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View Full Version : Can HMTD be a safe primary explosive? - Archive File


megalomania
June 18th, 2003, 03:39 PM
HNIW
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Posts: 46
From: Poland
Registered: JAN 2001
posted 06-10-2001 04:02 AM
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I have been preparing blasting caps that contains HMTD for about 4 months. I use Al pipes. To reduce the reaction between HMTD and Al, I usually mix HMTD with pure NC and acetone. This mixture can be easily pressed and pressed explosive has higher detonation velocity. I've heard that HMTD can explode without any reasonable reason when one uses copper or brass pipes for blasting caps. My oldest blasting caps have more then 2 months and they set off ANFO without any problems. I know that problems with HMTD may occur when we mix it with powdered metal, but I would like to know if it can react with aluminium pipe. When I opened an old blasting cap containing HMTD I noticed that the pipe walls were covered with Al2O3. So my question is: Is it safe to use HMTD as a compound for blasting caps?


wantsomfet
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Posts: 236
From: EU
Registered: JAN 2001
posted 06-10-2001 06:49 AM
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HMTD will react with aluminium, copper, brass, zinc, antimony, iron & lead, even when dry. Use AP for your detonators or cover the metal with some varnish!
Putting HMTD in Al pipes could result in an accident. (You where lucky that you used HMTD putty...)
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Mr Cool
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Posts: 991
From: None of your bloody business!
Registered: DEC 2000
posted 06-10-2001 08:54 AM
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Line the inside of the pipe with varnish, or a layer of greaseproof paper. This should keep the HMTD and the Al seperate.
HMTD is a better choice than AP. I have had a bit of loose HMTD for years now, and I keep testing it to see how it is, and it still seems fine. There was even some interest in HMTD for commercial detonators. I'll post the file up here if I still have it.


HNIW
Frequent Poster
Posts: 46
From: Poland
Registered: JAN 2001
posted 06-10-2001 11:22 AM
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The problem with varnish is that I use acetone to make something like a glue from NC, then I add HMTD. This mixture I can easilly press, in addition NC cause it stronger and pressing provides higher density.


wantsomfet
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Posts: 236
From: EU
Registered: JAN 2001
posted 06-10-2001 12:20 PM
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Then you should perhaps use another material for the detonator. I use glass tubes, thats perfect.
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a_bab
Frequent Poster
Posts: 44
From: doesn't matter
Registered: MAY 2001
posted 06-10-2001 03:56 PM
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Here is some post I found at rec.pyrotechnics about HMTD:

"From: billw@puli.cisco.com (William )
Newsgroups: rec.pyrotechnics
Subject: Re: Question on Chemical Compound
Date: 05 Oct 1996 03:08:37 GMT
In-reply-to: mikpits@ix.netcom.com's message of 3 Oct 1996 14:28:08 GMT

I've got a freind telling me of a compound made with Hexamine, Citric
Acid, and Hydrogen Peroxide. What is it and what are it's hazards?

Sounds like they mean Hexamethylenetriperoxidediamine, or HMTD. It's a
sensitive primary explosive. It deteriorates quickly over time, however.
The most serious unobvious hazard is that it is apparently made much more
sensitive when in contact with brass or copper. People try to make their
own blasting caps by pressing it into old rifle cartridges, with nasty
results. Here's an except from an old email on the subject:

Newsgroups: rec.pyrotechnics
Subject: Re: HMDT
Date: 10 Mar 92 04:53:20 GMT
Organization: Tampere Univ. of Technology, Finland.
:
:
Well, I put a small piece of HMTD into a brick, and hitted it with a
hammer, and it didn't detonate. I also tried a 'spark-test' from a
lighter, and didn't managed to detonate HMTD. ( Indeed in ntp, and in
normal condition, HMTD wont detonate If you light it, It'll burn like
cellulose nitrate - with a yellow flame. Well, I was more than
Happy to see, That I'd found A PERFECT Primary-explosive to detonate
high-explosives.
Well At the July of 1989 It happened, I was damping HMTD into a .22
LR copper cartridge, with a standart match, you see holding that
cartridge in my left hand ,when it suddendly detonated, A HUGE explosion,
and I found that for some reason, my hand was bleeding abt 1/2 liter
of blood per min ( 1/9 gallon per min ) , and I could see my bone
'shining' through scraped human tissue.

Epiloque. Never NEVER load B-caps in your hand, Always use special
tamping device when loading Blasting caps - any other use for HMTD is
silly - Believe me, I had hitted HMTD with a Hammer, It didn't
detonate, and now, when I try to load that stuff from same batch into
a copper container, It detonates, even I press with maybe 1/2 kg
( = 1 pound ) force it.
Maybe the batch was impure, but believe me, It really explode
without no reason. I must say that HMTD is a good explosive, but It's
truly unpredictable. I'm sure that there are many others in this
newsgroup who can tell the same thing - months of hard handling, and
then, a explosion by a minumum force.
"

So, you were relly lucky not to blow off your hand...




mark
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Posts: 195
From:
Registered: OCT 2000
posted 06-10-2001 04:21 PM
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Just use hanger tube. Its cardboard. Or use aquarium tubing. Dont use glass or metal.


