Real Copper !
OK, So I've ruined a few connectors for the sake of illustration, but, I did this to show what you should find beneath that tinned surface. I simply ground away the tinned coating to reveal the solid copper.
Harbor Freight Heat Shrink Crimp Terminals
I found these on a customers boat then pulled an FTZ heat shrink terminal out of my assortment bin and handed it too him. He took the HFT terminals and tossed this entire box into the trash.
Of course doing what I do for a living, I grabbed them out of the trash to use in this article. Cheap almost always comes at a price.
Harbor Freight Top - FTZ Crimp 'N Seal Bottom
No I am not kidding..... Are they really saving that much money by shorting you on a few tenths of an ounce of copper..? Compare the metal of butt splices in terms of length. Heck the jaws on my high quality Pro-HST tool are wider than the area Harbor Freight has left you to crimp to.
I Removed the Insullation
A few things things I noticed right away:
#1 The insulation on the HFT terminal came right off and really had little to no adhesive properties.
#2 The FTZ Crimp 'N Seal terminal fought me the entire way of removing the insulation.
#3 The FTZ terminal was more robust.
#4 The OD and ID of these terminals are not the same either.
HFT OD = 5.36mm
FTZ OD = 5.52mm
HFT ID = 3.69mm
FTZ ID = 3.38mm
Making A Heat Shrink Termination
This picture illustrates a crimped then heat sealed butt splice crimp. Read on to see how this was done.
First Make The Cut
This is fairly self explanatory. My only suggestion here is to use decent wire cutters similar to the ones pictured. In this photo I've chosen a pair of Klein High-Leverage Cable Cutter's Part No. 63050. They cost about $20.00 at Home Depot & Chanel-Lock also makes a set that are slightly less money but they do a rather sloppy cut in comparison to the Klein. The right tool, for the right job, is always well worth the expense.
Using a set of Diagonal Cut Pliers or "Dykes" as they are normally called will not make as clean or as nice a cut as a good set of cable cutters will and will not work very well at all as the wire gauge gets bigger. I can cut up to 2/0 battery cable with these Klein cutters.
Examining The Cut
As you can see the Klein High Leverage Cutters make a beautiful cut. A good clean cut is one that will strip well and then slide into the terminal with no "stray" wires..
Strip the Wire
For stripping the wire I use the Ideal Stripmaster Part No. 45-092. There are many strippers that will work, and also that sell for less money, but the most important thing to consider is how carefully you strip with them.
It's somewhat important that you do not nick the wire or remove any strands when stripping. The blue Klein crimper/strippers I showed earlier are also a decent DIY quality stripper, but not as easy to use. They are also not as easy to get a consistent strip with without damaging some of the strands.
The Ideal Stripmaster 45-092 is one of the most reliable tools I own. I own a few of them and one of them I've owned since the early 90's. That tool has literally made thousands and thousands of strips and I can't tell which one is twenty years old and which one is 5 years old. Keep it oiled/lubed and clean, easier said than done working on boats, and they will perform well for decades.
When using the Ideal Stripmaster please be aware of the AWG and SAE markings on the stripping dies. If using AWG wire, as we should on boats, be sure to use the AWG slot for the wire gauge you're using and not the SAE slot.
Which ever stripper you use, always examine the wire after the strip to check for strand damage. If the wire will carry any sort of high load you'll want a good clean strip with all strands intact..
With the Ideal Stripmaster all you do is set the wire you your desired strip depth, usually about 5/16 of an inch, and squeeze. They make beautiful and repeatable strips every time.
Checking The Strip Length
When using butt splices compare the strip length to the terminals depth. Most quality butt splices will have a stop or detent to denote the insert depth. If you look closely at this image you'll notice the center dimple on this butt connector. The wire should go as deep as the center dimple.
A Dry Fit To Confirm Strip Depth
Insert the stripped wire for a dry fit test. As you can see the red of the wire jacket butts right up next to the metal of the butt connector. This wire has been stripped to a satisfactory depth.
Making The Crimp
To make the crimp insert the terminal, centering the jaws over the barrel, and then tighten down slightly to about the first ratchet click. This will hold the terminal in place so you can then insert your wire. Once the wire is in, and properly seated, continue squeezing until the ratchet mechanism on the crimper releases. The ratchet mechanism of this crimp tool will not release until the crimp has been properly executed.