The lid for the German flask model 1931 of black synthetic resin (copy).
The appearance of resin lids was obviously connected with the reform of 1940, when a number of simplifications were made in the uniform and equipment of the German army. Such caps have been installed 1940-1941 (some 1942) by flask manufacturers marked MN (Metallindustrie GmbH. Neunkirchen-Saar (MENESA)), W.A.L. (Westfalische Aluminum Industrie, Junger & Co., Lüdenscheid), H.R.E., M.K.L., S.S.L., ESB and other. Such caps are very often found with in veneer (they are also not quite rightly called "bakelite"), which were used by the German African Corps (DAK).
The cap has the same design as the earlier aluminum caps. In 1940, the Germans essentially made a copy of the aluminum cover from a cheaper material.
Price per set: cap, red rubber gasket (type with a hole in the middle) and peg (rivet).
How to install the peg in the cover?
The pegs were installed nip and tuck into the bakelite caps, and were fixed by a blow to the center of the peg (with a pointed metal “finger” like a nail). From the blow, the peg expanded and fixed itself. It should be understood that the impact force was calculated and tested in advance before the production of caps. But when you work with a single cap, you have no trial attempts and can split the cap. Therefore, we recommend fixing the peg with epoxy resin (epoxy glue) — this is reliable, safe method and it will give 100% tightness to the cap.
Caps from our "Replika" shop, pegs are inserted but not fastened. All pegs has the same sizes of the top half but different tip lenght.
Original bakelite cap with installed aluminium peg. Picture from 44thcollectorsavenue.com