Bamboo Bike #2

Step 10 Final shaping of lugs/joints and touch up paint

I did one last final re-wrap of carbon tow on each and every last lug/joint.  Afterward I dug into my supply of files and rasps.  I found a medium file with a flat side and a rounded side along with a very narrow round rasp and a thicker diameter round file.  The files help aide in getting flat tapers in each lug.  I wanted the lugs to taper into the bamboo this time, asthetically I think it looks better.  I filed and rasped each joint until they were smooth and to the desired look - this is a feel and sight thing. 

After the filing/rasping I sanded with 100 grit dry sand paper.  I sanded with strokes toward the bamboo and back making sure thecarbon/bamboo interface was smooth and clean.  At this point I had some small pits (pin holes) and spots in the carbon that needed to be filled in before final paint.  So, I mixed up some resin and spread a thin layer over each lug with my gloved finger. 

This can get messy and I figured out early on that this needs to be done a small area at a time.  The reason - the stuff has a tendency to run.  My last project was done outside, under the hottest sun at as high as 116 degrees.  Now nights are in the high 20s so I brought the whole project indoors.  It's about 74 degrees F inside but the cureing process is quite a bit longer than I remember it being during the last build. 

Once each lug had been coated I set the frame somewhere and and every 5 minutes or so turned it over so that no runs would appear.  They did and I wiped them away.  We're not looking for a very thick layer here, it is purely cosmetic and adds weight, it is just to lay a good foundation for paint.  Once each lug cured I wet sanded the entire frame.  Yes, bamboo and all.  I did this with 220 wet sandpaper. 

I Wiped the entire frame down with a clean towel, allowed to the next day to dry and repeated the entire process.  Filed a bit, sanded a bit, here and there and hit it with another thin layer of resin.  I only added about 35 grams in this process, so you can see I sanded away quite a bit of the resin after first application. 

I wet sanded again, the entire frame and am now ready for paint!

You can see further down the photos that I painted the aluminum rails black.  I also hit anything that was shiny with a touch of black.  Places where the aluminum showed through the carbon, like the water bottle bosses, and brake and derailleur cable stops, were touched with black.  It is all going to be covered by translucent red, so I don't want the silvery aluminum shining through. 

I also decided on this frame to utilize some wood stain - dark teak.  I sanded this frame alot to get all the resin off of it, the finger prints, the drops, the stuff I messed in wiping up.  This lightened the frame beyond my liking.  So, at this time I began to experiment with how much, how long, and how to wipe up.  I ended up using papertowels and just wiped the stain on and then back off rather quickly.  It ended up looking quite nice.  I'll apply another coat of stain after paint and before the Tung Oil finish.