Stripping Paint From a Bicycle Frame

If you were to send your dismantled frame to a company such as Redditch Shotblasters, they would remove all the paint by grit blasting. Following this process, the frame would have the perfect textured surface to accept a powder coated finish. Nevertheless, even if you are going down this route I think that there are advantages to removing the paint yourself and it only takes 2 or 3 hours in most cases. For one thing, you can inspect the frame as you go for rust or cracks. For another, the grit blasting needed will be far less and this must be kinder to the frame from the point of view of minimising erosion.

I once owned a Saracen Tuff Trax mountainbike that was the brightest red you could imagine- when it was new. After a few years of being kept in a sunporch, the colour had faded to a yucky pink, so I decided to paint it. On with the paintstripper; nothing happened. Several coats of stripper and a couple of hours passed and still nothing. I washed it off and the finish was unaffected. This, I assume, was a powder-coated paint. Years later, when working as a bicycle assembler, I saw the quick way to take off this type of paint finish. A roaring gas blowtorch melted and burnt away the polymer followed by a second trip through the sand blasting box to clean the frame up again.

This area of the site is about painting frames at home, in which case there is no alternative to stripping the paint off yourself. My preferred method is to use a chemical paint stripper (Nitromors and Mangers are effective on bicycle enamel) and an old chisel that is fairly blunt. It is kept especially for the task. I find that the sides of the tool are just as adept at scraping paint off as the tip. The corners are good for getting into internal corners at the seams of frame joints. Frequently the top coat of paint will be harder to remove than the softer undercoats and you will find that two or three applications of paintstripper are needed. I have sometimes used wirewool as an applicator on the undercoats.

The Moulton Mk3 frame that is presented in the slideshow has a top coat of laquer, under which is a clour coat of metallic red. Under that is a coat of gold which reflects light through the colour coat giving enhanced sparkliness. Moulton used to call this type of finish "polychromatic", a word possibly invented by someone in marketing at Bradford-on-Avon. The bottom layer of paint on the Mk3 is a grey colour. So you see that Raleigh went to a lot of trouble to get an attractive finish on the frame. The purple frame below is the same one that was stripped in the slideshow, painted by Redditch. "Pop Purple" was a colour used by Raleigh on the Moulton Mini, so it is reasonable to think they could have painted the Mk3 in this shade if they had wanted to.

Where's the saddle clamps?

Several fruitless hours had been spent searching in ‘the stuff’ for a chrome saddle clamp. Not the modern cheap painted version with no washers and a nut on only one side. I knew there was a biscuit tin somewhere with a good selection of beautifully made clamps that could be polished to a sparkling finish.  Or was it a tub they were in? An ice cream tub? That kind of rings a bell. Or perhaps it contained bells? I just wasn’t sure.

Over the forty plus years that I’ve restored old bikes and stripped them for bits, the ever-expanding collection of parts taken off has moved with me many times without being seriously weeded, and would easily fill a garage. Often, I know very well that I have, for example, a Duraglit tin containing bulbs for Sturmey-Archer headlamps, but despondent that I’ll never be able to find them. Bicycles don’t usually reject a transplant, so I feel compelled to save things for future use.  And old bikes are cheap, because they are generally unwanted. For compact storage, collected machines are always reduced to their discrete components and gobbled up by the collection of cardboard boxes, margarine tubs, sauce jars and biscuit tins. It will all come in useful sooner or later. 

When you enjoy tinkering with old bikes, the value that even small things have makes you lavish disproportionate care and attention upon them. For instance, I hardly ever throw away bearing balls automatically. Even though you can buy all sizes new easily, I will put the old ones into degreaser, scrub them with a toothbrush, wash them in detergent and polish each individual ball with a clean cotton rag. Old British steel balls will frequently emerge with a shining mirror finish. Shame to waste ‘em.

