Hey folks, does anyone have any experience with these hold down mats?
vs
http://www.johnsonplastics.com/tapes-fastening-systems/table-mat/rowmark-fat-mat-12-x-12-engraving-table-hold-down-mat (costs $30)
Is the first one really worth twice as much as the second one? I’m considering both of these to use for stencils and papers instead of double sided tape.
I’ve never tried those, but I have a lot of plastic cutting mats for the digital cutters that I decided I’d better not try with the laser.
They’re expensive enough (about 17$ for two of them) and I was afraid the first time I used it with a laser I’d likely slice it to ribbons. 
If you want to make a cheaper, disposable one…spray a couple of coats of Krylon Easy Tack #7020 Repositionable adhesive onto a large sheet of heavy watercolor paper and then tape that down at the edges to the grid. (Or I think Aileen’s makes a liquid repositionable adhesive if you don’t want the spray.)
If you want something more permanent and reusable than just the one use mat…grab one of those cheap bamboo cutting boards that everyone uses for everything and spray that. (Or scrap plywood). It should be good for several reuses (like 30) before you have to refresh the adhesive. It will get a little cut up, but should still hold until it’s completely charred.
I use Seklema in my Roland engravers to hold materials while engraving. Works pretty well for that since you are looking to keep any side to side movement to an absolute minimum. All of the force in an engraver is directly downward, but there is pretty strong torque that will try to move the material to the side.
Don’t think Seklema would work well in a CNC machine because it has very little ability to hold material to the table. This makes it easy to remove material after being engraved, but a CNC machine would pick it up and throw it all over the place.
I’ve never tried to put paper on the engraver bed, so just checked to see if it would hold. Seemed to do so well. No side to side and easy to pull off.
Would think it would work well with a laser since there really isn’t any downward or side forces except for the air assist. It should keep things pretty stable. Don’t have any idea if it would be safe in a laser. I guess you would need to check the MSDS sheet.
One thing that I do really like about the Seklema is the ability to give it a quick rub with a cloth dampened with alcohol and refresh the surface. The ones I have on at present have been in use for a couple of years.