Hey gents. I just bought an oven from mti that is similar to the across international. This specific one
http://mtixtl.com/Bench-TopVacuumOvenWith28SegmentsTemperatureController-EQ-DZF-6050series.aspx. It's working fine so far I am just having one problem with purging. I use an IR thermometer to measure my oil and it reads in the high 90s to 100 degree range. Problem is after numerous vacuum pulls I still notice the shiny swirls of oil on the surface of my slab.
I have a yellow jacket superevac 6cfm that gets down to 15 micron and a 8 cfm robinair that gets to 40. I've used both and am not satisfied with the results. If anyone knows some possible solutions/advice it is greatly needed. I've been racking my brain trying to figure things out and raising temps is the last thing I want to resort to I just don't know what else to try out. I have an analog thermometer that reads the oven temp. next to the sample and I keep it at 105 max if not lower. I've stalked Graywolf on several different forums and have read tons of posts about ovens, pumps, etc. I've got a bunch of cool tools, but they are of no use to me until I figure out how to use them.
I've tried purging in the pyrex by setting it in the oven and then scraping to finish on parchment. Most recently tried scraping directly onto parchment shortly after the pool of liquid tane evaporated and have run into the same issue of getting the surface molten enough for bubbles to rise out. I always spread my oil as thin as possible. No folding, just flipping.
