John Walliker wrote:

>A galvanised bucket would hardly have moved.

Which reminds me about a test report written by one of my
colleagues about 45 years ago.

They had built a prototype railway rolling stock dc chopper based
on a string of thyristors. The assembly was placed on a
substantial metal bedplate in the test area. It was connected to
the power supply through a water fuse. This consisted of a
plastic bucket filled with water, having a couple of submerged
cable connectors and a thin wire between them. For safety, the
bucket had a wooden lid with a heavy weight sitting on it.

When the inevitable fault occurred, the fuse blew with some
force, creating a waterspout which lifted the lid high in the
air. Unfortunately, on the way back down, the heavy weight was
faster then the wooden lid, and it wedged itself between the
cable connectors, re-making the circuit. This would have been bad
enough on its own, but with all the water sloshing around on the
bedplate, the supply was now both shorted and earthed.

I believe it took some time to get supplies restored, and there
were no intact thyristors left.

Chris
--
Chris J Dixon Nottingham UK
chris@cdixon.me.uk @ChrisJDixon1

Plant amazing Acers.

On 23/11/2022 11:18, Chris J Dixon wrote:
> John Walliker wrote:
>
>> A galvanised bucket would hardly have moved.
>
> Which reminds me about a test report written by one of my
> colleagues about 45 years ago.
>
> They had built a prototype railway rolling stock dc chopper based
> on a string of thyristors. The assembly was placed on a
> substantial metal bedplate in the test area. It was connected to
> the power supply through a water fuse. This consisted of a
> plastic bucket filled with water, having a couple of submerged
> cable connectors and a thin wire between them. For safety, the
> bucket had a wooden lid with a heavy weight sitting on it.
>
> When the inevitable fault occurred, the fuse blew with some
> force, creating a waterspout which lifted the lid high in the
> air. Unfortunately, on the way back down, the heavy weight was
> faster then the wooden lid, and it wedged itself between the
> cable connectors, re-making the circuit. This would have been bad
> enough on its own, but with all the water sloshing around on the
> bedplate, the supply was now both shorted and earthed.
>
> I believe it took some time to get supplies restored, and there
> were no intact thyristors left.
>
> Chris
Brilliant! :-) Similar to Gerard Hoffnung's bricklayer tale

Martin Brown <'''newspam'''@nonad.co.uk> writes:

> No. He is overstating it a little. About half a gramme will turn a
> brick into dust though. Not near habitation. *DO NOT TRY THIS AT HOME
> FOLKS*.
>
> One theoretician I know calculated the explosive energy content of a
> particular novel highly strained cubane molecule that had become
> within reach of synthetic chemistry in the 1980's.
>
> Some American's made the damn stuff without paying any attention to
> how volatile it might be. Fortunately they didn't make very much and
> the test tube after it had been turned to dust gave them a very bad
> case of sunburn. ISTR they were deaf for a week. There is more in the
> open literature on this stuff than I had supposed (very definitely not
> DIY).
>
> https://www.sciencedirect.com/science/article/pii/S2667134421000444
>
> Moral of story be careful what you wish for...

The "Things I Won't Work With" blog by Derek Lowe is always a good read, e.g.

https://www.science.org/content/blog-post/things-i-won-t-work-hexanitrohexaazaisowurtzitane

"I'd call for all the chemists who've ever worked with a hexanitro
compound to raise their hands, but that might be assuming too much about
the limb-to-chemist ratio. Nitro groups, as even people who've never
taken a chemistry class know, can lead to firey booms, and putting six
of them on one molecule can only lead to such."

and (staying on-topic)

https://www.science.org/content/blog-post/things-i-won-t-work-nitrotetrazole-oxides

"the that latter two blew up so violently that they ruptured the pans on
the apparatus while testing 1.5 milligrams of sample."

