Tuesday, January 31, 2012

Adding the "training" wheels...

Remember when you were a kid and you had training wheels on your bike...
That is what I have now... training wheels

The problem is, I do not deflect the bike enough with my weight to keep the angle rather small.  After weighting the bike down with 200 lbs last week and recording the deflection, I decided to increase the amount of carbon fiber on the side rails.  The purpose was to decrease the deflection (35mm).  Well it worked so well that the bike deflects between 12 and 15mm with my weight. That keeps my training wheels higher off the ground. Thus the angle of lean for the bike in order for the training wheels to hit the ground is a bit steeper in feel than I expected.  The calculation:

I designed the wheel housing so that I can take up to 110mm wheels.  So I will go to bigger training wheels -- initially anyway.

As a side-note: The chain-line is lllloooooonnnnnggggg:

Monday, January 30, 2012

Making it look better...Adding a fixed chain-tensioner

Since I am working more on the finishing the handcycle, I have decided to lift the "pride factor" a bit and attempt to get the finish closer to what I may conclude with.  Therefore, I have filled in the small voids, pinholes, wrinkles, and areas of carbon fiber for which the peel ply was not in proper contact. In other words, I am trying to make the product look better albeit, what ever I do will have no consequence on strength.

The first mistake I made was using a low-quality (hear "cheap") paint brush.  I spent more time removing bristles from the resin finish than I did brushing on the resin.  So, I picked up a more expensive brush (about 30 times the cost of the cheap one).  This was not a throw-away brush.  Therefore, per Jakob's suggestions on saving a brush from hardening epoxy, I built a "bush-saver".  It works beautifully.  An no fumes escape to speak of.

Here is the result of a single coat of West System's 105 resin with 205 Fast Hardener:

With the foot holders attached to the fork and the fork attached to the base:

My front hub -- the I-Motion 9-speed from SRAM -- has a single cog.  I may change that cog out and therefore, the chain length may change.  On a regular bike, the derailleur's tensioner takes care of the chain tension when one shifts and changes cogs.  In my case, my hub's internal gears take care of gearing with the exception that I may decide to change the single exterior cog.  I may use a 17 tooth cog when I ride around Westerville and flat areas.  I may go to 19 tooth cog when I will be completing big climbs (e.g. New York's Gran Fondo and central Ohio's Reysnolds Hill).  Therefore I added a fixed idler/tensioner to the fork:

Wednesday, January 25, 2012

A handcycle pumping iron... Putting weights on the bike

OK, now the scary part... But I gotta do it.  I am going to add weight to the bike to see if it creaks and cracks -- but especially to see how much deflection there is.  I weigh in at 193 lbs.  I will be adding up to 200 lbs of iron to the bike.  I should probably add about 400 lbs -- but I am not quite ready for that (mentally speaking that is).

I have used the fast-hardener on most of the bike and therefore, can expect the bike to be near full strength.

Here we go... Got some weights and a tape measure...

90mm off the floor with 0 lbs. of weight applied:

...Drop of 10 mm at 70 lbs added
...Drop of 15 mm at 120 lbs added

...Drop of 25 mm at 160 lbs added
...Drop of 35mm at 200 lbs added

I have not completed any calculation nor have any real expectations of what I should have expected relative to deflection. After hitting 200 pounds,  the whole bike shifted and the weights fell off the bike.  There was no damage to the bike and it sprung right back to the original 0 lbs./90mm clearance.  That is a somewhat good sign I guess -- at least better than the alternative!

Tuesday, January 24, 2012

The small stuff...

The foot holders and the removable carbon fiber tool bag...

This is the rough carbon fiber tool bag -- after some sanding.  It fits well.  I will add some Velcro to hold it in place.   Hopefully it is large enough to hold an extra tube and a few tools.  I will split it into two parts with a 3" air cut-off tool.  The cut-off tool will breeze through the carbon fiber like butter.  BTW, I wear a respirator whenever I sand or cut carbon fiber. As well I have a ShopVac running normally to suck in the dust.   The carbon fiber dust is considered dangerous from what I have read.

Here is one of the foot-holders after applying an extra coat of epoxy, applying 50, 300, 600 and 1000 grit wet/dry sandpaper and rubbing on some wax...  It is not perfect, but I can live with it without losing sleep.

