The original blade collar of the Practical Katana is made of solid brass. It is one-piece, plain and without any decoration.
I will create a brass cover to make it better looking.

You can see on this paper template how the cover should look like. Actually such a template is not necessary, because anyway the stripe should be made wider for the time beeing.

Material for the cover is 0,2 mm brass sheet.
I have cut off a stripe wide as the Habaki.

The stripe is bent around the lower edge (Ha side) and the upper side edges of the Habaki. The joint is on the upper edge (Ha side).

Here you can see how the cover should fit the Habaki.
The joint edges are filed as precise as possible to keep the soldering preferably invisible.

The cover is fixed with wire to close the joint for soldering.

I have put some swarf of soldering metal inside the cover and held it into a blow torch flame.
The solder melted and closed the joint.

Now the casing has to be customized that it covers only the backside of the Habaki and leaves the frontside blank.
The cover should overlap the opening of the Habaki by 1 mm.

The cover should fit the Habaki tightly. In this picture the overlapping part is bent around the bottom of the Habaki.

The finished Habaki
I have polished the inner part and grinded the cover slightly.
Be aware, that the Habaki always should fit to the scabbard opening (Koiguchi) to ensure a safety halt.