Hi guys,

I am trying to re-hab an old Curtis air tank for home shop use @ 125 psi.
It is OLD, as in rolled plate, riveted, with the seam filled with a
silver color metal.
The drain bung is almost rusted out, so I drilled and tapped it for
1/2'' pipe,
still only 1/8'' thread. Will weld in a bushing for 3/8" pipe to fit a
drain cock.

Question is: does anyone here have an idea what the silver filler is? It
seems too hard for solder.

Thanks, wws.

"wwsnot" wrote in message
om...
Hi guys,

I am trying to re-hab an old Curtis air tank for home shop use @ 125 psi.
It is OLD, as in rolled plate, riveted, with the seam filled with a silver
color metal.
The drain bung is almost rusted out, so I drilled and tapped it for 1/2''
pipe,
still only 1/8'' thread. Will weld in a bushing for 3/8" pipe to fit a
drain cock.

Question is: does anyone here have an idea what the silver filler is? It
seems too hard for solder.

Thanks, wws.


Long time lurker here, let me see if I can help.

1st: I don't know what the silver solder like stuff is.

2ond: If the tank is old and severely corroded (rusted out ) It would be
extremely dangerous to use it for any pressurized application. I would use
it for a water barrel or a burn barrel or scrap ect.

Compressed air (gases) can be extremely hazardous, when pressurized they
store incredible amounts of energy and cause severe damage when released
uncontrolled.

YMMV

Be VERY Carefull

Andrew

wwsnot wrote:

Hi guys,

I am trying to re-hab an old Curtis air tank for home shop use @ 125 psi.
It is OLD, as in rolled plate, riveted, with the seam filled with a
silver color metal.
The drain bung is almost rusted out, so I drilled and tapped it for
1/2'' pipe,
still only 1/8'' thread. Will weld in a bushing for 3/8" pipe to fit a
drain cock.

Question is: does anyone here have an idea what the silver filler is? It
seems too hard for solder.

Thanks, wws.

Silver solder. Best bet, anyway.

Cheers
Trevor Jones

I just went through a similar situation. Ultimately I trashed an old
tank for a new 26 gallon tank I purchased for $75 at Cummins with a
drain cock and a check valve already installed. You really have no idea
what condition the rest of your tank is in. Anything special about the
tank that you just wouldn't replace it with a new tank? Seems like
you're throwing a lot of time and good money at something that should
be replaced for safety reasons anyway.
-M

On Thu, 19 Jan 2006 11:54:46 GMT, wwsnot
wrote:

Hi guys,

I am trying to re-hab an old Curtis air tank for home shop use @ 125 psi.
It is OLD, as in rolled plate, riveted, with the seam filled with a
silver color metal.
The drain bung is almost rusted out, so I drilled and tapped it for
1/2'' pipe,
still only 1/8'' thread. Will weld in a bushing for 3/8" pipe to fit a
drain cock.

Question is: does anyone here have an idea what the silver filler is? It
seems too hard for solder.

Thanks, wws.

Just a note that generally riveted lap-seam tanks and steam engine
boilers are condemned on general principles for very little
provocation - it's just impossible to tell what condition that seam
and the rivets in it are in without destructive testing, and they can
unzip without warning. Compressed air doesn't have the 'flash into
steam' factor that a boiler does, but the tank rupturing still
releases a whole lot of stored energy and can easily kill anyone in
the area when it lets go.

And your note about the drain bung being almost rusted out is VERY
troubling - old tanks like that can be repaired by cutting out the
rusty spots, fabricating patches out of new plate and welding them up,
but you are going to have a whole lot of time and money invested by
the time you are done.

What's worse is, you know the metallurgy of the new steel in the
patch, but the stuff the old tank is made of is questionable at best.
Look at the Titanic - they sideswiped an iceberg that should have
bounced off with a big dent, and the steel failed. Very brittle at
low temps. They had no idea at the time what they were doing wrong.

They usually only invest effort like that into repairing rusted-out
corners and low spots on antique steam engine boilers - and even at
that, when they get too bad to patch they will start over and
fabricate a brand new boiler out of modern materials to the same
dimensions, just so they know it's safe for continued use.

