Answer: The powder loss of putty powder is mainly related to the quality of hydrated lime (calcium hydroxide) and has little to do with HPMC. A low calcium content in hydrated lime and an inappropriate ratio of CaO to Ca(OH)2 can both cause powder loss. If there is some relation to HPMC, it would be that poor water retention of HPMC can also cause powder loss. For specific reasons, please refer to question 9.