How Important Is Surface Preparation?

Question:  How important is surface preparation when installing a shrink sleeve?

Answer: It is VERY important!  The simple fact is that when considering the cleanliness of the bare steel field joint (and the adjacent factory applied coating), the cleaner it is; the better your bond will be (generally speaking).  When considering the strength of a bond between a coating of some type and a substrate of some type; we can illustrate this point simply using real world examples.

How well will a bumper sticker stick to this car?

     Imagine slapping a bumper sticker on this car.  How long do you think it would stay put?  My guess is that it would fall off just about the second your hand stopped holding it up!  In any bond scenario; a bond is only as strong as its weakest link.  In a case like this (pictured above) no matter what you put on the outside of the dirt; the weakest bond will always be the bond between the dirt and the car.  How strong it that bond?  So weak that you can destroy it with something as weak as a wet finger or a squirt gun.

     Another factor in determining surface preparation requirements is the specific adhesive type involved in the coating.  In general, an aggressive mastic will require minimal surface prep (though it will still need to be free of dust, dirt, grease, etc).  The higher performance the adhesive, the higher the required surface prep is likely to be.  

     Keep in mind when considering minimum surface preparation requirement, these are the cleanliness levels that have been determined to meet or exceed the data as reported on data sheets or manufacturing specifications.