Hello friends,

I went to make a piece and I used the epoxy resin as gelcoat (this for not finding gelcoat for epoxy in small quantities in my country).
I put the carbon fiber when the resin was already dry and lightly marking the fingerprint.

After that I laminated and then put it in the vacuum bag.

The problems were as follows:

- dry areas on the carbon behind the surface resin coat that I made to replace the gelcoat

- Corners with air bubbles, even putting carbon with tacky resin.

What should I have done wrong?

I think what you have is pretty normal for wet layup and bagging. It's not really a great to do it.

I do hand laid parts with a gelcoat and no vacuum bagging, just really careful hand laminating and even then only for simple and suitable shapes. 

You could do some hand surface finishing after it is moulded but for this I would make the part without a gelcoat and then finish with a resin etc, preferably Duratec Sunshield.

Or you should switch to infusion process which is great for cosmetic finish and no air bubbles.