I have been hobby MIG welding for 8 years. In the last few months I
have discovered braising with high content silver. I give extra
attention to safety. Something happened today that was a total shock.
I'm trying to determine what caused a small explosion and probably
could have killed me. I had a short piece of 1/2" round steel that was
2" long. I needed to lengthen that piece by another 4". I had a rod of
1/2" diameter steel. I cut it to 4" in length. I also had a mild steel
rod of just under 1/4" diamter. I cut it to 1" long. I drilled the
center of each 1/2" diameter rod to a depth of 1/2" so that I would
have an internal rod to support the two thick rods during braising and
to play with some new cobalt drill bits I just purchased. The fit was
tight. I applied a coating of "Stay Silv" white paste braising flux to
the 1/4" rod and the ends of the 1/2" rods. I wanted whatever COULD be
braised to BE braised with ease. It took a few blows with a hammer to
seat the 1/4" rod into both thicker rods so that they were now butted
together ready to braise. I used a MAP gas torch to heat the assembly.
I had braised 1/3 of the assembly when BAM!!! The small piece SHOT off
the end with an explosion similar to a 38 pistol going off!!! The
piece shot 20 feet and hit a wall. WHAT in the world caused this
TOTALLY UNEXPECTED explosion? Does the STAY SILV flux become
EXPLOSIVE?

On Oct 25, 1:28*pm, bababondoman wrote:
Something happened today that was a total shock.
I'm trying to determine what caused a small explosion and probably
could have killed me.

Does the STAY SILV flux become
EXPLOSIVE?

I think what happened was the following. The flux has water in it.
And some water was trapped in the hole you drilled and then sealed
with the small rod you press fitted in. The water turned to steam but
could not escape until the pressure was enough to force the small rod
out of the hole.

When you are fitting something up to silver braze, you ought to have
some clearance for the silver solder. A clearance of about .002
inches will give you the highest strength.

Dan

On Sun, 25 Oct 2009 06:28:25 -0700 (PDT), bababondoman
wrote:

I have been hobby MIG welding for 8 years. In the last few months I
have discovered braising with high content silver. I give extra
attention to safety. Something happened today that was a total shock.
I'm trying to determine what caused a small explosion and probably
could have killed me. I had a short piece of 1/2" round steel that was
2" long. I needed to lengthen that piece by another 4". I had a rod of
1/2" diameter steel. I cut it to 4" in length. I also had a mild steel
rod of just under 1/4" diamter. I cut it to 1" long. I drilled the
center of each 1/2" diameter rod to a depth of 1/2" so that I would
have an internal rod to support the two thick rods during braising and
to play with some new cobalt drill bits I just purchased. The fit was
tight. I applied a coating of "Stay Silv" white paste braising flux to
the 1/4" rod and the ends of the 1/2" rods. I wanted whatever COULD be
braised to BE braised with ease. It took a few blows with a hammer to
seat the 1/4" rod into both thicker rods so that they were now butted
together ready to braise. I used a MAP gas torch to heat the assembly.
I had braised 1/3 of the assembly when BAM!!! The small piece SHOT off
the end with an explosion similar to a 38 pistol going off!!! The
piece shot 20 feet and hit a wall. WHAT in the world caused this
TOTALLY UNEXPECTED explosion? Does the STAY SILV flux become
EXPLOSIVE?


I'd suspect the paste flux was trapped and "boiled" to high pressure
steam, causing the plug to blow out. Understand that as you heated
the two, the hole that was so tight initially would have expanded with
the heat. Next time, file or grind just the lightest groove the
length of the dowel to release the tapped moisture, just as you see a
wooden manufactured dowel has lengthwise or spiral serrations to allow
excess glue to flow.

Some years ago, a very experienced welding/steamfitting crew was
installing some additional pipe-work over a couple of weekends to an
already operating system. The work was begun late on Friday, and
carried out by multiple crews in shifts over this first weekend. One
item was a future-use stub that was controlled by a new 12" gate valve
welded in place while the system was down. The valve required just a
1 foot stub to be capped for safety reasons so that it would protect
in case the gate valve was turned on by mistake. By early Monday
morning (Sunday late shift), they had welded in the valve completely,
but the cap was left with just one pass completed, and the system was
put back in operation for the week, with the valve still in the "off"
position of course.
On the following Friday, the first shift returned, and with the system
"down" again, began the second of 4 required passes to complete the
stub. After about 15 minutes of welding, the cap blew off, killing
the four workers. The investigation suggested that the valve had
leaked very slightly during the week, allowing the "stub" to fill with
water, and that the heat of the second welding pass had driven the
pressures to over 4,000 PSI in that short time.

Take care.

Brian Lawson,
Bothwell, Ontario.


including a domed "cap" on a short stub for future further additions.

On Oct 25, 10:09*am, " wrote:
On Oct 25, 1:28*pm, bababondoman wrote:
*Something happened today that was a total shock.

I'm trying to determine what caused a small explosion and probably
could have killed me.

*Does the STAY SILV flux become

EXPLOSIVE?