Also discusses highly corrosive substances, e.g.

https://www.science.org/content/blog-post/sand-won-t-save-you-time

"chlorine trifluoride" ... "It burned its way through a foot of concrete
floor and chewed up another meter of sand and gravel beneath"

--
Alan J. Wylie https://www.wylie.me.uk/

Dance like no-one's watching. / Encrypt like everyone is.
Security is inversely proportional to convenience

On 22/11/2022 18:09, Cursitor Doom wrote:
> On Mon, 21 Nov 2022 09:06:49 +0000, Martin Brown
> <'''newspam'''@nonad.co.uk> wrote:
>
>> On 19/11/2022 21:48, Cursitor Doom wrote:
>>> This was prompted by ARW's query about small blue LEDs.
>>> I didn't want to hijack his thread so this is under a new heading.
>>>
>>> Does anyone remember about 40-45 years ago there was a 'toy' : a small
>>> wrap of paper which you would hurl at your friends and it would
>>> explode on contact with them or any other hardish surface. They
>>> weren't around long. I expect Thatcher banned them pretty quick, being
>>> the killjoy bitch she was. WTF were they?
>>
>> Still available if you frequent the right sort of shops and/or
>> understand the relevant chemistry. I haven't seen them on sale for ages.
>>
>> https://en.wikipedia.org/wiki/Bang_snaps
>>
>> One prominent pyrotechnician I knew made his views about such volatile
>> explosive compositions very clear. All of the worlds best fireworks
>> makers are missing *precisely* one finger.
>>
>> If you get the chemistry wrong you can sometimes end up inadvertently
>> making it when trying to silver a telescope mirror.
>>
>> https://en.wikipedia.org/wiki/Silver_fulminate
>>
>> Mistakes can easily result in loss of digits or worse. YMMV
>
> Likewise mercury fulminate. The tiniest drop on a sheet of blotting
> paper hit with a hammer will shatter nearby windows. You need to be so
> fucking careful handling shock-sensitive high explosive compounds.

Breaking bad myth-busters suggest you need an awful lot more than a
"tiniest" drop.

Where did you find this 'tale'?

On Wed, 23 Nov 2022 22:04:24 +1100, Martin Brown
<'''newspam'''@nonad.co.uk> wrote:

> On 22/11/2022 19:26, John Walliker wrote:
>> On Tuesday, 22 November 2022 at 18:09:16 UTC, Cursitor Doom wrote:
>>> On Mon, 21 Nov 2022 09:06:49 +0000, Martin Brown
>>> <'''newspam'''@nonad.co.uk> wrote:
>>>
>>>> On 19/11/2022 21:48, Cursitor Doom wrote:
>>>>> This was prompted by ARW's query about small blue LEDs.
>>>>> I didn't want to hijack his thread so this is under a new heading.
>>>>>
>>>>> Does anyone remember about 40-45 years ago there was a 'toy' : a
>>>>> small
>>>>> wrap of paper which you would hurl at your friends and it would
>>>>> explode on contact with them or any other hardish surface. They
>>>>> weren't around long. I expect Thatcher banned them pretty quick,
>>>>> being
>>>>> the killjoy bitch she was. WTF were they?
>>>>
>>>> Still available if you frequent the right sort of shops and/or
>>>> understand the relevant chemistry. I haven't seen them on sale for
>>>> ages.
>>>>
>>>> https://en.wikipedia.org/wiki/Bang_snaps
>>>>
>>>> One prominent pyrotechnician I knew made his views about such volatile
>>>> explosive compositions very clear. All of the worlds best fireworks
>>>> makers are missing *precisely* one finger.
>>>>
>>>> If you get the chemistry wrong you can sometimes end up inadvertently
>>>> making it when trying to silver a telescope mirror.
>>>>
>>>> https://en.wikipedia.org/wiki/Silver_fulminate
>>>>
>>>> Mistakes can easily result in loss of digits or worse. YMMV
>>> Likewise mercury fulminate. The tiniest drop on a sheet of blotting
>>> paper hit with a hammer will shatter nearby windows. You need to be so
>>> fucking careful handling shock-sensitive high explosive compounds.
>> Are you really sure about that? (Blowing out the windows with a tiny
>> drop
>> I mean, not the part about being careful.)
>
> No. He is overstating it a little. About half a gramme will turn a brick
> into dust though. Not near habitation. *DO NOT TRY THIS AT HOME FOLKS*.
>
> One theoretician I know calculated the explosive energy content of a
> particular novel highly strained cubane molecule that had become within
> reach of synthetic chemistry in the 1980's.
>
> Some American's made the damn stuff without paying any attention to how
> volatile it might be. Fortunately they didn't make very much and the
> test tube after it had been turned to dust gave them a very bad case of
> sunburn. ISTR they were deaf for a week. There is more in the open
> literature on this stuff than I had supposed (very definitely not DIY).
>
> https://www.sciencedirect.com/science/article/pii/S2667134421000444
>
> Moral of story be careful what you wish for...
>>
>>>> Way back pre WWII there used to be an even more evil bang mix sold by
>>>> high street chemists that is now fundamentally banned.
>
>>> I remember the fireworks we had back in the early post-war period. An
>>> ordinary 1d banger had enough grunt to blow a galvanised bucket clean
>>> over the house's roof ridge. Younger people these days have no clue as
>>> to the freedoms we had back then; they couldn't even imagine it, poor
>>> fuckers.
>
> In my time I knew some very interesting pyrotechnicians.
>
> Including one who ended up staggering around after a detonation of a
> largish firework composition that went disastrously wrong. Again nothing
> permanent that time wouldn't heal but he was unable to hear anything we
> said to him for hours afterwards.

