The Carbon Fiber Layup

Posted: 27th June 2010 by Nigel in Bamboo Bike, The Build

Once the frame was tacked with 5-minute epoxy, we were ready for the layup. Here is what you will need for a wet layup:

1. Carbon fiber tow, basically 5mm wide unwoven carbon fiber (find it on eBay)

2. Epoxy resin and hardener suitable for use with carbon fiber

3. 100 grit sand paper

4. Cheap paint brushes (get at least 5, you will throw one out after every batch of epoxy sets)

5. Lots of pairs of gloves

6. Plastic masking material

7. Ideally a gram scale, but disposable volume measures will due (such as shot glasses)

I would have taken more pictures, but with wet epoxy everywhere it was a real challenge.

Start by mixing up a batch of epoxy. Be sure to follow the directions because mixing ratios vary. Also, you should be well aware of the working time, as it can range from a couple minutes to a few hours.

Next you should paint it onto the part. The surfaces should all be rough, so sand first if necessary.

Then wrap the wet surface with carbon fiber tow until it starts to look dry. Wrap a couple more layers and then paint on some more epoxy. It is easiest if you spool off 20 or 30 meters at a time onto a smaller spool so you can get around tricky corners. They key is to ensure that you wrap in all the directions where load is expected to be applied. Remember, carbon fiber is only strong in the direction of the tow, so if you don’t wrap in a direction where load is applied, the joint will fail.

The wet layup took about 4 hours, and the working time for the epoxy we used was just over an hour, so we made three pots. After 48 hours of curing time, the joints were strong!