Hi from BC, Canda

First Stop Introductions
#1

Hi members,

It’s great to find such an active community on this subject…I’m seeing many interesting posts on this forum so wanted to join.

In a nutshell, I’m a carbon bicycle wonk in my not so abundant spare time and write database software for a biotech company to pay for my habit…and kids…mostly kids. LOL

I caught the human powered fever in my undergraduate years (mid '80s) doing a material science program in Toronto. I still commute on two wheels to this day.

Currently, I’m building a carbon recumbent frame. The design goal is to get the total frame weight under 900 g (2 lb.). I’ve had some previous experience using composites in the sailing world and spent the last two years teaching myself and experimenting with resin infusion materials and techniques. I built an oven for post curing and many frame molds from particle board and automotive finishing products.

The bulk of my fabricating experience came in the '90s when I started a small metal fab business specializing in exotic metals, most notably magnesium and titanium. I built a few bicycles frames out of these materials but realized that carbon was a far better structural material for a stiffness critical structure like a frame. Its amazing fatigue strength coupled with the freedom to orient the fibres is hard to beat. The downside is that it remains a very black art that requires a lot of expensive trail and error. Hopefully great forums like this will help clear up at least some of the fog and help the hobbyist community save some valuable time and money on repeating the same mistakes others have made many times before.

Cheers,
konaMike

#2

Hello Mike,
I just joined this site and have worked with carbon fiber in the airline industry and have made steel frames as a hobby for over 40 years but just had to try building a carbon frame to satisfy my curiosity. But have found mostly bad advise so far on places like youtube. I have some preformed tubes from Dedacciai and wonder if you have any tips on the layup/lashing of the tubes. Seems like mostly applying the fibers to create a lug looks the most promising and cosmetically pleasing.I am trying to avoid the mess others create by wrapping the hell out of the joint until it resemble a baseball at the intersection.

#3

I have not experimented with joining pre-fab carbon tubes using tow or tape. My focus with carbon has been on building a “single element” frame made in two halves with a 1/4 inch honeycomb layup. The halves are then joined and then filament wound by hand to add additional torsional stiffness. The frame cross section is approx 2.25 x 6 inches.

I do own a Calfee fork however and have seen his system for joining tubes using tows and tapes…but with the addition of mechanical clamping pressure to squeeze out the excess resin. Short of having tooling to apply pressure to the joint I would probably start testing with pre-preg and then apply pressure using silicon tape. (You will need an elastomer that can take the heat). Hoipe this helps :slight_smile: