I got some whisper black for the front of my box, smooth flat mdf surface, and wanted to get 3M 80, but no one seemed to have it. Got 90 instead, but have not done the deed. Will that be sufficient? Thanks
I like to brush it on over spraying it. I can get a much more smooth surface on both the vinyl and the piece I am applying it on over spraying. Get your spray pattern wrong and you get these wonderful lumps in the surface and it will show through the vinyl. Most people wouldn't worry about it as nearly everyone that sprays glue will have the same thing going on.
If you brush, brush in only one direction and do NOT go back over the glue that you've already have put down.
Regardless, let the glue dry as long as possible. I usually try to let my glue dry for 4-6 hours to make sure all of the solvent as evaporated out of it. And no, heating it with a heat gun will not do the same thing. And yes, it will stick after drying that long...and stick down really hard. What causes vinyl to peel is the solvents evaporating out...they can't pass through the vinyl so they form bubbles. The gas to trapped. So the best thing to do is to make sure all of that stuff is gone before you stick the pieces together.
Technically the DAP Weldwood Landau glues are contact cements. But the stuff at Lowes and places like that have changed over the years and has very poor adhesion to vinyl. Fabrics go for it, but I would stay away from vinyl with it.