Brass vs Silver

Joining metal by brazing became the method of choice when the bicycle was invented in the late 1800s. Early bicycle lugs were in fact pipe fittings, but greater strength was needed, so brass was used instead of lead base solder.

Soldering and brazing are pretty much the same process, flux is required to allow the solder or brazing material to flow. The difference is the melting temperature of the different materials.

Soldering takes place at 427 degrees centigrade and below. Brazing between 593 and 895 degrees centigrade. Different sources will give a slightly different range, but as silver and brass will both melt within the range for brazing, that is the correct term. Brass brazing or silver brazing,

Silver is often known as Silver Solder, but strictly speaking it is not soldering because the melting temperature is above 427 degrees. Silver brazing rods come in soft, medium and hard, the soft being at the low end of the temperature range, progressing to a higher melting point for the medium and hard.

Silver is more expensive as it is for the most part silver, alloyed with other materials such as cadmium, or nickel. The price of silver brazing rods, will fluctuate with the price of silver on the Precious Metals Market.

Brass is already an alloy of copper and zinc, other materials will be added to give desired characteristics, like flow properties and workability. Brass melts at the higher end of the brazing range.

Often silver brazing is quoted as being best for lightweight bicycle frames because it melts at lower temperature. However, in the hands of a novice it is just as easy to overheat a joint using either silver or brass. In fact if you overheat a joint using silver, the silver will no longer flow, and the joint will have to be torn apart, thoroughly cleaned and start all over again.

Most framebuilders become proficient in either silver or brass, but my guess is, only a few totally master both. I became proficient with brass, but never built a complete frame using silver. The only time I used silver, was for brazing water bottle bosses, and top tube cable guides. The reason: Using the higher temperature brass would put a slight ripple in the thin un-butted part of the tube that would show after painting.

The traditional front and rear drop-outs, (Campagnolo for example. (picture left.) The type where the front fork blade, chainstay and seatstay are slotted to take the drop out, have to be brass brazed.

Silver will not fill in the gaps, or fill the hole in the end of the tube. So even a builder who uses silver for the main frame will use brass for this type of drop-out.

Silver requires closer tolerances for example where the tubes fit in the lug. My method of altering the angle of the lug with a small hammer as I brazed, could not have been done with silver. The steel lug had to be at a bright red heat in order to be malleable enough to reshape. This would be too hot for silver.

Brass historically has always been used in Europe, which of course includes the UK where I learned to braze using brass. As a framebuilder becomes proficient at brass brazing, he learns to braze a joint cleanly, and not spill globs of brass over the edges of the lug. If this happens the builder will spend hour’s hand filing the excess brass away. Possibly leaving behind ugly file marks.

Silver on the other hand is softer and the excess can be sand-blasted away, or even scraped away with a small penknife. The fine and intricate, sharp edge lug work carried out by the late Brian Baylis, could not have been achieved using brass. English builder Hetchins did some fine elaborate brass brazed lug work, but on close inspection the corners and edges are not as fine and sharp as one can achieve with silver. (Baylis below left. Hetchins below right.) 

Silver brazing bicycle frames on the scale it is used today is an American development that can be traced all the way back to the Schwinn Paramount. Read the history here. One of the reasons the Schwinn Paramount was built using silver, was the easy clean up.

The intricate Nervex lugs used (Right.) would have been a pain to brass braze cleanly.

Many of the early American builders were influenced by the Schwinn Paramount, and a few even apprenticed there.

Brass or Silver? Both have their own advantages and disadvantages. Both require different skill-sets.

I could never have done what Brian Baylis did, and on the other hand, he could not have built the number of frames I built using the methods he did.

Brass is more suited to production, silver is more suited to the artisan builder, custom building frames one at a time.

In my opinion, brass in many ways is more forgiving from a workability standpoint. For an absolute beginner, don’t be misled into thinking silver is easier.

Try brass brazing a few pieces of scrap metal together. You will have a lot of fun for not too much money. And a lot less heartache, than spending a ton of money by plunging straight in, and trying to silver braze a frame with little or no experience.

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The day the bicycle lost its heart and soul

When some one sent me a picture of a Fuso bike, (Above.) I knew at first glance that I did not build it. This one was built by Russ Denny, my former apprentice who took over my business when I retired in 1993. The frame had a sloping top tube, and while this is normal today, back prior to 1993 it was not.

