So far, I have stripped the bike, segregated all the bits into boxes and sprayed the frame, forks, petrol and oil tanks black – see previous blog. However, there is a still a lot of work to be done in finishing the petrol tank (pinstriping. “Velocette” insignia etc) and putting “something” on the bare metal of all the other parts. There are also decisions to be made as to exactly what that “something” will be…
I have a few general rules for this; in no particular order:
- 2k paint for the petrol and oil tanks
- Plating – for this era of bike I use chromated zinc plating rather than nickel (up to around 1928/9) for shiny parts
- Chemical blacking for parts for which it is important to retain the as-manufactured dimensions
- Chrome plating for post-1928/9 bike exhaust pipes
- Powder coating (gloss black) for the myriads of little bits and pieces that make up most of the bike
As these are my rules, I can break them! For this bike I already decided to also paint the frame and forks (rather than powder coat) – see previous blog – so that I could use high-build primer to smooth out some irregularities, but the parts for the rest of the bike have otherwise followed this format.
Please bear in mind when reading the next part of this blog about painting that although I have been putting paint on motorbikes for around 60 years (see here) I am not a professional painter and there are probably some alternative ways of achieving the same end; anyway, what I’m describing seems to work for me.
The first step in preparing the tank for pinstriping is to define the pinstripe with a piece of masking tape that is the same width as the pinstripe itself (It is useful to have masking tape in a selection of widths)
This will not follow the curve on the inside of the tape at the front of the tank (the outside of the curve is fine) – the curve is too tight - and so some judgement is needed for the next stage to maintain a constant width in this region when the pinstripe tape is bounded on both sides with very narrow masking tape (which does follow the tight curve).
The wider tape is now removed
and the part where paint will be applied is carefully rubbed down with 800 grit wet-and-dry paper cut into thin strips from an A4 sheet and using a thin piece of wood (this is a piece fashioned from a wooden garden plant name tag).
I have now applied 2k gold paint using a fine artists brush, rubbing between coats; this is quite time consuming because the paint needs to cure sufficiently between coats and I can only do one side of the tank at a time. I have put on 5 coats to avoid the black showing through.
The tape is now removed, the entire tank is rubbed down with 1200 grit wet-and-dry and the Velocette waterslide transfers are carefully affixed.
The transfers come from Classic Transfers who have been in this business for many years and, in my experience, one could not wish for a higher quality product.
It’s then back in the garden to apply 2 good coats of 2k lacquer.
It is very important to first spray 2 very light coats of lacquer on the transfers, separated by a 15-minute interval. If this is not done there is a good chance that the transfers will “crinkle up” and spoil the appearance.
After leaving the tank a couple of days for the lacquer to cure I have then flatted it with 1200 grit paper followed by polishing (I use a DA9 Dual Action polishing machine) with, firstly, G10 rubbing compound followed by polishing with Meguiar’s Carnauba polish.
Not perfect (one always sees one’s own imperfections!) but not too shabby.
By the way, if you happen to have a cylinder of Argon gas in your workshop (which I do, for TIG welding) then I always give any open tins of paint and hardener a short blast of gas before putting the top on the tin. 2k paint seems to last indefinitely anyway but hardener doesn’t, once opened, and other paints and varnishes will not form a skin if they are shielded by the inert heavier-than-air Argon gas.
I described some years ago the plating and blacking processes that I use, so only a brief summary here for this bike.
For the shiny bits, the zinc plating bath is set up
and, after polishing each part, scrubbing with “VIM” (an abrasive usually used for cleaning household sinks) with a toothbrush, fondling with soapy hands and rinsing in clean water the parts are plated for around 3 - 4 hours.
After plating, each part is washed and then dipped into another bucket containing a blue passivate solution that converts the zinc to zinc chromate.
After rinsing and polishing, these parts are finished. The picture below shows some of the copper oil pipes for KTT 305 plated in this way.
The finish is not as bright as chrome but I’m quite happy with the appearance as it is not too shiny and “blingy” for a vintage motorcycle.
The chemically blacked parts are treated using 3 separate liquids – see here.
Last, but by no means least, the exhaust pipes for all 3 bikes
have gone to Dorsetware for chrome plating. They do all the plating for Armours (who bent these pipes) and with whom I have only ever had good experience. It will be a few weeks before these come back but I have plenty to do in the meantime.
And all the remaining metal parts have gone to Autoblast for powder coating.
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