Blued (oil blackened) versus Parkerized

[Neuraleanus]

I'm curious, I have a Enfield No. 1, Mk III that has a mixture of blued (oil blackened?) and parkerized metal parts. The Noise cap, magazine, and bolt head are parkerized while the remaining metal parts are blued. Are the parkerized components an arsenal repair or later substitution? This rifle is a Century Arms import.

[Alan de Enfield]

I'm curious, I have a Enfield No. 1, Mk III that has a mixture of blued (oil blackened?) and parkerized metal parts. The Noise cap, magazine, and bolt head are parkerized while the remaining metal parts are blued. Are the parkerized components an arsenal repair or later substitution? This rifle is a Century Arms import.

Bluing of barrels was nothing to do with 'oil' (and no oil is used in the process) It is actually a chemical 'browning' of barrels as it is a form of rust, that leaves a blue finish when the whole process is finished.

Hence the name 'Blueing'.

The formulation was a closely guarded secret from the 'head chemist' at each manufacturing plant but details were published in a magazine in the early 1900s that describe the process.

Click the thumbnail and then the 'full page' icon to get it big enough to read.

[Sapper740]

Bluing of barrels was nothing to do with 'oil' (and no oil is used in the process) It is actually a chemical 'browning' of barrels as it is a form of rust, that leaves a blue finish when the whole process is finished.

Hence the name 'Blueing'.

The formulation was a closely guarded secret from the 'head chemist' at each manufacturing plant but details were published in a magazine in the early 1900s that describe the process.

Click the thumbnail and then the 'full page' icon to get it big enough to read.

Do you measure 'scruples' by weight or volume?

---------- Post added at 06:21 AM ---------- Previous post was at 06:16 AM ----------

Oil blackening is applied with heating a metal part and quenching in oil to cause black finish...which isn't so durable.

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.

[Alan de Enfield]

Do you measure 'scruples' by weight or volume?

A Scruple is a weight of 20 grains.

A Dram is 3 Scruples and an Ounce is 8 Drams

[Sapper740]

A Scruple is a weight of 20 grains.

A Dram is 3 Scruples and an Ounce is 8 Drams

Thank you for that tidbit of information Alan, in celebration of gaining new knowledge, I'm going to pour myself a half gill of bourbon.

[browningautorifle]

only used in fume hoods and kept well away from water as it would boil, splashing nitric acid everywhere if water is added to nitric acid instead of the other way around.

Yes you want a large evacuation hood running if bluing in a closed shop. We added the salts to water without incident as it's salt crystals and Parkerizing is a blueish liquid. No incidents.

I'm going to pour myself a half gill of bourbon.

You're in Texas now? Make it a half gallon...

[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.

[browningautorifle]

So to expand without the secrets...

Bluing is a salt dissolved in water and boiled at a temperature to cause it to go into the pores of the steel and prematurely "Rust" and protect the metal. It leaves a nice polished finish the same as the metal is prepared to.

Parkerizing is a liquid chemical that is added to water and boils at a different temperature to form a coating of crystalline structure on the surface of the steel. Therefore giving it a coating that will alter fitment of parts and the coating will protect and hold oil to some extent. It's used in military applications more as it has a durable attribute. There are several lesser grades of parkerizing and some isn't so durable...

Oil blackening is applied with heating a metal pert and quenching in oil to cause black finish...which isn't so durable.

---------- Post added at 04:37 PM ---------- Previous post was at 04:36 PM ----------

Are the parkerized components an arsenal repair or later substitution?

Does it have rebuild markings?

[Neuraleanus]

So to expand without the secrets...

Bluing is a salt dissolved in water and boiled at a temperature to cause it to go into the pores of the steel and prematurely "Rust" and protect the metal. It leaves a nice polished finish the same as the metal is prepared to.

Parkerizing is a liquid chemical that is added to water and boils at a different temperature to form a coating of crystalline structure on the surface of the steel. Therefore giving it a coating that will alter fitment of parts and the coating will protect and hold oil to some extent. It's used in military applications more as it has a durable attribute. There are several lesser grades of parkerizing and some isn't so durable...

Oil blackening is applied with heating a metal pert and quenching in oil to cause black finish...which isn't so durable.

---------- Post added at 04:37 PM ---------- Previous post was at 04:36 PM ----------



Does it have rebuild markings?

No, Just:
BSA Co
1923
SHTLE III

The rifle has a mixture of III and III* components. For example, it has the older cocking piece and the magazine cutoff, but the newer sight protector. The rear sight is square with no windage adjustment. The brass unit disc has been replaced with a wooden plug.

[Bruce_in_Oz]

"Oil blackening is applied with heating a metal pert and quenching in oil to cause black finish...which isn't so durable."

A variation on Oil Blacking is "Blazing Off.

This is generally used on low-Carbon items (malleable cast iron, as specified in the original documents.

The part (often screws and washers, is heated then "quenched quickly in a "suitable oil", the still HOT item ignites the oil immediately after that "quick quench and it burns off, leaving a thin "black" oxide surface. This, just like Parkerizing, blueing / browning, has a porous structure which conveniently holds a "film" of oil which reduces the rate of "corrosion. A Zillion small arms components, from early Ordnance muskets to the Bren (and possibly later?) had "low-stressed" screws and other components components thusly finished by "blazing off". It seemed to work OK.

Phosphating / "Parkerizing requires a "grit-blasted" surface for best application. "Grit-blasting" springs is a guaranteed way to induce "stress-risers" in the spring steel and thus premature cracking / catastrophic failure