Both options are applied by hand, without the need for heat or laminators. Just press and peel the liner to apply.
The difference between the 830 and 870 can be boiled down to the weight and strength of each. Watch this quick video for a visual of each:
The Gudy 870 (also known as Gudy O) is an incredibly thin adhesive film, which virtually has no thickness. This means that you can adhere two objects without adding any visible thickness and without a gummy edge. The lack of substance does make it more difficult to apply, but it certainly has its uses and it is quite strong when applied. Requires careful handling. Adhesive will pickup and bead up easily if touched, handled too quickly, or not burnished down fully.
The Gudy 831 (also known as Gudy V) is still a very thin adhesive, but is essentially two pieces of Gudy 870 with a thin paper carrier sandwiched in the middle. This carrier gives the adhesive more substance and body on its own. It is easier to work with, and stronger.
Both the Gudy 870 and Gudy 831 have their own pros and cons, and different applications where both excel.
Some Pro Tips for Applying Gudy 870 and Gudy 831
- First lay the adhesive flat (barrier layer down) and slowly lower your mounted material on top. Lay & trim accordingly.
- For optimal control of your mounted material, mold on opposing corners.
- Use low and deliberate movements, as to avoid trapping any air bubbles.
- Use a burnisher, like a bone folder or teflon folder, to ensure proper adhesion.