Monday, January 23, 2012

Punching holes through the carbon fiber... Disc brakes... Built-in tool bag


Well, not exactly "punching holes"...

During my 100 mile and 200 K rides, I often go through about 200 oz of water.  Therefore, in the design of the handcycle, I provided a couple of places to store the water in hydration bags.  (As a side note, I am fairly certain I will be building the bags unless I can find one with a small opening.)  One area is between the seat/bottom/rear wheel area.  The other is under the "U" shaped headtube support area.

(Thanks Dr. Lee for suggesting that I move the water more to the front in order to get better wheel traction.)

The two inline-skate wheel housing are now open from the bottom in order to accommodate the wheels...

Disc Brakes

The disc brakes that hang from the front and rear dropouts leave little room for error when fitting the actual disc that hangs from the hub (things that keep me from falling asleep quickly).  They fit!  That is, the holes through the dropouts (that are part of the frame),  exactly line up correctly to receive the disc brake housing, which exactly line up to receive the disc attached to the wheel hub... Thankfully!

Built-in Tool Bag

Sometimes, I just get tired of adding layer after layer of carbon fiber... So I building a tool bag now that is to fit in the "U" shaped headtube support. I always had the intention of doing this.  But I expected that I would have begun this part of the project later.

Friday, January 20, 2012

So how many layers of carbon fiber?

The calculation of the number of layers of carbon fiber is a guess on my part.  I have attempted to take into account some notes written by other DIY bike builders.  No matter, these calculations are "seat-of-my-pants" .
..And where does that term originate:

"Douglas Corrigan was described as an aviator 'who flies by the seat of his pants' today by a mechanic who helped him rejuvinate the plane which airport men have now nicknamed the 'Spirit of $69.90'. The old flying expression of 'flies by the seat of his trousers' was explained by Larry Conner, means going aloft without instruments, radio or other such luxuries."

Either way, we both crash if we are (were) egregiously wrong...  BTW, Corrigan did not crash, but instead landed in Ireland after crossing the Atlantic Ocean.  His original flight plan (rejected) called for him to travel west whereas he traveled east, and therefore, he became know as "Wrong Way Corrigan".  If I am wrong, I may become known as "Crash Chase"... oooops I think I already am...

Here are my intentions:

The "U" shaped head-tube area is about finished.  I need to add a couple of more layers in area of greatest depth of carbon fiber.  As well, the most of the front fork is finished sans a few layers around the head-tube. Presently I am working on the rear bike's dropout area and tail.  This is going better than expected since I am slowly gaining experience.  I have another layer to go on the bottom as well.  As previously mentioned though, adding layers of carbon fiber in flat areas and areas of larger curvature is easy as pie (blueberry in my case).

Wednesday, January 18, 2012

Changing method of laying up carbon fiber in complex curve areas...

Over the last few days I have been laying up carbon fiber around the "U" shaped holder of the headtube -- and I have a lot of layers there in my layup diagram.  The shape consists of compound curves which make the laying up of carbon fiber difficult.  The reason for this is that the stresses -- deriving from the front wheel and fork -- that must be handled by the shape, call for many layers of carbon fiber. I doubt that a mere four layers will suffice.  In fact, I intend to lay up about 10 layers on the shape.

Steerer Tube/Head Tube Area

The 2x2 twill fabric will easily lay down around the compounded curves. But the peel ply fabric, whether nylon or polyester, does not adopt to the shape as does the twill carbon fiber.  Therefore, the peel ply must be cut into smaller pieces as compared to the carbon fiber.  As well, darts have to be cut in the peel ply. In the end, I found that the "wet" carbon fiber/peel ply will shift and bunch. Additionally, since there are many pieces of carbon fiber due to all the curves of the shape, the possibility of having a perfect layup is nearly impossible.  Therefore, I decided to try a technique that I originally did not have a lot of trust in.  That technique is to use a spray adhesive (3M's 77 General Purpose Adhesive) to tack the carbon fiber in place.

The use of the spray adhesive greatly improves (seemingly -- more about that later) the layup characteristics of the carbon fiber.  It stays in place through the tortuous cycle of adding more carbon fiber, resin, and peel ply.  Additionally, since during a layup I have to put down quite a number of pieces of carbon fiber, I can take my time in doing so since I am laying up "dry" carbon fiber.

