Troy -From what Tox and other say follow the directions to the LETTER and there will be no problems. I have mine still in the box waiting for a warm weekend, but on the keelshield site they are very specific (see below). When I put mine on it will be done exactly as they direct, so I have no issues with adhesion.
Surface Preparation
Note: The following steps must be done with great care.
If any step is left undone or done improperly, the adhesive will not bond and you will have failure. If the bottom of your craft is painted, it is crucial there is no peeling paint. If your boat has anti-fouling paint on the bottom you must remove it where the KeelShield will be installed,the adhesive will not stick to that paint.
Hold your KeelShield to your hull to determine where it will be placed. For ease of application on the following steps, it is suggested that you use a wax pen, pencil and trace or tape off the area where your Keelshield will be placed.
Using isopropyl alcohol and paper towels you need to thoroghly clean a small area.While this area is still wet, use a clean paper towel and wipe it off. Repeat this step until you have cleaned the entire area where the KeelShield will be installed. NOTE: For removing a heavy wax you can use a laquer thinner Before you begin step #2. Just be sure to do step #2 after using any other cleaning agents. Most all will leave a invisible film behind except isopropyl alcohol.
Using the 3M scotch brite pad provided, use a circular motion and scuff the area where your KeelShield is to be applied. Be sure to scuff the entire surface,this step removes the gloss and provides a proper bonding surface for the adhesive.
Repeat step #2 . This will remove all of the residue and ensures the surface will bond with the adhesive.
http://www.keelshield.com/51.html