I made another attempt at doing a PCB with the UV exposure method except this time, I added two transparency sheets on top of the artwork and the lazer printer toner of the artwork touching the presensitized PCB board. The good part is the entire design appeared this time, but as I was assembling components, I had to drill larger holes just to get most of the components to fit, yet I was using standard eagle libraries to insert the components onto my circuit before printout, and I also printed at normal 1:1 scale.
I came across one website mentioning about using a vacuum to suck the air out between the PCB and the circuit board for better contact.
At first I was thinking placing the entire PCB in a clear plastic sandwich bag and tape it up to a household vacuum and leave the vacuum running for the entire exposure time, but that would give my family grief as well as raise electricity costs.
Does a tiny vacuum (and/or relevant parts) strictly for the purpose I mention exist for the general public to use? If so, what's the technical name for it?
I'm just sick of my PCB production going wrong all the time and I feel if I can get the artwork to go 100% flat to the PCB with zero light shining in the wrong places then I'll buy the necessary equipment.
Would heat shrink wrap bags work?
I remember heat-shrinking the shrink wrap on my windows in my house back in the day to keep the cold air out and I ran over the wrap with a hair blow-dryer for a good 20 minutes and the wrap produced a really tight seal on the windows. I see that ebay sells heat shrink-wrap bags in small sizes that can fit my circuit board as well as my multi-function printer transparency (bought from Staples office store). The question is, would this approach work? or would the blow-dryer melt the transparency and/or screw up any part of the circuit board (especially the photo-resist layer)?