Wonder how that effect happens, in the ears.

> I expect he is quite deaf by now...

On 23/11/2022 14:52, Alan J. Wylie wrote:
> Martin Brown <'''newspam'''@nonad.co.uk> writes:
>
>> No. He is overstating it a little. About half a gramme will turn a
>> brick into dust though. Not near habitation. *DO NOT TRY THIS AT HOME
>> FOLKS*.
>>
>> One theoretician I know calculated the explosive energy content of a
>> particular novel highly strained cubane molecule that had become
>> within reach of synthetic chemistry in the 1980's.
>>
>> Some American's made the damn stuff without paying any attention to
>> how volatile it might be. Fortunately they didn't make very much and
>> the test tube after it had been turned to dust gave them a very bad
>> case of sunburn. ISTR they were deaf for a week. There is more in the
>> open literature on this stuff than I had supposed (very definitely not
>> DIY).
>>
>> https://www.sciencedirect.com/science/article/pii/S2667134421000444
>>
>> Moral of story be careful what you wish for...
>
> The "Things I Won't Work With" blog by Derek Lowe is always a good read, e.g.
>
> https://www.science.org/content/blog-post/things-i-won-t-work-hexanitrohexaazaisowurtzitane
>
> "I'd call for all the chemists who've ever worked with a hexanitro
> compound to raise their hands, but that might be assuming too much about
> the limb-to-chemist ratio. Nitro groups, as even people who've never
> taken a chemistry class know, can lead to firey booms, and putting six
> of them on one molecule can only lead to such."

Back in school days, I attended an outside lecture on explosives. My
chemistry teacher vowed to never carry out one of his demonstrations
again, as the lecturer was missing some fingers from the same experiment.

<Snip>

> https://www.science.org/content/blog-post/sand-won-t-save-you-time
>
> "chlorine trifluoride" ... "It burned its way through a foot of concrete
> floor and chewed up another meter of sand and gravel beneath"

Sounds like the blood in Alien.

On Wed, 23 Nov 2022 15:54:33 +0000, Fredxx <fredxx@spam.uk> wrote:

