Most welders will not weld any tank that has ever held gasoline. Could be a
big clue here!
"terry" wrote in message
...
washing and letting it vent will probably not work.

BE SURE TO INFORM SERVICE PERSONAL OF THE FORMER PRESENCE OF GASOLINE.
Otherwise you may face a costly lawsuit for wrongful death.

Only way to weld it is to leave it filled with water which will displace
any
air needed to create an explosion.

It just takes care. If you can, you wash out the tank. Regardless, you
purge it with air for many hours to guarantee it is dry. You fill the tank
with inert gas such as argon, then weld. Same process if you weld tanks of
unknown condition or which had unknown contents. Welders do it all the
time.

Brian


--
http://www.advantagecomposites.com/tongass -- My 22' Tolman Skiff project
http://www.advantagecomposites.com/catalog -- Discounted System Three
Resins products



"Dave W" wrote in message
...
Most welders will not weld any tank that has ever held gasoline. Could be
a
big clue here!
"terry" wrote in message
...
washing and letting it vent will probably not work.

BE SURE TO INFORM SERVICE PERSONAL OF THE FORMER PRESENCE OF GASOLINE.
Otherwise you may face a costly lawsuit for wrongful death.

Only way to weld it is to leave it filled with water which will displace
any
air needed to create an explosion.

"Brian D" wrote in message
news:9Qmfc.39212$wP1.153766@attbi_s54...
It just takes care. If you can, you wash out the tank. Regardless, you
purge it with air for many hours to guarantee it is dry. You fill the
tank
with inert gas such as argon, then weld. Same process if you weld tanks
of
unknown condition or which had unknown contents. Welders do it all the
time.

Once the tank is inerted, I would still be concerned about the residual gas
fumes in the bilges. An area where you can properly perge or inert.

If it doubt, or you can't test it before welding, then the tank should be
removed from the boat.

Steve
s/v Good Intentions

Steve wrote:
"Brian D" wrote in message
news:9Qmfc.39212$wP1.153766@attbi_s54...

It just takes care. If you can, you wash out the tank. Regardless, you
purge it with air for many hours to guarantee it is dry. You fill the

tank

with inert gas such as argon, then weld. Same process if you weld tanks

of

unknown condition or which had unknown contents. Welders do it all the
time.


Once the tank is inerted, I would still be concerned about the residual gas
fumes in the bilges. An area where you can properly perge or inert.

If it doubt, or you can't test it before welding, then the tank should be
removed from the boat.

Steve
s/v Good Intentions


why not inert those areas as well?

--
A significant part of courage is realizing that only you need to know
how terrified you are..

"dazed and confuzed" wrote in message
...

why not inert those areas as well?

The problem would be to effeciently purge and then keep the inert gas in the
area. Most all effective inert gases are lighter than air and would be lost
as fast as you could pump it in.

Steve

You're right. I was assuming the tank is out of the boat and in a shop.

--
http://www.advantagecomposites.com/tongass -- My 22' Tolman Skiff project
http://www.advantagecomposites.com/catalog -- Discounted System Three
Resins products


..
"Steve" wrote in message
...

"Brian D" wrote in message
news:9Qmfc.39212$wP1.153766@attbi_s54...
It just takes care. If you can, you wash out the tank. Regardless, you
purge it with air for many hours to guarantee it is dry. You fill the
tank
with inert gas such as argon, then weld. Same process if you weld tanks
of
unknown condition or which had unknown contents. Welders do it all the
time.

Once the tank is inerted, I would still be concerned about the residual
gas
fumes in the bilges. An area where you can properly perge or inert.

If it doubt, or you can't test it before welding, then the tank should be
removed from the boat.

Steve
s/v Good Intentions

The inert gas can blow away and if fuel is still sitting around, then it's
still creating fumes and can ignite itself too. Unless it can't be done,
I'd take the tank out and put it in a shop to weld. But where there's a
will, there's a way. Once the tank is empty and purging, the boat can be
purged also. We used to purge aircraft tanks for up to a week before
working on them, and even then we'd enter the tank with a fumes tester that
checked the air to see if there was jet fuel or gas fumes floating around.

Brian


--
http://www.advantagecomposites.com/tongass -- My 22' Tolman Skiff project
http://www.advantagecomposites.com/catalog -- Discounted System Three
Resins products


..
"dazed and confuzed" wrote in message
...
Steve wrote:
"Brian D" wrote in message
news:9Qmfc.39212$wP1.153766@attbi_s54...

It just takes care. If you can, you wash out the tank. Regardless, you
purge it with air for many hours to guarantee it is dry. You fill the

tank

with inert gas such as argon, then weld. Same process if you weld tanks

of

unknown condition or which had unknown contents. Welders do it all the
time.


Once the tank is inerted, I would still be concerned about the residual
gas
fumes in the bilges. An area where you can properly perge or inert.

If it doubt, or you can't test it before welding, then the tank should
be
removed from the boat.

Steve
s/v Good Intentions


why not inert those areas as well?

--
A significant part of courage is realizing that only you need to know
how terrified you are..

Steve wrote:
"dazed and confuzed" wrote in message
...

why not inert those areas as well?


The problem would be to effeciently purge and then keep the inert gas in the
area. Most all effective inert gases are lighter than air and would be lost
as fast as you could pump it in.

Steve


co2 is heavier than air, Argon or nitrogen are cheap. Just let it flood
the area while you are working....For the time needed to do the cutting
or welding, the losses are negligible.

--
A significant part of courage is realizing that only you need to know
how terrified you are..

On Thu, 15 Apr 2004 21:54:49 -0500, dazed and confuzed
vaguely proposed a theory
.......and in reply I say!:
remove ns from my header address to reply via email


...and from this we should take advice on welding petrol-laden areas?
G.

--
A significant part of courage is realizing that only you need to know
how terrified you are..

************************************************** **
I went on a guided tour not long ago.The guide got
us lost. He was a non-compass mentor.........sorry
.........no I'm not.

Old Nick wrote:
On Thu, 15 Apr 2004 21:54:49 -0500, dazed and confuzed
vaguely proposed a theory
......and in reply I say!:
remove ns from my header address to reply via email


..and from this we should take advice on welding petrol-laden areas?
G.


--
A significant part of courage is realizing that only you need to know
how terrified you are..


************************************************** **
I went on a guided tour not long ago.The guide got
us lost. He was a non-compass mentor.........sorry
........no I'm not.
;-)

--
A significant part of courage is realizing that only you need to know
how terrified you are..