Keith Nuttle wrote in :

I would believe that a cast iron boiler is several times thicker that an
air compressor tank. I am sure the radiator is.

Indeed it is. But the water sits there longer, too. The point remains that once the oxygen in the
system is used up, no further oxidation (read: rusting) can take place unless fresh oxygen is
introduced.

On Sunday, May 5, 2013 8:57:31 PM UTC-5, woodchucker wrote:
Sounds like that might not be a bad idea. how do I neutralize the muriatic acid in the tank after, just water or baking soda...

Flush with water. It shouldn't take much acid (1-2 cups) to rinse/slosh the bottom of the tank, where there would likely be the most rust. Concrete is cleaned with muratic acid and simply rinsed with water. The old saying is to add acid to water, to prevent a splattering reaction when mixing the two. In this situation, adding water to the acid (to neutralize it), inside the tank, shouldn't be a problem, plus it would be difficult to pour out the acid, first, into a safe container without having it pour irradically from the petcock hole. Further, pour the mix into a 5 gal bucket of water, to further dilute it.

Will that clean off most of the loose rust?

Maybe/yes, to some extent. I've used it to assist in removing rust on stuff at home(shop) and used it on (our past) boat dock surfaces. Since you can't readily see inside the tank, we don't know if there is significant rust in there, or not. Muratic acid is more readily available, I think, and will help loosen at least some rust without having to scrub, since you can't readily scrub the inside. Any potential loose rust may block the petcock, in the future, so removing the most you can is preferrable. Using acid is the easiest way, IMO, hence my entertaining the idea of using the acid as a "rinse" or possible (assistant) rust remover.

Summer jobs, during college days, I worked on a dredge boat/barge along the Gulf coast. There were times when we'd clean parts of the deck for repainting. An acid was used to help remove (or treat?) the rusted areas. I don't recall what acid was used. We'd slosh it on, do some minimal scrubbing, then rinse with water. On tough or deeply rusted areas, we'd use a grinder to remove the rust, best we could. Apparently the acid "treatment" did some kind of good.

Muratic acid is pretty potent. If spilled on the outside of the tank, it will likely peel the paint off, fast.

Sonny

"Lew Hodgett" wrote in news:51872d87$0$28468$c3e8da3
:




Lew Hodgett wrote:

Don't want to rain on your parade, but how big do you think those
pressure
cookers in Boston were/are?

BTW, a pressure relief valve is a must.

Even your hot water tank has one.
------------------------------------------------------------------

"-MIKE-" wrote:

I hope you're joking.
There was a lot more than air in those things.
--------------------------------------------------------------
Absolutely not kidding, shrapnel is shrapnel regardless of the source.

For someone who claims to be an engineer, you have some odd notions. Those pressure
cookers were ruptured by exploding gunpowder. Do you *really* think that the pressure
developed by an air compressor (9 to 10 atmospheres is typical) is anywhere nearly
comparable to the pressure developed by igniting gunpowder in a small confined volume?
Do you *really* think that a bursting compressor tank will create the same kind of
"shrapnel" as a pressure cooker that was packed with ball bearings and nails?

On Mon, 06 May 2013 11:34:44 +0000, Doug Miller wrote:

Do you *really*
think that the pressure developed by an air compressor (9 to 10
atmospheres is typical) is anywhere nearly comparable to the pressure
developed by igniting gunpowder in a small confined volume?

I found this:

"One gram of blackpowder gives you 718 calories of heat, 270 cubic
centimeters of gas,"

So if we knew how much powder the bombers used and the volume of the
pressure cooker we could come up with a pressure.

--
When fascism comes to America, it will be wrapped in the flag and
carrying a cross.

Larry Blanchard wrote in :

On Mon, 06 May 2013 11:34:44 +0000, Doug Miller wrote:

Do you *really*
think that the pressure developed by an air compressor (9 to 10
atmospheres is typical) is anywhere nearly comparable to the pressure
developed by igniting gunpowder in a small confined volume?

I found this:

"One gram of blackpowder gives you 718 calories of heat, 270 cubic
centimeters of gas,"

So if we knew how much powder the bombers used and the volume of the
pressure cooker we could come up with a pressure.

Typical pressure cooker is about 5 liters. It would take 5000 / 270 = 18.5 grams of black
powder to produce 5 l of gas at 1 atm pressure -- so developing a pressure of, say, 25
atmospheres would require 25 times that much: 463 g, or just over a pound.

And that's assuming there's nothing else in the pressure cooker, which we know is not the
case. Suppose the interior volume was reduced by half, by the ball bearings and nails
these guys added. In that case, we're talking a free volume of only about 2.5 liters, and a
kilogram of powder would generate pressure well over 100 atmospheres.

On Mon, 6 May 2013 17:14:58 +0000 (UTC), Doug Miller
wrote:

Larry Blanchard wrote in :

On Mon, 06 May 2013 11:34:44 +0000, Doug Miller wrote:

Do you *really*
think that the pressure developed by an air compressor (9 to 10
atmospheres is typical) is anywhere nearly comparable to the pressure
developed by igniting gunpowder in a small confined volume?

I found this:

"One gram of blackpowder gives you 718 calories of heat, 270 cubic
centimeters of gas,"

So if we knew how much powder the bombers used and the volume of the
pressure cooker we could come up with a pressure.

Typical pressure cooker is about 5 liters. It would take 5000 / 270 = 18.5 grams of black
powder to produce 5 l of gas at 1 atm pressure -- so developing a pressure of, say, 25
atmospheres would require 25 times that much: 463 g, or just over a pound.

And that's assuming there's nothing else in the pressure cooker, which we know is not the
case. Suppose the interior volume was reduced by half, by the ball bearings and nails
these guys added. In that case, we're talking a free volume of only about 2.5 liters, and a
kilogram of powder would generate pressure well over 100 atmospheres.

Assuming that it didn't rupture first.

I know it isn't near as much of an adventure when compared to acid
washes, cleaning rust and sealing, ultrasound inspections, and all
other kinds of solutions, but why not just buy a new tank and be done
with it?

http://tinyurl.com/cptqhe4

You could even wait for the ever present 20% off coupon.

We have done this to several compressors over the years. I have seen
tanks leak, but never rupture. What I see is tanks damaged badly
enough from dropping the compressors while loading or unloading them
for daily use, loading material on top of them, and then just plain
wear and tear from carrying them from job to job.

