PDA

View Full Version : Darwin award candidate



radkins
05-18-2013, 10:45 AM
I went to a farm to pick up a leaky gasoline tank for a farm owner when called me about a leak on a gasoline powered tractor, he told me his hired hand would have it off and cleaned for me. I wash these things out with a Sodium Hydroxide solution and then purge them with CO2, also if practical I fill with water prior to welding. When I got there the worker had the tank off and cleaned and was preparing to pressurize it to find the leak but since he had no way to regulate the air compressor to less than 40 PSI he needed another way to pressurize it, no problem for this genius since there was a torch in the shop and that regulator would go all the way down to about 1 or 2 PSI. He had all the fittings plugged except one and had the OXYGEN hose from the torch connected to that with the regulator set at 10 PSI, he had soapy water ready and was waiting on me to arrive so he could pressurize the tank and show me where it was leaking. Had he turned on this rig we would have had 10 PSI of pure Oxygen in a 20 gallon tank filled with gasoline fumes and about a quart of liquid gasoline!

Zero_Divide
05-18-2013, 12:05 PM
Hmmm.
Oil is known to spontaniously combust in presence of pure O2.
Gasoline fumes would have blown him to the moon.
I wonder if he replied "i ve been doin' this for years" when you told him.

danlb
05-18-2013, 12:51 PM
Why don't they teach this stuff in high school? Don't use pure 02 with hydrocarbons. It seems so easy.

It's surely more important to know how to avoid dieing than some silly fact about the feudal system in medieval Europe.

Dan

Tony Ennis
05-18-2013, 01:08 PM
Don't use pure 02 with hydrocarbons.

Dan

How about, "Don't use pure O2*" No need to qualify it!

* unless you want to burn something

Dr Stan
05-18-2013, 01:14 PM
Why don't they teach this stuff in high school? Don't use pure 02 with hydrocarbons. It seems so easy.

It's surely more important to know how to avoid dieing than some silly fact about the feudal system in medieval Europe.

Dan

The yuppie helicopter parents have effectively eliminated high school technical programs. Besides they are more expensive than just warehousing 30+ students in a room with a talking head at the front.

barts
05-18-2013, 01:23 PM
The yuppie helicopter parents have effectively eliminated high school technical programs. Besides they are more expensive than just warehousing 30+ students in a room with a talking head at the front.

Perhaps the fact that since a college degree makes a huge difference in potential earnings is more to blame. I loved taking shop in school - but it was really obvious to me even back in the 1970s that a professional career as an engineer was far more economically rewarding than working as a machinist or technician.

Frank Ford
05-18-2013, 01:48 PM
I loved taking shop in school - but it was really obvious to me even back in the 1970s that a professional career as an engineer was far more economically rewarding than working as a machinist or technician.

Way back in the late 50s, my high school still had an active shop program, but my parents made it crystal clear to me that only "loser" kids took shop, so I was not allowed to take those classes. Now, Dad was the consummate DIY-er, and Grandpa was Gyro Gearloose, so I learned a lot at their sides. But, I was headed to college to become "somebody" - you know, doctor, lawyer, etc. Well, I did go to college, and it was there I learned that I already was somebody, and eventually I found my own track, which, of course, had nothing to do with what my parents had in mind.

Got to take some shop courses, but later, as a graduate student. Sorta did the education thing backwards, I guess. . .

radkins
05-18-2013, 02:49 PM
As soon as I saw what he had rigged up there I told him in a rather urgent tone to not turn on the Oxygen and that if he did it was quite likely the tank would explode. When he said it would be ok because it was only 10 PSI and that was not enough pressure to rupture the tank I tried to explain to him it was the O2 mixed with the gasoline that would explode but I don't think he ever did understand what he was doing wrong, anyway the tank is soaking in my cleaning tank and no harm was done but I can't help but wonder what else this guy might do!

Paul Alciatore
05-18-2013, 03:18 PM
Yea, but you are defeating the Darwin/evolution thing by stopping him from self destruct before he can reproduce. Perhaps that is even more dangerous.

And the gene pool is further diluted every day.

Yea, yea, I know. I would have stopped him too.




As soon as I saw what he had rigged up there I told him in a rather urgent tone to not turn on the Oxygen and that if he did it was quite likely the tank would explode. When he said it would be ok because it was only 10 PSI and that was not enough pressure to rupture the tank I tried to explain to him it was the O2 mixed with the gasoline that would explode but I don't think he ever did understand what he was doing wrong, anyway the tank is soaking in my cleaning tank and no harm was done but I can't help but wonder what else this guy might do!

Alistair Hosie
05-18-2013, 03:42 PM
I worked in a workshop back in the seventies where they had an open trough of cyanide (used in silver plating ) and some hydrochloric acid next to each other when the health and safety guy came he evacuated the whole building as it makes the same gas asused in the gas chambers no smell or anything we were just told if one drop of either made contact we wouldn't make it to the door yet it was used this way for years without harm the owner had to get fume cupboards and store it in different rooms.It just shows what ignorance can do. Alistair

Black_Moons
05-18-2013, 03:45 PM
So why do you use sodium hydroxide to clean them anyway?

When I had a small tank to clean, I used laqure thinner to rinse it a few times. After a 24 hour dry I could not smell any trace of gas or other solvent fumes. Didn't use CO2 purge, even though it would be a great idea, now that I have a CO2 cylinder and hose for it. ($20 Paintball cylinder + $20 remote hose (with valve/pressure gauge) from ebay, costs $4 to refill!)

