Subject: ANFO
Date: 6 Mar 90 10:44:09 GMT

Fertilizer and oil is one of my favorite mixtures. I haven't even calculated
how many hundred kilograms I've consumed. The fertilizer is cheap and readily 
available. As a drawback its brisance is low. However, that doesn't matter,
if one kilogram is not enough I take two or five or ten. It is still cheaper
than using some high explosives like pentrite or similar.

The fertilizer in Finland contains 75..80 % of ammonium nitrate, the rest 
being dolomite earth. It doesn't matter at all, although the safety instructions
on the bags tell: This fertilizer won't burn or explode under any conditions..
Well, that's not actually true, it does react, if it is ground a little and 
mixed with 4 % of oil. The best oil available is waste motor oil. It is the
cheapest, it doesn't stink is the mixture and it ignites the best. The best of 
all, think about the the environmental problems involved in waste oil! This
is the way how to get rid of such problems! I use a 5.5 % mixture, calculated
on pure ammonium nitrate. More oil means difficulties with the ignition and
a bad smelling cloud of smoke after the explosion.

The problem is only to get a strong boost to set the mixture off. You need at 
least 30 grams of TNT or stronger to ignite the unconfined stuff. If confined,
it can be ignited even with explosives of a lower brisance. Usually I take
20 to 30 grams of octogen and the ignition is 100 % sure. Another "problem"
with unconfined charges is the minimal amount. You have to take at least 5 cm
thick layer in every directions around the detonator to get a sure ignition. 
That means about a kilogram. A kilogram makes a blast that can be heard 7 km 
away upwind. I know, I have been told that after I had made some tests..

The minimal charge problem doesn't arise with confined charges, i.e. buried 
into ground, underwater charges etc. On the other hand, these make less noise 
and that's why you can use more stuff at one time. Underwater explosions are 
my favorite, they don't make noise, but look very spectacular and beautiful. 
Underground blasts are nice too, but you have to have a good shelter against
falling stones. For example, a 4 kg charge in 1 meter depth in sand threw 
about 4 cubic meters of sand 200..300 meters away. The crater was about 4 meters
wide and 2.5 meters deep. The ignition was carried out with delay fuse, which
is readily available here. (Just walk into a store and buy some 10 meters).