Have a look at the original Plycycle here .

5 December 2013

Making it hollow.

As I am not an engineer these stages of a build often cause me to procrastinate over the next stage. The solution has usually been just to get on with it and follow my instinct. So that is what I did for this bit, the hollowing. On Plycycle Mk1 i created a lattice of triangles along the top and down tube sections. I wanted to try something different, so I have used a simplified version of a technique that Renovo Bikes in Oregon USA use. Rather than hollowing out the whole frame section as one, the idea is to add some strength by creating a devider and making two cavities. I really hope this works as it is critical to the integrity of the frame. I am not reducing weight to make some sort of feather light bike, I just want it to be a reasonable weight, with out compromising the strength or becoming too flexible.

Here I removed the outer two layers of the frame and bolted the two center sections back together so that the holes lined up, obvious, but really vital that it all lines up when it is time to bond it all together.
Just on a technical note, I was possibly a bit hasty with my 27mm spade drill and I caused a couple of laminate layer chips in a couple of places, I will have to cut them clean and resin in some filler strips. unfortunately two of them are on the top tube section and will be very visible if not patched up well.

The two middle sections with cavities cut out.

I think I will drill additional holes once more of the finishing is done. Once I am happy with this it will be time to bond the two half's together to allow for more accurate shaping to continue.