To do this easily, the original tank assembly is bypassed or removed,
and in some cases the motor/head is mounted to something else, and
this tank along with a manifold is used to replace the original. You
cannot mount a motor/head to this as purchased, so this is a perfect
time to put the compressor in its own little corner and the tank out
of the way. All you need to connect the two is inexpensive air hose.

Not as much fun as some of the ideas here, but if you leave the old
compressor on its original pinnings, you can be up and running with
one of these tanks in about 20 minutes. I have one of these (bought
mine at Northern) and it works great. I like the extra tank capacity,
too.

Robert

wrote in :

On Mon, 6 May 2013 17:14:58 +0000 (UTC), Doug Miller
wrote:

Larry Blanchard wrote in news:km8ne6$4hj$1
@speranza.aioe.org:

On Mon, 06 May 2013 11:34:44 +0000, Doug Miller wrote:

Do you *really*
think that the pressure developed by an air compressor (9 to 10
atmospheres is typical) is anywhere nearly comparable to the pressure
developed by igniting gunpowder in a small confined volume?

I found this:

"One gram of blackpowder gives you 718 calories of heat, 270 cubic
centimeters of gas,"

So if we knew how much powder the bombers used and the volume of the
pressure cooker we could come up with a pressure.

Typical pressure cooker is about 5 liters. It would take 5000 / 270 = 18.5 grams of black
powder to produce 5 l of gas at 1 atm pressure -- so developing a pressure of, say, 25
atmospheres would require 25 times that much: 463 g, or just over a pound.

And that's assuming there's nothing else in the pressure cooker, which we know is not the
case. Suppose the interior volume was reduced by half, by the ball bearings and nails
these guys added. In that case, we're talking a free volume of only about 2.5 liters, and a
kilogram of powder would generate pressure well over 100 atmospheres.

Assuming that it didn't rupture first.

Well, yes, but the point is that a consumer-grade air compressor can't even come close to
developing that kind of pressure.

On 5/6/2013 12:21 PM, wrote:
On Mon, 6 May 2013 17:14:58 +0000 (UTC), Doug Miller
wrote:

Larry Blanchard wrote in :

On Mon, 06 May 2013 11:34:44 +0000, Doug Miller wrote:

Do you *really*
think that the pressure developed by an air compressor (9 to 10
atmospheres is typical) is anywhere nearly comparable to the pressure
developed by igniting gunpowder in a small confined volume?

I found this:

"One gram of blackpowder gives you 718 calories of heat, 270 cubic
centimeters of gas,"

So if we knew how much powder the bombers used and the volume of the
pressure cooker we could come up with a pressure.

Typical pressure cooker is about 5 liters. It would take 5000 / 270 = 18.5 grams of black
powder to produce 5 l of gas at 1 atm pressure -- so developing a pressure of, say, 25
atmospheres would require 25 times that much: 463 g, or just over a pound.

And that's assuming there's nothing else in the pressure cooker, which we know is not the
case. Suppose the interior volume was reduced by half, by the ball bearings and nails
these guys added. In that case, we're talking a free volume of only about 2.5 liters, and a
kilogram of powder would generate pressure well over 100 atmospheres.

Assuming that it didn't rupture first.



Pressure cookers are designed to release pressure, that hissing you
hear, at 15 lbs.

Leon lcb11211@swbelldotnet wrote in
:

Pressure cookers are designed to release pressure, that hissing you
hear, at 15 lbs.

It's not very hard to remove the safety valve and replace it with a nut and bolt.

On Mon, 6 May 2013 18:20:30 +0000 (UTC), Doug Miller
wrote:

wrote in :

On Mon, 6 May 2013 17:14:58 +0000 (UTC), Doug Miller
wrote:

Larry Blanchard wrote in news:km8ne6$4hj$1
:

On Mon, 06 May 2013 11:34:44 +0000, Doug Miller wrote:

Do you *really*
think that the pressure developed by an air compressor (9 to 10
atmospheres is typical) is anywhere nearly comparable to the pressure
developed by igniting gunpowder in a small confined volume?

I found this:

"One gram of blackpowder gives you 718 calories of heat, 270 cubic
centimeters of gas,"

So if we knew how much powder the bombers used and the volume of the
pressure cooker we could come up with a pressure.

Typical pressure cooker is about 5 liters. It would take 5000 / 270 = 18.5 grams of black
powder to produce 5 l of gas at 1 atm pressure -- so developing a pressure of, say, 25
atmospheres would require 25 times that much: 463 g, or just over a pound.

And that's assuming there's nothing else in the pressure cooker, which we know is not the
case. Suppose the interior volume was reduced by half, by the ball bearings and nails
these guys added. In that case, we're talking a free volume of only about 2.5 liters, and a
kilogram of powder would generate pressure well over 100 atmospheres.

Assuming that it didn't rupture first.

Well, yes, but the point is that a consumer-grade air compressor can't even come close to
developing that kind of pressure.

A pressure cooker can't either.

On Mon, 06 May 2013 14:37:18 -0500, Leon lcb11211@swbelldotnet
wrote:

On 5/6/2013 12:21 PM, wrote:
On Mon, 6 May 2013 17:14:58 +0000 (UTC), Doug Miller
wrote:

Larry Blanchard wrote in :

On Mon, 06 May 2013 11:34:44 +0000, Doug Miller wrote:

Do you *really*
think that the pressure developed by an air compressor (9 to 10
atmospheres is typical) is anywhere nearly comparable to the pressure
developed by igniting gunpowder in a small confined volume?

I found this:

"One gram of blackpowder gives you 718 calories of heat, 270 cubic
centimeters of gas,"

So if we knew how much powder the bombers used and the volume of the
pressure cooker we could come up with a pressure.

Typical pressure cooker is about 5 liters. It would take 5000 / 270 = 18.5 grams of black
powder to produce 5 l of gas at 1 atm pressure -- so developing a pressure of, say, 25
atmospheres would require 25 times that much: 463 g, or just over a pound.

And that's assuming there's nothing else in the pressure cooker, which we know is not the
case. Suppose the interior volume was reduced by half, by the ball bearings and nails
these guys added. In that case, we're talking a free volume of only about 2.5 liters, and a
kilogram of powder would generate pressure well over 100 atmospheres.

