Heat Shrink melted wiring together - please avoid my mistake

[Prophammer]

I was replacing taillights on the boat trailer, wiring was standard trailer wiring : yellow , green , brown all cased together , I cut the old butt connectors off and crimped on 2 new heat shrink butt connectors on the yellow and on the brown (ground was provided by a jumper wired to mounting stud of lamp assembly) I heat shrinked the new butt connectors, taped up and shoved it back into trailer tube frame. All was fine. We went weeks or months with no problem - - - all lights working, Then on vacation I backed into a pole on my right side, I mashed right tail light and bracket flat as a fritter, so I went to Walmart and bought a new light and borrowed a hammer to hammer the bracket halfway straight again, Installed new light , once again using heat shrink butt connectors, new light wouldn't operate properly , If I remember right , both taillights would flash when only left turn signal was supposed to, right running light was dim but would flash normally with t/s , to make a long story longer , I found out way back months ago when I heat shrunk R. hand tail light wiring, yellow and brown in the in-cased yellow,green,brown casing were melted together inside the casing, Way back then when I was heat shrinking, I got it too hot and the heat traveled up the wire and melted them, so now I hope someone can learn from my mistake, when using heat shrink be careful to not overheat adjacent wiring and keep hot butt connectors still, let them cool before proceeding to next step, I don't know why it took months of use and abuse before it shorted out , but electricity is tricky sometimes.

 

[dingbat]

What did you use for a heat source?

Quality PVC heat shrink and wire have very different melt temps.

 

[Prophammer]

hate to admit , it was map gas , gotta be careful with that stuff in the future

 

[Grub54891]

I use a micro torch myself, but very carefully.

 

[GA_Boater]

A Bic works great and has built in heat indicator. It gets too hot holding the valve thingie down and burns your thumb.

 

[Prophammer]

fireplace lighter is my first choice but it does't do well on windy days, I had a micro torch for soldering but I don't know what I did with it, but that sounds like a good idea

 

[achris]

:facepalm:

Anything that produces a flame is an absolute no-no! It's called 'heat shrink', not 'flame-shrink'...

The only thing anybody should be using to shrink this stuff is one of these.....



Chris.......

Mapp gas. What were you thinking? :facepalm:

 

[Grub54891]

I use the heat gun when ever possible. Sometimes when working in a boat there is no way to get in them tight spots, or there is no power to run the darn thing.

 

[dingbat]

hate to admit , it was map gas , gotta be careful with that stuff in the future

Working in the electronics industry, I have a commercial heat gun but often use my butane micro torch working on the boat.

A couple of tricks....
No flame in contact with material whatsoever.

Use a quality heat shrink material of the proper size (ID) and material.

Using the proper id is important. Too small the material may tear during install. To large and the tube doesn’t seal or you over heat it trying to get it to shrink small enough to seal

Good info on selecting and using heat shrink tubing

https://www.digikey.com/en/articles/techzone/2018/jan/selecting-the-appropriate-heat-shrink-tubing

 

[Scott Danforth]

hate to admit , it was map gas , gotta be careful with that stuff in the future

MAP gas torch on heat shrink is like trying to drive a nail with a 200# wrecking ball

small heat gun is all that is needed.

 

[AShipShow]

MAP gas torch on heat shrink is like trying to drive a nail with a 200# wrecking ball

LOL, good analogy.

I work for the company that invented heat shrink and we don't have any application specs that call out a mapp gas torch haha. Most heat shrink will begin to recover at about 135°C(275°F) except the highly flame retardant stuff which is about 220°C. Either one of those is actually warm enough to soften a PVC wire insulation but not going to be an issue... direct flame is just a no-no. If you have to use butane or something like that, just take your time it keep it at a reasonable distance.

 

[Prophammer]

Thank you for all the responses , I've decided to buy a heat gun , I found Dewalt makes a 20v heat gun (532 degrees C) it will be just as mobile as anything, I've been using Bic lighters , fireplace lighters and Mapp gas too many years , awesome forum, gives me great ideas, thanks again

 

[Prophammer]

I got a heat gun now, but I might still need map gas to melt the ends of my ropes

 

[Lou C]

I imagine some may disagree but what I have done with sucess is use good quality marine crimp on terminals and then coat all the crimps with 2 coats of liquid electric tape. I usually go over them at the beginning of each season and re coat any connection that looks questionable. I installed a good set of LEDs about 5 years ago and have not had to re do any of the connections since. Liquid electric tape is a bit messy but way safer than torches lol!

 

[JASinIL2006]

I like liquid tape, too, but using it slows down a project quite a bit. I've been using it in a few places as I work on my trailer wiring and having to wait while cures is a bit of a pain.

 

[bruceb58]

I use the heat shrink crimp connectors. No need for any liquid tape.

 

[Grub54891]

I use the heat shrink crimp connectors. No need for any liquid tape.

Me to. Never a problem.

 

[Lou C]

gents, there is more than one way to solve a problem.

 

[Prophammer]

liquid tape is a good reminder, I have used it before, but my little can of it dried up and I kind of forgot about it in a couple years, but now that Lou C and JASinIL2006 mentioned it , it inspires me to get under the dash and coat some of the connections before they corrode, at least on my saltwater boat, thanks for bringing that up !

 

[gm280]

I hear that if you add in some oxygen with the Mapp gas, it shrinks a lot quicker......not the heat shrink but the entire project... lol

I always, even if I have to go get an extension cord, use a heat gun. It shrinks all heat-shrink tube perfectly and correctly. Just my OCD kicking in there!