Hi, how long do I have to knead the gum paste for getting the total flexibility?

Okay...now the answer to that varies a lot depending on which recipe the gum paste was made from, how hot or cold your hands are and the weather. So I'll just be basic.

Gum paste does take quite a lot of kneading to make it pliable, especially if you took it from the fridge or it is a cold day.

To make it all easier, knead just the amount you think you need for whatever you are making at the time. If it is quite hard when you squeeze it, you can wrap it in plastic food wrap and zap it in the microwave...but very carefully because it softens incredibly quickly. For about a 4 oz piece of gum paste (125gm), I would just use 5 second bursts. Take it out after each one and try kneading it. It also tends to heat in the inside before it shows outside. Do not heat it to runny as it is likely not to return to the previous texture.

If heated, you would find it kneads up well within a couple of minutes. If not using the microwave and not really hard when you start, it might take 4 or 5 minutes.

When kneading don't use cornflour (cornstarch) as it will dry it out. Having said that I had better say that for those in a very humid country, kneading in a small amount of cornflour (cornstarch) helps it to resist humidity.

Also try not to add extra icing sugar (confectioners sugar) when kneading either. Just grease your work surface and hands very lightly with white vegetable fat.

You are looking for it to be rather like plasticine. Soft and supple. If you press it out a bit and then fold it over there should be no cracks.

For novices it is a good idea to add rolled fondant (sugarpaste) to the gum paste but no more than half the amount of gumpaste (50/50). That will slow down the drying time a lot. Adding too much rolled fondant will mean it will be more likely to lose its shape after drying, in damp weather.