It takes very little vac to operate a well made easel. That's part of the problem. They make these things out of pegboard without proper internal support, with way too many and too big holes; and too much vac draw not only flexes the board, but pulls the paper into dimples. Even a tiny vac pump needs either a bleeder valve or variable power.
You could make your own using a small fan intended to keep computer processors cool: http://t1.gstatic.com/images?q=tbn:A...rEoo8xJlbZFFMj
At work, we print conductive silver ink onto polyester to make flexible circuits. To look for defects, I have set up a video camera connected to a high definition large TV. The depth of field of the camera looking at about a square inch area is not very wide so I have made small vacuum boxes using fans like the one linked to in order to create a vacuum and keep the sheet flat. The operator just moves the vacuum box around whilst looking at the TV screen to look for print defects.
Holes about 1mm diameter on a 20mm pitch would be about right. Fit the fan so it's rectangular outlet fits into a rectangular hole in the side of the box and seal round it.
This will provide plenty of vacuum to hold a piece of paper and will not pull the paper into the holes.
hahhaha..... then you have to develope it glued to the easel? :laugh:
Originally Posted by Sirius Glass
Make the thinest border you can wwith the easel blades, trim em off later.
Plain piece of plywood. Roofing nails around the perimeter. Put glow paint on the nails so you know where to swing the hammer in the dark. But then that will fog the adjacent paper, so add a caulking gun and black caulk to fill the nail holes afterwards, if you can find a caulking which selenium tones properly.
+ plenty of spare enlarger lenses. Don't forget to wear eye protection.
Originally Posted by DREW WILEY
Also DO NOT USE TAPE. It glows when you peel it off.