>On 22/11/2022 18:09, Cursitor Doom wrote:
>> On Mon, 21 Nov 2022 09:06:49 +0000, Martin Brown
>> <'''newspam'''@nonad.co.uk> wrote:
>>
>>> On 19/11/2022 21:48, Cursitor Doom wrote:
>>>> This was prompted by ARW's query about small blue LEDs.
>>>> I didn't want to hijack his thread so this is under a new heading.
>>>>
>>>> Does anyone remember about 40-45 years ago there was a 'toy' : a small
>>>> wrap of paper which you would hurl at your friends and it would
>>>> explode on contact with them or any other hardish surface. They
>>>> weren't around long. I expect Thatcher banned them pretty quick, being
>>>> the killjoy bitch she was. WTF were they?
>>>
>>> Still available if you frequent the right sort of shops and/or
>>> understand the relevant chemistry. I haven't seen them on sale for ages.
>>>
>>> https://en.wikipedia.org/wiki/Bang_snaps
>>>
>>> One prominent pyrotechnician I knew made his views about such volatile
>>> explosive compositions very clear. All of the worlds best fireworks
>>> makers are missing *precisely* one finger.
>>>
>>> If you get the chemistry wrong you can sometimes end up inadvertently
>>> making it when trying to silver a telescope mirror.
>>>
>>> https://en.wikipedia.org/wiki/Silver_fulminate
>>>
>>> Mistakes can easily result in loss of digits or worse. YMMV
>>
>> Likewise mercury fulminate. The tiniest drop on a sheet of blotting
>> paper hit with a hammer will shatter nearby windows. You need to be so
>> fucking careful handling shock-sensitive high explosive compounds.
>
>Breaking bad myth-busters suggest you need an awful lot more than a
>"tiniest" drop.
>
>Where did you find this 'tale'?

Sub tiniest drop. You cannot form a drop small enough to replicate
this effect with a standard 1ml pippette. You would not believe it if
you were not there. That's why they're so twitchy about anyone trying
to acquire nitric acid (and especially nitric and sulphuric acid
together raises the loudest of alarm bells).

On Wed, 23 Nov 2022 02:15:21 -0800 (PST), John Walliker
<jrwalliker@gmail.com> wrote:

>On Tuesday, 22 November 2022 at 20:01:34 UTC, Tim+ wrote:
>> Cursitor Doom <c...@notformail.com> wrote:
>> >
>> >
>> > I remember the fireworks we had back in the early post-war period. An
>> > ordinary 1d banger had enough grunt to blow a galvanised bucket clean
>> > over the house's roof ridge.
>> Um, that sounds improbable. Can anyone corroborate?
>
>Not a galvanised bucket, but yes for a tin can.

Haha! You jest. You're obviously too young to remember the power of
the firworks of yesteryear. The crap they've been selling since about
1980 is a joke compared to what we had back in the early post-war
period. So yes, galvanised bucket clean over the house. Back in those
days, galvanised buckets where a common sight in every hardware store,
along with a rack of shotguns and ammo. In the countryside anyway; not
sure about the cities.

> In order to get a tin can
>to go high enough to clear a two-story house the process was:
>Place large banger in slightly moist sand (to get a good seal).
>Light blue touch paper.
>Push can (normal size soup or baked beans tin) firmly down onto banger.
>Run
>
>A galvanised bucket would hardly have moved.
>
>John

On Wednesday, 23 November 2022 at 23:56:26 UTC, Cursitor Doom wrote:
> On Wed, 23 Nov 2022 02:15:21 -0800 (PST), John Walliker
> <jrwal...@gmail.com> wrote:
>
> >On Tuesday, 22 November 2022 at 20:01:34 UTC, Tim+ wrote:
> >> Cursitor Doom <c...@notformail.com> wrote:
> >> >
> >> >
> >> > I remember the fireworks we had back in the early post-war period. An
> >> > ordinary 1d banger had enough grunt to blow a galvanised bucket clean
> >> > over the house's roof ridge.
> >> Um, that sounds improbable. Can anyone corroborate?
> >
> >Not a galvanised bucket, but yes for a tin can.
> Haha! You jest. You're obviously too young to remember the power of
> the firworks of yesteryear. The crap they've been selling since about
> 1980 is a joke compared to what we had back in the early post-war
> period. So yes, galvanised bucket clean over the house. Back in those
> days, galvanised buckets where a common sight in every hardware store,
> along with a rack of shotguns and ammo. In the countryside anyway; not
> sure about the cities.

My experience of bangers and galvanised buckets started in the mid 1960s. I agree
that later on bangers were made much less powerful. Nevertheless, I still don't
believe that a 1d banger could propel a galvanised bucket any significant distance
let alone over a roof -not even a single storey one.
I did once manage to punch several holes in the sides of a thick-walled galvanised
steel firebucket with a firework that used the gunpowder from several bangers
combined with very strong containment, but the bucket stayed firmly on the
ground. It was after that event that I decided things were getting too dangerous
and I stopped trying to make ever better fireworks.

