Screwed on breach danger.

[lapetit]

I've been reading the cannon section for some time and finally registered. My concern is that I have read about using loose powder and screwed on breaches. There is a GREAT possibility of powder grains, black and smokeless, being trapped in the threads and the compression, crushing, friction setting off a spark and the main charge, resulting in a catastrophic failure, CATO for short. I had the unfortunate job several years ago of cleaning up the remains of a young man that was experimenting with pipe bombs made with black powder. The young man's friend stated that on other occasions there had been the odd "puff of smoke" while screwing on the pipe caps, they thought nothing of it. The friend had walked out the basement while the other lad was capping the last of the evenings efforts, they were using the devices to blow up the odd rock and tree around the country side, when there was sudden nothingness. He regained consciousness as the emergency vehicles were arriving. After putting out a small fire we, the emergency crew, when looking for the other lad. The largest identifiable body parts we recovered was approximately 2/3 to 3/4  of this head and an ankle with foot attached. The rest of the remains were in fist size and smaller pieces, spread throughout the basement and first floor. According to the survivor they had not put detonators in the pipe bombs yet, so, we concluded that compression, crushing or friction set off the charge, about 2 oz of 2FFg black, and the other 5 bombs lying on the bench, which lead to the boy's death and destruction for a 2 bedroom 6 room house.
After talking with an explosives engineer we were told that we were correct in our assumption about the source of detonation.
Finally, I come to the message that I want to convey, -  NEVER USE LOOSE POWDER AROUND THREADED COUPLINGS!!!! THE LIFE YOU SAVE MAY BE YOUR OWN!!!!.
Please forgive the length of this missive, but I felt the background was necessary to make the point of my warning.
Lapetit

[jj1]

thanks lapetit, very sound advise.

[Double D]

Lapetit,

I think you have things confused as to the relationship of threaded breeches and loading loose powder.  One is not done to accommodate the other. Nor is one done in conjunction with the other, with an exception.

The threaded breech plug is not unscrewed for loading.  It is made to seal the end of a seamless tube during construction and is only removed for barrel inspection and cleaning. In fact if properly made it is not readily removable. It is the same type screw breech plug that is found in muzzle loading rifles.

If you follow this board, you will know the Moderators preach safety.  We have Safety rules prominently and permanently posted as part of this forum.  One thing we harp on is when ever possible load powder in foil cartridges, before loading into cannon, don't load loose powder.  But loading cartridges is not always possible in the small scale cannons.  The advice for  small cannons is to follow the loading procedures for muzzle loading rifles.

There are breech loaded black powder cannons, with screw breeches.  But by the very nature of their design they do no lend themselves to the loading of loose power. They can only be properly loaded with bagged or cartridged power.

Your post is a very good warning for bomb makers, an activity that is highly illegal.   It's sad a young man lost his life.  Let that be a warning to anyone contemplating bomb making.  Since your post seems to be about teenage bombers blowing themselves it would appear to be off topic.  But it is not.

Your post is a good reminder that we are handling a very dangerous substance and great care needs taken so we are able to enjoy our sport.

I hope your post makes everyone stop and think, and I thank you posting it

[Cat Whisperer]

My concern is that I have read about using loose powder and screwed on breaches.

Lapatit - we share your level of concern when dealing with any black powder.  Having made a few of the devices you mentioned when I was in H.S., I KNEW for years I wasn't going to live to 21.

I agree with DD - safety with removeable threaded breach cannon, there are methods traditionally used that prevent loose powder from being anywhere near the threads.  Certainly extra care and inspection is warrented.

In most cases with threaded breaches, the breach is screwed on and left on - generally welded.  We're talking about muzzle loaders here.  Proper care should be taken in the design such that there is no possibility (by cruch-fit) of any gasses seaping into the threaded area.

So, we appreciate your comments on raising the awareness of the potential dangers - and the need to design and act such that there is NO POSSIBILITY of a cannon or a mortar becoming a bomb.

Most of y'all know that I speak from the experience of having seen a cannon (1" bore, bronze yacht cannon) explode - 5 of us standing right behind it (VERY fortunately).

I generally over design wall thicknesses and materials to ensure that there is no 'event' with any of my productions that would ever hit the national news.

[Cat Whisperer]

Let me just add that black powder is VERY sensitive to pressure and spark.  MOST companies that make it cover HUGE areas of realestate with buildings that are built so that WHEN the explosion occurs the roof goes up and the walls contain the blast.

Further, the storage requirements are much more stringant that with smokeless powder.

And if you read the handling requirements of any of the competions (see our 'sticky' on safety) you will find very rigorous methods of handling and segregating powder when firing rounds.


I take pride in razing the folks at work that drive motor cycles and race bicycles that what I'm doing with mortars and cannon is much safer that what they're doing!