Talking of shininess, when you have a good eye for rusty chrome, you can tell a part that is spoiled from one that can have the surface rust carefully brushed away with a brass brush and polished brilliantly with Autosol to leave only a few characterful speckles. In the old days, handlebars, cranks and rims were first plated with a layer of brass, and then chrome on top of this. Sometimes the brass becomes visible on a very heavily polished part. Reversing years of neglect to reveal a gleaming piece of sculpture like a Raleigh ‘Heron’ chain wheel is intensely rewarding. Worth all the effort.

But all these parts! Right! I’m going to have a clear out. First, a box 16” classic Moulton rims. These are very worn on the sides; they can go. Ah, but they are Dunlop rims, early ones. Alex Moulton couldn’t have got anywhere without Dunlop making excellent wheels and tyres for him. Can’t throw away a Dunlop rim. It won’t make any difference anyway; the box won’t be any smaller. What about that bucket of Dynohubs? They are heavy and I’ll probably never use them. “Do not remove magnet without keeper” The classic warning. Designed for maintenance. And will power a modern LED light. Reprieve granted. Okay- that box of brakes then. Three hours later, each brake examined, scraped and polished, parts combined from different callipers to make ‘best of’ units, and I have about three rusty brakes to chuck.

Oh! I give up.

Sturmey-Archer Dynohub

"Where's your lights sonny?"

Many's the time a pale blue Ford Escort Mk1 would pull up in front of me with a blue light going around in a perspex dome on the roof. I usually didn't have lights because I didn't want to pay for batteries and an Ever-Ready back light would exhaust them within a week. Most of the time, the bulb would barely glow until a swift clout was directed at the casing. And the tin front light by Ever-Ready with it's cardboard battery was equally lacklustre. Then I came across a brown Bakelite Dynohub, aged about 13. At first I had no idea what it was, some kind of a brake? "Dyno" didn't register at all, as "Bakelite" will probably whizz over your head. Then I tried connecting some wires up to the small brass bolts and soon found that a 2.4 Volt bulb could be made to glow white hot, then pop.

The classic GH6 Dynohub (Generator Hub, 6 Volt) was a dynamo contained in either the front or rear wheel hub.  Originally they had been introduced during the war at 12 Volt, then 8 Volt before settling on 6 Volts. Sturmey-Archer made the Dynohub to the same design for almost forty years and the year of manufacture was stamped on the hub shell. The original power output was quoted as 2 Watts, but during the 1970's this was reduced to 1.8 Watts, possibly because of a change of magnet material. The early Dynohubs had a dark brown and rather delicate faceplate made from an early kind of thermosetting plastic, Bakelite. After that, they had a tin face with a satin silver finish that continued until the seventies. Lastly, the face was chromed like the one in the photo, the most handsome Dynohub of all. You are very likely to see a Dynohub on an old bike and if so, it is a good omen. The bicycle will generally be a good quality machine well worth restoring. Do not be put off by age. Sometimes the oldest Dynohubs are in the best condition inside their casings.

As a reckless youth, the thing to do was to connect a 3.5 Volt bulb on the front in series with a 2.5 Volt bulb at the rear. This combination worked brilliantly, allowing night-time racing around the smooth tarmacked paths of Crawford Park. However, bulbs expired frequently and met certain death at anything over 15 miles-per-hour. To be freed from the pocket-money sapping tyranny of Ever-Ready was worth the job of bulb replacement, and the fun derived from a burning searchlight scorching through the darkness plentiful reward. Years later I learned the correct values of bulb to be used with the GH6, and have never had quite so much enjoyment out of it since. The maintenance leaflet shown above is for a 1970's Dynohub and sets out the bulb values as 6V, 0.2A front and 6V, 0.1A rear. However, on earlier Dynohub systems you will usually find 6V, 0.04A in the rear. I have seen little tags in headlamps giving equal values for front and rear bulbs.

