Gloss not working

gloss in tins should always be stirred as the oil will form on the top surface of the tin,thus producing streaky and patchy results, due to the oli and paint not properly mixed. Always use same base undercoat as gloss coat and you should not get any reactions.

2 coats of undercoat is definitely required. Finished with a coat of gloss. Oil based gloss reacts with the door surface. I hope this is helpful

I would guess the problem you're having is caused by using two conflicting paint types. You probably used an oil-based undercoat, and then painted over the top with a water-based gloss. You should only use two of the same kind of paint: oil with oil, water with water. If unsure how to tell difference, read the instructions on the can for cleaning brushes. If it says use water to clean, then paint is water-based. If it says use turps or white spirit, then it is oil-based.

Patches and streaks can also come from the incorrect shade of undercoat . For instance , grey undercoat can vary from light grey to mid , charcoal etc . Red and yellow can also be a problem with the pigments involved.