Hi, I have a Aluminum road frame with carbon stays. It is a former local team frame with multiple layers of paint. I sanded it down to the original paint but because there is so much excess paint on in areas where it shouldn't be like the seat collar and derailleur clamp surface I want to strip it down completely. The carbon stays have the original clear and I will keep them that way. I plan to buy some stripper and do it myself then pay to have it painted by a local professional. My only question is that I am worried about the carbon getting damaged by the stripper or other processes.

I wouldn't want to get paint stripper anywhere near CF composite, not to mention the epoxy that's binding them to the aluminum. Chances are your painter can easily media blast the difficult areas (after "masking" off the stays). I'm all for DIY, but some things are best left to the pros.

+1 and be sure the painter knows the tubes are thin wall aluminum and uses appropriate medium and air pressure. Harsh, high pressure sand blasting can remove both the paint and tube wall.

+3. I'd be wary of a chemical stripper's possible effect on the CF surface, and I wouldn't put a chemical stripper anywhere near the CF/aluminum joints.

If you insist on doing the stripping yourself instead of having it blasted, maybe something like a Dremel could help you get into tight spots? There are all sorts of wire wheels, abrasive buffers, etc. I've also used things like emery boards, although my wife wasn't too happy about it.

I have an aluminum/carbon combo frame I will be prepping for paint in a few weeks. I will tape off the carbon, extending about a 1/4" onto the aluminum. Paint stripper and sanding by hand at the overlap areas.

No need to strip the original paint. Just sand down to it, rough up the surface, and paint over it.

Most modern aircraft have exterior surfaces of aluminum and composites combined. Maybe take a close look at how that industry strips and repaints.

https://www.facebook.com/carbolift/

also can you bake carbon if it goes into a oven for powder coating the aluminum part?

I am pretty sure you can't powder coat when carbon is involved. Wet paint is going to be your solution.

Here is what Cycle Art says.
https://www.cyclart.com/can-my-carbon...hed-powdercoat