Assuming that it didn't rupture first.



Pressure cookers are designed to release pressure, that hissing you
hear, at 15 lbs.

Sure, but that's not going to relieve much of the blast pressure. What
does mean, I suppose, is that the cooker is only designed for 1ATM, or
so (*much* less than a compressor tank).

It's very rare for an air compressor tank to violently explode. In cases
where it did happen, usually there was defective construction, the
the compressor had been modified, relief valve stuck closed, etc. A
rusty tank will almost always fail with a pinhole leak or small crack.
I would turn the compressor upside down and tap all over the bottom with
a small hammer. You will hear or feel any thin spots.

You could also have it hydro-tested. This is a requirement for
industrial pressure vessles over a certain size in most states but
perhaps you could find someone willing to test your small compressor the
same way. I think you could do a fair job of testing it yourself by
filling the tank with water and then pressurizing it to about 10% over
it's nominal pressure rating. Personally, I would be satisifed with the
hammer-tap test.


--
Better to be stuck up in a tree than tied to one.

Larry W. - Baltimore Maryland - lwasserm(a)sdf. lonestar.org

On 5/6/2013 2:47 PM, Doug Miller wrote:
Leon lcb11211@swbelldotnet wrote in
:

Pressure cookers are designed to release pressure, that hissing you
hear, at 15 lbs.

It's not very hard to remove the safety valve and replace it with a nut and bolt.


Correct. You would also have to defeat the secondary pressure relief
and probably glue the lid on.

I made this comment more to address Lew's comment when comparing
pressure in a compressor to a pressure cooker being an explosive container.

The compressor in no way would possibly have a comparable amount of
pressure that the pressure cooker with the explosives had nor would it
come apart the same should it fail under normal operating conditions.


Relatively speaking I seriously doubt that a pressure cooker would
contain the extreme pressure generated in an explosive inside more than
say a shoe box. With every thing that was in the pressure cooker to
create the damage the weight would have probably been too great for a
shoe box to hold up. I wold be willing to bet the the lids gave way first.

On 5/6/2013 4:23 PM, wrote:
On Mon, 06 May 2013 14:37:18 -0500, Leon lcb11211@swbelldotnet
wrote:

On 5/6/2013 12:21 PM, wrote:
On Mon, 6 May 2013 17:14:58 +0000 (UTC), Doug Miller
wrote:

Larry Blanchard wrote in :

On Mon, 06 May 2013 11:34:44 +0000, Doug Miller wrote:

Do you *really*
think that the pressure developed by an air compressor (9 to 10
atmospheres is typical) is anywhere nearly comparable to the pressure
developed by igniting gunpowder in a small confined volume?

I found this:

"One gram of blackpowder gives you 718 calories of heat, 270 cubic
centimeters of gas,"

So if we knew how much powder the bombers used and the volume of the
pressure cooker we could come up with a pressure.

Typical pressure cooker is about 5 liters. It would take 5000 / 270 = 18.5 grams of black
powder to produce 5 l of gas at 1 atm pressure -- so developing a pressure of, say, 25
atmospheres would require 25 times that much: 463 g, or just over a pound.

And that's assuming there's nothing else in the pressure cooker, which we know is not the
case. Suppose the interior volume was reduced by half, by the ball bearings and nails
these guys added. In that case, we're talking a free volume of only about 2.5 liters, and a
kilogram of powder would generate pressure well over 100 atmospheres.

Assuming that it didn't rupture first.



Pressure cookers are designed to release pressure, that hissing you
hear, at 15 lbs.

Sure, but that's not going to relieve much of the blast pressure. What
does mean, I suppose, is that the cooker is only designed for 1ATM, or
so (*much* less than a compressor tank).


That is what I was getting at. I am sure the lids popped off first. I
think pressure cookers were used simply because they are relative strong
for carrying weight and are not them selves heavy. It was the exploding
contents, not the pressure build up because of the pressure cookers
ability to hold pressure that caused the damage. Sure it was part of
the shrapnel but a metal ammo box would have done the same thing.

wrote in :

On Mon, 6 May 2013 18:20:30 +0000 (UTC), Doug Miller
wrote:

wrote in :

On Mon, 6 May 2013 17:14:58 +0000 (UTC), Doug Miller
wrote:

Larry Blanchard wrote in news:km8ne6$4hj$1
:

On Mon, 06 May 2013 11:34:44 +0000, Doug Miller wrote:

Do you *really*
think that the pressure developed by an air compressor (9 to 10
atmospheres is typical) is anywhere nearly comparable to the pressure
developed by igniting gunpowder in a small confined volume?

I found this:

"One gram of blackpowder gives you 718 calories of heat, 270 cubic
centimeters of gas,"

So if we knew how much powder the bombers used and the volume of the
pressure cooker we could come up with a pressure.

Typical pressure cooker is about 5 liters. It would take 5000 / 270 = 18.5 grams of black
powder to produce 5 l of gas at 1 atm pressure -- so developing a pressure of, say, 25
atmospheres would require 25 times that much: 463 g, or just over a pound.

And that's assuming there's nothing else in the pressure cooker, which we know is not
the
case. Suppose the interior volume was reduced by half, by the ball bearings and nails
these guys added. In that case, we're talking a free volume of only about 2.5 liters, and
a
kilogram of powder would generate pressure well over 100 atmospheres.

Assuming that it didn't rupture first.

Well, yes, but the point is that a consumer-grade air compressor can't even come close
to
developing that kind of pressure.

A pressure cooker can't either.

Did this discussion ruffle your hair at all?

On Mon, 6 May 2013 22:29:03 +0000 (UTC), Doug Miller
wrote:

wrote in :

On Mon, 6 May 2013 18:20:30 +0000 (UTC), Doug Miller
wrote:

wrote in :

On Mon, 6 May 2013 17:14:58 +0000 (UTC), Doug Miller
wrote:

Larry Blanchard wrote in news:km8ne6$4hj$1
:

On Mon, 06 May 2013 11:34:44 +0000, Doug Miller wrote:

Do you *really*
think that the pressure developed by an air compressor (9 to 10
atmospheres is typical) is anywhere nearly comparable to the pressure
developed by igniting gunpowder in a small confined volume?

I found this:

"One gram of blackpowder gives you 718 calories of heat, 270 cubic
centimeters of gas,"

So if we knew how much powder the bombers used and the volume of the
pressure cooker we could come up with a pressure.

