

Actually early military inerting systems used engine exhaust as the inerting medium...........Bob