Potting Electrical Components

I have had trouble getting SCL to shrink down tightly enough onto the DR25 sheathed cable when potting sensors.

For instance I potted a knock sensor (the cable was 2 core shielded + DR25)

The SCL shrank nice and tight onto the body of the receptacle but did not shrink completely back to the cable.

This has lead me to worry about the SCL on other sensors with a large receptacle to cable ratio.

My coil packs for example have a large receptacle so will require a large diameter piece of SCL the cable by contrast is quite narrow as such I am concerned I will not get a nice snug fit when the SCL is fully recovered.

Attached is image of the problem knock sensor where SCL did not recover enough. I ended up trying to add some SCL to increase the diameter of the cable

Also attached are potted sensors awaiting SCL that I am concerned about the shrink ratio with - wanted to check with people before I pressed forward.

I appreciate any comments / advice.

Hi Tony,

Sometimes you need to add a couple of steps of SCL or similar to the base wire so that the final layer from the sensor to the wire seals correctly. Another option is to get a smaller diameter piece of SCL and stretch it to fit over the sensor and then recover it.

You can buy heat shrink boots, such as sold here - https://www.digikey.co.nz/en/products/filter/heat-shrink-boots-caps/499?gad=1&gclid=CjwKCAjw_aemBhBLEiwAT98FMrn34qWmC6jVl9TaqlfvLfkPurFe1MTxvYKdWRje6_eSahTKoM04PBoCYIMQAvD_BwE&s=N4IgTCBcDaIBYFMCGAXABAZzgJwJYDsBrEAXQF8g&utm_adgroup=General&utm_campaign=EN_Product_Heat%20Shrinks&utm_medium=cpc&utm_source=google&utm_term=heat%20shrink%20tubing%20electrical - but they can be freaking expensive!

I'm also wondering this, if you're adding let's say a few "steps" of SCL... Won't it look abit odd?