Typical pressure cooker is about 5 liters. It would take 5000 / 270 = 18.5 grams of black
powder to produce 5 l of gas at 1 atm pressure -- so developing a pressure of, say, 25
atmospheres would require 25 times that much: 463 g, or just over a pound.

And that's assuming there's nothing else in the pressure cooker, which we know is not
the
case. Suppose the interior volume was reduced by half, by the ball bearings and nails
these guys added. In that case, we're talking a free volume of only about 2.5 liters, and
a
kilogram of powder would generate pressure well over 100 atmospheres.

Assuming that it didn't rupture first.

Well, yes, but the point is that a consumer-grade air compressor can't even come close
to
developing that kind of pressure.

A pressure cooker can't either.

Did this discussion ruffle your hair at all?

Of course not. My hair comes pre-ruffled. You're not going to change
it.

On 5/6/13 4:20 PM, wrote:

Assuming that it didn't rupture first.

Well, yes, but the point is that a consumer-grade air compressor can't even come close to
developing that kind of pressure.

A pressure cooker can't either.


Gun power can.


--

-MIKE-

"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com

---remove "DOT" ^^^^ to reply

On Mon, 06 May 2013 18:33:16 -0500, -MIKE-
wrote:

On 5/6/13 4:20 PM, wrote:

Assuming that it didn't rupture first.

Well, yes, but the point is that a consumer-grade air compressor can't even come close to
developing that kind of pressure.

A pressure cooker can't either.


Gun power can.

Only if contained. Gun powder a low explosive (the shock wave is
sub-sonic in the powder) and will not explode unless it's contained. A
pressure cooker isn't the best pressure vessel for this sort of thing,
either.

Although this wasn't gun powder, either. It was flash powder
(fireworks), which has a higher burn rate (usually contains metal
powder).

wrote:
On Mon, 06 May 2013 18:33:16 -0500, -MIKE-
wrote:

On 5/6/13 4:20 PM, wrote:

Assuming that it didn't rupture first.

Well, yes, but the point is that a consumer-grade air compressor can't
even come close to
developing that kind of pressure.

A pressure cooker can't either.


Gun power can.

Only if contained. Gun powder a low explosive (the shock wave is
sub-sonic in the powder) and will not explode unless it's contained. A
pressure cooker isn't the best pressure vessel for this sort of thing,
either.

Although this wasn't gun powder, either. It was flash powder
(fireworks), which has a higher burn rate (usually contains metal
powder).

Yep, and also depends upon the sensitivity of the explosive on whether it
needs a primary explosion (blasting cap) to activate, otherwise it just
burns. Cooked my meals, by boiling water for LRP rations, with explosives
(C4) for the better part of 7 months, using a thumb sized chunk, in a
C-ration peach can "stove" vented with holes made by a church key.

--
www.ewoodshop.com (Mobile)

"Leon" wrote in message
...

On 5/6/2013 4:23 PM, wrote:
On Mon, 06 May 2013 14:37:18 -0500, Leon lcb11211@swbelldotnet
wrote:

On 5/6/2013 12:21 PM, wrote:
On Mon, 6 May 2013 17:14:58 +0000 (UTC), Doug Miller
wrote:

Larry Blanchard wrote in
:

On Mon, 06 May 2013 11:34:44 +0000, Doug Miller wrote:

Do you *really*
think that the pressure developed by an air compressor (9 to 10
atmospheres is typical) is anywhere nearly comparable to the pressure
developed by igniting gunpowder in a small confined volume?

I found this:

"One gram of blackpowder gives you 718 calories of heat, 270 cubic
centimeters of gas,"

So if we knew how much powder the bombers used and the volume of the
pressure cooker we could come up with a pressure.

Typical pressure cooker is about 5 liters. It would take 5000 / 270 =
18.5 grams of black
powder to produce 5 l of gas at 1 atm pressure -- so developing a
pressure of, say, 25
atmospheres would require 25 times that much: 463 g, or just over a
pound.

And that's assuming there's nothing else in the pressure cooker, which
we know is not the
case. Suppose the interior volume was reduced by half, by the ball
bearings and nails
these guys added. In that case, we're talking a free volume of only
about 2.5 liters, and a
kilogram of powder would generate pressure well over 100 atmospheres.

Assuming that it didn't rupture first.



Pressure cookers are designed to release pressure, that hissing you
hear, at 15 lbs.

Sure, but that's not going to relieve much of the blast pressure. What
does mean, I suppose, is that the cooker is only designed for 1ATM, or
so (*much* less than a compressor tank).


That is what I was getting at. I am sure the lids popped off first. I
think pressure cookers were used simply because they are relative strong
for carrying weight and are not them selves heavy. It was the exploding
contents, not the pressure build up because of the pressure cookers
ability to hold pressure that caused the damage. Sure it was part of
the shrapnel but a metal ammo box would have done the same thing.
================================================== ======================
Black powder, unrestrained, will not explode. It will burn releasing its
energy into the atmosphere without much effect. It has to be compressed.
The pressure cooker is what makes it a bomb. On a stove, the pressure build
up is relatively slow, giving the top, the weakest part, time to distort and
separate. If it is filled with black powder, the pressure build up is so
fast that the lid does not have time to distort and detach itself. The
entire container will let loose. A weaker container such as an ammo can,
would not produce near the blast that a pressure cooker would.

On Sun, 05 May 2013 23:19:01 -0500, -MIKE-
wrote:

On 5/5/13 11:11 PM, Lew Hodgett wrote:
Lew Hodgett wrote:

Don't want to rain on your parade, but how big do you think those
pressure
cookers in Boston were/are?

BTW, a pressure relief valve is a must.

Even your hot water tank has one.
------------------------------------------------------------------

"-MIKE-" wrote:

I hope you're joking.
There was a lot more than air in those things.
--------------------------------------------------------------
Absolutely not kidding, shrapnel is shrapnel regardless of the source.

Lew


That's kind of the point. There is no shrapnel when an air tank "explodes."
Why do I keep putting explodes in quotation marks? Because of the very
misconception you have and others are having. The energy from a bursting
air tank is no where near enough to cause shrapnel.

The energy caused by gun powder is many multitudes higher than an air
tank. The velocity of the explosion is also many magnitudes higher.