After laying the many carbon fiber pieces, I then apply a VERY LIBERAL amount of wet resin with West System's 206 Slow Hardner to the dry carbon fiber. I then push the resin through the carbon fiber with many, many dabs of the brush.  I use 2" cheap Chinese model brushes with about 1/3 of the length of the bristles cut off.  The reduced length of the bristles allow the brush to push the epoxy better as compared to a longer-bristle brush.

The slow hardner gives me about double the amount of time to work (pot life) as compared to the fast hardner (West System's 205).  For flat areas and large curves, I usually use West System's 205 Fast Hardener verses the 206 Slow Hardener that I am using in the above situation.

After the layup of the carbon fiber and the wetting down of it with the resin, I can then layup the peel ply (many more pieces) over the wet carbon fiber.  I brush and dab the peel ply until it is throroughly wet. This takes the predominate share of time relative to the working time of the epoxy.  Matter of fact, it is during this stage of laying up the peel ply where I find that most problems appear.  If the peel ply does not completely lay down, then I can feel pretty assured that a problem exists. The problem can be that:

  • The peel ply is stretched past a concave curve;
  • The carbon fiber is not saturated with epoxy;
  • And/or there is an air bubbles.

These problems have to be resolved quickly since the pot life of the carbon fiber may be near its end. For me, it is imperative that I have all the tools right at hand:

  • Peel ply cut to different widths and lengths
  • SHARP scissors (keep the scissor sharpener handy!)
  • Extra clean brush (if the pot life is ending, the brush becomes nearly unworkable, so a clean one may help for a few more minutes)
Additionally, I usually mix the epoxy resin and hardeners in small quantities (2 pumps on the West System's pump system). I rather have a multiple mixing sessions in order that I can continue to work longer since each mixing has its own pot life.

Of course, there is a hitch to this  dry layup.  If the carbon fiber is laid up on a dry surface and the epoxy resin is never worked into and through the surface of the carbon fiber to the surface below, then I could end up with a dry area without adhesion to the underlying carbon fiber.  This is really bad and the bike will almost certainly have failure problems.  From what I read, manufacturers of carbon fiber bicycles expect about 3% of the area covered to have problems of adhesion. I hope mine is less, but I really will not know unless I have a failure of the handcycle for which I would perform an autopsy.  At that point, I can cut away and determine if there are indeed dry areas for which plys of carbon fiber did not adhere to its neighbor.  

You might ask, "Why chance it?"  The reason is, the layup of "wet" carbon fiber on these curves proves to have other problems:

  • Shifting carbon fiber
  • Bunching of carbon fiber
  • Dry spots due to shifting and bunching carbon fiber.

For long curves, this is not a problem.  For instance, I layup a layer of carbon fiber over the entire bottom in very little time and with no problems. There will be almost no air bubbles or dry spots.  If so, they may represent a aggregate of maybe a square inch in size over an area that is probably three square feet -- or a quarter of 1%.

A few tips on laying out and removing the peel ply:

  • Always, if possible, keep some part of each peel ply in an area that is "dry" of epoxy.  When pulling the peel ply from a finished layer, you need to be able to grab a portion of the peel ply in order to remove it.  If the whole of the piece of peel ply is wet in the epoxy, on the surface of the carbon fiber, and if the peel ply is laying flat to the surface as it should be, then you will have headaches in removing it.  So keep some of each piece of peel ply dry.
  • When removing the peel ply, attempt to remove it as soon as you can.  For instance, do not wait a couple of days. I attempt to remove it after four hours with the 205 hardener and eight hours with the 206 hardener.  The epoxy is still "green."
  • Attempt to pull the peel ply as parallel to the carbon fiber surface as possible in order to not to disrupt the carbon fiber layers beneath it.  The peel ply sticks quite well to epoxy.  So when you pull it hard, you could dislodge to carbon fiber on a microscopic level.

So, for those that are interested in designing and building something out of carbon fiber, think about limiting the areas of small complex curves. Those areas require infinitely more time as compared to the larger curves and flat areas.

In total, I expect the above shape will take about 15 hours of work to complete in terms of carbon fiber layup.  But I may just be ssssslllllloooooowwww.....

Thursday, January 12, 2012

First view of handcycle in Carbon Fiber!

