18pr question

[US-Subs]

Last weekend I was passed a live 18pr shrapnel, no stamped markings so I have no idea if it was UK or (more likely) Canadian. I passed it on to a local Squad and asked them to hit it with a small oil well perforator charge (shaped charge) through the rotating band, to destroy the expulsion charge and leave something for training. Their initial shot blew the charge and split the base, but left the body and adapter intact. They decided to use a second charge (15 gram) to pop the body, and this cracked the body lengthwise, exposing the balls and a yellow powder space filler. My question, what is the yellow powder? Looking at shrapnel rounds from different countries in the past I have seen yellow resin (hardened), sulfur, and explosive. This does not have the appearance of any resin fill that I've seen, and examination with Raman spectrometry does not identify the fill. Normally an explosive fill or something as basic as sulfur would identify immediately. Guesses?

 

[pzgr40]

I know dutch shells used pure sulfer, as one could melt it into a low viscocity liquid that could easily be poured between the balls and which solidified without too much shrinkage. It was also quite a cheap filler and easy to obtain.

Ps; next time use a hacksaw to make a cutaway model, the rersult is much more neat

 

[Snufkin]

Assuming the above round was of US or Canadian manufacture, made for the UK, then the powdered yellow material should simply be aged resin.

(Canada made 15 million complete 18-pr Shrapnel for Britain 1915-1918, but the US also made 4.5 million complete 18-pr Shrapnel between Q2 1916 and Q2 1917. The British specification called for the fill to be resin, to set the balls and to provide black smoke to locate the point of bursting.)

 

[FZG76]

I think it's a rosin.

The lead balls were mixed with pine rosin (the substance left over after turpentine is distilled out of pine sap) and poured into the shell. The rosin was allowed to harden in the shell. The purpose of the rosin was to prevent the lead balls from rattling around in the shell during flight, which might have caused premature ignition of the gunpowder. The rosin also provided smoke so that artillery spotters could determine if the shells were being timed correctly to explode above their targets.

 

[FZG76]

I think it's a rosin.

The lead balls were mixed with pine rosin (the substance left over after turpentine is distilled out of pine sap) and poured into the shell. The rosin was allowed to harden in the shell. The purpose of the rosin was to prevent the lead balls from rattling around in the shell during flight, which might have caused premature ignition of the gunpowder. The rosin also provided smoke so that artillery spotters could determine if the shells were being timed correctly to explode above their targets.

 

[US-Subs]

Thanks guys, works for me.

 

[Gspragge]

See drawing and sectioned shrapnell. There are lots of these around, some the better ones have the
loading of balls intact. One presumes these were rejects for some reason, I have never observed one to
have any charge in it.
This information is easily available and the drawing though a 13pr is identicle to an 18pr except in size.
If there was a test question here the answer would be ---- water.

 

[US-Subs]

If there was a test question here the answer would be .... don't. There are about a thousand different things that contain variations, flaws, damage and unexpected outcomes. Misinterpretation of unqualified testing in unsafe environments does not equal safety or assurance. In the US most bomb squads are not going to accept this or try this, and offering a description that you did this as a procedure is not going to fill them with confidence in you or your activities. Just don't.