My reasoning was the laqure thinner would dissolve any gasoline/oil deposits in the tank, allowing the majority of the remaining residue to be rinsed out.
What would be left as deposits on the walls would be mainly laqure thinner and would evaporate in minutes when exposed to air.

Thoughts on using a highly volitile solvent to clean gas tanks verus sodium hydroxide?

darryl
05-18-2013, 04:14 PM
Have not played with gas tanks except to seal leaks externally, so I have no input on the cleaning thing. But I have had occasion to clean out used propane tanks so they can be used for other applications. It has been suggested that bleach gets the odor out, but since that's chlorine based, I would think that it would affect the metal over time. I wonder if lye would be safer and maybe just as effective? Maybe lacquer thinner would do the job? The mercapton smell is not easy to get rid of.

Never really thought about the Darwin award thing much, but come to think of it, I suppose I've 'studied' the phenomenon a few times- although I've always filled the tanks with water and cut or drilled them that way.

MotorradMike
05-18-2013, 05:12 PM
I had a Honda 305 with a leak around the filler neck that I decided to seal with solder.
I rinsed the tank and FILLED it with water to within 1/2" of the top.
The SOB blew on me as I was trying to get solder to flow with a propane torch!
I was very surprised and have had a healthy respect for hydrocarbons ever since.
No harm done to me or the tank.

Black_Moons
05-18-2013, 06:31 PM
Water and gasoline/oil do not mix very well. Hence why rinsing a gas tank with water is not very effective. Also tends to promote rust in the tank.

radkins
05-18-2013, 07:32 PM
So why do you use sodium hydroxide to clean them anyway?



Because that's what's in the degreaser vat that is used to boil greasy engine and tractor parts, it's been the standard solution for this purpose for many years and will take oily baked on sludge down to bare metal after a few hours in the hot solution. I suppose it's not the very best method of cleaning a gas tank but it does work very well and since I already have the setup I just drop in the gas tank, take it out after a few hours and rinse it out then it's safe to weld on. As far as rinsing a tank with water not being effective I don't think anyone is suggesting it is and the water is used simply as a means of reducing the air space, and thus the space for fumes to collect. A 20 gallon tank with nothing but air and gasoline fumes could make a really big bang but if that space is reduced to only a couple of cubic inches or so by using water any explosion that might occur would be very minor by comparison.

Black_Moons
05-18-2013, 08:43 PM
Ah ok, I was just wondering of sodium hydroxide was somehow the 'correct' thing to be cleaning them with, or just what you liked/happened to have on hand that did the job.

It was MotorradMike who mentioned cleaning the tank with water, then filling it, and still having a 'poof'.

Mike Folks
05-18-2013, 08:48 PM
When ever the US Navy, and USAF Thunderbirds demonstration teams go to cities/towns, the local TV/Radio stations usually provide an employee to ride in the back seat of the two place aircraft brought along for this purpose.

Before going flying with the selected pilot(s), there's safety procedures to follow in case of emergencies, one of the most important, is that women remove all traces of lipstick and other possible flamable makeup, as it/they will ignite upon exposure to the 100% Oxygen being breathed through the mask.

Don Young
05-18-2013, 09:18 PM
So why do you use sodium hydroxide to clean them anyway?

When I had a small tank to clean, I used laqure thinner to rinse it a few times. After a 24 hour dry I could not smell any trace of gas or other solvent fumes. Didn't use CO2 purge, even though it would be a great idea, now that I have a CO2 cylinder and hose for it. ($20 Paintball cylinder + $20 remote hose (with valve/pressure gauge) from ebay, costs $4 to refill!)

My reasoning was the laqure thinner would dissolve any gasoline/oil deposits in the tank, allowing the majority of the remaining residue to be rinsed out.
What would be left as deposits on the walls would be mainly laqure thinner and would evaporate in minutes when exposed to air.

Thoughts on using a highly volitile solvent to clean gas tanks verus sodium hydroxide?

In old tanks there is often a heavy deposit of gum/varnish that is very hard to dissolve. I have used lacquer thinner, acetone, carburetor cleaner, lye, and just about everything I could think of. I rarely get the tank clean enough that I feel the tank is non-explosive. I worry about the fumes from the flammable cleaners, too.

My favorite gas tank repair tool is a 300 watt American Beauty electric soldering iron. With a good acid flux it makes it easy and I can solder on patch or reinforcement panels if needed.

cameron
05-18-2013, 09:35 PM
Google "hot work on tanks and drums".

It's pretty hard to beat the effectiveness of a strong hot lye solution for cleaning baked on oil and grease, paint , fuel varnish and other organic materials from steel and iron. It's not something to be used carelessly.

Hopper
05-19-2013, 12:24 AM
My reasoning was the laqure thinner would dissolve any gasoline/oil deposits in the tank, allowing the majority of the remaining residue to be rinsed out.
What would be left as deposits on the walls would be mainly laqure thinner and would evaporate in minutes when exposed to air.

Thoughts on using a highly volitile solvent to clean gas tanks verus sodium hydroxide?

Good theory.
But remember: In theory, practice is the same as theory. In practice it often aint.

radkins
05-19-2013, 06:18 AM
Google "hot work on tanks and drums".

It's pretty hard to beat the effectiveness of a strong hot lye solution for cleaning baked on oil and grease, paint , fuel varnish and other organic materials from steel and iron.


Yep hot lye (I called it Sodium Hydroxide but by either name it works!) it's been the standard for many years and it will get a gas tank as close to 100% clean as anything a person can use. Although doing this may render a gas tank safe to weld on I never take anything for granted when welding on ANY kind of container and even after the hot lye bath I still approach these things with a great deal of caution.