Hello guys I am new here. Congrats to all of you for the great work.I am using carbon fiber pre-preg that cures for 2 hours at 175 degrees . Is it possible to cure at 50 degrees for much more time ?

Possibly, but sort of impossible for us to tell you that as it depends on your specific material. If 50 degrees is enough to activate the resin, then it should be able to cure after a sufficient amount of time and just achieve a much lower Tg. However, if it isn't enough to activate the resin, then it obviously won't cure.

The only way to know is either to try it yourself and conduct a series of tests, or to contact the manufacturer and speak to a technician. Else, if you can tell us what specific material you are using then someone here might have experience with it and may be able to guide you a bit better.

Additional to what hanaldo said, it is almost certain that you will get a very bad surface, as the resin will never reach a low viscosity to give a nice finish.

There are some pre pregs that will cure as low as 65C and this takes about 16 hours I think.
I think many can cure at 80C but thsi can take all day.
I use polyester moulds and always cook at 100C which is about the limit of the moulds and will takes 4 hours dwell time plus ramping up.

sounds like you are trying to use an aerospace resin system prepreg if its that elevated temp, you might be able to cure at a lower temp but as above the surface finish wont be that nice and the properties of it wont be great as it will come out more like cardboard than a nice laminate.

You can get tooling prepregs that cure from 50degrees upwards and then postcure at 180degrees if thats what you are needing for your application?

Thanks guys for all the support. I will take into consideration all the above & I will notify you for the results of my experiment.