Seat Action!!!

The frame and balsa (I swapped the insulation spacer for a larger piece)

Progress continues and the deadlines keep coming. We have decided it is time to put the house up for sale in anticipation of our posting message which should have already arrived and will hopefully be here anyday. With the house up for sale my "workshop" is going to have to be put away everyday. A hassle and a time consumer, but necessary to sell the house.

I have struggled significantly to come up with a good seat design that is both comfortable and buildable by a fabricator (hacker) of my caliber. This hasn't been easy and I have decided that the first version won't likely be comfortable but that I will hopefully be able to modify or add on to give it some curves to fit my cheeks and lumbar once I try it out. Once again, this is just theory. I know a good seat needs to have a "horn" in the centre of the seat area and some other shape to hold you in place.  I have also learned that it is very difficult to create that shape without some sort of 3d modelling clay or something along those lines. My theory is to add some foam once I am sitting on the seat. I will hopefully be able to carve and shape the foam to a decent form and then cover it with a layer of CF to create a masterpiece seat.

The balsa laying on the frames and posterboard

The parts, pretty flimsy by themselves

Profile of the seat.

Seat with 2 layers of CF, pink peel ply and custom clamp system (rice and flower in ziploc)

All this being said, the seat is another product of my own creativity. I couldn't find any info on how to build a seat similar to what I had in mind so I created my own concept. I already had the seat frames built from quite a few weeks ago. The plan was to lay balsa strips across the frames and then lay the CF sheet over the balsa. Cover the whole thing in a nice layer of CF and repeat. In order to keep the balsa flat I needed to add in a piece of poster board between the balsa and the frames. It all went as planned and this evening I just finished laying on the two layers of CF. So far so good.

Progress over the last week or so....

steering stem the black stripe is CF over thickened epoxy

Things continue to evolve, although I continue to hit "engineering challenges" at every corner. So far so good and I keep finding solutions that seem to work. I have the stem put together, if you recall from a few posts ago, it was cut in half so I could reattach it with a 90 degree turn in order to facilitate my steering mast. It is ugly, but it seems pretty strong. It is wrapped with fibreglass, then thickened epoxy followed by some CF ribbons wrapped around. I wrapped the entire package with the electrical tape to hold it nice and tight while it cured. So far so good, but I think some paint may be required or perhaps some finely wrapped CF ribbon to make it look a bit better. I have told myself all along that I'm not trying to build a beautiful bike, just one that is strong and that works. It is still some times frustrating to look at something that is really rough looking after looking at some of the beautiful sleek CF bikes that have been made. I guess you have to start somewhere! I will be happy if it goes off-road and does what I want.

I have put the bike into as complete a state as possible and had a "sit" on it to get a feel. I am very happy so far. Just to get an understanding of the size, the wheelbase is right around 6' so small she isn't. I have the necessary parts now to build my custom roof rack as soon as the bike is done.

The front end with the hole drilled for the bottom bracket

This week I drilled the hole for the bottom bracket and put a bit of CF inside to ensure I have a strong base to bond the BB to when I put it in. I made an attempt to put the BB in today but ran into problems trying to square it off in all three planes. This is my toughest engineering challenge so far and have decided that I need to wait until the seat is on so I can have a good location to measure distances from. Since nothing on the bike is square, it is really difficult to make one component perfectly square. Now I understand why diamond frame builders put the main components in a jig and then build the frame around them......maybe next time?

I have continued with work on the swing arm. This week I added some thickened epoxy to strengthen the joint between the arms and the shock mount. Today, I installed some aluminum angle pieces on the underside which will be the lower connection piece for the shock. I attempted to make some CF angles using the aluminum as a mold, but they just didn't seem strong enough and I didn't want to take more days building them up. The swing arm is looking pretty ugly and has managed to get a slight warp in it from the last session in the vacuum bag. I thought it was strong enough to resist the bag from causing a warp, but my estimate was wrong. This swing arm will do for now, but I think it is definitely V1.0 which will be near the top of the list of parts to rebuild.

Swing arm with aluminum shock mounts bonded

The frame hanging and wrapped with electician tape

Today I added the next layer of CF to the frame. I have been having a problem with this process getting annoying wrinkles in the vacuum bag. Since I only have this plus one more layer to go, I want to ensure things are starting to look at least partially smooth so the bike doesn't look like I used a stipple brush to apply the epoxy. I decided to use the electrical tape wrapped backwards technique that has been used by other homebuilders instead of the vacuum bag. I also applied the epoxy with the frame hanging instead of on the workbench. The hanging worked much better and the panic at the end was only moderate this time. The last few minutes of epoxy application have gone from chaos the first time, through to moderate panic this last time. I consider that a good learning curve!!

Starting to Resemble a Bike!!!

