From: unx.sas.com!sasdvp@mcnc.org (David V. Phillips)
Newsgroups: rec.guns
Subject: Re: Ballistic gelatin
Date: 7 Apr 92 13:05:16 GMT
Organization: SAS Institute Inc.

mcrware!!rgreen@uunet.UU.NET (Randy Green) writes:

#  A while back someone posted the formula for balistic gelatin.  Could
#you please repost it?


I don't know if I posted it before, but here it is.  

#From 'Ordnance Gelatin for Ballistic Studies' by Martin L. Fackler, in
The American Journal of Forensic Medicine and Pathology 9(3): 218-219,
1988.

(Reference given so I don't have to type in the whole article.)

I'm leaving out the reasons, but trust me, you must follow the
instructions exactly.

Using 250 A Ordnance Gelatin, from Kind and Knox Division of Knox
Gelatine (Sioux City, Iowa)

1.  Always start with COLD - 45-50 F (7-10 C) water.

2.  Always add the powedered gelatin to water.  Never pour water into
gelatin.  Use 1,000 g gelatin with 9,000 ml water.  (This gives 10%
solution.)

3.  Agitate (by stirring) a bare minimum just to wet all particles
(avoid violent agitation to prevent entrainment [ that's what the
article says! ] of large quantities of air).

4.  Let stand in refigerator for 2 h to hydrate all gelatin particles.

5.  Heat the container in a hot water bath or double cooker, and again
stir gently until all gelatin is in solution and evenly dispersed
throughout the container.  DO NOT HEAT OVER 104F (40C)!  Do not stir
rapidly, to prevent entrainment of air.

6.  Pour into molds, set in refrigerator or cold - 45-50 F (7-10 F) -
water bath until firmly set. (Leave overnight for best results.)

7.  AFTER REMOVAL FROM MOLDS, STORE IN REFIGERATOR AT 39 F (4 C) IN
AIRTIGHT PLASTIC BAGS.  DO NOT USE BLOCKS UNTIL AT LEAST 36 H HAVE
ELAPSED FROM THE TIME GELATIN WAS POURED INTO MOLDS.

General notes:

1.  Gelatin is insoluble in cold water.

2.  Final concentration will depend on desired firmness of block.

3.  Firmness of block will increase with time in cold water bath, up
to 24-30 h.

4.  Blocks may be reused simply by heating to melting temperature then
rechilling as in original procedure.

5.  Add 5 ml propionic acid (pure stock solution obtained from Fisher
Scientific, Fair Lawn, NJ) per liter to inhibit mold (optional).

6.  Gelatin firmness varies greatly (inversely) with temperature of
the block.  Gelatin temperature must be constant throughout each block
and there must be no temperature variation between blocks.  We shoot
our gelatin blocks within thirty minutes of removal from refrigerator.
We measured the temperature 2 cm from the block surface; in takes 90
min to rise 1 C in our shooting range which is kept at about 68 F (20
C)




Additionally, see the American Handgunner 1992 Combat Annual for a
'Fackler Box' which uses gallon freezer baggies of water instead of
gelatin.  It's alleged that penetration in water x 1.8 equals
penetration in gelatin.  It will at least be consistent, and requires
much less preparation !

--
David Phillips         sasdvp@unx.sas.com
"They that can give up an essential liberty to obtain a little temporary
safety deserve neither liberty nor safety". -- Benjamin Franklin (1759)
"Gun control is being able to hit your target." -- Me.