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Anorak's Corner / CB160 Steering Damper Knob Restoration.
« on: September 06, 2024, 08:48:12 AM »
Well I got lumbered (only joking Jim ) with one of a good mate's problems again. He's restoring his 1965 CB160 but the steering damper knob top was only half there when he bought the bike and he didn't get the missing broken bit
Here in pictures is my 'restoration' of it.
The knob was originally made of hard black phenolic thermoset plastic. (like the body of old 13A plugs).
I decided to restore it with epoxy heavily filled with ultra-fine ceramic powder that sets rock hard. (the same RS 2-part epoxy I use for my coil refurbs).
The problem is the underside of the knob has convolutions that act, along with a springy clip thingy, as a detent mechanism, so I had to come up with a method of faithfully reproducing them.
I used hot melt adhesive run into the underside of the knob to make a mould part for the convolutions. I used a slight smear of silicone oil (same as I use in gauge dampers) as a release agent to stop the adhesive sticking to the damper knob plastic.
Here is the broken part with the hot-melt profile pictured next to it.
[ Guests cannot view attachments ]
Then the mould part fitted to the broken knob
[ Guests cannot view attachments ]
I drilled the knob and glued in 1mm pins to give reinforcement.
Then I used Blu-Tack to form the outside of the mould and filled with the ceramic filled epoxy compound
[ Guests cannot view attachments ]
The part with moulding bits removed and rough finishing before final fettling and paint.
[ Guests cannot view attachments ]
After fettling and painting...pleased with the result ! Paint needs knocking back a bit but I will leave that to Jim !
[ Guests cannot view attachments ]
Here in pictures is my 'restoration' of it.
The knob was originally made of hard black phenolic thermoset plastic. (like the body of old 13A plugs).
I decided to restore it with epoxy heavily filled with ultra-fine ceramic powder that sets rock hard. (the same RS 2-part epoxy I use for my coil refurbs).
The problem is the underside of the knob has convolutions that act, along with a springy clip thingy, as a detent mechanism, so I had to come up with a method of faithfully reproducing them.
I used hot melt adhesive run into the underside of the knob to make a mould part for the convolutions. I used a slight smear of silicone oil (same as I use in gauge dampers) as a release agent to stop the adhesive sticking to the damper knob plastic.
Here is the broken part with the hot-melt profile pictured next to it.
[ Guests cannot view attachments ]
Then the mould part fitted to the broken knob
[ Guests cannot view attachments ]
I drilled the knob and glued in 1mm pins to give reinforcement.
Then I used Blu-Tack to form the outside of the mould and filled with the ceramic filled epoxy compound
[ Guests cannot view attachments ]
The part with moulding bits removed and rough finishing before final fettling and paint.
[ Guests cannot view attachments ]
After fettling and painting...pleased with the result ! Paint needs knocking back a bit but I will leave that to Jim !
[ Guests cannot view attachments ]