Oh, and last time I looked at air compressors, non of the tanks were
packed with ball bearings, either. sheesh.


OK, when it comes to air receiver failures that cause damage or
injury, they are virtually NEVER rust related. They are almost always
brittle fractures - related to a bad weld or a fatigue crack - most
often a fatigue crack related to a bad weld. This caused a
catastrophic failure and instand decompression - which DOES cause
serious structural damage and can cause grievious injuries.

Rust failure is virtually ALWAYS a gradual failure, which causes
little if any damage or injury in the average small air receiver

On Mon, 6 May 2013 17:14:58 +0000 (UTC), Doug Miller
wrote:

Larry Blanchard wrote in :

On Mon, 06 May 2013 11:34:44 +0000, Doug Miller wrote:

Do you *really*
think that the pressure developed by an air compressor (9 to 10
atmospheres is typical) is anywhere nearly comparable to the pressure
developed by igniting gunpowder in a small confined volume?

I found this:

"One gram of blackpowder gives you 718 calories of heat, 270 cubic
centimeters of gas,"

So if we knew how much powder the bombers used and the volume of the
pressure cooker we could come up with a pressure.

Typical pressure cooker is about 5 liters. It would take 5000 / 270 = 18.5 grams of black
powder to produce 5 l of gas at 1 atm pressure -- so developing a pressure of, say, 25
atmospheres would require 25 times that much: 463 g, or just over a pound.

And that's assuming there's nothing else in the pressure cooker, which we know is not the
case. Suppose the interior volume was reduced by half, by the ball bearings and nails
these guys added. In that case, we're talking a free volume of only about 2.5 liters, and a
kilogram of powder would generate pressure well over 100 atmospheres.
ANd a pressure cooker is often made of CAST Aluminum - which is
fragile / brittle in nature.

Lew Hodgett wrote:

Don't want to rain on your parade, but how big do you think those
pressure
cookers in Boston were/are?

BTW, a pressure relief valve is a must.

Even your hot water tank has one.
------------------------------------------------------------------

"-MIKE-" wrote:

I hope you're joking.
There was a lot more than air in those things.
--------------------------------------------------------------
Lew Hodgett wrote:

Absolutely not kidding, shrapnel is shrapnel regardless of the
source.
------------------------------------------------------------------

"-MIKE-" wrote:

That's kind of the point. There is no shrapnel when an air tank
"explodes."
-----------------------------------------------------------------
Lew Hodgett wrote:

What do you call the parts of the vessel that are created when
a vessel bursts?

Chopped liver?

---------------------------------------------------------------------------------
"-MIKE-" wrote:

Why do I keep putting explodes in quotation marks? Because of the
very
misconception you have and others are having. The energy from a
bursting
air tank is no where near enough to cause shrapnel.

The energy caused by gun powder is many multitudes higher than an
air
tank. The velocity of the explosion is also many magnitudes higher.

Oh, and last time I looked at air compressors, non of the tanks were
packed with ball bearings, either. sheesh.
-----------------------------------------------------------------
Lew Hodgett wrote:

You seem to have difficulty understanding what is written.

I made no mention of gun powder, ball bearings or any other items of
IBS
(Intellectual Bull ****) you attempt to introduce to confuse the
issue.

My comment simply stated that the size of the vessel is totally
independent of it's ability to raise the havoc created if it were to
burst
in an area where people were assembled.

What causes a vessel to exceed design specifications and fail
by bursting is a totally different discussion.

What remains relevant is that if a vessel bursts in an occupied area,
chances are pretty good that somebody is going to get hurt.

Nothing more, nothing less.

Lew

On May 5, 7:14*pm, -MIKE- wrote:
On 5/5/13 6:26 PM, woodchucker wrote:









On 5/5/2013 6:45 PM, -MIKE- wrote:
On 5/5/13 4:21 PM, woodchucker wrote:
On 5/5/2013 5:16 PM, woodchucker wrote:
On 5/5/2013 4:56 PM, -MIKE- wrote:
On 5/5/13 2:53 PM, woodchucker wrote:
When I got it home still did not hear water in it...
opened up the petcock after charging it up and holy crap the most
rusted
water... and probably a pint to quart of water came out.

So what chance do I have of saving this tank?

I guess I don't understand what's to save.
Does it still compress air?
You drained out the water.
Put a filter on the output and use it.

I think we'd all be surprised by how much water and rust are on the
inside of the tanks we use every day. *:-)

Well, this tank hadn't been used for years the owner said. I let the
water out of my tank weekly, how long do you let it sit there.
I figure that years of sitting means deep rust inside. Based on the
stink of that water, I'd have to say it's been in there a long time.

I also remember that there used to be an additive to tanks to protect
them.
I knew what it was 30 years ago.

Might be too late, but anyone know what the name is.

I'm going on 13 years with my current compressor and it work like
the day I bought it. *I think i remember letting a few ounces of water
out of it several years ago. *Yes, it was brown.

To the best of my knowledge, emptying water is important to keep water
out of your pneumatic tools and the finish material you might be
spraying using the compressor.

I don't think it affects the performance of the compressor.

Years ago I read about a tank having a catastrophic failure. It didn't
just pinhole, it blew from rust.

So I worry, I wanted to bring this into the basement. My current one
wakes me up at night when I forget to shut it...

This one will be quieter if I forget. But I need to know it will be ok.

I keep hearing about it, too, but it's always a friend of a friend of an
uncle's boss.
And I hear about it being from rust, too, but it's never confirmed.
There are always other factors responsible when investigations are done.
I've seen articles about talks in big shops "exploding" and causing
damage and injuries.
These are usually big, big tanks and the injured were standing nearby
and got cut by metal shards still attached to the tank.

13-20 gallon tank isn't going to "explode" with enough force to cause
the kind of damage you read about. BTW, when the pressure in mine gets
to high, the pressure release valve lets out a bunch of air. If you're
doesn't have one of those, it's probably a good idea to instal one.

--

* -MIKE-

* "Playing is not something I do at night, it's my function in life"
* * *--Elvin Jones *(1927-2004)
* --
*http://mikedrums.com
*
* ---remove "DOT" ^^^^ to reply

http://www.cpsc.gov/PageFiles/80175/sanborn2.pdf

On 5/6/13 6:43 PM, wrote:
On Mon, 06 May 2013 18:33:16 -0500, -MIKE-
wrote:

On 5/6/13 4:20 PM, wrote:

Assuming that it didn't rupture first.

