As I understood you have chinese laser with glass tube. So best way is buy industrial water cooler. We have purchased our from
Richard.Zhao
Oversea Dept.
Sales Representative
ShenZhen Sunrise Industrial Co., Ltd.
Direct Line: +86-755-3393 5303
Fax: +86-755-2997 4586
Mobile: +86-134 2376 5300
E-mail: RichardZhao@dly-China.com
Web Site: http://dly-china.en.alibaba.com/
Expensive - $1000 in China, but you will save on laser tubes and engraving will be stabile.