I have a 22 gallon (or so) fuel tank that originally had gasoline in
it.

I want to use it for diesel.

I would like to drill it and install a through-hull fitting, which
would be for the fuel return line. Ideally, I would like to braze the
fitting in place also.

My question is how do I drill it and braze, so that it would not
explode.

The tank has not had gasoline in it for a couple of weeks.

Today, I recently set it up with the fuel cap open, turned it over so
that the fuel fill hole pionts down, and set it out so that it would
becmoe quite hot under the sun.

Would it be correct to assume that after a few days I could purge it
with compressed air, and then drill and braze it, without exploding?

Would purging with argon be a good idea?

i

On Jul 11, 3:57*pm, Ignoramus24437 ignoramus24...@NOSPAM.
24437.invalid wrote:
I have a 22 gallon (or so) fuel tank that originally had gasoline in
it.

I want to use it for diesel.

I would like to drill it and install a through-hull fitting, which
would be for the fuel return line. Ideally, I would like to braze the
fitting in place also.

My question is how do I drill it and braze, so that it would not
explode.

The tank has not had gasoline in it for a couple of weeks.

Today, I recently set it up with the fuel cap open, turned it over so
that the fuel fill hole pionts down, and set it out so that it would
becmoe quite hot under the sun.

Would it be correct to assume that after a few days I could purge it
with compressed air, and then drill and braze it, without exploding?

Would purging with argon be a good idea?

i

Steam clean, if possible. Just a little vapor can cause a lot of
trouble. Old-timers would work on one if it was filled with water
first. Inert gas is a good idea, but how can you tell if it's full
enough? With water, there's no doubt.

Stan

On Mon, 11 Jul 2011 16:57:11 -0500, Ignoramus24437
wrote:

I have a 22 gallon (or so) fuel tank that originally had gasoline in
it.

I want to use it for diesel.

I would like to drill it and install a through-hull fitting, which
would be for the fuel return line. Ideally, I would like to braze the
fitting in place also.

My question is how do I drill it and braze, so that it would not
explode.

The tank has not had gasoline in it for a couple of weeks.

Today, I recently set it up with the fuel cap open, turned it over so
that the fuel fill hole pionts down, and set it out so that it would
becmoe quite hot under the sun.

Would it be correct to assume that after a few days I could purge it
with compressed air, and then drill and braze it, without exploding?

Would purging with argon be a good idea?

i

You're probably safe if it's been empty for a while & the air purged
out. Still the argon or CO2 wouldn't hurt

On steel tanks fittings tend to be soldered rather than brazed,
getting thin sheet metal hot enough to braze but not to cause any
number of problems you don't want is a bit of an art.


H.

I have heard that the gas tank repair places fill it with water, weld it and
then dump it out to dry.

---------

"Ignoramus24437" wrote in message
...

I have a 22 gallon (or so) fuel tank that originally had gasoline in
it.

I want to use it for diesel.

I would like to drill it and install a through-hull fitting, which
would be for the fuel return line. Ideally, I would like to braze the
fitting in place also.

My question is how do I drill it and braze, so that it would not
explode.

The tank has not had gasoline in it for a couple of weeks.

Today, I recently set it up with the fuel cap open, turned it over so
that the fuel fill hole pionts down, and set it out so that it would
becmoe quite hot under the sun.

Would it be correct to assume that after a few days I could purge it
with compressed air, and then drill and braze it, without exploding?

Would purging with argon be a good idea?

i

On Mon, 11 Jul 2011 16:57:11 -0500, Ignoramus24437
wrote:

I have a 22 gallon (or so) fuel tank that originally had gasoline in
it.

I want to use it for diesel.

I would like to drill it and install a through-hull fitting, which
would be for the fuel return line. Ideally, I would like to braze the
fitting in place also.

My question is how do I drill it and braze, so that it would not
explode.

The tank has not had gasoline in it for a couple of weeks.

Today, I recently set it up with the fuel cap open, turned it over so
that the fuel fill hole pionts down, and set it out so that it would
becmoe quite hot under the sun.

Would it be correct to assume that after a few days I could purge it
with compressed air, and then drill and braze it, without exploding?

Would purging with argon be a good idea?

i
My experience has been good with washing it out with hot soapy water,
then discharging a CO2 extinguisher into the tank to displace all air
and vapours.

Argon would likely work too - it is denser than air at 1.78+ g/l
compared to air at something close to 1.25 g/l at atmospheric pressure
- not as heavy as CO2 at 1.96.

On Mon, 11 Jul 2011 15:11:56 -0700 (PDT), wrote:

On Jul 11, 3:57Â*pm, Ignoramus24437 ignoramus24...@NOSPAM.
24437.invalid wrote:
I have a 22 gallon (or so) fuel tank that originally had gasoline in
it.

I want to use it for diesel.

I would like to drill it and install a through-hull fitting, which
would be for the fuel return line. Ideally, I would like to braze the
fitting in place also.

