Originally Posted by
jedrider
I've successfully drilled into the brake bridge of a vintage frame. Drilled like butter.
I thought about the water bottles, too. I am not willing to drill into the down tube.
You probably should decide how good a frame it is. The best frames were double butted and thin in the center, so I wouldn't drill those.
That said, 'silicone' what?? Cement?? I have the clamp-on bottle holders. Haven't figured out how to keep them from sliding, especially around and around!
You can't just drill into a frame tube and expect the bolts of the bottle cage to hold on to the down or seat tube's thin material. You will need a threaded boss or insert to make it work if you go that way. for steel frames, you need to the bosses brazed on by a frame builder, for Aluminum, there are threaded hat shaped inserts that slips into the drilled holes. CF is a bit tricker as the tube might be very thin, specially on monocoque type frames. The bosses on those bikes would probably need to be moulded into the tube when the frame is laid up. Forget trying to drill your frame yourself and just clamp the cage on. Quick, simple, safe and you do not end up with a mod that irreversible.
Chombi