From: ahahma@kontu.utu.fi
Newsgroups: rec.pyrotechnics
Subject: Re: recipes anyone?
Message-ID: <1990Nov24.174029.36655@kontu.utu.fi>
Date: 24 Nov 90 17:40:29 GMT

In article <1990Nov21.215005.7625@Neon.Stanford.EDU>, marks@Neon.Stanford.EDU (Michael M. Marks) writes:
>>Do any readers know the recipes for Semtex or C4?
>>
>> ..G..
>
> Is anyone else on rec.pryo a little bit bothered by requests like this for
> recipes/sources for explosives that are more appropriate for violent than for
> recreational uses?  This is not the first I've seen.

No. There are a hundred and one easier ways to make a big bomb. If someone
is planning to blow up something, why would (s)he bother making plastic
explosives for such purposes?

However, there are uses, in which a plastic explosive can not be replaced.
For example, have you ever seen art made by explosives? Tree leaves, flowers,
small objects can be nicely printed on a metal plate with explosives.
The resulting positive picture on the plate ( three dimensional actually) is
a very accurate copy of the object, including the very smallest details.
I have made this, and I used C4 ( or respective composition) for doing it.
The explosive has to be fast detonating and evenly spread over
the plate. Plastic explosive it perfectly suited in these requrements.

Or, metal carbides, hard and high melting ceramics can be sintered together
, bimetal plates (for example aluminum on copper) and much more can be
made explosively, often a lot easier and better than with any other
means.

These kinds of activities are recreational, aren't they?

> - Michael

ArNO
    2

From: ahahma@kontu.utu.fi
Newsgroups: rec.pyrotechnics
Subject: Explosive metalworking
Message-ID: <1990Nov26.182656.36670@kontu.utu.fi>
Date: 26 Nov 90 18:26:55 GMT

In article <1990Nov26.014152.29715@hayes.ims.alaska.edu>, fskjk1@acad3.fai.alaska.edu (KELLY KEVIN J) writes:
> In article <1990Nov24.174029.36655@kontu.utu.fi>, ahahma@kontu.utu.fi writes...

>>The resulting positive picture on the plate ( three dimensional actually) is
>>a very accurate copy of the object, including the very smallest details.

> 	How would you do this...  (how thick does  the c4 have to  be?)
> How  would you  prepare the small objects??

It depends on how deep you want to have the pictures. There are limitations
to the objects, the have to be less than 2..3 mm thick, or the picture will
look "splashed". For example pictures of berries look just as if the berries
had been stepped on, splash! The objects don't have to be prepared in any
way, just put them onto a metal plate (preferably copper or aluminum),
put a rubber plate on them (10 to 15 mm thick, thicker plates allow thicker
objects but require much more explosive) and spread about 7 to 15 mm thick
layer of C4 on the rubber plate. The exact amount has to be tested. Too
little explosive, and you won't get good pictures, too much and the plate
cracks at the edges.

The whole system is then laid on a thick (> 5 cm) steel plate or a thick and
even concrete block to prevent the plate from totally bending into a knot.
The steel underplate should also be covered with a thin rubber mat to prevent
the target plate from welding together with it. With concrete this is also
useful to prevent a copy of the concrete surface from printing onto the oppo-
site side of the target.

If you have Detasheet (r) then you don't absolutely need the thick underplate,
since Detasheet is of very uniform thickness. In this case you can put the
plate on mud or fine, wet sand without bending it too much (have fun
when digging it from there ;))

Finally, put blasting caps into opposite sides of the explosive (to prevent
the plate from flying away, if you'd ignite just at one side) and detonate them
at the same time, i.e. use detonating fuse or electric caps to achieve this.
You might have problems in finding the plate after detonation anyway, if
you use the steel underplate. It acts much like a spring and may throw the
target plate quite far away.

Steel plates can also be etched this way, but you'll need about twice
as much of an explosive as with copper. Stainless steel will work fine, however.

If you put small metal objects on the plate, they will be welded together with
it. This way you can make really pretty effects, for example by using silver
wire on copper etc.

> 				-Kevin-

ArNO
    2

From: ahahma@polaris.utu.fi (Arno Hahma)
Newsgroups: rec.pyrotechnics
Subject: Re: Blasting Cord
Message-ID: <1992Feb21.105229.138@polaris.utu.fi>
Date: 21 Feb 92 10:52:29 GMT

In article <4192@umriscc.isc.umr.edu> dshipley@cs.umr.edu (Dan Shipley) writes:

>Hi all!  I recently saw a program on public TV about a woman who uses
>'blasting cord' to make metal art.  It looked really cool (the art).  The

I have seen pictures of that art as well. However, there are better
ways to do it: use plastic explosives. With them you are better able
to direct the detonation as you wish. Also, they are easier form to
whatever shape desired, and the amounts are also easier to control.
They are also suitable for making "detonograms" of whatever thin
objects - really nice positive, three dimensional "photographs" in
solid metal. I have one on my front door, made in stainless steel and
copper.

>problem is you need an explosives liscence to get the stuff.  Is there an
>explosive that can be made at home that has similar power to blasting cord?

That is true. And it may be even more difficult to get, say C4. There
are easily made explosives, take a look at any chemical encyclopedia.
You will find exact laboratory procedures. However, it is quite a mess
to make them and they will become more expensive than the ready,
industrial products, unless you also make the raw materials yourself.
In that case, you will get them for a fraction of their market price.
Before you get that far, you have to invest a lot - that is exactly
why explosives are expensive, there are also the safety precautions
and costs due to them.

>I need something that is (relatively) safe to make and handle.  i.e. I DON'T
>want to try making nitro or anything even remotely as dangerous to handle.

The explosives themselves are not dangerous, but the process chemicals
are. Handling strong acids in large quantities not spilling any is
really difficult. In fact, that is the major concern in a modern
explosives factory as well. The risks related to the explosives are
much easier to overcome.

>Now, I know that someone out there is ready to flame me because I
>want to play with high explosives.  Please don't.  I HAVE played with
>high explosives

Just like in anything, there is nothing wrong with that as long as you
don't excessively disturb other people. The terrible noise from even
small amounts of explosives cause is not one of the least problems.

I have played with them, too and it is fun, indeed. The problem is,
that you have to know a great deal about them, before you can start
using them safely.  Thinking a little before trying will help a lot.

>play in a rock quarry out in the boondocks (where I live & where I

A rock quarry is not the best place for making art. You need a soft
base (soil).

>Dan