Drilling hole in aluminium frame I want to attach a pump holder to my aluminium frame. Can I drill holes in it ? I would then use blind rivets with some glue for waterproofing to attach the holder.
Is there a place on the frame where this would be better?
I know this question, but it is for carbon frames.
Do not do that. Although the question you referenced is about carbon fiber, the answer mostly applies. Aluminium alloys used in bicycle frames are quite fragile. Drilling may easily start cracks that will then spread under stress. Even if it does not happen, you weaken the frame unpredictably. Not only the warranty is gone, but you just don't know if it will fail catastrophically or not. And professional metal defectoscopy is too expensive for bike frames. (Yes, expensive X-ray machines are not just for carbon fiber even if some say so).
It is easy to use the bottle-holder screw holes. Many pumps come with these brackets as already mentioned by @Renaud. If your frame does not come with bottle mount holes, you can use other solutions based on velcro straps or something similar.