My question is how do I drill it and braze, so that it would not
explode.

The tank has not had gasoline in it for a couple of weeks.

Today, I recently set it up with the fuel cap open, turned it over so
that the fuel fill hole pionts down, and set it out so that it would
becmoe quite hot under the sun.

Would it be correct to assume that after a few days I could purge it
with compressed air, and then drill and braze it, without exploding?

Would purging with argon be a good idea?

i

Steam clean, if possible. Just a little vapor can cause a lot of
trouble. Old-timers would work on one if it was filled with water
first. Inert gas is a good idea, but how can you tell if it's full
enough? With water, there's no doubt.

Stan
Filling an old tank with water is NO guarantee you will not have a
problem - and if you do, all the water is forced out the filler at
once, under high pressure. Had a friend tried welding the tank for his
53? ford that way - and he caught the tank in the chest as it emptied
itself, forcefully, against the shop wall where he had it stood up. He
ended up flat on his back on the driveway - quite sore. Not sure if it
was just steam, or if some gasoline vapour managed to ignite - but it
appeared to be significantly more powerfull than you would expect of
steam, given the amount of heat involved and the short time the torch
had been applied. He was just trying to solder or braze a pinholed
area (rusted) on the end of the tank, which was pointed up.

You can't get the tank hot enough to solder or braze when it is
TOTALLY full of water, so there had to be enough "air space" to either
trap steam or gasoline vapour.

I'm betting on gasoline trapped in the rust scale at the weak spot in
the tank.

I know a lot of old mechanics who would run exhaust through a tank for
half an hour before attempting to solder, braze, or weld on it.,

With inert gas fill, you can weld at the BOTTOM of the tank, where you
KNOW it is full of (particularly) CO2. Plug the hole as much as
possible to keep all the CO2 from draining out before you finish the
job.

I've repaired oil pans while still on the engine using this method -
any other method is foolhardy (on oil pans)

On Mon, 11 Jul 2011 20:05:40 -0400, "Carl Ijames" wrote:

CO2 is the cheapest purge gas. You could mostly fill the tank with water
and then purge the remaining headspace with CO2 gas or get some dry ice and
toss it into the tank and let most of it sublime then start heating. To
remove 95% of the air you need three tank volumes of gas, assuming the
exhaust line is long and skinny to keep air from back-diffusing into the
tank. Without water, 22 gal is 82.5 L so 3x is 247 L. If you have a
flowmeter on your MIG CO2 tank you can crank the flow up and calculate how
long to wait. You will get roughly 1000-fold expansion from the dry ice so
247 L/1000= 0.25 L of dry ice. Winging the density that would be about 500
g or 1.1 lbs, so get two or three pounds and wait until 2/3 or 3/4 has
sublimed then fire up the torch. Again, you want the exhaust line to be
long and skinny, not just the fill neck :-).


3X purge is not required with CO2 because CO2 is so much heavier than
air. Put it in at the bottom of the tank and it will displace all air
and vapour as it fills. 20% more than tank capacity is all that is
really required - but I always play it safe and add a bit more part
way through the job - particularly when brazing oil pans.

And a long and skinny exhaust is NOT required if the filler kneck is
located at the top when filling/welding.
-----
Regards,
Carl Ijames
"Ignoramus24437" wrote in message
m...

I have a 22 gallon (or so) fuel tank that originally had gasoline in
it.

I want to use it for diesel.

I would like to drill it and install a through-hull fitting, which
would be for the fuel return line. Ideally, I would like to braze the
fitting in place also.

My question is how do I drill it and braze, so that it would not
explode.

The tank has not had gasoline in it for a couple of weeks.

Today, I recently set it up with the fuel cap open, turned it over so
that the fuel fill hole pionts down, and set it out so that it would
becmoe quite hot under the sun.

Would it be correct to assume that after a few days I could purge it
with compressed air, and then drill and braze it, without exploding?

Would purging with argon be a good idea?

i

On Mon, 11 Jul 2011 17:11:09 -0700, Gunner Asch
wrote:

On Mon, 11 Jul 2011 16:57:11 -0500, Ignoramus24437
wrote:

I have a 22 gallon (or so) fuel tank that originally had gasoline in
it.

I want to use it for diesel.

I would like to drill it and install a through-hull fitting, which
would be for the fuel return line. Ideally, I would like to braze the
fitting in place also.

My question is how do I drill it and braze, so that it would not
explode.

The tank has not had gasoline in it for a couple of weeks.

Today, I recently set it up with the fuel cap open, turned it over so
that the fuel fill hole pionts down, and set it out so that it would
becmoe quite hot under the sun.

Would it be correct to assume that after a few days I could purge it
with compressed air, and then drill and braze it, without exploding?

Would purging with argon be a good idea?

i
Fill it with carbon monoxide from your exhaust pipe on your welder, car
or any other internal combustion system..and while the engine is
running..make the weld.