I never built any frame with anything but a level top tube, with the exception of a few drop top ladies model, and the occasional twin tube “Mixtie” frame, which is a whole different frame design. I m talking of the standard road frame.

It made me think, what a run this simple design had. From the early 1900s until the mid to late 1990s, almost made it a hundred years without any major changes. Apart from basic geometry, tube angles, etc., once the standards were established, they remained the same, a level top tube was one of them, and any deviation from that was not acceptable, to either the framebuilder or the customer.

What I find amazing is that everything else changed so dramatically over the same period, I think of automobiles, aircraft, and just about any other manufactured item. They have all been though many changes over the same period.

It all started with the invention of the chain drive. The first was the British model “Rover” Safety Bicycle.So-called because its fore-runner was the Ordinary or High-wheeler model, (Below right,)

Although this was the first “Enthusiasts” bike, one had to be young, athletic, and have nerves of steel to even mount such a machine.

The Rover design pretty much established that the chain would drive the rear wheel, while the front wheel would provide a means of steering. The chainwheel, cranks and pedals would be just ahead of the rear wheel, and below the rider’s saddle.

The rider’s position was copied from the ordinary, and lead to those early frames having laid back “Slack” frame angles that would prevail into the 1950s.

Early frames were a hodge-podge of tubes of various shapes and sizes. The bicycle soon became mass-produced, which lead to it becoming an affordable means of transport for the working classes. Prior to that the only personal form of transport was a horse,

Mass production also lead to standard-ization and simplification of design. The chain itself is still half an inch pitch today the whole world over, even though most countries use the metric system.

Wheel sizes became standardized, and the frame design became the simple straight tube, diamond design, that we are all so familiar with.

Most of these standardizations came within the first ten years into the early 1900s. Tube sizes, 1 ¼ Head tube, 1 1/8th. Down and seat tube, 1-inch top tube. Most countries in the world including Italy, use these same Imperial size tubes. Hand brazed, lugged steel frames were, for the most part, the norm throughout this period.

It soon became obvious that frames would have to be different sizes to accommodate different size people, and the level top tube being parallel to the wheel centers, made it a point of reference, for the framebuilder to easily design and build a frame of any size.

The front fork being the same height for any frame, the position of the bottom head lug, and the length of the head tube is easy to arrive at, and head and seat angles are measured from horizontal top tube.

The advantage for the customer was, once he had established a size of frame that suited him, he could buy another of any make in that size, and it would fit.

Plus, the handlebars would be the correct height in relation to the saddle. No one spoke of handlebar drop.

When I left England in the late 1970s, my customers were almost exclusively amateur racing cyclists, their bikes all had the same componentry. Campagnolo Group, Cinelli handlebars and stem. Christophe toe clips, Binda laminated toe-straps. Tubular tires, and usually Mavic rims. Frames were either by a local builder like me, and therefore varied from one area to another.

If the frame was not by a local builder, it was by one of the larger English builders. Holdsworth, Mercian, Jack Taylor. Italian frames were not big in England at the time.  They were expensive compared to the UK built frames.

When the US Bike Boom happened in the 1970s English framebuilders, even the larger ones could not supply the demand, and they lost out to the Italian companies that  were larger, as they had been supplying most of the continent of Europe for years.

By moving to America, I was able to compete for a small niche of the market, but when the second bike boom hit, namely the Mountain Bike craze. Only a few high-end established mountain bike specialists were able to take advantage of their particular niche. The rest was taken over by companies like Giant, who found by building frames with sloping top tubes, they were able to build less sizes.

Above illusrates the evolution from the "One size fits all" BMX Bike, to the limited size MTB and Road Bike.

When this look became the norm, it made its way to road bikes, and by then carbon fiber was taking over from steel. Lugged steel had a good run, and I am proud to have been around at the end of that era.

The only other products I can think of that are made by craftsmen and remain the same year after year, are musical instruments. Everything else, including bicycles are now the same as any other consumer product that can become obsolete at the whim of the manufacturer.  

The bicycle, and in particular the lugged steel racing bike, took about ten years to establish standard designs and practices that would last for another 90 years. Towards the end changes in componentry came at a fast pace, (Index shifting, clipless pedals, etc.) culminating in the demise of the frame itself, which is fitting because after all the frame is the heart and soul of the bicycle.

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Vent Holes

I am sometimes asked, why are there tiny holes drilled in certain parts of a bicycle frame, like the ones shown on the left?