At last! I got to put wheels on something other than a foam plug.  The carbon fiber is coming along and extremely rigid.  Matter of fact as an example of rigidity, when I initially inserted the the steering headtube into the base, I needed another millimeter of so in total length between the "U" shaped legs.  But I could not spread the "U" apart.  I did some filing in an area that is not of consequence in order to get it to fit.

The rear wheel does not have much room to the left and right in the "tail" part of the headrest.  I think I will be fine there though.

The structural areas are not finished yet.  There are more layers to go.  So far, I am surprised by the strength -- but then again, I have not put any weight on the bike.

Before adding the bottom bracket I had to insure that the bottom bracket would not get epoxy into the threads.  Therefore, I coated the inside of the headtube with grease.  Of course I had to be careful not get any grease on the fiberglass surrounding the headtube.

Tuesday, January 10, 2012

Etch Aluminum for Bottom Bracket (my "top" bracket)

Since there can be an electrolytic reaction between the aluminum bottom bracket for the crank and the carbon fiber that surrounds it, I am applying a layer of fiberglass between the two.  The fiberglass will insulate the aluminum from the carbon fiber.  Since aluminum should be etched first before applying epoxy to it, I am using the West System's 860 Etching Kit to etch the aluminum in order that it better receive the layer of fiberglass.

The etching is a pretty quick process... about 10 minutes.  The "wait" is the time it takes for the West System's 105 resin with 205 quick hardner to solidify before I can insert the bottom bracket in the fork.

West System's 860 Etching Kit
Getting ready for wrapping bottom bracket in fiberglass

Sunday, January 8, 2012

Most of carbon fiber in place on plugs

I bought 72 2" paint brushes, 15 yards of carbon fiber, peel plies, bleeder film, vacuum bagging film, West Systems 105 epoxy with 205 (fast) hardener and 206 (slow hardener)... and more.

Now I finally have some carbon fiber in place on both the fork plug and base plug.  My calculations suggest that relative to the time to just lay down the carbon fiber to this point, I have spent about 100 hours.. Here it is:

Carbon Fiber at last!

The picture depicts both the base and front fork plugs covered in carbon fiber.  This has been a learning process (and I am still learning!).  After some disappointing results (waviness in the carbon fiber), I changed the process of building up the carbon fiber to using smaller pieces in order that problems are limited to smaller area.  This helped to reduce the problems as well.

At this stage, I have used around 25 paint brushes.  Often I put down a few pieces of carbon fiber per paint brush.  So I would guess that I have put down around 50 pieces of carbon fiber.  It is a slow process.

At this point, I still have more layers of carbon fiber to complete.  This is especially true for the areas of the bike that will be under a lot of stress -- head tube, center of base, and rear fork area.  The front fork with the exception of the crank area, is nearly complete in relation to layers of carbon fiber.

Thursday, January 5, 2012

Some finished carbon fiber (Left foot-holder)

The left foot-holder is nearly finished.  I will probably have to put a spray finish coat -- or at least a faster drying one -- on the surface since the West System 105 resin -- with slow 206 slow hardner -- remains sticky for about 10 hours.  It thus picks up a fair amount of dust.  

Since the West Systems 105 epoxy is very clear -- even when hard -- one can see the carbon fiber material through it quite well... mistakes and all.  Overall, I cannot complain too much since the shape is pretty "curvy" and the 3 to 4 layers of twill carbon fiber fabric must be cut in many pieces to fit. 

Over the next few days I will start posting the results of the fork and base plug with carbon fiber wrap.  The plugs are coming along. But it is a very slow process since each section of carbon fiber takes about 1.5 hours to put into place. And there are endless numbers of carbon fiber pieces -- maybe 70 to 100 as a guess.

Tuesday, January 3, 2012

This is a chronicle of my attempts to design and build a Do-It-Yourself (DIY)  handcycle.  A little background first.

I use a handcycle since my legs do not respond to my brain particularly well and vice versa.   (My wife I am sure believes my brain does not respond to her – but I digress...)   Riding a bike is not feasible.  While I am relatively fast as compared to the handcyclist community (I won the U.S. Air Force Marathon, hand-crank division ), I have a difficult time keeping up with many legged cyclists  But I enjoy riding with legged-cyclists since it allows me to push myself much harder as compared to riding solo.  As well, I complained so thoroughly about my existing handcycle that I decided I had to design and build my own.  Then I could complain to myself if nothing more!

