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Monday, April 17, 2017

WPCT Shrink Temperature

At What Temp do Shrink Sleeves Shrink?

     As you might expect, this is actually not a simple question.  Shrink sleeve backing can be made from many different material types.  Each of those material types have their own chemical make up - and as a result; can often have different crystalline melt points.  The crystalline melt point is the temperature at which the structure of the backing begins to melt.  If the backing has been crosslinked it doesn't melt, it instead shrinks back to its original dimension (pre-stretch). 

     With most of our Covalence (formerly Raychem) heat shrinkable sleeves (products like WPCT, TPS, WPC100M, HTLP60, DIRAX, etc) that backing is comprised of a modified polyethylene (a polyolefin).  Speaking generally, the crystalline melt point of those product is ~267F.  That means that the backing temperature must reach 267F (minimum) before the sleeve will begin to shrink.  This could certainly be done in an oven or some other situation - but what we see most is the heating taking place with a propane torch (propane torch with a broad bushy flame). 

     Most of the time, we see our shrink sleeves installed on a steel pipeline, overlapping onto some form of a factory applied corrosion coating (FBE / Powercrete / TLPE / etc).  In those cases, that installation temperature is not a big deal.  Most of those coatings (FBE and TLPE at least) are often seeing temperaturese greater to or equal to that during the original application time.  In some cases though, there are cases where someone wants to install a shrink sleeve on something else - perhaps a PE line; or some sort of flexible composite material. 

     In cases like that, it is always critical to speak to the manufacturer of your non-steel pipeline to find out what temperature range those materials are able to withstand without sacrificing their integrity or performance.  I couldn't possibly be an expert in every type of specialty tubing, so please rely on the folks you purchased the pipe from to determine what is acceptable if you're using something significantly different than standard steel pipeline tubing. 

Monday, April 3, 2017

WPCT Rated to 149F

WPCT Shrink Sleeves Temperature Rating

      WPCT is the most commonly used heat shrinkable sleeve in the United States.  It can be used on just about any pipeline outside diameter from 2" up through 144+".  Available in a number of product widths, WPCT can be purchased in 11", 17", 24" and 34" wide sleeve -- or just about any custom product width.  Fully compatible with all commonly applied factory coatings (including PP), WPCT is sort of the 'jack of all trades' of shrink sleeves and pipeline coatings.

     WPCT can be used on pipelines operating at temperatures as high as 149F (65C).  This makes it an excellent, low cost option as a pipeline coating on pipelines that will operate at moderately high temperatures.  In addition, WPCT is fully UV resistant and can be used above ground. 

     In order to determine what product width is required, you must know what the factory applied coating cutbacks are.  The shrink sleeve must be wide enough to coat all bare steel, and overlap onto the adjacent factory applied coating by at least 3" per side (some end users allow a 2" overlap in their specifications). 

     Shipped to the field with their closure strip pre-attached; WPCT is a simple installation that requires no special training, no special expensive tools and a minimal amount of supervision.  All that is needed is a method to clean the pipe, a propane torch and tank and a silicon roller to achieve a proper installation. 

Tuesday, October 25, 2016

TWDB Thermofit Cut Lengths

Cut Lengths for TWDB Thermofit Wraparound Duct Bands

     Ok, everything I will share here is printed on the actual TWDB boxes themselves (whether 3" wide or 4" wide).  No need to take notes.  When your TWDB arrives you will have all of this data and info right at your fingertips (literally).

TWDB Installation Instructions:
Materials and Equipment required:
- High temperature closure tape (included in the TWDB package)
- JS2601 torch or equal
- Propane tank
- Heat resistant work gloves

1: Join duct sections using internal couplers or crimped end male female type connection.  Apply sheet metal screws.  2 screws 180 degrees apart are usually sufficient.
2: Wipe joint area to remove foreign materials.  Preheat joint to remove moisture and burn off surface oil that may be present.
3: Cut TWDB to appropriate length (see sizing chart).  Center TWDB and wrap around duct joint.  Using the supplied closure tape, secure the loose TWDB end by taping in place across the width of the overlap.
4: Adjust torch to provide soft billowy flame.  Heat TWDB uniformly.  As heat is applied, the TWDB will chrink and bond to the duct to form a pressure tight seal.
5: With gloved hand pat down overlap area to ensure proper adhesion.
6: Recovering is complete when the TWDB is in 360 degree contact with duct and the molten adhesive is visible at both ends. 

The following chart is organized:  Duct Size / TWDB Cut Length
2" / 9"
3"/ 12"
4"/ 15"
5"/ 18"
6"/ 21"
7"/ 24"
8"/ 28"
9"/ 31"
10"/ 34"
11"/ 37"
12"/ 40"
14"/ 46"
16"/ 53"
18"/ 59"
20"/ 65"
22"/ 72"
24"/ 78"
26"/ 84"
28"/ 90"
30"/ 97"
32"/ 103"
34"/ 109"
36"/ 115"
38"/ 122"
40"/ 128"
42"/ 134"
44"/ 141"
46"/ 147"
48"/ 153"
50"/ 160"
52"/ 166"
54"/ 172"
56"/ 178"
58"/ 185"
60"/ 191"
62"/ 197"
64"/ 204"