Type 95 Brass-Colored Tsuka Discovery!

[Bruce Pennington]

We have all seen numerous Type 95s with brass-colored tsukas. Most are fakes and have many other signs proving them to be so. But I have a Nagoya side-latch that I KNOW is legit, yet the tsuka has that yellowish, brassish tint to it.

 

Well, I was examining another guy's 95 on the facebook page that has this tint too, but everything else looks pretty good. In the discussion I was asked for some pics of my Nagoya. WELL ... after taking some pics and seeing some close-ups, I realized that where the surfaces get rubbed or contacted a lot, the yellowish coloring is rubbed off and it is clear the handle is real aluminum!

 

So, something along the way has caused the surface to yellow - possibly a chemical reation to the original paint-job? possible oxidation for an aluminum type that yellows this way?

 

It has made me more cautious, now, to jump to conclusions about other 95s just because of the brassish color to a tsuka. There must be other indications about fakery before I'll label somebody's 95 as a fake.

[Shamsy]

Yep, the early Gifu like yours (under 20k) and early Suya (around 7k) sometimes exhibit the tinge you are referring to. I've not seen it on later swords that I can recall. I can't say why, but I'd assume a chemical reaction or a different composition of aluminum?

 

It's not necessarily a new thing, but uncommon enough that It’s good you have mentioned this for others benefit.

 

Oh, just had a thought. Reminds me of the colouring used on the all aluminum NCO’s.

[IJASWORDS]

Aluminium is very difficult to get paint to adhere to, certainly for any length of time and with hard usage. It has been common practice to etch prime the aluminium with a chemical (usually chromium based) that bites into the aluminium, but also "keys" the paint finish. Acid chrome compounds leave a goldy yellow colour on aluminium and its alloys. You may have noticed some aircraft aluminium components look a goldy yellow colour before painting.  

[Bruce Pennington]

Aluminium is very difficult to get paint to adhere to, certainly for any length of time and with hard usage. It has been common practice to etch prime the aluminium with a chemical (usually chromium based) that bites into the aluminium, but also "keys" the paint finish. Acid chrome compounds leave a goldy yellow colour on aluminium and its alloys. You may have noticed some aircraft aluminium components look a goldy yellow colour before painting.

 

Neil, you nailed it buddy! Nick Komiya, over on Warrelics, confirmed your point, saying that they used oxalic acid to anodize the aluminum to prevent corrosion, giving it a yellowish color!

 

I might even have a lead as to why this is only seen on early production blades:

 

From Nick: "The army had Riken to thank for making aluminum the robust material it had become for field use, but when Riken tried to renew its patent in 1939 (patents were valid only for 15 years), citing that it's investment in two new large factories had not yet been fully amortized, the army prevailed upon its Minister to block this renewal. Riken's patent in those days restricted Almite processing to designated production facilities only and the army saw that as a very unwelcome bottleneck for expansion of its military production capacity, not to mention the extra cost of patent royalties to Riken"

 

The Armlite (copyrighted name of the oxalic acid treatment) patent was blocked in 1939 and it seems the army discontinued the treatment to speed up production, which would fit what we already know about the severe shortage of gunto in those early years.