I would err on the side of caution and get a new welded receiver
that meets all the ASME codes. People restoring old equipment take a
new tank and apply fake rivet heads to make it 'look right'. (They
hide the modern inspection info plate on the back side.)

The old tank is worth more as an old tank than as an operating air
receiver - There are lots of artsy places that will pay good money for
an old riveted tank like that to use it as outdoor decoration,
standing next to an old Fairbanks-Morse stationary steam engine...

If you really want to use that old tank (damn the expense), spend
the money and find an expert Boiler and Pressure Vessel Inspector to
check it over first. The life you save may be your own - or to be
very crude in getting my point across: Do any other family members
ever go into your shop? Do you want THAT on your conscience?

-- Bruce --

--
Bruce L. Bergman, Woodland Hills (Los Angeles) CA - Desktop
Electrician for Westend Electric - CA726700
5737 Kanan Rd. #359, Agoura CA 91301 (818) 889-9545
Spamtrapped address: Remove the python and the invalid, and use a net.

Bruce L. Bergman wrote:
On Thu, 19 Jan 2006 11:54:46 GMT, wwsnot
wrote:


Hi guys,

I am trying to re-hab an old Curtis air tank for home shop use @ 125 psi.
It is OLD, as in rolled plate, riveted, with the seam filled with a
silver color metal.
The drain bung is almost rusted out, so I drilled and tapped it for
1/2'' pipe,
still only 1/8'' thread. Will weld in a bushing for 3/8" pipe to fit a
drain cock.

Question is: does anyone here have an idea what the silver filler is? It
seems too hard for solder.

Thanks, wws.


Just a note that generally riveted lap-seam tanks and steam engine
boilers are condemned on general principles for very little
provocation - it's just impossible to tell what condition that seam
and the rivets in it are in without destructive testing, and they can
unzip without warning. Compressed air doesn't have the 'flash into
steam' factor that a boiler does, but the tank rupturing still
releases a whole lot of stored energy and can easily kill anyone in
the area when it lets go.

And your note about the drain bung being almost rusted out is VERY
troubling - old tanks like that can be repaired by cutting out the
rusty spots, fabricating patches out of new plate and welding them up,
but you are going to have a whole lot of time and money invested by
the time you are done.

What's worse is, you know the metallurgy of the new steel in the
patch, but the stuff the old tank is made of is questionable at best.
Look at the Titanic - they sideswiped an iceberg that should have
bounced off with a big dent, and the steel failed. Very brittle at
low temps. They had no idea at the time what they were doing wrong.

They usually only invest effort like that into repairing rusted-out
corners and low spots on antique steam engine boilers - and even at
that, when they get too bad to patch they will start over and
fabricate a brand new boiler out of modern materials to the same
dimensions, just so they know it's safe for continued use.

I would err on the side of caution and get a new welded receiver
that meets all the ASME codes. People restoring old equipment take a
new tank and apply fake rivet heads to make it 'look right'. (They
hide the modern inspection info plate on the back side.)

The old tank is worth more as an old tank than as an operating air
receiver - There are lots of artsy places that will pay good money for
an old riveted tank like that to use it as outdoor decoration,
standing next to an old Fairbanks-Morse stationary steam engine...

If you really want to use that old tank (damn the expense), spend
the money and find an expert Boiler and Pressure Vessel Inspector to
check it over first. The life you save may be your own - or to be
very crude in getting my point across: Do any other family members
ever go into your shop? Do you want THAT on your conscience?

-- Bruce --

Thanks Bruce, et al.
The as art option is something that probably would not cross my mind
anytime soon.
I'm quite leery of this tank as well.
If my donor would like to dig a 2' hole 6' deep out in the backyard,
I'll test it under pressure.
A plumber suggested a water heater tank as a temporary replacement.
Maybe I'll do that instead, my air tools only need 90 psi anyways.

wws

wwsnot wrote:

Hi guys,

I am trying to re-hab an old Curtis air tank for home shop use @ 125
psi.
It is OLD, as in rolled plate, riveted, with the seam filled with a
silver color metal.
The drain bung is almost rusted out, so I drilled and tapped it for
1/2'' pipe,
still only 1/8'' thread. Will weld in a bushing for 3/8" pipe to fit a
drain cock.

