The seat was in the cards from the beginning. Originally (and still, actually) I had wanted to pound it out of aluminum… well I’ve never worked aluminum, and am more than a little embarrassed to admit that I have no idea how to weld. Not that this was enough to stop me; not having a torch, hammers, a welder, or sandbags however did stop me. So I decided to do the next best thing and lay it up out of carbon. I briefly considered fiberglass but I wanted a running theme through this bike to be the truth behind its’ makeup (hence the ground tank, the visible machine finish and the polished parts) I had partially chosen this because I hate trying to pick a color… I think any painter will tell you the same.
I don’t have any pictures for the first part so I’ll have to try and explain it as best I can. I started with a sheet of corrugated cardboard that I cut out to the shape of the frame to makeup the bottom of the pan. Using the same board I also cut out some ribs to outline the hump at the front of the seat where it mates up with the gas tank. Then I covered the whole thing with painters tape to fill in the holes, and make a solid foundation that I then laid fiberglass matt over. This made up everything with the exception of the rear end cap. Just to make sure everything was all symmetrical and straight I created the end cap I wanted in ProE and machined it out of #10 foam (also commonly called sign foam, it’s what most of the fancy 3D signage is made out of in your’ local mall) The first half of the seat was Bondoed smooth and a heavy coat of primer was applied and sanded. I glued the end cap to this part and then mated them together with another layer of fiberglass:
That part (the plug) was also Bondoed, primed, painted, polished, waxed (don’t use expensive car wax for this, many types have a cleaning agent in them that will stick to your’ mold… ask me how I found that out). At which point I laid another couple of layers of fiberglass over it with some ribbing built in to hold it straight (the mold) once the resin has kicked off the two can be pulled apart. Now the mold needs to be cleaned of any residue and waxed for the carbon fiber to be laid into. It’s best to keep the plug around and stretch the carbon weave over the plug before putting it into the mold, this way it will already be stretched to the proper shape, and will go in much easier. Lay the carbon fiber into the mold (I think I used 3 layers, with stripped foam core for support on the seat base and the back) and let it kick off. Pull them apart and trim your’ part:
On the left is the plug painted black and polished. Remember what I said about the wax… I used the wrong kind and had to rip the plug in half in order to extract it from the mold. In the middle is the mold and on the right is the part.
Here you can see the dirty finish that using the wrong wax created. I decided to wrap the whole thing in a fourth layer of carbon to clean up the finish and round out the edges. Unfortunately with all the resin that went into the last layer to make it smooth and pretty, the seat’s not very light (in comparison to how light it could have been)
I didn’t want it glass smooth glossy, but more like the carbon you see on race machines so I gave it a real quick sand and buff but didn’t clear it.
ba-donk-a-donk
Add a little shaped foam for comfort (mostly shaped with the belt sander and finish sealed with a heat gun)
I’m still on the fence whether to get this covered or not. If I did, the leather would wrap the entire front of the seat leaving just the end cap exposed. But I do like the honest street fighter-esk quality the bare foam has.
BTW: thanks for the encouraging words, they help keep me motivated