> > In order to get a tin can
> >to go high enough to clear a two-story house the process was:
> >Place large banger in slightly moist sand (to get a good seal).
> >Light blue touch paper.
> >Push can (normal size soup or baked beans tin) firmly down onto banger.
> >Run
> >
> >A galvanised bucket would hardly have moved.
> >
> >John

On 23/11/2022 10:15, John Walliker wrote:
> On Tuesday, 22 November 2022 at 20:01:34 UTC, Tim+ wrote:
>> Cursitor Doom <c...@notformail.com> wrote:
>>>
>>>
>>> I remember the fireworks we had back in the early post-war period. An
>>> ordinary 1d banger had enough grunt to blow a galvanised bucket clean
>>> over the house's roof ridge.
>> Um, that sounds improbable. Can anyone corroborate?
>
> Not a galvanised bucket, but yes for a tin can. In order to get a tin can
> to go high enough to clear a two-story house the process was:
> Place large banger in slightly moist sand (to get a good seal).
> Light blue touch paper.
> Push can (normal size soup or baked beans tin) firmly down onto banger.
> Run
>
> A galvanised bucket would hardly have moved.

Agreed. In the 60s I once put a small amount of a well-known sugar mix
at the bottom of a small metal empty Nitromors can (the type which was
about 3" diameter and high, with a 3/4" screw cap). I drilled a 1/8"
hole in the cap, and ignited the mix with a Jetex fuse. It caught fire
and the jet of smoke through the hole in the cap got longer and longer.
After ten seconds there was a loud bang, and the can was no longer
there; well, the base of it was! Wondering where the rest was, I
suddenly heard some clanging. It was the body of the can bouncing on a
roof well over a 100 ft away!

--

Jeff

On 23/11/2022 23:56, Cursitor Doom wrote:
> On Wed, 23 Nov 2022 02:15:21 -0800 (PST), John Walliker
> <jrwalliker@gmail.com> wrote:
>
>> On Tuesday, 22 November 2022 at 20:01:34 UTC, Tim+ wrote:
>>> Cursitor Doom <c...@notformail.com> wrote:
>>>>
>>>>
>>>> I remember the fireworks we had back in the early post-war period. An
>>>> ordinary 1d banger had enough grunt to blow a galvanised bucket clean
>>>> over the house's roof ridge.
>>> Um, that sounds improbable. Can anyone corroborate?
>>
>> Not a galvanised bucket, but yes for a tin can.
>
> Haha! You jest. You're obviously too young to remember the power of
> the firworks of yesteryear. The crap they've been selling since about
> 1980 is a joke compared to what we had back in the early post-war
> period. So yes, galvanised bucket clean over the house. Back in those
> days, galvanised buckets where a common sight in every hardware store,
> along with a rack of shotguns and ammo. In the countryside anyway; not
> sure about the cities.
>
A pyro friend and I used to get old pain tins and the like, add a few
grammes of weedkiller and sugar mix, tamp the lids down, and place them
on a tray on more weedkiller and sugar, light that, which cause the
material inside to detonate, and we could easily get to gutter height.

>> In order to get a tin can
>> to go high enough to clear a two-story house the process was:
>> Place large banger in slightly moist sand (to get a good seal).
>> Light blue touch paper.
>> Push can (normal size soup or baked beans tin) firmly down onto banger.
>> Run
>>
We dint run, just stepped back.

>> A galvanised bucket would hardly have moved.

Use more explosive?

>>
>> John

--
There is nothing a fleet of dispatchable nuclear power plants cannot do
that cannot be done worse and more expensively and with higher carbon
emissions and more adverse environmental impact by adding intermittent
renewable energy.