Stop! NOW! Do not pressurize this tank. Have you ever seen an air
receiver
explosion? I haven't, but have seen the remains of the exploded tanks! I'm
glad I was spared the scene the paramedics and the coroner had to view.
It isn't as bad as a pipe bomb, but it is DAMN close. Actually, it can
be more
dangerous, because a pipe bomb will only kill people in the room with
it, but
a burst air tank can bring the entire building down on you after the
walls have
blown out.

If the drain plug is rusted out, what is the condition of the bottom of
the tank?
If it is significantly rusted, it is dangerous.

I just would not use anything this old without at least a hydro test.
I'm sure,
however, that no one in their right mind would do the hydro test for you.

Please take my word for this, you are dealing with a SERIOUS safety
issue here!

Jon

I'd scrap it, but if you insist that you want to
use it,pressure test it with water to twice the
pressure that you intend to use it. The water
doesn't store much energy when you compress it so
if it lets go, it will just squirt.

I've scrapped better sounding vessels, out of self
preservation .


Tom

"wwsjr" wrote in message
. net...
Bruce L. Bergman wrote:
On Thu, 19 Jan 2006 11:54:46 GMT, wwsnot

wrote:


Hi guys,

I am trying to re-hab an old Curtis air tank
for home shop use @ 125 psi.
It is OLD, as in rolled plate, riveted, with
the seam filled with a silver color metal.
The drain bung is almost rusted out, so I
drilled and tapped it for 1/2'' pipe,
still only 1/8'' thread. Will weld in a bushing
for 3/8" pipe to fit a drain cock.

Question is: does anyone here have an idea what
the silver filler is? It seems too hard for
solder.

Thanks, wws.


Just a note that generally riveted lap-seam
tanks and steam engine
boilers are condemned on general principles for
very little
provocation - it's just impossible to tell what
condition that seam
and the rivets in it are in without destructive
testing, and they can
unzip without warning. Compressed air doesn't
have the 'flash into
steam' factor that a boiler does, but the tank
rupturing still
releases a whole lot of stored energy and can
easily kill anyone in
the area when it lets go.

And your note about the drain bung being
almost rusted out is VERY
troubling - old tanks like that can be repaired
by cutting out the
rusty spots, fabricating patches out of new
plate and welding them up,
but you are going to have a whole lot of time
and money invested by
the time you are done.

What's worse is, you know the metallurgy of
the new steel in the
patch, but the stuff the old tank is made of is
questionable at best.
Look at the Titanic - they sideswiped an
iceberg that should have
bounced off with a big dent, and the steel
failed. Very brittle at
low temps. They had no idea at the time what
they were doing wrong.

They usually only invest effort like that
into repairing rusted-out
corners and low spots on antique steam engine
boilers - and even at
that, when they get too bad to patch they will
start over and
fabricate a brand new boiler out of modern
materials to the same
dimensions, just so they know it's safe for
continued use.

I would err on the side of caution and get a
new welded receiver
that meets all the ASME codes. People
restoring old equipment take a
new tank and apply fake rivet heads to make it
'look right'. (They
hide the modern inspection info plate on the
back side.)

The old tank is worth more as an old tank
than as an operating air
receiver - There are lots of artsy places that
will pay good money for
an old riveted tank like that to use it as
outdoor decoration,
standing next to an old Fairbanks-Morse
stationary steam engine...

If you really want to use that old tank (damn
the expense), spend
the money and find an expert Boiler and
Pressure Vessel Inspector to
check it over first. The life you save may be
your own - or to be
very crude in getting my point across: Do any
other family members
ever go into your shop? Do you want THAT on
your conscience?