CragHack
Frequent Poster
Posts: 618
From:
Registered: DEC 2000
posted 06-10-2001 04:56 PM
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assuming you are going to make a blasting cap the right way, and press the explosive into the container, you might not want to use glass. The glass container might not be able to stand the pressure of tamping. And if it does, i bet it would be a poor material to use anyway. It is to brittle, there would be no pressure buildup, the glass would shatter to quickly. I would suggest placing the primary explosive in a paper baggy then placing the baggy inside a metal tube. Don't use plastic bags, static electricity is not a friend in this case.
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blackadder
Frequent Poster
Posts: 313
From: London
Registered: DEC 2000
posted 06-10-2001 06:14 PM
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Whenever my mum finishes using the rolls of Al foil (or even when she hasn't), I steal the cardboard tube on the inside of the foil which the foil wraps around. I then wrap this tube with tons of electrical tape, and presto, I have a sweet container for some explosive. It won't react with shit, since it's cardboard.


wantsomfet
Frequent Poster
Posts: 236
From: EU
Registered: JAN 2001
posted 06-10-2001 06:21 PM
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I wouldn't tamp the primary that strong. I don't apply very much pressure on it. OK, you'll get a better cap if you press it stronger, but i personally wouldn't use any mechanical means like a loading press.
But if you use one, glass won't be good, that's true.
But from the chemical point of view its the best choice, you can be sure your primary doesn't react with the container.
And a thin walled commercial metal detonator tube stands no pressure buildup, too. But its not even necessary, the primary *detonates*, the container is only to hold it in shape.
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[This message has been edited by wantsomfet (edited June 10, 2001).]



10fingers
Frequent Poster
Posts: 411
From: USA
Registered: SEP 2000
posted 06-10-2001 10:57 PM
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HNIW, if you don't want to use varnish in your tubes try using wax, it is not affected by acetone. Just melt some wax in a small can and dip your tube into and then let the excess run out.
HMTD is an excellent primary explosive and quite easy to make, it seems to last in storage quite a bit longer than some people think.





sealsix6
Frequent Poster
Posts: 154
From: NYC,NYC,USA
Registered: NOV 2000
posted 06-11-2001 12:02 AM
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HNIW or anyone woule you be able to tell me the proportions for the acitone and nc to make the HMTD putty?


-A-
Frequent Poster
Posts: 100
From:
Registered: JAN 2001
posted 06-11-2001 02:20 AM
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Laboratories use a lot of kinds of plastic tubes, you can find them also on some plastic shops, you can also try cardboard tubing from pyro supplies.


HNIW
Frequent Poster
Posts: 46
From: Poland
Registered: JAN 2001
posted 06-11-2001 05:20 AM
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I can't use cardboard tubing, the answer is simple. If I use it HMTD won't detonate, there will be a noise of explosion but it will only be a fast burning. The results are also simple, 2g won't set of ANFO. I know that unpressed 2g of HMTD detonate only in metal pipe. If I press it, it may detonate in glass pipe. I am pressing it using pencil, not a hammer. What is more with NC it is much stronger then pure HMTD. I thing that roll of paper inside this pipe is the best solution. Now about this email, author used copper or brass pipes and I'm using Al pipes. Now I have to destroy 25 blasting caps . To press HMTD I use 4% of NC that with acetone and HMTD create something like small balls, that can be easily put and pressed in the pipe.
Thanks for suggestions !!


the freshmaker
Frequent Poster
Posts: 175
From: Heaven
Registered: DEC 2000
posted 06-25-2001 01:55 PM
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Here is a sad story taken from rec.pyrotechnics, about a man who experimented with HMTD.
"Well, I put a small piece of HMTD into a brick, and hitted it with a hammer, and it didn't detonate. I also tried a 'spark-test' from a lighter, and didn't managed to detonate HMTD. ( Indeed in ntp, and in
normal condition, HMTD wont detonate If you light it, It'll burn like cellulose nitrate -with a yellow flame. Well, I was more than
Happy to see, That I'd found A PERFECT Primary-explosive to detonate high-explosives. Well At the July of 1989 It happened, I was damping HMTD into a .22 LR copper cartridge, with a standart match, you see holding that cartridge in my left hand ,when it suddendly detonated, A HUGE explosion, and I found that for some reason, my hand was bleeding abt 1/2 liter of blood per min ( 1/9 gallon per min ) , and I could see my bone 'shining' through scraped human tissue."

Epiloque. Never NEVER load B-caps in your hand, Always use special tamping device when loading Blasting caps - any other use for HMTD is silly - Believe me, I had hitted HMTD with a Hammer, It didn't detonate, and now, when I try to load that stuff from same batch into a copper container, It detonates, even I press with maybe 1/2 kg( = 1 pound ) force it. Maybe the batch was impure, but believe me, It really explode without no reason. I must say that HMTD is a good explosive, but It's truly unpredictable.
I'm sure that there are many others ón this forum who can tell the same thing - months of hard handling, and then, a explosion by a minumum force. Play it safe guys!!!