After crimping an un-insluated wire terminal onto a wire, you’ll need to apply heat shrink over the terminal barrel for a bit of added electrical protection and strain relief, and that is exactly what we are going to cover here in lesson #4 of this Wire Terminals playlist. My name is Nate, and welcome to the EXPLORIST.life Mobile, Marine, and Off-Grid Electrical Academy.
Let’s get started.
Heat Shrink 101 VIDEO
Choosing the Right Heat Shrink
My favorite heat shrink, and therefore the heat shrink we include in all of our kits at shop.explorist.life, is 3:1, dual wall heat shrink; but what does that mean?
3:1 just tells us how much the heat shrink will shrink when heated. For example: If a piece of 3:1 heat shrink was 3 inches in diameter before heating; it could be as small as one-inch afterwards.
The ‘Dual Wall’ feature of our heat shrink is also known as ‘adhesive lined’ heat shrink. The outer ‘wall’ is the actual heat shrink. The inner ‘wall’ is a tube of adhesive that will melt and activate at a temperature just slightly less than the ‘shrinking’ temperature of the outer wall.
This glue adds a tiny bit of strain relief to the connection, but also makes the connection water-tight which may help with corrosion over time.
What Size of Heat Shrink is Best?
For the diameter of the heat shrink, you just have to make sure that the heat shrink will fit over the terminal you are using and that it’s also not so big that it will still shrink down enough to seal up the connection. Here is a graph of the 3:1 heat shrink sizes that we find the best for various sizes of wire and that we include in our kits:
How to Use Heat Shrink:
I have a wire lug crimped onto this wire; and don’t worry… we will be covering how to crimp terminals; but I wanted to cover heat shrink first…because all of those upcoming tutorials use it.
Using heat shrink is pretty simple:
- Put the heat shrink over the terminal
- Position it so it doesn’t interfere with the electrical connection.
- Use a heat gun to shrink the heat shrink.
- Rotate the wire so that the heat shrink is heated evenly and doesn’t burn or split.
- You’re finished when the tubing is tight and there is adhesive squeezed out of the ends.
Can I use an open flame for Heat Shrink?
A lot of people like to use an open flame for heat shrink… and an open flame will most definitely shrink heat shrink and melt the adhesive. But in my experience, it’s really easy to burn or split the heat shrink when using an open flame, so be careful. It also leaves some soot on the heat shrink which doesn’t look very nice.
If I’m building one of these systems without access to power, I’ll use a battery-powered heat gun rather than an open flame. It’s not quite as powerful and hot as a version that plugs into the wall, so it’s not quite as fast, but I still think it’s a better option than fire.