-- Bruce --

Thanks Bruce, et al.
The as art option is something that probably
would not cross my mind
anytime soon.
I'm quite leery of this tank as well.
If my donor would like to dig a 2' hole 6' deep
out in the backyard,
I'll test it under pressure.
A plumber suggested a water heater tank as a
temporary replacement.
Maybe I'll do that instead, my air tools only
need 90 psi anyways.

wws

On a related note, a nearby testing facility got a contract to simulate
a backhoe striking a 24" diameter high pressure natural gas line. The
concern was that line high pressure lines would rip lengthwise until
meeting a flange or valve. For the first simulation they buried a 20'
long section of pipe, 6 foot down. It was then pressurized to 1000
psi. with nitrogen. The backfilled area was covered with several very
heavy blasting mats that were covered with sand bags. A small shaped
charge had also been attached to the outside wall of the pipe to make a
small cut similar to what a backhoe bucket tooth would do.
Everyone retired to a bunker about 500 feet away. What happened when
the button was pressed amazed ...and then concerned everyone..the 2000
lb blasting mats were way up in the air..and starting to come down!
Luckily they did not land on the bunker roof. Shreaded sand bags were
hanging form trees.

Jon Elson wrote:
wwsnot wrote:

Hi guys,

I am trying to re-hab an old Curtis air tank for home shop use @ 125
psi.
It is OLD, as in rolled plate, riveted, with the seam filled with a
silver color metal.
The drain bung is almost rusted out, so I drilled and tapped it for
1/2'' pipe,
still only 1/8'' thread. Will weld in a bushing for 3/8" pipe to fit a
drain cock.

Stop! NOW! Do not pressurize this tank. Have you ever seen an air
receiver
explosion? I haven't, but have seen the remains of the exploded tanks! I'm
glad I was spared the scene the paramedics and the coroner had to view.
It isn't as bad as a pipe bomb, but it is DAMN close. Actually, it can
be more
dangerous, because a pipe bomb will only kill people in the room with
it, but
a burst air tank can bring the entire building down on you after the
walls have
blown out.

If the drain plug is rusted out, what is the condition of the bottom of
the tank?
If it is significantly rusted, it is dangerous.

I just would not use anything this old without at least a hydro test.
I'm sure,
however, that no one in their right mind would do the hydro test for you.

Please take my word for this, you are dealing with a SERIOUS safety
issue here!

Jon

On 19 Jan 2006 17:18:40 -0800, "oldjag"
wrote:

On a related note, a nearby testing facility got a contract to simulate
a backhoe striking a 24" diameter high pressure natural gas line. The
concern was that line high pressure lines would rip lengthwise until
meeting a flange or valve. For the first simulation they buried a 20'
long section of pipe, 6 foot down. It was then pressurized to 1000
psi. with nitrogen. The backfilled area was covered with several very
heavy blasting mats that were covered with sand bags. A small shaped
charge had also been attached to the outside wall of the pipe to make a
small cut similar to what a backhoe bucket tooth would do.
Everyone retired to a bunker about 500 feet away. What happened when
the button was pressed amazed ...and then concerned everyone..the 2000
lb blasting mats were way up in the air..and starting to come down!
Luckily they did not land on the bunker roof. Shreaded sand bags were
hanging form trees.

Holy Sheeeeit.

Now try it again, this time with 1000 PSI of real natural gas and
enough volume to simulate a real pipeline, and a few ignition sources
like an idling backhoe. But before you touch off that little squib,
I'd stand WAY back. Like a half-mile or so...

Oh, another impressive KABOOM is to take a 30-gallon water heater,
fill it to the top with water, and plug all openings. Disable the
thermostat, and superheat the water to somewhere above 225F... Then
take a .22 rifle and pop a small hole in the tank - again, this is
another instance where you want to be WAY FAR BACK when you do it.

Watts Regulator (the people who make T&P Relief Valves) did this and
filmed it back in the 1950's - rather impressive.

When we say "Kids, Don't try this at home!" we MEAN it.

-- Bruce --

--
Bruce L. Bergman, Woodland Hills (Los Angeles) CA - Desktop
Electrician for Westend Electric - CA726700
5737 Kanan Rd. #359, Agoura CA 91301 (818) 889-9545
Spamtrapped address: Remove the python and the invalid, and use a net.