Modern cycle dynamos are more powerful than the Sturmey-Archer Dynohub, typically 3 Watts. This means that it is virtually impossible to get the right rating filament bulbs for Dynohubs from bike shops. However, with the advent of screw-in dynamo bulb replacements you can perform a valuable upgrade by changing the old filament bulbs to Nicelite LED bulbs. These are available from Reflectalite.com (website) and can also be bought from the same company on ebay here.

You don't want to be unlit when waiting at a traffic light, so it is a good idea to maintain an additional constant, reliable LED light on the rear. If you have upgraded to Nicelite bulbs, you can stay lit even with your Dynohub stopped for 45 seconds using the Standlight capacitor system. This is not available to buy but must be made by the cyclist; full approval given. See the circuit diagram by clicking on the photo below. Standlight also prevents strobing of Nicelite LED bulbs at slower speeds. A supplementary voltage regulator is recommended if you are not using the Standlight capacitor system. Raleigh bicycles of the 1950's were often fitted with a backup battery tube and these are still found occasionally. They maintain the lights when stationary and need to be switched on and off at the headlamp. Bit of a hassle.Moulton bicycles, with their 16" diameter wheels, are the perfect partners for Dynohubs because the wheels rotate much faster than a 26" wheel roadster, for example. That gives 62.5% more energy output for the Moulton at the same speed as the Triumph Palm Beach, and brighter lights. With modern LED bulbs that offer a searchlight level 120 lumens at the front and a red coloured foglight at the rear, now is the perfect time to polish up those beautiful chrome headlights and neat little Sturmey tail lights and reinstate them where they belong. 

Bicycle Frame Painting

Painting a frame is a really tricky area of bicycle restoration. The main problem is finding a paint that will be durable enough to withstand inevitable knocks and scratches. Secondly, preparing the frame for painting is fairly hard work and messy. Thirdly, getting a good finish can be difficult. I painted frames by hand at home for many years, and was rarely completely happy with the result. I'd think it was pretty good until putting the bike near a similar model that somebody else had spent a lot of money on; then I'd feel insecure about it. There's no question that other people do look at your paint finish almost before anything else.

An excellent solution for bicycle frame painting is the tough, colourful and glossy finish that powder-coating can give you for approximately £85 plus VAT. There is a huge range of RAL colours to choose from and different paint effects too: metallic, pearlescent, metal flake for example. A company such as Redditch Shotblasting will prepare a perfect surface before applying the coating and they are experts at painting frames in all kinds of vehicles. It's nice having somebody else do all the hard work and get the bike frame back looking just as you had imagined it. Also, you don't have to buy any paint or primer, no undercoat, no colour coat and no laquer. You won't have the nearly-full tins sitting on the shelf. Furthermore it will last for many years and look marvellous. Powder-coating is money well spent- providing that you actually have the money.

Many of the bicycles that we might consider restoring do not have a high monetary value, although prices are steadily climbing. Some of those shown on this website were bought for £5 and even after a complete restoration might only fetch £150-£200 on ebay. Deduct the selling fees and money for parts like tyres, tubes, cables, bearings and chain from that and you are going to be out of pocket. Now, this could be a reason why people do not bother restoring bicycles.

To cut a long story short, if you think of bicycle restoration in purely monetary terms, you miss the environmental value of repair and re-use. In other words, we should not just keep buying new imports of poor quality and throwing things away. It is amazing how rapidly mountainbikes have disappeared from British roads. Chances are, if you are reading this then you have some sympathy for this view. You may well have very little money to spend and simply not care that much about cosmetics such as paint finish. It is only skin deep after all.

I have gone around the houses, but what I'm saying is that bicycles are for riding, not hanging on the wall. We absolutely should be able to brush some paint on ourselves and not feel guilty that we have done a bad job. Hand painting is creative, reasonably cheap and can protect the frame well against rust. And you can get some very acceptable results with the right equipment. I'm no expert, but I'll tell you all I know about it.