Before you are completely bored, here are design iterations :

Why is it difficult for a handcylist to maintain the same speed as legged cyclists? There are three main problems for a handcyclists as compared legged-cyclist:

  • Power: To give you an idea of the difference between a legged cyclist and a handcyclist, a top-notch legged-cyclists will maintain 33 mph over a very flat 40K time-trial without many turns  whereas the top handcyclist can only maintain 23 mph.  If hills are introduced, the comparison for the handcyclists becomes decidedly bleaker since the arms cannot generate nearly the power required to lift the body as compared to legs.  As an example, the next time you climb a ladder consider pulling yourself up with your arms rather than pushing with your legs. You will get the point immediately.  No matter the amount of gearing involved, the arms will never match the legs.  Now think of climbing 5500 feet with your arms over 100 miles of cycling…
  • Turning: The handcyclist must slow considerably more on a turn as compared to a bike since the handcycle cannot be “leaned” into a turn due to the three-wheeled design.  I roll my handcycle far more than I would roll a bike.  The bicyclist need only lean more on an aggressive turn or as speed builds.
  • Circulatory system:  The human body’s design is one of the best in nature for long-distance hunting with the legs and picking berries with the arms/hands.  Surprisingly, arm muscles are 38 percent less efficient as compared to the legs given the same muscle mass.  Some of the best ultra-marathoners have put in over 300 miles without stopping.  It would be completely impossible to have the arms carry one for such a distance without mechanical assistance.  The aerobic use of the arms are hindered when compared to the legs.

For my design work (about five months) I used a free 3D program from Google called SketchUp. (http://sketchup.google.com/) The learning curve was a bit steeper than I expected.  Additionally, SketchUp is not a true solids modeling program.  But it is free! So I used it.  Ultimately the design process lead me to a two-wheeled handcycle design.  (I have yet to find a commercial handcyle with two wheels.) My design goals are to:
  • Increase aerodynamic efficiency: A bicycle front wheel consumes about 7%-10% of the total energy.  The problem with a 3-wheel handcycle is that all three wheels are essentially front wheels since none are protected as normal bicycle rear wheel is. One is out in front and the other two are out to the sides.  And since the speed is lower on handcycling, the wheels may very well consume 30% of the power.  With two wheels (and other aerodynamic efficiencies), I may decrease my aerodynamic drag  and rolling resistance by enough to attain 11-13% higher speed.  As an example, on  a regular bike, the seat tube alone can decrease a rear wheel drag by 25%.  
  • Turning:  Two wheels will allow me to lean during a turn and thus I can maintain more speed.  But a handcycle’s three wheels allow for stability on stops and low speed.  By moving to a two-wheel design, I would lose stability – especially on stops since  I cannot just put my leg down to the ground.  In order to regain stability, I have added two inline skate wheels as out-riggers.  The wheel would contact the surface when the bike leans further than 12 degrees.  For stops, I should be fine (hopefully!).
  • Add disc brakes!  I was coming down a very curvy mountain road in New York.  Since I cannot lean into a turn, I was afraid that the considerable “G” forces would tip me over.  The speedometer read 46 mph.  At that point, I could smell my brake pads burning.  My only choice was to put my shoulders/arms into the rear wheels to help generate some more friction and slow the bike until I hit a straightaway… or the bottom.

 (Here a picture from that race and that hill -- -- Grand Mondo of New York)…
  • Get rid of as many moving parts as possible!  A handcycle seems to break down about 10 times more often than a bicycle.  Bicycle design has been improved over many years and with many millions of users.  Handcycle design is more primitive and without the size of community of users.  My handcycle design deletes the “front” derailleur, requires only one chainring, uses a single “rear” cog, and uses a transmission hub with no rear derailleur.  Additionally, the front fork and body both employ monocoque construction with carbon-fiber.
  • Comfort:  My existing handcycle is of the one-size-fits-all variety.  Again, without a large community of users, there is not the financial rewards available for the manufacturer to maintain many sizes.  For my design, I can have it fit me exactly. 
IfIf one wants to really go fast on a bike, then I presume that the closer one gets to this design, the faster one will go -- downhill at least:

In order to build the handcycle, I decided to use carbon-fiber as the structural element.  Carbon-fiber is stronger than aluminum, titanium or steel for a given weight.  And it allows me to build the handcycle “in the garage.”   Since the bike is one-of-a kind, I decided to use the “plug method” as compared to the mold method.  With the plug method, one creates a foam plug (the shape) that is then wrapped in carbon-fiber and epoxy.  Sometimes, the builder will then dissolve the foam with acetone after the carbon-fiber/epoxy cures.