Starting to resemble a bike

swing arm rear view

It has been a very fruitful weekend with the bike. Now that the headtube and pivot are bonded on nicely, I was able to set the bike up much like it will look when it is completed in a week or two. This morning I carved the swing arm cross piece/lower shock mount. It got CF'ed and epoxied in between the rear stays during the same layup as the final tube of CF on the stays. Since I couldn't get the entire contraption into my vacuum bag and I wouldn't want stray epoxy getting sucked onto components such as the pivot or rear wheel, I decided to wrap the entire part with electrical tape. I have read about this technique from other builders who have made bikes. The theory is that the stretch of the electrical tape provides sufficient clamping pressure to hold the CF tight against the part. I am currently about 60 minutes into the curing and things look good so far. I used nylon in between the CF and tape on the area around the cross member because I need it ready for more CF to strengthen that area. In the lower (in pic) area I wrapped the tape directly onto the wet CF. This should give a smooth shiny appearance with little wet sanding. If it works, I may use this technique for my final layup on the frame.

Swing arm taking shape

I also mounted the front fork, tire, stem and steering mast to get and idea of dimensions for the mast and to have a look at how it look overall. The first word, which Richard can attest to, is LONG. Now that it is starting to look like a bike and the weather is very springlike I really have the urge to get riding.

Yesterday I bought a hole saw bit for the drill so I can drill out the hole for the bottom bracket. I will likely take the frame to work tomorrow and use the drill press to cut the hole. I will then be ready to CF the hole and bond in the BB. Once that is on I have a couple more lays of CF for the frame and it will be done. I will also be able to calculate how much chain, gear cable and brake line I will need. The LBS told me they can get that all in a couple of days.

swing arm with cross piece ready for CF

The biggest challenge ahead of me now is the seat. I have the base frames made. I now need to work on the balsa slats/cross pieces which will be covered in CF to make a smooth seat. I haven't been able to figure out how to create the carved shape for the bottom or a curve for the lumbar, so I am going to create a basic flat seat with straight back to start. Once I get on it I am planning on adding carved foam to create the shape I want and then covering that with one layer of CF......sounds good in theory!!

With electrical wrapped over layup

Bike in a jig

This lumber jig proved useless as the lumber wasn't square enough

The angle iron jig worked great!

More learning over the past two days. I haven't been able to find a significant amount of info regarding the best way to set up a recumbent bike in a jig to ensure it remains square in all planes while you epoxy on the various components such as the headtube, bottom bracket and in my case the swing arm pivot point. I started by using lumber and was hoping this would be square and sturdy enough. I struggled for the better part of two days to get everything straight. By lunchtime today I decided I would need to use something stronger and squarer than lumber. I decided angle iron should do the trick, so I went to Lowes and got 2 - 6' lengths of the largest angle iron they sell and built a jig for the

rear wheel to go in. This immediately made a huge difference and I quickly had things squared up. I used some 5 minute epoxy to "tack" the pivot axle on and held it in place for 20 minutes until it was sturdy enough to move. I then took it to the basement and applied a significant amount of epoxy thickened with 404 thickener to make a good bond and hold the axle in place. Over the next few days I will give it a few layers of CF to give it the necessary strength. The headtube installation is the next squaring challenge, that will happen tomorrow morning.

modified stem with fibreglass tube inside and fibreglass wrap on outside

Today I also made the modification to my stem. In order to create a steering mast the goes from the fork up to my handlebar which is about 24" away I need to have a stem that has both clamps in the same plane. They all come with the handlebar clamp 90 deg from the fork clamp. I also want my stem to have an adjustable angle so I can have a good variety of hand positions available. I bought an adjustable stem from MEC and cut it in half. I then built a small fibreglass tube to go inside the cut off piece to give it some strength when I bonded it back together. I didn't get a photo of the glass tube, but so far the installation has gone well. Fingers are crossed that this experiment will work. If not it will be back to the drawing board for  my steering solution.

stem and frame with pivot bonded on rear-end

pivot axle bonded on rear of frame

Early Bird gets the......epoxy

An early start today so I can try to get two batches through the vacuum in one day. I started around 5 and by 9 had the swing arms bonded to the dropouts and the frame with another layer of CF on and in the vacuum.

Swing arms with dropouts attached

It is amazing what experience does to the ease of laying on CF. This time when I did the frame I cut the CF into 2 pieces. One piece for the front end where it angles up and one much longer piece for the remainder. I also used 3M spray adhesive to glue the CF to the frame as I laid it on. This prevented the sagging and sliding problem I had on the first layer. From how it looked going into the vacuum bag, it is going to be very nice. Once this layer cures I will be ready to attach the headtube and the swing arm pivot. I may also do the cutouts for the bottom bracket and chain management idlers.

Check out the new pink nylon peel ply!!

I ran out of epoxy this morning doing the frame, so I have to make a run to Kingston to get more today as tonight I plan on putting another layer of CF on the swing arms as the bonding epoxy will be cured by tonight. The next tube that goes on the swing arms will wrap around the dropouts and really start to strengthen and stiffen the entire arms. By tomorrow I am hoping to have the shock mount/cross piece on the swing arm.

I also need to spend a few minutes today doing a shop cleanup, well not really a shop cleanup, more like a basement floor cleanup. Someday I will have a shop and I will be able to actually work while I sit or stand instead of kneeling or sitting on the floor. At least this is a bit of exercise since I haven't been able to put much time to working out as of late.

A disaster to some, a genius at work to others!