On 24/11/2022 08:33, Jeff Layman wrote:
> On 23/11/2022 10:15, John Walliker wrote:
>> On Tuesday, 22 November 2022 at 20:01:34 UTC, Tim+ wrote:
>>> Cursitor Doom <c...@notformail.com> wrote:
>>>>
>>>>
>>>> I remember the fireworks we had back in the early post-war period. An
>>>> ordinary 1d banger had enough grunt to blow a galvanised bucket clean
>>>> over the house's roof ridge.
>>> Um, that sounds improbable. Can anyone corroborate?
>>
>> Not a galvanised bucket, but yes for a tin can.  In order to get a tin
>> can
>> to go high enough to clear a two-story house the process was:
>> Place large banger in slightly moist sand (to get a good seal).
>> Light blue touch paper.
>> Push can (normal size soup or baked beans tin) firmly down onto banger.
>> Run
>>
>> A galvanised bucket would hardly have moved.
>
> Agreed. In the 60s I once put a small amount of a well-known sugar mix
> at the bottom of a small metal empty Nitromors can (the type which was
> about 3" diameter and high, with a 3/4" screw cap). I drilled a 1/8"
> hole in the cap, and ignited the mix with a Jetex fuse. It caught fire
> and the jet of smoke through the hole in the cap got longer and longer.
> After ten seconds there was a loud bang, and the can was no longer
> there; well, the base of it was! Wondering where the rest was, I
> suddenly heard some clanging. It was the body of the can bouncing on a
> roof well over a 100 ft away!
>

I did the same with a 16 gauge aluminium tube, with a washer epoxied
over the end to make a nozzle. Suspended from the washing line by two
stirrups. The idea was to make a rocket, but I actually made a mortar round.

I found what was left of it a year later in the hedge - just twisted
shrapnel.
I got my hearing back after a few hours.

--
“Progress is precisely that which rules and regulations did not foresee,”

– Ludwig von Mises

On 24/11/2022 08:30, John Walliker wrote:
> On Wednesday, 23 November 2022 at 23:56:26 UTC, Cursitor Doom wrote:
>> On Wed, 23 Nov 2022 02:15:21 -0800 (PST), John Walliker
>> <jrwal...@gmail.com> wrote:
>>
>>> On Tuesday, 22 November 2022 at 20:01:34 UTC, Tim+ wrote:
>>>> Cursitor Doom <c...@notformail.com> wrote:
>>>>>
>>>>>
>>>>> I remember the fireworks we had back in the early post-war period. An
>>>>> ordinary 1d banger had enough grunt to blow a galvanised bucket clean
>>>>> over the house's roof ridge.
>>>> Um, that sounds improbable. Can anyone corroborate?
>>>
>>> Not a galvanised bucket, but yes for a tin can.
>> Haha! You jest. You're obviously too young to remember the power of
>> the firworks of yesteryear. The crap they've been selling since about
>> 1980 is a joke compared to what we had back in the early post-war
>> period. So yes, galvanised bucket clean over the house. Back in those
>> days, galvanised buckets where a common sight in every hardware store,
>> along with a rack of shotguns and ammo. In the countryside anyway; not
>> sure about the cities.
>
> My experience of bangers and galvanised buckets started in the mid 1960s. I agree
> that later on bangers were made much less powerful. Nevertheless, I still don't
> believe that a 1d banger could propel a galvanised bucket any significant distance
> let alone over a roof -not even a single storey one.
> I did once manage to punch several holes in the sides of a thick-walled galvanised
> steel firebucket with a firework that used the gunpowder from several bangers
> combined with very strong containment, but the bucket stayed firmly on the
> ground. It was after that event that I decided things were getting too dangerous
> and I stopped trying to make ever better fireworks.

+1

A penny banger couldn't do that to a bucket. It might turn it over or
blow it a foot or two into the air. It would need far more gunpowder to
lift it dozens of feet. The cardboard casing is too weak to sustain the
pressure build up needed. If you wanted a really big bang, you needed
more gunpowder and a stronger case. In the late 60s I got an empty
cardboard "tube" from a London bus conductor's ticket machine. It was
about 2" long, with a 1/2" diameter hole. The important thing was that
the cardboard was almost half an inch thick. I araldited a 1/4" of 1/2"
dowel in each end, and drilled a hole in one just enough to take a penny
banger fuse. It became a "6d" banger with the contents of six penny
bangers. When it went off, the shock wave noticeably moved in a 6 x 4 ft
pane of glass more than 30 feet away.

Agree about things getting silly. A friend's older brother made a
"banger" out of a Sparklets bulb! Not sure if it was just gunpowder or
his own mix, but it easily split a 6" wooden post. I didn't see the
explosion, as I made sure I was round the corner of the house. Nobody
else seemed to think that there might be some dangerous shrapnel flying
around!

