Japanese gun sight part??

[MiTasol]

Gidday

Attached are two photos of a Japanese part that I suspect is part of a gun or bomb sight.

Is anyone able to identify what it is off for me? Note I do not have any other parts of what it comes off.

Secondly does anyone know of a way to prevent it rusting again? Seconds after removing from the rust bath it has a thin layer of rust growing.

Obviously it was not painted originally so do not want to paint it.

Thanks

Mi Tasol

 

[beihan62]

Hi Mi Tasol,after it is removed from rust cleaning bath rinse in clean water dry it (in sinshine which will get some heat in to it),then put oil on it,the heat will help the oil spread and penetrate all the tiny nooks and crannies,I have used this method on dug up aircraft parts and it seems to work,
Cheers,
Don,

 

[ordnance]

Mi Tasol, The sight looks like the rear sight post assembly for the Japanese Type 92 heavy machine gun.

 

[25thapril]

Ordnance is correct here are some pic's from my weapon

 

[BMG50]

What type of rust bath are you using? If it's an acid type rust remover, I use hydrochloric weak 32% mix to remove rust for metal finishing, ie parkerizing, when the blast machine is not working, the important part to stop further rusting after the process is not to let the metal be exposed to air as the rusting effect will take hold straight away. Remove from acid tank when you are happy with the results and immediately dunk in cold running water submerged and in warm or hotwater as well to remove all traces of acid rince very well but not for too long without exposing the piece to air. When satisfied, remove and with WD 40 (water repellent) soak spray item and remove excess water and oil at the same time. Your item should be rust free. I would then use Waxol with a hot air gun to finish the piece for display. I have carried out this method on 37mm rusty shell heads with perfect results, use a fine stainless steel or metal wire brush to clean stubborn rust such as the pitted areas, then soak again until all rust has gone. Don't acid soak overnight, you can clean up a shell over about 3 or 4 hours depending on the size and condition of rust.

 

[MiTasol]

Thanks to all for your replies.
I use the standard kiwi rust remover - ten parts clean water and one part molasses, soak for two days, clean with hard tooth brush (and scotchbrite if necessary), resoak for seven days and finish cleaning with toothbrush/scotchbrite or similar "soft" abrasive, repeat if required (seldom is if you use enough elbow grease). In extreme cases a wire brush is needed.
For items I am painting (everything before now) I then treat with deoxidine, air dry in the sun (it is usually above 25 C here so quick and easy), cool in the shade and prime with a thin coat of PPG BMS10-11. Paint as required