These are vent holes. During the brazing process the air inside the tube expands as it is heated. The vent hole allows the air to escape as it warms up and allows for air to enter as it cools.

If the tube is totally enclosed, on cooling the air contracts sucking the molten brass inside the tube leaving a pin hole that is almost impossible to fill.

Worse still pressure can build up in an un-vented tube and hot brass can blow back in your face. Anyone not knowing this will soon learn the importance of vent holes after picking little globules of brass embedded in their face or finds little brass balls hanging like tiny Christmas Tree decorations from eyebrows, mustache, or other facial hair

Vent holes are only needed when a tube is closed both ends like the example shown above. The top tube is closed at both ends and is usually vented with holes into the seat tube and head tube. (When the bike is assembled these holes are hidden.)

Seatstays are enclosed with a fork dropout one end and the seatstay cap at the top. The front fork blades are also  enclosed both ends between the fork crown and the fork tip or dropout.

Other tubes like the seat tube, down tube and the chainstays are open inside the bottom bracket shell. These tubes are not totally enclosed so do not need any additional vent holes; neither does the brake bridge because it has a brake bolt hole.

On some of my custom frames you won't see holes in the chainstay bridge like the one in the picture. They are hidden inside the bridge tube by drilling holes sideways through the left and right chainstay tube, before the bridge tube was put into place. Only one hole is needed for venting but often two holes are drilled for better drainage of moisture later.

The vent hole in the seatstays on my frames is on the inside up near the seat lug. You might have to turn the bike upside down to see it.

On my front fork blades I drilled one vent hole in each fork blade near the bottom, but after the fork was fully brazed and had cooled I went back and filled it by brazing a piece of wire in the hole. The heat generated in doing this was so small and the air space inside the fork blade was big enough that it did not cause a problem. This whole process only took a minute to complete.

I did this for two reasons. Front fork blades are highly stressed, so filling the hole eliminated a potential weakness at that point. Also rust needs oxygen, and with the fork blades completely enclosed and airtight, no corrosion inside is possible, even years down the road.

A small and probably unnecessary precaution, but one that took such a small amount of time, I always figured, why not?

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Creating the perfect fork blade

When a fork blade comes from the tube manufacturer’s factory, it is straight, the framebuilder bends it to a curve that suits his requirements. 

An un-raked road fork blade is oval at the top. The oval section runs parallel for about a third of its length.

Then the cross section becomes round and starts to taper gradually to its smallest diameter section at the bottom end.

The fork blade is bent cold on a curved form that is sometimes made from hard wood. I used one I made myself from two heavy-duty steel fork blades, bent in the desired curve, and brazed together side by side. This made a natural groove between the two blades where the blade would sit as I was bending.

I would slip a short piece of tube over the thin end of the form and the blade I was bending. This acted as a collar to hold it in place. Then I'd start bending, first by pushing down by hand. The thin end of the blade bends easily, and I would finish off by squeezing it in a vise.

Bicycle tubing is hardened, and it will spring back after bending. Because of this, the form needs to be a greater curve than the finished fork blade will be. 

A fork blade is several inches longer than it needs to be. The framebuilder chooses where he will put the bend, and where he will cut to length. For example, if I were making a criterium frame and wanted a very stiff fork, I would cut from the bottom, thin end. The desired fork rake (Offset.) also has to be considered. The amount of bend, and where the tube is cut will determine this.

If I were building a touring frame, and wanted a flexible fork for a more comfortable ride and more offset, I would cut from the top end and leave the blade thin at the bottom end. The framebuilder creates the perfect fork blade, by selecting the best place to bend the blade, the amount of bend and by choosing how much to cut from either end.

It is rather like a furniture maker choosing where to cut from a piece of wood to achieve the best end product. Once I arrived at the perfect fork blade, it was then an easy matter to repeat the process again and again. On this John Howard frame below, for example.

 

One exception to this process was the Reynolds 753 fork blades. 753 was heat treated to a degree that the material could not be bent after. These were bent at the factory, then heat treated, and the framebuilder then cut the blade to the required length.

The cut alone determined the fork rake, and I had no control over the placement or shape of bend. You will notice on this 753 Fuso Lux frame (Pictured below.) that the fork bend is a different shape than the ones bent by me.

On the red 753 frame there appears to be more rake, but this is not the case, the amount of offset is the same. The 753 blade has a tighter bend near the bottom, whereas the one’s I bent by hand, have a gradual curve that begins about half way.