--

Jeff

On Thursday, 24 November 2022 at 09:13:20 UTC, Jeff Layman wrote:
> On 24/11/2022 08:30, John Walliker wrote:
> > On Wednesday, 23 November 2022 at 23:56:26 UTC, Cursitor Doom wrote:
> >> On Wed, 23 Nov 2022 02:15:21 -0800 (PST), John Walliker
> >> <jrwal...@gmail.com> wrote:
> >>
> >>> On Tuesday, 22 November 2022 at 20:01:34 UTC, Tim+ wrote:
> >>>> Cursitor Doom <c...@notformail.com> wrote:
> >>>>>
> >>>>>
> >>>>> I remember the fireworks we had back in the early post-war period. An
> >>>>> ordinary 1d banger had enough grunt to blow a galvanised bucket clean
> >>>>> over the house's roof ridge.
> >>>> Um, that sounds improbable. Can anyone corroborate?
> >>>
> >>> Not a galvanised bucket, but yes for a tin can.
> >> Haha! You jest. You're obviously too young to remember the power of
> >> the firworks of yesteryear. The crap they've been selling since about
> >> 1980 is a joke compared to what we had back in the early post-war
> >> period. So yes, galvanised bucket clean over the house. Back in those
> >> days, galvanised buckets where a common sight in every hardware store,
> >> along with a rack of shotguns and ammo. In the countryside anyway; not
> >> sure about the cities.
> >
> > My experience of bangers and galvanised buckets started in the mid 1960s. I agree
> > that later on bangers were made much less powerful. Nevertheless, I still don't
> > believe that a 1d banger could propel a galvanised bucket any significant distance
> > let alone over a roof -not even a single storey one.
> > I did once manage to punch several holes in the sides of a thick-walled galvanised
> > steel firebucket with a firework that used the gunpowder from several bangers
> > combined with very strong containment, but the bucket stayed firmly on the
> > ground. It was after that event that I decided things were getting too dangerous
> > and I stopped trying to make ever better fireworks.
> +1
>
> A penny banger couldn't do that to a bucket. It might turn it over or
> blow it a foot or two into the air. It would need far more gunpowder to
> lift it dozens of feet. The cardboard casing is too weak to sustain the
> pressure build up needed. If you wanted a really big bang, you needed
> more gunpowder and a stronger case. In the late 60s I got an empty
> cardboard "tube" from a London bus conductor's ticket machine. It was
> about 2" long, with a 1/2" diameter hole. The important thing was that
> the cardboard was almost half an inch thick. I araldited a 1/4" of 1/2"
> dowel in each end, and drilled a hole in one just enough to take a penny
> banger fuse. It became a "6d" banger with the contents of six penny
> bangers. When it went off, the shock wave noticeably moved in a 6 x 4 ft
> pane of glass more than 30 feet away.
>
> Agree about things getting silly. A friend's older brother made a
> "banger" out of a Sparklets bulb! Not sure if it was just gunpowder or
> his own mix, but it easily split a 6" wooden post. I didn't see the
> explosion, as I made sure I was round the corner of the house. Nobody
> else seemed to think that there might be some dangerous shrapnel flying
> around!

The containment I used was so strong that it took a few seconds to
rupture after the gunpowder had been ignited. What really worried me was
that it might have lasted a bit longer still and I might have gone back to
inspect it.
It had been ignited from a range of 100 yards which was just as well.
John

On 24/11/2022 09:12, The Natural Philosopher wrote:
>
> I did the same with a 16 gauge aluminium tube, with a washer epoxied
> over the end to make a nozzle. Suspended from the washing line by two
> stirrups. The idea was to make a rocket, but I actually made a mortar
> round.
>
> I found what was left of it a year later in the hedge - just twisted
> shrapnel.
> I got my hearing back after a few hours.

My one was to put an old 7.62 cartridge case - loads of them lying
around on army training areas - into the end of a bit of copper pipe,
with the idea that when the banger powder in it detonated the case would
take off with some velocity.

I never found the pipe.

Andy