I think what happened was the following. *The flux has water in it.
And some water was trapped in the hole you drilled and then sealed
with the small rod you press fitted in. *The water turned to steam but
could not escape until the pressure was enough to force the small rod
out of the hole.

When you are fitting something up to silver braze, you ought to have
some clearance for the silver solder. *A clearance of about .002
inches will give you the highest strength.

* * * * * * * * * * * * * * * * * * * * * * * * * * * * *Dan

I agree The joint should have proper clearance (depending on the
materials to be joined) and that would have allowed the gases made by
heating the flux to escape and allow wetting the joint when braze was
applied. Brazing works by "capillary action".. See:
http://www.lucas-milhaupt.com/htmdoc...eps_braze.html
or http://tinyurl.com/llc3pv

What's that Lassie? You say that fell down the old
rec.crafts.metalworking mine and will die if we don't mount a rescue
by Sun, 25 Oct 2009 07:09:30 -0700 (PDT):

On Oct 25, 1:28*pm, bababondoman wrote:
Something happened today that was a total shock.
I'm trying to determine what caused a small explosion and probably
could have killed me.

Does the STAY SILV flux become
EXPLOSIVE?

I think what happened was the following. The flux has water in it.
And some water was trapped in the hole you drilled and then sealed
with the small rod you press fitted in. The water turned to steam but
could not escape until the pressure was enough to force the small rod
out of the hole.

When you are fitting something up to silver braze, you ought to have
some clearance for the silver solder. A clearance of about .002
inches will give you the highest strength.

Dan
Exactly.
Just filing a flat on the 1/4" rod would have done it.
--

Dan H.
northshore MA.

bababondoman wrote:
I have been hobby MIG welding for 8 years. In the last few months I
have discovered braising with high content silver. I give extra
attention to safety. Something happened today that was a total shock.
I'm trying to determine what caused a small explosion and probably
could have killed me. I had a short piece of 1/2" round steel that was
2" long. I needed to lengthen that piece by another 4". I had a rod of
1/2" diameter steel. I cut it to 4" in length. I also had a mild steel
rod of just under 1/4" diamter. I cut it to 1" long. I drilled the
center of each 1/2" diameter rod to a depth of 1/2" so that I would
have an internal rod to support the two thick rods during braising and
to play with some new cobalt drill bits I just purchased. The fit was
tight. I applied a coating of "Stay Silv" white paste braising flux to
the 1/4" rod and the ends of the 1/2" rods. I wanted whatever COULD be
braised to BE braised with ease. It took a few blows with a hammer to
seat the 1/4" rod into both thicker rods so that they were now butted
together ready to braise. I used a MAP gas torch to heat the assembly.
I had braised 1/3 of the assembly when BAM!!! The small piece SHOT off
the end with an explosion similar to a 38 pistol going off!!! The
piece shot 20 feet and hit a wall. WHAT in the world caused this
TOTALLY UNEXPECTED explosion? Does the STAY SILV flux become
EXPLOSIVE?

Trapped moisture,steam explosion, very common!
Always drill a small release hole

"bababondoman" wrote in message
...
I have been hobby MIG welding for 8 years. In the last few months I
have discovered braising with high content silver. I give extra
attention to safety. Something happened today that was a total shock.
I'm trying to determine what caused a small explosion and probably
could have killed me. I had a short piece of 1/2" round steel that was
2" long. I needed to lengthen that piece by another 4". I had a rod of
1/2" diameter steel. I cut it to 4" in length. I also had a mild steel
rod of just under 1/4" diamter. I cut it to 1" long. I drilled the
center of each 1/2" diameter rod to a depth of 1/2" so that I would
have an internal rod to support the two thick rods during braising and
to play with some new cobalt drill bits I just purchased. The fit was
tight. I applied a coating of "Stay Silv" white paste braising flux to
the 1/4" rod and the ends of the 1/2" rods. I wanted whatever COULD be
braised to BE braised with ease. It took a few blows with a hammer to
seat the 1/4" rod into both thicker rods so that they were now butted
together ready to braise. I used a MAP gas torch to heat the assembly.
I had braised 1/3 of the assembly when BAM!!! The small piece SHOT off
the end with an explosion similar to a 38 pistol going off!!! The
piece shot 20 feet and hit a wall. WHAT in the world caused this
TOTALLY UNEXPECTED explosion? Does the STAY SILV flux become
EXPLOSIVE?

"Honey, could you stand here and hold this small piece while I braze
it?"..............

http://www.thefreedictionary.com/braise
You had an explosion while "To cook (meat or vegetables) by
browning in fat, then simmering in a small quantity of
liquid in a covered container." What flew? A potato, or
carrot?

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"bababondoman" wrote in message
...
I have been hobby MIG welding for 8 years. In the last few
months I
have discovered braising with high content silver.

I wanted whatever COULD be
braised to BE braised with ease.

I used a MAP gas torch to heat the assembly.
I had braised 1/3 of the assembly when BAM!!! The small
piece SHOT off
the end with an explosion similar to a 38 pistol going
off!!! The
piece shot 20 feet and hit a wall. WHAT in the world caused
this
TOTALLY UNEXPECTED explosion? Does the STAY SILV flux become
EXPLOSIVE?