Its cheap, only requires a shop vac hose and works well enough. But let
it run for an hour or so before starting the weldment.

Or you could simply drill a hole..thread it..and screw in your fitting.
Id suggest a 3/4" fitting, with an adapter to the proper size, if done
this way.

Gunner
In order to get enough CO from the exhaust of either of my cars you'd
need to run it a LONG time. Less than .03 parts per million CO on the
one car, and less than .003 parts per million on the other.
And CO isn't the best purge gas anyway.

Thankfully the concentration of CO2 in engine exhaust is quite high,
and O2 content extremely low - so engine exhaust works reasonably
well. Has the advantage of being HOT so it boils out any gasoline
absorbed into rust scale etc, and trapped in pinch seams etc..

For gas tanks I generally either soldered or brazed repairs and fuel
fittings

Thanks, Clare. I wanted to be sure that any error was on the side of
safety, just like I would if I were the one holding the torch :-).

-----
Regards,
Carl Ijames
wrote in message ...

On Mon, 11 Jul 2011 20:05:40 -0400, "Carl Ijames" wrote:

CO2 is the cheapest purge gas. You could mostly fill the tank with water
and then purge the remaining headspace with CO2 gas or get some dry ice and
toss it into the tank and let most of it sublime then start heating. To
remove 95% of the air you need three tank volumes of gas, assuming the
exhaust line is long and skinny to keep air from back-diffusing into the
tank. Without water, 22 gal is 82.5 L so 3x is 247 L. If you have a
flowmeter on your MIG CO2 tank you can crank the flow up and calculate how
long to wait. You will get roughly 1000-fold expansion from the dry ice so
247 L/1000= 0.25 L of dry ice. Winging the density that would be about 500
g or 1.1 lbs, so get two or three pounds and wait until 2/3 or 3/4 has
sublimed then fire up the torch. Again, you want the exhaust line to be
long and skinny, not just the fill neck :-).


3X purge is not required with CO2 because CO2 is so much heavier than
air. Put it in at the bottom of the tank and it will displace all air
and vapour as it fills. 20% more than tank capacity is all that is
really required - but I always play it safe and add a bit more part
way through the job - particularly when brazing oil pans.

And a long and skinny exhaust is NOT required if the filler kneck is
located at the top when filling/welding.
-----
Regards,
Carl Ijames
"Ignoramus24437" wrote in message
m...

I have a 22 gallon (or so) fuel tank that originally had gasoline in
it.

I want to use it for diesel.

I would like to drill it and install a through-hull fitting, which
would be for the fuel return line. Ideally, I would like to braze the
fitting in place also.

My question is how do I drill it and braze, so that it would not
explode.

The tank has not had gasoline in it for a couple of weeks.

Today, I recently set it up with the fuel cap open, turned it over so
that the fuel fill hole pionts down, and set it out so that it would
becmoe quite hot under the sun.

Would it be correct to assume that after a few days I could purge it
with compressed air, and then drill and braze it, without exploding?

Would purging with argon be a good idea?

i

wrote in message
...
On Mon, 11 Jul 2011 17:11:09 -0700, Gunner Asch
wrote:

On Mon, 11 Jul 2011 16:57:11 -0500, Ignoramus24437
wrote:

I have a 22 gallon (or so) fuel tank that originally had gasoline in
it.

I want to use it for diesel.

I would like to drill it and install a through-hull fitting, which
would be for the fuel return line. Ideally, I would like to braze the
fitting in place also.

My question is how do I drill it and braze, so that it would not
explode.

The tank has not had gasoline in it for a couple of weeks.

Today, I recently set it up with the fuel cap open, turned it over so
that the fuel fill hole pionts down, and set it out so that it would
becmoe quite hot under the sun.

Would it be correct to assume that after a few days I could purge it
with compressed air, and then drill and braze it, without exploding?

Would purging with argon be a good idea?

i
Fill it with carbon monoxide from your exhaust pipe on your welder, car
or any other internal combustion system..and while the engine is
running..make the weld.

Its cheap, only requires a shop vac hose and works well enough. But let
it run for an hour or so before starting the weldment.

Or you could simply drill a hole..thread it..and screw in your fitting.
Id suggest a 3/4" fitting, with an adapter to the proper size, if done
this way.

Gunner
In order to get enough CO from the exhaust of either of my cars you'd
need to run it a LONG time. Less than .03 parts per million CO on the
one car, and less than .003 parts per million on the other.
And CO isn't the best purge gas anyway.

In fact, there are muffle-type heat-treating furnaces that use CO for fuel.
It doesn't sound like something I'd fool with.


Thankfully the concentration of CO2 in engine exhaust is quite high,
and O2 content extremely low - so engine exhaust works reasonably
well. Has the advantage of being HOT so it boils out any gasoline
absorbed into rust scale etc, and trapped in pinch seams etc..

That sounds better. d8-)


For gas tanks I generally either soldered or brazed repairs and fuel
fittings