Chainstays and seatstays are also tapered and the same selective cutting to length is employed. In this case, where the cut is made depends a great deal on the size of frame and its end use. 

The perfect fork blade is stiff enough to allow precise handling, but with some flex to absorb road shocks. It also looks pleasing to the eye. I have a theory that when something is designed correctly from a functional standpoint, it has a natural aesthetic beauty. This is true of a boat, a bridge, a building, and even a bicycle frame.

The modern trend of building straight forks of course saves the framebuilder a great deal of time and effort. If this look has become acceptable, why should today’s builder go through all the time consuming process I have described here? 

The straight blade is angled forward so the same fork rake or offset is achieved and handling would be the same. I can’t comment on the shock absorption qualities because I have never built a frame with a straight fork.

In my view, a great deal is lost aesthetically, so where does that leave my theory about function being linked to aesthetics? On the other hand, is it simply that beauty is in the eye of the beholder?

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Owning and maintaining a paint facility

One of the largest outlays in setting up a framebuilding business is a paint facility, by that I mean to include a totally enclosed, dust free paint booth.

It is a large expense to set up and maintain, because it takes up a lot of space. It therefore it prohibits one from working out of their home, or some tiny hole-in-the wall shop. In most places you can’t spray paint in a residential neighborhood anyway. You have to own or rent space in an industrial area.

Rent is a huge overhead when running any business. It is the reason I eventually went out of business in 1993. The demand for road frames had dropped to a level where I could not generate enough income to pay the rent on a 1500 sq. ft. industrial unit.

I could have maybe squeezed into a 1000 ft. space, but the rent would not have been that much lower, plus I would have had the expense of moving, costing money I didn’t have.

My paint booth was totally enclosed, it measured 20 x 20 feet. That is 400 sq. ft. and with at least a 3-foot clear space required all around it, as a fire precaution, actual floorspace required is 676 sq. ft. You can perhaps appreciate that any space under 1500 sq. ft. for the rest of the shop would be a squeeze.

At one end of the booth was a large fan that drew the air from inside the booth and exhausted it through a 2 ft. diameter vent through the roof. The air was drawn through replaceable filters that caught the paint over-spray. Thus preventing it from being exhausted outside into the atmosphere. These filters had to be replaced every month.

At the opposite end of the booth were air intake filters. These were “Sticky” so they caught dust and prevented it from entering the booth. The booth had a partition inside, one side to hang frames waiting to be painted, the other side was where the painting took place.

The partition prevented frames waiting and those just pained, from getting over-spray on them. I also had an electric paint curing oven that baked the paint to 250 degrees. This was another essential piece of equipment, as It allowed paint to cure in less than a hour. It could then be sanded for the next coat, rather than wait a day or more for it to air dry.

Owning a similar facility with a paint booth, is also the reason why I never started up again years later when the demand for road frames picked up. My shop cost $30,000 to set up in 1983, today that figure would be closer to $100,000. Too large an initial outlay, with no guarantee I would ever see a return on the investment.

Is it essential to have a paint facility? I am often asked. The answer is no, but it was for me. Many framebuilders build frames and ship them somewhere else to be painted. But the paint job is more than half the profit in building a frame.

To me, the paint is as important as the building of the frame, and the two go hand in hand. The paint is what the customer sees, it is too significant to be left in the hands of some outside entity. I would never build frames and not have total control over painting them.

There is the cost of shipping the frames both to and from the painter, and there is also the time factor. When you have your own facility, you can handle a rush job easily. Mistakes and flaws can be fixed immediately, and even a complete strip and re-paint is not the end of the world.

The one drawback is, you have to produce enough frames to warrant the expense of owning your own paint facility. One or two frames a week won’t cut it. Initially I painted myself, but at the height of my production in the mid-1980s, it became necessary to train and employ a full-time painter. I produced as many as 30 frames a month. It was a good and profitable business.

When the demand dropped below 20 frames a month, I could lay off employees, but I still had the rent and overhead on the large industrial space. Times have changed. In the eighties if you wanted a top of the line bicycle frame, it was hand brazed, lugged steel.

Those days are gone forever, and it is the reason why builders like myself and others are no longer building frames. And really I do not need to build anymore frames, there are thousands of them still out there. They come up for sale every week on eBay and Craig’s List, many of them hardly used and still in mint condition.

Even on frames that have had a lot of use, the paint has held up well, which speaks volumes for my always having my own paint facility.

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