Hi Kevin, thx for the input. I actually read this tip before. But it seems like they only offered a way to make a mold master same as their SU-8 original using epoxy, and their PDMS replica will always be negative patterns. I actually want to make PDMS replicas same as my SU-8 originals. I do see a chips & tips article talking about PDMS molding using PDMS mold: http://www.rsc.org/Publishing/Journals/lc/Chips_and_Tips/moldingPDMS.asp But the result I got was not encouraging :( Guocheng ________________________________ From: Kevin NicholsTo: General MEMS discussion Sent: Mon, October 11, 2010 8:53:52 AM Subject: Re: [mems-talk] PDMS molding using a PDMS mold There was a Lab on a Chip "Chips & Tips" segment on something similar to what you need published last year: "Chips & Tips: An inexpensive and durable epoxy mold for PDMS" http://www.rsc.org/Publishing/Journals/lc/Chips_and_Tips/epoxy_mould.asp - Kevin