It’s really hard to get it with Fiberglass, because Fiberglass is very dry, and it doesn’t dry when it’s dry. After it’s dry, it’s sanded. You can buy some soft clay. It’s very popular now, the price may be slightly more expensive. Some, see how big you make the cake, I suggest you make a little more refined so that the effect is better than the one you use, the color is also rich (the Fiberglass you have to paint later).
Another method is to use sculpture mud to make the model first. The cake is very good. It is very easy to use the glass fiber reinforced plastic of “Jieqiang Brand”. If you want to not damage the abrasive tools, you should use silica gel. When you will give you some silicone curing agent, the mud is ready to put some gasoline in the silica gel, and then put some curing agent evenly. Don’t put too much and don’t put too little. Apply evenly on the mud with a small brush. (Must be even) The thickness can be 4,5 mm, then wait for the silica gel to dry on the cover glass, about 1 cm thick. If it is completely dry, the mud can be dug out from the inside.