Don't need an ignition source. The static electricity from the outpouring
gas will take care of it.
Karl

"Bruce L. Bergman" wrote in message
...
On 19 Jan 2006 17:18:40 -0800, "oldjag"
wrote:

On a related note, a nearby testing facility got a contract to simulate
a backhoe striking a 24" diameter high pressure natural gas line. The
concern was that line high pressure lines would rip lengthwise until
meeting a flange or valve. For the first simulation they buried a 20'
long section of pipe, 6 foot down. It was then pressurized to 1000
psi. with nitrogen. The backfilled area was covered with several very
heavy blasting mats that were covered with sand bags. A small shaped
charge had also been attached to the outside wall of the pipe to make a
small cut similar to what a backhoe bucket tooth would do.
Everyone retired to a bunker about 500 feet away. What happened when
the button was pressed amazed ...and then concerned everyone..the 2000
lb blasting mats were way up in the air..and starting to come down!
Luckily they did not land on the bunker roof. Shreaded sand bags were
hanging form trees.

Holy Sheeeeit.

Now try it again, this time with 1000 PSI of real natural gas and
enough volume to simulate a real pipeline, and a few ignition sources
like an idling backhoe. But before you touch off that little squib,
I'd stand WAY back. Like a half-mile or so...

Oh, another impressive KABOOM is to take a 30-gallon water heater,
fill it to the top with water, and plug all openings. Disable the
thermostat, and superheat the water to somewhere above 225F... Then
take a .22 rifle and pop a small hole in the tank - again, this is
another instance where you want to be WAY FAR BACK when you do it.

Watts Regulator (the people who make T&P Relief Valves) did this and
filmed it back in the 1950's - rather impressive.

When we say "Kids, Don't try this at home!" we MEAN it.

-- Bruce --

--
Bruce L. Bergman, Woodland Hills (Los Angeles) CA - Desktop
Electrician for Westend Electric - CA726700
5737 Kanan Rd. #359, Agoura CA 91301 (818) 889-9545
Spamtrapped address: Remove the python and the invalid, and use a net.

On Thu, 19 Jan 2006 22:27:04 GMT, wwsjr wrote:

If my donor would like to dig a 2' hole 6' deep out in the backyard,
I'll test it under pressure.

I watched an old guy pressure testing a riveted tank once, where he used
a stethoscope (rigid wooden one) to listen for creakings and groaning
around the rivets. You might note that neither of us were cowering away
from this thing behind blast walls! The tank was already over 100 years
old and was of finest Low Moor iron. These days I'd buy him a brand new
steel one and scrap the old wrought iron tank for art blacksmithing
stock!

When you pressure test you _ALWAYS_ hydraulically pressure test and you
take great care that there's no air bubble in there. As "water is
incompressible", then a high hydraulic pressure is easy to obtain and
represents little stored energy. If it leaks, then it ****es a little
water out, then stops - no big deal, no need for bunkers. Air needs
energy to compress it before you build up the pressure and it's this
stored energy that kills you.

You also pressure test with a HAND pump. If it takes too much effort to
pressurise it, you have an air bubble in there and it's getting
dangerous. All the energy you pump in is available to hurt you later -
so don't pump any harder than you want to be hit by.

Pressure testing is a good way to test for the integrity of a new
vessel, but it does nothing to measure corrosion and thinned plates that
could fail later. If you're testing an old vessel, then you need to use
NDT (ultrasound or similar) to measure wall thicknesses and look for
cracks. Then you can think about pressure testing it.

I forgot to mention that the 24" pipe was neatly split from end to end
as had been predicted. Looked just like a very large steel canoe. The
rip stopped at the dished heads on each end and was very uniform. I
have since heard of high pressure natual gas lines ripping for several
miles after failing due to damage from impact or internal
damage...evidently once a fracture starts, it can continue at very high
speed with relatively low energy input until a flange or valve stops
its progress. I wonder what precautions gas pipeline companies may or
may not now use to prevent such scenerios where lines go thru populated
areas? I know they do some internal testing with intrumented pigs for
flaw testing and I guess they are usually buried fairly deep but...