German 8,8cm round black cross

[fert]

Hello,
I came across these pictures that show a German 8,8 round with black cross stencilled in case and shell.
I have in my docs pic t that indicates “Magnesiakitteinguss” but I can translate except it s made of cast iron.
Anyone could help me please?

All the best

 

[Busta]

1) Id of explosive
2) indication for projectiles made of this specific material
3) engraved sort of explosive, location, month and year of filling.
3) location, day, month, year and id of responsible person for the filling.

 

[Alpini]

The explosive charge cardboard container was fixed with Magnesia-cement in the shell. Magnesia cement is a white ceramic-like very hard substance (mixed MgCl2 + MgCO3 prior to reaction). In larger shells it was often used.

The shells were made from steel with different ways of manufacturing but never made from cast iron.

 

[fert]

Thank you Alpini.
Do you know if the cement had other function or just to hold the cardboard container?
all the best

 

[AKON_]

Paraffin melts at 40-50°C, which is used to define the charge in the cardboard against the wall of the projectile.
a) during firing, the chamber heats up and the temperature is transferred to the projectile.
b) the temperature in the desert definitely exceeds 40 degrees
This will cause the cardboard with explosives to become unstable in the sense of movement (rotation and displacements of the longitudinal axis of rotation). If the block of explosives is sealed (in height) with cardboard inserts, there is less influence. Anyway, at temperature and paraffin, the longitudinal axis of rotation is broken ...
Akon

 

[greif]

The explosive charge cardboard container was fixed with Magnesia-cement in the shell. Magnesia cement is a white ceramic-like very hard substance (mixed MgCl2 + MgCO3 prior to reaction). In larger shells it was often used.

The shells were made from steel with different ways of manufacturing but never made from cast iron.

That is not correct. The black cross indicates the opposite, namely that the explosive charge was pourred directly into the shell body. To separate the pourred-in explosive from the base plug and it’s threading, a layer of magnesiakit was applied. Down below 3 figures, the first one with an inserted cardboard container with explosive charge, the second with pourred-in explosive.

 

[AKON_]

The solution to not using a Pb ring to seal against gas leaks during a shot is to use magnesium putty in the thread and make a "plug" from this mixture, which protected the explosive from contact with the gases during the shot...

 

[fert]

Hello
Thanks for info.

In this pic Magnesiakitt applied over base plug.
Is the same cement as Magnesiakitteinguss?
All the best

 

[Alpini]

"-einguss" means it was "cast into" (should have noticed this difference)

Basically it's the same material but consistency was set up more liquid. The word "Kit" itself describes a consistency between solid and liquid. Normally "Kit" (putty) is to thick for casting. After drying both become as hard as concrete.

 

[AKON_]

The old system was built on a sealing ring (Pb) and coupand ,,Numata,,

When the filling laboratory system was changed, the bottom of the projectile (thus also the body of the projectile) was modified and the recess in the bottom part (space for the Pb ring) was replaced with a new flat sealing ring (cardboard, ..) and the thread in the bottom was newly sealed with a two-component coupand and magnesium putty at the bottom of the explosive.