Closer to a carrot?

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"Brian Lawson" wrote in message
...

I'd suspect the paste flux was trapped and "boiled" to high
pressure
steam, causing the plug to blow out. Understand that as you
heated
the two, the hole that was so tight initially would have
expanded with
the heat. Next time, file or grind just the lightest groove
the
length of the dowel to release the tapped moisture, just as
you see a
wooden manufactured dowel has lengthwise or spiral
serrations to allow
excess glue to flow.

That's tragic. I've heard also of old wood stoves. They
often had a water heater loop in the back, with a couple
pipes. I've heard of water trapped in these (after they had
been decomissioned) and stove exploding.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"Brian Lawson" wrote in message
...

Some years ago, a very experienced welding/steamfitting crew
was
installing some additional pipe-work over a couple of
weekends to an
already operating system. The work was begun late on Friday,
and
carried out by multiple crews in shifts over this first
weekend. One
item was a future-use stub that was controlled by a new 12"
gate valve
welded in place while the system was down. The valve
required just a
1 foot stub to be capped for safety reasons so that it would
protect
in case the gate valve was turned on by mistake. By early
Monday
morning (Sunday late shift), they had welded in the valve
completely,
but the cap was left with just one pass completed, and the
system was
put back in operation for the week, with the valve still in
the "off"
position of course.
On the following Friday, the first shift returned, and with
the system
"down" again, began the second of 4 required passes to
complete the
stub. After about 15 minutes of welding, the cap blew off,
killing
the four workers. The investigation suggested that the
valve had
leaked very slightly during the week, allowing the "stub" to
fill with
water, and that the heat of the second welding pass had
driven the
pressures to over 4,000 PSI in that short time.

Take care.

Brian Lawson,
Bothwell, Ontario.

On Mon, 26 Oct 2009 20:46:44 -0400, "Stormin Mormon"
wrote:

That's tragic. I've heard also of old wood stoves. They
often had a water heater loop in the back, with a couple
pipes. I've heard of water trapped in these (after they had
been decomissioned) and stove exploding.
When my parents set up housekeeping in 1934, they bought a cook stove
with this feature (water front). It came as a separate cast iron
section to be installed in the firebox It never did get installed
before the stove was replaced in 1957 with a more modern wood/electric
range which came complete with the installed water front. When we
installed the bathroom, the removal of the home made concrete bathtub
from behind the kitchen stove, we had room to install the storage tank
and plumbing. When my mother sold the house in1974, she still had to
build a fire in the cook stove to have hot water. I saw a similar set
up three years ago while visiting friends near St. John NB.
Gerry :-)}
London, Canada

wrote:
On Oct 25, 1:28*pm, bababondoman wrote:
Something happened today that was a total shock.
I'm trying to determine what caused a small explosion and probably
could have killed me.

Does the STAY SILV flux become
EXPLOSIVE?

I think what happened was the following. The flux has water in it.
And some water was trapped in the hole you drilled and then sealed
with the small rod you press fitted in. The water turned to steam but
could not escape until the pressure was enough to force the small rod
out of the hole.

When you are fitting something up to silver braze, you ought to have
some clearance for the silver solder. A clearance of about .002
inches will give you the highest strength.

Dan

On Oct 26, 6:46*pm, "Stormin Mormon"
wrote:
That's tragic. I've heard also of old wood stoves. They
often had a water heater loop in the back, with a couple
pipes. I've heard of water trapped in these (after they had
been decomissioned) and stove exploding.

--
Christopher A. Young
Learn more about Jesus
*www.lds.org
.

"Brian Lawson" wrote in message

...

Some years ago, a very experienced welding/steamfitting crew
was
installing some additional pipe-work over a couple of
weekends to an
already operating system. The work was begun late on Friday,
and
carried out by multiple crews in shifts over this first
weekend. *One
item was a future-use stub that was controlled by a new 12"
gate valve
welded in place while the system was down. *The valve
required just a
1 foot stub to be capped for safety reasons so that it would
protect
in case the gate valve was turned on by mistake. * By early
Monday
morning (Sunday late shift), they had welded in the valve
completely,
but the cap was left with just one pass completed, and the
system was
put back in operation for the week, with the valve still in
the "off"
position of course.
On the following Friday, the first shift returned, and with
the system
"down" again, began the second of 4 required passes to
complete the
stub. *After about 15 minutes of welding, the cap blew off,
killing
the four workers. *The investigation suggested that the
valve had
leaked very slightly during the week, allowing the "stub" to
fill with
water, and that the heat of the second welding pass had
driven the
pressures to over 4,000 PSI in that short time.

Take care.

Brian Lawson,
Bothwell, Ontario.


To Brian and to all the SUPER EXPERIENCED welders that have replied to
my post...I want to thank you VERY much for the time you took to
explain to me, and other readers, exactly what happened. It surely has
been a lesson WELL learned and will never happen again. I will take
all your advice and implement it on every project from now on. It
really was a wakeup call and your expert comments very possibly might
save someone's life. Thanks again to all that commented. BABABONDOMAN
in Colorado