Please use the tinpot which we specially made for the pouring. Pour the liquid into the mould, according to the principle of firstly slowly to fast, then fast to slowly. The pinpot mouth should be closely to the mould to let the liquid flowing in along the mould wall. And at the same time, turn on the cooling water to cool down the mould and the tin bar. (When casting, the circulation water should turn on little by little. And after some more time, the temperaturer gets more stable, then turn on it fully. And during the casting period, the bar surface may suffered a little from oxidation. On this case, buyer need to prepare some tool to remove it to ensure the surface as bright as a mirror.