@Jules, I tried using that Krylon easy tack spray you once recommended to me for re-stickying the Silhouette mat. Sprayed on two sheets of regular paper and used to mask. Seems to work, prevents the smoke discoloration, although there is still charring on very fine features from the power setting I need to burn through the whole stack.
I bet one could even use this for a quick and dirty mask on wood, since you can adjust the tackiness by spraying both parts.
Thanks. Just trying to figure out why there is such a difference between 110, 105 and 120.
Guess I have to play some more… Bummer 
Oh good, I hadn’t tried to use it on regular paper yet since I’ve got the masking tape. Glad to hear it worked. 
(You could probably just keep using that and save some bucks on the masking tape.)
Low and slow! I read that for paper, you should go for max speed and the highest setting that will cut. I’ve been following that advice for all my previous attempts, but the large swings in head velocity through corners was causing charring and spotting. I figured, why not try using a low speed with super low power, which will tend to cause less variation overall?
I ran a bunch of tests and determined that 200/2 will cut through paper. And the result:
No charring, very little discoloration on the reverse.
I was actually thinking two passes at low power, if the first pass doesn’t cut all the way through. Maybe even dampening the paper just a little, then placing under flat boards to prevent warping while drying.
Those turned out so well! Thanks for the setting suggestions - can’t wait to try it out someday soon!!
Just wanted to say thanks to @jsc for all of your testing. Finally got through #120 duplex cardstock.
Took four passes at your setting.
How pretty! 
Which settings did you use? The 200/2 I cited was what I use on printer paper, not cardstock! On what I think is ~80# dual sided cardstock from Michael’s, I use 200/15 bare, or 200/20 masked. What you might want to do is cut out a series of tests (I like star shapes because they have lots of points that will show off overburning) in increments of 5, then pick the one that looks the best to you. I like settings where there is very little weeding to do. Also, 200 speed was just a speed that looked slow enough without me dying of impatience, it may not be optimal.
I used the 200/2 with 4 passes. Worked great.
I was using 250/15 for 110# but had slight charring. No charing now. The marks that you see on the white are reminents from my pad that I hadn’t cleaned off.
Some more cutting and scoring experiments. 200/1 will score cardstock just fine:
Design from http://www.rabbitlaserusa.com/DownloadableProjects.html#CardstockBoxes
Wow, that page is a treasure trove. Especially if you click “Open the directory examples on this server” link, which takes you here: http://www.rabbitlaserusa.com/examples/
The bit of char makes it interesting and gives it dimension. I love your design. Thank you for sharing,
Thank you so much for the info because i’m Awaiting for my forge and my main job is to work with card stock and I was wondering what setting to use not to get the smoke color on the card stock, because i’ve Played on a deferent laser before cutting a sample of my work on card stock and it also was making the smoke coloration on the paper and that is not good for business lol
