I'm trying to find somewhere to buy (on the cheep, as much as possible, so preferably used) a vacuum pump capable of pulling up to 29" of mercury. So far in searching, it seems like most portable vacuum pumps peak at 27". I'm using it to degas silicone for mold-making, and I know very little about automotive fabrication, but my Google-searches have lead me to believe that the people in this hobby are going to be the most knowledgeable about vacuums and compressors. So can anybody tell me if there are particular key-words I should be looking for or good online or physical stores that deal in used vacuum pumps? If relevant, I'm in Seattle.