Well, yes, but the point is that a consumer-grade air
compressor
can't even come close to
developing that kind of pressure.
A pressure cooker can't either.


Gun power can.

Only if contained. Gun powder a low explosive (the shock wave is
sub-sonic in the powder) and will not explode unless it's contained. A
pressure cooker isn't the best pressure vessel for this sort of thing,
either.

Although this wasn't gun powder, either. It was flash powder
(fireworks), which has a higher burn rate (usually contains metal
powder).



Ok, change everything I wrote to include "flash" powder.
The point is, an air tank doesn't "explode" sending shrapnel and...
A pressure cooker packed with an explosive plus ball bearings... does...
very well.


--

-MIKE-

"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com

---remove "DOT" ^^^^ to reply

On 5/6/13 2:37 PM, Leon wrote:


Pressure cookers are designed to release pressure, that hissing you
hear, at 15 lbs.

Assuming the thing wasn't plugged in, it's probably just a decent vessel
for a bomb and not a functional part of the explosion mechanism.

Of course, one could easily find out exactly what, why, and how it works
and how to make your own with a simple google search. But I don't care
to start a homeland security file on myself, so I'll pass. :-)


--

-MIKE-

"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com

---remove "DOT" ^^^^ to reply

On 5/7/13 7:56 PM, Lew Hodgett wrote:
Lew Hodgett wrote:

Don't want to rain on your parade, but how big do you think those
pressure
cookers in Boston were/are?

BTW, a pressure relief valve is a must.

Even your hot water tank has one.
------------------------------------------------------------------

"-MIKE-" wrote:

I hope you're joking.
There was a lot more than air in those things.
--------------------------------------------------------------
Lew Hodgett wrote:

Absolutely not kidding, shrapnel is shrapnel regardless of the
source.
------------------------------------------------------------------

"-MIKE-" wrote:

That's kind of the point. There is no shrapnel when an air tank
"explodes."
-----------------------------------------------------------------
Lew Hodgett wrote:

What do you call the parts of the vessel that are created when
a vessel bursts?

Chopped liver?


Shrapnel: Fragments of a bomb, shell, or other object thrown out by an
explosion.
When an air tank fails from over pressure there is not enough energy to
create shrapnel.
Could a part come flying off, perhaps. But that is certainly a very
loose interpretation of the accepted definition when talking about true
explosions.


---------------------------------------------------------------------------------
"-MIKE-" wrote:

Why do I keep putting explodes in quotation marks? Because of the
very
misconception you have and others are having. The energy from a
bursting
air tank is no where near enough to cause shrapnel.

The energy caused by gun powder is many multitudes higher than an
air
tank. The velocity of the explosion is also many magnitudes higher.

Oh, and last time I looked at air compressors, non of the tanks were
packed with ball bearings, either. sheesh.
-----------------------------------------------------------------
Lew Hodgett wrote:

You seem to have difficulty understanding what is written.

I made no mention of gun powder, ball bearings or any other items of
IBS
(Intellectual Bull ****) you attempt to introduce to confuse the
issue.


Quit bull****ting and digging the hole deeper. We're talking air tanks
failing from over pressurization and you're the one who brought up the
marathon bombers' pressure cooker bombs. YOU are the one attempting to
confuse the issue by introducing a BOMB into a conversation about air
compressors.


My comment simply stated that the size of the vessel is totally
independent of it's ability to raise the havoc created if it were to
burst in an area where people were assembled.

What causes a vessel to exceed design specifications and fail
by bursting is a totally different discussion.

What remains relevant is that if a vessel bursts in an occupied area,
chances are pretty good that somebody is going to get hurt.

Nothing more, nothing less.

Lew


I can pop a balloon ("vessel burst") in an occupied area? Who gets hurt?

There has to be enough energy to create the shrapnel. Even without
shrapnel, there would have to be a enough energy released to create a
pressure wave for anyone to be injured seriously. How do you not get that?

An air compressor "vessel" "bursting" has a tiny fraction of the energy
of a bomb. Aren't you the engineer, here? How do you not see that?


--

-MIKE-

"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com

---remove "DOT" ^^^^ to reply

On Wed, 08 May 2013 23:23:46 -0500, -MIKE-
Of course, one could easily find out exactly what, why, and how it works
and how to make your own with a simple google search. But I don't care
to start a homeland security file on myself, so I'll pass. :-)

One thing I was wondering, did these Boston bombers make a practice
bomb first anywhere? Was there ever any mention of that? After all, if
someone intends to go out with their homemade bomb to do some damage,
they usually want to know if the damned thing will work before they
head out.

"-MIKE-" wrote in message ...

On 5/6/13 2:37 PM, Leon wrote:


Pressure cookers are designed to release pressure, that hissing you
hear, at 15 lbs.

Assuming the thing wasn't plugged in, it's probably just a decent vessel
for a bomb and not a functional part of the explosion mechanism.

Of course, one could easily find out exactly what, why, and how it works
and how to make your own with a simple google search. But I don't care
to start a homeland security file on myself, so I'll pass. :-)
================================================== ===============
The pressure cooker is a needed part of the bomb. The pressure relief valve
is not an issue. The pressure build up is too fast for it to vent it fast
enough to make any difference. You could put the same components in a paper
bag instead of the pressure cooker and all you would get is a fire.

On 5/9/2013 12:11 AM, CW wrote:


"-MIKE-" wrote in message ...

On 5/6/13 2:37 PM, Leon wrote:


Pressure cookers are designed to release pressure, that hissing you
hear, at 15 lbs.

Assuming the thing wasn't plugged in, it's probably just a decent vessel
for a bomb and not a functional part of the explosion mechanism.

Of course, one could easily find out exactly what, why, and how it works
and how to make your own with a simple google search. But I don't care
to start a homeland security file on myself, so I'll pass. :-)
================================================== ===============
The pressure cooker is a needed part of the bomb. The pressure relief
valve is not an issue. The pressure build up is too fast for it to vent
it fast enough to make any difference. You could put the same components
in a paper bag instead of the pressure cooker and all you would get is a
fire.




