Blued (oil blackened) versus Parkerized

[Bruce_in_Oz]

The "dull ring" is probably because the bodies of No1 and No4 rifles are not all one piece.

On the No1, the entire charger bridge is riveted to the body. The No4 has a pair of "risers" forged and finished machined. The "cross-bar" is then fitted with a variety of techniques, .

ANY "discontinuity" in the structure will "dull' the ring. Also bear in mind the very different steels in use: No1 bodies were a straight Carbon steel. No4 bodies seem to have introduced some additional alloying traces; I do not have the data sheet on this. Any offers?. A "dull" M1 / M14 body is usually the result of Bubbas and Bozos using a long bar of steel inserted through the nag-well as a "wrench", instead of the correctly-profiled EXTERNAL type that fits around the front of the body. The Bubba method can crack the small "bolt-support bridge" inside the body.

Mi and M14 bodies are hogged out of 8620, a serious alloy steel. Carbide tooling was "invented" for such stuff.

Anyone who has played seriously with M1 and M14 receivers / bodies will have noted that a fully stripped body will ring like a bell. ANY "dullness" indicates a fault. Time for the magnetic or fluoro-dye test kits.

[Surpmil]

Sometime I'll take some chunks down a local scrapyard and see if I can get them to run their spectrometer over them.

[bigduke6]

Interesting thread, the best results I,ve ever had with traditional Bluing ( Rusting ) was cleaning the item in all manor of cleaning products, then actually using a sliced lemon to rub all over, left mother nature to do the rest, a few repeats and boiling left an excellent finish.

Parkerizing, I've never been able to produce as good results as I did when using the facilities of the ships galley and one of the cleaning products on board that contained phosphoric acid, (Unitor, Metal Bright)

Cold black oxide kits , can be used for some excellent finishes, you can match bluing using these kits, but its trial and error, the metal finish is the key to these kits, highly polished = light to very dark blue, Beadblast/sandblst using aluminium oxide or course media will produce a black matt finish. I,ve restored many bayonets and rifles using the black oxide kits, certain steels ( New Walther barrels in particular ) tend to rust very quick for some reason, the last few I did I just boiled these as in traditional bluing and repeated the cold black process.

[BurtonP]

Interesting aside: I recently watched a documentary on the discovery of two Viking long ships that had been buried in Scandinavia in the 9th or 10th centuries if memory serves me correct. One of the ships had its wooden timbers completely rotted away but they were able to ascertain the ship's length from the oil blackened spikes which survived a Millenia in the damp earth relatively intact.

Archaeologist here - This preservation effect has less to do with the oil (or any other anti-rust treatment) and is almost entirely due to anaerobic soil conditions (probably wet clay). Without Oxygen iron will not rust. Nevertheless, it always surprises me when I find buried ancient iron in good condition.