Here are some of the pictures (and commentary) of the building process.

Start building… Build a base to hold the plug:

I printed the plan view of the base of the handcycle from SketchUp -- scaled to 1.06X on the length due to the 20 degree sloping angles of the base.  The print was then adhered to malanite board (1/8” thick).  The board was cut with a jigsaw to fit the plan view.

I also printed a side  view to full scale as well.  This was adhered to a ¾” thick MDF.  This was cut and became a template for the base.  Two of the MDF boards, connected with 2x4’s, became the base for the malanite board. The malanite was glued to the MDF boards/2x4’s.  These became the working base for building the bike’s base (see picture below...) 

After the glue dried between the malanite and MDF, I essentially had the form of the base with curves in the X, Y, and Z directions to match my design.

Base formed from urethane foam:
In the following steps I laid of sheet of ¼” last-a-foam 4305 on top of the above form.  I applied a 1500 watt heat gun to the foam.  The specs call for the form to be formable someplace between 230 and 260 degrees Fahrenheit.  The foam fell into place by little more than gravity (use a gloved finger to add a little downward pressure) as foam reached the appropriate temperature.   I then added the sides (2” x ¾”) foam. This took additional bending.

As the work progressed in bending the foam, gluing it and clamping it…

There are cracks in the urethane due to the turns against a 2” thickness:

But with enough filling and sanding, most can be made “right”

Here is the urethane base for the handcycle removed from the MDF/malimite base:


Inline Skate wheels housing:

Due to my fear that the base of the handcycle may not have enough depth in the edge to accommodate the vertical bending moments generated by my weight combined with the forces caused by bad bumps in the road, I wanted to beef up the sides.  I decided to move the inline skate wheels into the base itself and to essentially increase the height of the sidewall of the base at the same time.  This took a lot of time to cut the existing foam out of the base, build a foam mold of the wheel housing, and build that into the base foam.

Rough-out of Front Fork

The fork was roughed out in Styrofoam (2” insulation from Home Depot), layered/glued together to create a deep enough section.  In order to cut the Styrofoam, I created a DIY foam cutter/hot-wire from NiChrome wire (from a local hobby store), a battery charger, and $5 worth of electrical conduit and eyebolts (again from Home Depot).  I placed the hotwire through a router table in order that I have a movable guide for the straight cuts.  The router table already had the guide.  The hot wire worked very well – much better than I expected.  I could cut through many inches of foam with ease.  Matter of fact, the hot wire worked as well whether the foam was 3” thick or 8” thick.  The moveable guide on the router table was invaluable.  

DIY foam cutter (hot-wire):

There was not enough amperage with the batter-charger set to “slow charge.”  As soon as I set the mode to “Start” (up to 50 amps), the NiChrome wire turned red and the contraption worked!  I had no NiChrome wire breakage in all the cutting that I did – and it breezed through the cuts.  I suspects that the amperage drawn was about right.  No animals were harmed and no circuit breakers were tripped.

Roughed-out Front Fork:
The front fork plug is comprised of Dow Styrofoam (15 PSI compression rated).  The urethane foam (used in the main base of the bike) cannot be shaped with a hot-wire whereas the Styrofoam can be.  I decided to use the Styrofoam on the front fork due to large amount of shaping required and since I wanted to use the hot-wire to achieve that shape.

Testing the size of the foam plug:
After laying upon the base plug – built from the original design drawn in SketchUp – I found that the seat in particular required quite a bit of shaping to fit my body.  Albeit, the original design was fairly close in overall dimensions, the design required a bit of tweaking in order to make the handcycle comfortable.  After many hours (20?) of shaping with a sanding block and filling with urethane/Styrofoam/epoxy, I got to a point where I could probably sleep upon it now since it is so comfortable. Hopefully I don’t fall asleep on the road.

Base foam plug with rear dropouts, seat form and rough-in steering support:
The seat area and steering support was form out of Styrofoam with the use of the foam cutter.  These were adhered to the base with gorilla glue.