I believe the vessel would have been better had it been stronger than a
pressure cooker. Like a circuit breaker that protects the wiring in a
house the 15 lb relief valve is to protect the cooker. I highly suspect
that the lid popped off long before the potential was reached with the
powder burn.

On 5/8/2013 10:05 PM, wrote:
On Wed, 08 May 2013 23:23:46 -0500, -MIKE-
Of course, one could easily find out exactly what, why, and how it works
and how to make your own with a simple google search. But I don't care
to start a homeland security file on myself, so I'll pass. :-)

One thing I was wondering, did these Boston bombers make a practice
bomb first anywhere? Was there ever any mention of that? After all, if
someone intends to go out with their homemade bomb to do some damage,
they usually want to know if the damned thing will work before they
head out.


yes. there was a newspaper article that the fbi was questioning some
people in reference to an explosion in the woods somewhere around boston.

On 5/9/13 12:05 AM, wrote:
On Wed, 08 May 2013 23:23:46 -0500, -MIKE-
Of course, one could easily find out exactly what, why, and how it works
and how to make your own with a simple google search. But I don't care
to start a homeland security file on myself, so I'll pass. :-)

One thing I was wondering, did these Boston bombers make a practice
bomb first anywhere? Was there ever any mention of that? After all, if
someone intends to go out with their homemade bomb to do some damage,
they usually want to know if the damned thing will work before they
head out.


Short answer, who knows?
Long answer, these guys get training on this stuff from very scary
people. The more they investigate this, I suspect it will show they had
overseas al qaeda training.
That said, there have been many attempts in the US that have failed.
These don't make the headlines and when they do, it's not for long.


--

-MIKE-

"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com

---remove "DOT" ^^^^ to reply

On 5/9/13 12:11 AM, CW wrote:


"-MIKE-" wrote in message ...

On 5/6/13 2:37 PM, Leon wrote:


Pressure cookers are designed to release pressure, that hissing you
hear, at 15 lbs.

Assuming the thing wasn't plugged in, it's probably just a decent vessel
for a bomb and not a functional part of the explosion mechanism.

Of course, one could easily find out exactly what, why, and how it works
and how to make your own with a simple google search. But I don't care
to start a homeland security file on myself, so I'll pass. :-)
================================================== ===============
The pressure cooker is a needed part of the bomb. The pressure relief
valve is not an issue. The pressure build up is too fast for it to vent
it fast enough to make any difference. You could put the same components
in a paper bag instead of the pressure cooker and all you would get is a
fire.


The only point that is pertinent in this discussion is that there is no
blast powder in a compressor air tank. :-)


--

-MIKE-

"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com

---remove "DOT" ^^^^ to reply

On Wed, 08 May 2013 23:43:02 -0500, -MIKE-
wrote:

On 5/7/13 7:56 PM, Lew Hodgett wrote:
Lew Hodgett wrote:

Don't want to rain on your parade, but how big do you think those
pressure
cookers in Boston were/are?

BTW, a pressure relief valve is a must.

Even your hot water tank has one.
------------------------------------------------------------------

"-MIKE-" wrote:

I hope you're joking.
There was a lot more than air in those things.
--------------------------------------------------------------
Lew Hodgett wrote:

Absolutely not kidding, shrapnel is shrapnel regardless of the
source.
------------------------------------------------------------------

"-MIKE-" wrote:

That's kind of the point. There is no shrapnel when an air tank
"explodes."
-----------------------------------------------------------------
Lew Hodgett wrote:

What do you call the parts of the vessel that are created when
a vessel bursts?

Chopped liver?


Shrapnel: Fragments of a bomb, shell, or other object thrown out by an
explosion.
When an air tank fails from over pressure there is not enough energy to
create shrapnel.
Could a part come flying off, perhaps. But that is certainly a very
loose interpretation of the accepted definition when talking about true
explosions.


---------------------------------------------------------------------------------
"-MIKE-" wrote:

Why do I keep putting explodes in quotation marks? Because of the
very
misconception you have and others are having. The energy from a
bursting
air tank is no where near enough to cause shrapnel.

The energy caused by gun powder is many multitudes higher than an
air
tank. The velocity of the explosion is also many magnitudes higher.

Oh, and last time I looked at air compressors, non of the tanks were
packed with ball bearings, either. sheesh.
-----------------------------------------------------------------
Lew Hodgett wrote:

You seem to have difficulty understanding what is written.

I made no mention of gun powder, ball bearings or any other items of
IBS
(Intellectual Bull ****) you attempt to introduce to confuse the
issue.


Quit bull****ting and digging the hole deeper. We're talking air tanks
failing from over pressurization and you're the one who brought up the
marathon bombers' pressure cooker bombs. YOU are the one attempting to
confuse the issue by introducing a BOMB into a conversation about air
compressors.


My comment simply stated that the size of the vessel is totally
independent of it's ability to raise the havoc created if it were to
burst in an area where people were assembled.

What causes a vessel to exceed design specifications and fail
by bursting is a totally different discussion.

What remains relevant is that if a vessel bursts in an occupied area,
chances are pretty good that somebody is going to get hurt.

Nothing more, nothing less.

Lew


I can pop a balloon ("vessel burst") in an occupied area? Who gets hurt?

There has to be enough energy to create the shrapnel. Even without
shrapnel, there would have to be a enough energy released to create a
pressure wave for anyone to be injured seriously. How do you not get that?

An air compressor "vessel" "bursting" has a tiny fraction of the energy
of a bomb. Aren't you the engineer, here? How do you not see that?
Perhaps, but IF it fails catastrophically - like a brittle fracture
( and they DO happen very occaisionally) they ARE very dangerous.

A hydrogen embrittled 20 gallon tank, 1/8" thick, at 200 psi could do
greivous harm to anyone within 20 feet.or more if struck, by say, a
falling hammer or other flying debris.

On 5/9/13 12:03 PM, wrote:
On Wed, 08 May 2013 23:43:02 -0500, -MIKE-
wrote:

On 5/7/13 7:56 PM, Lew Hodgett wrote:
Lew Hodgett wrote:

Don't want to rain on your parade, but how big do you think those
pressure
cookers in Boston were/are?

BTW, a pressure relief valve is a must.