Peel-ply vs nylon and breather fabric vs paper towel

When I first started researching how to do CF work I pretty much only read a couple of bike builders websites and blogs and got info from CF supplier websites. I quickly assumed that most of the materials required were specifically created for CF work. This includes the peel-ply which is the nylon fabric that you lay directly on top of your wetted CF and epoxy. As the epoxy cures, this fabric creates a slightly rough finish so the next layer will have good surface to adhere to. As well, the PP does not stick to the CF after it is cured and with a bit of persuasion, peels off. The other characteristic is the PP allows excess epoxy to soak through so you don't get any extra epoxy in your layer. The excess is pulled through the PP by the vacuum (or other pressure if you used a wrapping pressure) and is soaked up by a breather fabric. This leads me to other mysterious material that at first seemed specifically created just for CF work. Breather fabric is a polyester batting, something like you would see in a cheap blanket. This material serves two purposes when vacuum bagging. First it allows the air to be pulled out from the entire bag by the vacuum and second, it soaks up the excess epoxy that is pulled out through the PP.
I ordered my PP and breather from CF supply companies, and although they weren't overly expensive, they did cost a bit extra to get because I paid shipping and a brokerage fee to get them into Canada from the US.
Last week I did some reading on a RC airplane bulletin board and learned that many in that community use regular nylon from the fabric store as PP and paper towel as breather. On the weekend I went to the fabric store and bought some beautiful pink nylon from the clearance bin and put a roll of paper towel in the workshop to try as breather. Last night when I did my swing arm layup I threw together a balsa and scrap CF piece into the vacuum bag. I wrapped it with the pink nylon and used paper towel as breather. This morning when I took it out of the vacuum the nylon peeled off very easily and the paper towel was hardened with epoxy the same way the polyester was. A successful experiment and money will be saved in the future!!

Adding layers

Progress is slow but sure. I am back to normal after the two weeks off following my eye surgery. I can sand, grind, lift, etc now so things will progress faster. I am also off work this week so I have many hours to spend on the bike. All our house jobs are finished now and the house is ready to go on the market as soon as we have the official posting instruction. This is a bit of a new deadline for bike completion, as my "workshop" makes the basement look like a disaster. It is actually the workshop of a genius, but some prospective home buyers may not see this the same way as I do!!!

Last night I put the first layer of CF on the swing arms, this morning I added the second layer. These are 18" long made from pink styrofoam and will join the rear dropouts to the swing arm pivot under the seat. The shock will attach to these via a cross member that hasn't been built yet. I can't build the cross member until I have the bike in the shape of a.....bike as I can't engineer the dimensions exactly. The distance from the swing arm pivot to the rear axle is 20". Based on my 2D drawing of the rear tire pivot this will give me sufficient clearance for tire - seat clearance when I hit bumps and will allow the shock to bottom out before the seat hits the tire. The pic to the right is the swing arms in the vacuum bag with the second layer of CF applied. The second job of this morning was to put a second layer on the front end of the frame. I layed a 3" strip up one side, around the front where the headtube will go and then down the other side. I then clamped two pieces of laminate flooring to sandwich everything and applied a clamp to the front to hold in the actual headtube in order to give the front the necessary curve for the headtube to be bonded into after a couple more layers of CF are applied to the complete frame.

Seat Frames

My eye is recovering well, but the Doctor wanted me to wait until this coming Thursday before I get into any heavy work or dust. So no grinding or sanding on the frame yet. It is still in the slightly fuzzy and rough condition from my first carbon lay-up challenge.

Today I worked on the rear drop outs and the seat frame. The seat frame is made from balsa and is covered in the first layer of CF tube. They are currently in the vacuum bag overnight. I am definitely getting better at laying up the CF. They key is to do a complete walk through of every step before mixing the epoxy. Once the hardener is mixed in, there is no time to think about how you are going to do something, such as put the pieces into the vacuum bag without the peel ply getting all messed up. Todays layup went really well. So far it looks like the seat edge, which is the most important part to be flat, is going to be nice and smooth. This is the edge where the balsa/CF seat slats are going to sit and be bonded to.

I also bonded the balsa/CF read drop out pieces to the aluminum drop outs off the Rocky parts bike. I used West System 404 filler mixed with the epoxy to make a ketchup consistency. This was used to fill some of the gap between the rough pieces and to create a filet around the inside curve. In one of the photos you can see a white area. This is the thickened epoxy as it cures.

Last week I did my epoxy work in the upstairs bathroom with the fan on and then took the pieces down two floors into the basement to put them in the vacuum bag. Although this worked and I was very careful covering the bathroom cupboard with plastic sheet, the inevitable happened and I dropped some epoxy into the sink. Of course I didn't find it to clean, it was discovered by Mrs. LaidbackDave. Ooops. She chipped it  out and I decided to try doing my epoxy in the basement today. It worked very well and the smell wasn't bad at all. I now have a quasi-workshop area setup in a corner of the basement that is traditionally our stationary bike riding area.

I have next week off work, I will share my time working on the house (it will be up for sale soon) and working on my bike. I think in two weeks I should have the wheels on and will be working on the handlebars and mounting the chain, cables, brake lines, etc.