Disk Brakes:

This is the rear dropout with rear disk brake (the equivalent of a front wheel on a bike).  This took many hours of work.  In this case I used a drill press, large stationary sander, and band saw to build the carbon-fiber dropouts out of ¼” flat carbon-fiber plate.  I had designed the parts in Google’s Sketchup, printed it 1:1, adhered the printout to the carbon-fiber sheet, and cut the pieces out with a band saw.  The lower dropout is comprised of a double thickness of carbon-fiber since the brake body required it for the bolts to secure it in place.

Front fork plug with crank and gear hub.  The orange string is the chainline:

Front fork foam plug with gear hub (SRAM IMotion-9 speed…no derailleur required) and disc brake fitted;

Steering (Now the tough part…)

I actually had to build quite a  few carbon fiber parts that comprise the steering.  The headtube is 15 layers of carbon fiber – as are the steerer tube support tubes (2). Additionally, the flat ends (4) to the steerer tube supports required hand filing in order to accommodate the 1-1/8” steerer tube.  My drill-press just could not cut the holes well enough through 15 layers of carbon fiber.  It took 4 hours of filing to correctly size the holes.  Also, it took a couple of tries in order to come up with an acceptable headtube.  That is another story…

The “white” area around the carbon fiber is a material comprised of epoxy mixed with glass microballs.  The microballs allow for sanding and leveling of the carbon fiber areas.  Additionally, it is much lighter than 100% epoxy. This mixture of epoxy and microballs are applied after the carbon-fiber/epoxy was cured in place.

Now the steering head tube, steerer tube, and bearings are in place.  The steering actually works. 

I use a laser to align the pieces – base, front fork, head tube, and head tube supports. I therefore can feel assured that the pieces (base, steering, fork, wheels, dropouts) are in the correct position:

The orange string below is used to check the chainline to make sure the chain fits through the fork.  Since this is using a hub transmission, the chainline stays put.  There is only a single cog and a single chainring.

Foot Holders rough-out:
The foot holders are roughed out from Styrofoam with the use of the DIY foam cutter.  I then used foam sanding blocks to finish the shaping.

Vacuum Bagging:

The better method of impregnating and finishing the carbon-fiber is to “vacuum-bag” – put the carbon-fiber and epoxy, during the curing process, under pressure via a vacuum bag technique. In order to have a better vacuum bagging process, I built a DIY vacuum controller (about 5 hours or work including numerous trips to Home Depot). The reservoirs are constructed of schedule 40 (pressure type!!!) pipe and caps with holes threaded to take ¼ NPT fittings.  Here it is:

Testing a Venturi-based Vacuum Bagging System:
The system did not work the first time since I had a one-way valve in backwards!  After diagnosing and fixing the problem, it worked!  Matter of fact, when the valve to the vacuum bag is turned off, the system held vacuum for over 24 hours without losing an inch.

Foot-holder wrapped in carbon-fiber:
I found that wrapping the foot-holder was more difficult than I expected.  It took many tries.  I used 3M spray adhesive to hold the carbon-fiber in place as I wrapped the foam.  This helped considerably.  Many DIYers use the 3M 77 product.

Testing the plug:
I am glad I performed this test since on the first attempt, I could not insert the front wheel into the dropouts due to the front fork (the foam needed additional shaping).  Additionally, I have used a fair amount of epoxy mixed with abundant amount of glass microballs (very light weight material that is quite sandable mixed into the epoxy) to finish, feather and add support to the foam plug. 

View from the rear:

Building the Handles for the Crank:


Layout the Carbon Fiber on Plug:

I have found that the best way to cut the many, many pieces of carbon fiber is to follow a process.  That process is,
·         Build paper template in order to have the carbon fiber fit properly.
·         Spray light adhesive on back of template
·         Adhere paper template to the CF.  This will help alleviate the fraying that occurs easily with a “Twill” carbon fiber that I am using predominantly.
·         Cut carbon fiber AND accompanying peel ply (if peel ply is to be used) to the template.
·         Peel off the template after the carbon fiber is in place on the plug.

Foot Holder after Vacuum W/ 3 Layers of CF:

The sanded carbon fiber foot-holder has the plug’s Styrofoam melted out with acetone.  The foam had “crushed” some at 19” of vacuum.  Therefore, the finish is not perfect.  This may take 4 or 5 coats of resin – with the appropriate sanding between layers – in order to get a better finish.  If the foam had not crushed, I think the finish would have been better.