Even your hot water tank has one.
------------------------------------------------------------------

"-MIKE-" wrote:

I hope you're joking.
There was a lot more than air in those things.
--------------------------------------------------------------
Lew Hodgett wrote:

Absolutely not kidding, shrapnel is shrapnel regardless of the
source.
------------------------------------------------------------------

"-MIKE-" wrote:

That's kind of the point. There is no shrapnel when an air tank
"explodes."
-----------------------------------------------------------------
Lew Hodgett wrote:

What do you call the parts of the vessel that are created when
a vessel bursts?

Chopped liver?


Shrapnel: Fragments of a bomb, shell, or other object thrown out by an
explosion.
When an air tank fails from over pressure there is not enough energy to
create shrapnel.
Could a part come flying off, perhaps. But that is certainly a very
loose interpretation of the accepted definition when talking about true
explosions.


---------------------------------------------------------------------------------
"-MIKE-" wrote:

Why do I keep putting explodes in quotation marks? Because of the
very
misconception you have and others are having. The energy from a
bursting
air tank is no where near enough to cause shrapnel.

The energy caused by gun powder is many multitudes higher than an
air
tank. The velocity of the explosion is also many magnitudes higher.

Oh, and last time I looked at air compressors, non of the tanks were
packed with ball bearings, either. sheesh.
-----------------------------------------------------------------
Lew Hodgett wrote:

You seem to have difficulty understanding what is written.

I made no mention of gun powder, ball bearings or any other items of
IBS
(Intellectual Bull ****) you attempt to introduce to confuse the
issue.


Quit bull****ting and digging the hole deeper. We're talking air tanks
failing from over pressurization and you're the one who brought up the
marathon bombers' pressure cooker bombs. YOU are the one attempting to
confuse the issue by introducing a BOMB into a conversation about air
compressors.


My comment simply stated that the size of the vessel is totally
independent of it's ability to raise the havoc created if it were to
burst in an area where people were assembled.

What causes a vessel to exceed design specifications and fail
by bursting is a totally different discussion.

What remains relevant is that if a vessel bursts in an occupied area,
chances are pretty good that somebody is going to get hurt.

Nothing more, nothing less.

Lew


I can pop a balloon ("vessel burst") in an occupied area? Who gets hurt?

There has to be enough energy to create the shrapnel. Even without
shrapnel, there would have to be a enough energy released to create a
pressure wave for anyone to be injured seriously. How do you not get that?

An air compressor "vessel" "bursting" has a tiny fraction of the energy
of a bomb. Aren't you the engineer, here? How do you not see that?
Perhaps, but IF it fails catastrophically - like a brittle fracture
( and they DO happen very occaisionally) they ARE very dangerous.

A hydrogen embrittled 20 gallon tank, 1/8" thick, at 200 psi could do
greivous harm to anyone within 20 feet.or more if struck, by say, a
falling hammer or other flying debris.


But where is the evidence of this happening. I'm not talking about
damage or injury. I'm talking shrapnel, because that's what was brought
up early in this discussion.

I remember the mythbusters episode where they pumped up an air talk way
beyond normal operating pressure, having disabled the relief valve. They
proceeded to ram all kinds of stuff into it, even shooting it with a gun
and could not get it to "explode."


--

-MIKE-

"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com

---remove "DOT" ^^^^ to reply

On Wed, 08 May 2013 23:23:34 -0500, -MIKE-
wrote:

On 5/6/13 6:43 PM, wrote:
On Mon, 06 May 2013 18:33:16 -0500, -MIKE-
wrote:

On 5/6/13 4:20 PM, wrote:

Assuming that it didn't rupture first.

Well, yes, but the point is that a consumer-grade air
compressor
can't even come close to
developing that kind of pressure.
A pressure cooker can't either.


Gun power can.

Only if contained. Gun powder a low explosive (the shock wave is
sub-sonic in the powder) and will not explode unless it's contained. A
pressure cooker isn't the best pressure vessel for this sort of thing,
either.

Although this wasn't gun powder, either. It was flash powder
(fireworks), which has a higher burn rate (usually contains metal
powder).



Ok, change everything I wrote to include "flash" powder.


shrug TNT doesn't need containment and atomic bombs need
compression to explode, so?

The point is, an air tank doesn't "explode" sending shrapnel and...
A pressure cooker packed with an explosive plus ball bearings... does...
very well.

Not that I said...

On Wed, 08 May 2013 23:23:46 -0500, -MIKE-
wrote:

On 5/6/13 2:37 PM, Leon wrote:


Pressure cookers are designed to release pressure, that hissing you
hear, at 15 lbs.

Assuming the thing wasn't plugged in, it's probably just a decent vessel
for a bomb and not a functional part of the explosion mechanism.

No, it needs containment or the power will just "flash". Again, it's a
low-explosive.

Of course, one could easily find out exactly what, why, and how it works
and how to make your own with a simple google search. But I don't care
to start a homeland security file on myself, so I'll pass. :-)

On Thu, 09 May 2013 11:51:24 -0500, -MIKE-
wrote:

On 5/9/13 12:05 AM, wrote:
On Wed, 08 May 2013 23:23:46 -0500, -MIKE-
Of course, one could easily find out exactly what, why, and how it works
and how to make your own with a simple google search. But I don't care
to start a homeland security file on myself, so I'll pass. :-)

One thing I was wondering, did these Boston bombers make a practice
bomb first anywhere? Was there ever any mention of that? After all, if
someone intends to go out with their homemade bomb to do some damage,
they usually want to know if the damned thing will work before they
head out.


Short answer, who knows?
Long answer, these guys get training on this stuff from very scary
people. The more they investigate this, I suspect it will show they had
overseas al qaeda training.

They didn't need such "training" (though that's not to say that it
didn't happen). Everything needed to make such a bomb is on the WWW.
Terrorist-U is now an online curriculum.

That said, there have been many attempts in the US that have failed.
These don't make the headlines and when they do, it's not for long.

On Thu, 09 May 2013 13:51:23 -0400, wrote:
They didn't need such "training" (though that's not to say that it
didn't happen). Everything needed to make such a bomb is on the WWW.
Terrorist-U is now an online curriculum.

Sure, everything is there as per instructions, but it was me, I'd be
testing. I'd want to see if my homemade bomb goes 'pop' or goes
'BOOM'.

If terrorism is what I was aiming for, I'd want to see how small a
bomb I could make that still had devastating effects. Etcetera. Think
Mike called it though, they could have had practical training
elsewhere.