Heat Shrink Sleeve Installation Tip #2:
Proper Surface Preparation is Imperative
In case you missed it, Tip #1 (to do with proper pre-heat) can be found here.
How important is surface preparation (substrate cleanliness) during a heat shrink sleeve installation? It is absolutely imperative. Picture this: your entire arm is covered in mud and you see that you've got a little scrape just near your elbow. You get a band aid out of your pack and put it in place...right there on top of the mud. How well is that bandaid going to bond to your skin? Right - it isn't going to bond at all. It is probably laying on the ground within five seconds!
Coatings of any kind require a clean surface. For any coating; be that a fusion bond epoxy on your patio furniture, a bumper sticker on your car, a coat of paint on a fence, or a coating on the field joint coating of your billion dollar pipeline -- a coating is only as strong as its weakest link. In the example above (band aid in mud) - the weakest link is going to be the bond between the mud and the band aid. There will be no bond as gravity alone will probably displace the band aid.
So when looking at coating a pipeline, both the steel and the adjacent factory applied coating absolutely must be cleaned to whatever standard is required by the manufacturer. In some cases (stand along liquid epoxies like Powercrete J) the surface preparation will require that the pipe be cleaned with a specific anchor pattern. Other coatings might simply require a grit blasted surface with no anchor pattern requirements and still other coatings (like our WPCT product) a pipe can likely be cleaned with a simple power wire brush.
In any case though, please, please be sure that your crews are meeting the minimum surface preparation requirements for whatever pipeline coating they are using. No matter what the coating is - its future as a successful coating (that does exactly what it was expected to do) is almost always determined by its installation. Skip the pre-heating step...you will have problems. Utilize improper surface preparation...you will have problems. Shrink the sleeve with the wrong type of torch (never use a welding torch!)...you will have problems. Installation is simple, easy and repeatable. There is no need to cut corners; so please don't.