Best technique for waterproof solders?

[l008com]

I'm fully rewiring my trailer. New harness, new lights. I have to make a bunch of T connections I'm curious what the best technique is for making them waterproof.

What I've done so far is cut them so there are three wires and twist them together like i'm going to cap them (but don't cap them). Then solder them up, cover in dielectric grease, then heat shrink, flip the end of the shrink over on itself and another little piece of shrink on that.

This sounds like a good plan but all that grease is so slick that the heat shrink, even when fully "shrank", will slide right off.

Are there other, better techniques?

I trailer my boat so every time I use this trailer, it's getting fully dunked underwater twice. So these connections all have to be fully waterproof if they're going to last. In other words, this isn't a twice a year thing where the boat lives at a dock all summer.

 

[bigdee]

Skip the dielectric grease, cover the heat shrink with a thin coat of silicone sealant.

 

[poconojoe]

They make heat shrink tubing that has a sealer already inside of it. This is very good.

If you want, you can coat the outside of the heat shrink with liquid electrical tape. I have done this with great results.
You would probably get the same good results coating it with 100% silicone.

I have also used clear heat shrink that has a band of solder built into the center and a band of sealer on each end. You use a heat gun to melt the solder/tubing/sealer.

 

[mike_i]

First, try to minimize the number of splices. Use butt connectors instead of twisting wires. Slide a piece of heat shrink tubing over the wire. Crimp butt connector then cover with liquid tape and let it dry. Put heat shrink tubing over the butt splice heat it then cover with more liquid tape.

 

[Scott Danforth]

start with a new 100' spool of trailer wiring.

run a line down each frame rail of the trailer.

make your splices at the coupler end if posible. all others non-insulated butt connectors and epoxy lined heat shrink.

 

[dingbat]

Shrink tubing is not a viable option in locations prone to submersion and moisture.

Adhesive lined heat shrink butt connectors are the only way to go if you need a water proof connection.

Crimp, melt and your done.

Ancor Adhesive Lined Heat Shrink Butt Connectors

Seamless construction eliminates splitting. Premium nylon insulator will not crack or split. Highest grade electrolytic copper, tin plated for greatest corrosion resistance and least amount of power loss. UL Listed.

www.iboats.com

​

 

[Scott Danforth]

Shrink tubing is not a viable option in locations prone to submersion and moisture.

Adhesive lined heat shrink butt connectors are the only way to go if you need a water proof connection.

Crimp, melt and your done.

Ancor Adhesive Lined Heat Shrink Butt Connectors

Seamless construction eliminates splitting. Premium nylon insulator will not crack or split. Highest grade electrolytic copper, tin plated for greatest corrosion resistance and least amount of power loss. UL Listed.

www.iboats.com

​

its just a non-insullated butt connector inside of epoxy lined heat shrink

 

[robert graham]

That Liquid Electrical Tape in the little can works great for what you describe..

 

[dingbat]

its just a non-insullated butt connector inside of epoxy lined heat shrink

Key words.....epoxy lined....and a heck of a lot heavier jacketed than the cheap, Harry Homeowner shrink tubing available at the big box stores.

Don't get me started on the liquid electrical tape....lol
40+ years of electronics manufacturing and field support...akin to using JB Weld to repair a cracked cylinder block

 

[Scott Danforth]

Key words.....epoxy lined....and a heck of a lot heavier jacketed than the cheap, Harry Homeowner shrink tubing available at the big box stores.

Don't get me started on the liquid electrical tape....lol
40+ years of electronics manufacturing and field support...akin to using JB Weld to repair a cracked cylinder block

you forgot encapsulating in sillycone

 

[444]

Use either non-insulated butt connectors or twist and solder. Then use a double-wall heat shrink that has the glue already inside it. That stuff is nice once you shrink it down the glue barfs out the sides and seals everything up very nicely. I would do them in-line, not twisting like you're putting a cap on. The heat-shrink tube is not meant to use used without a wire in each end because it only shrinks down so-far.

 

[tdf-texas]

Twisted, soldered, and heat shrinked with sealant connections last the lifetime of the wire.

 

[l008com]

People like to read titles but not posts. This post is about sealing T-splices. Simply throwing heat shrink over them is either not an option, or will not seal it fully, depending on which kind of T splice you do.

So what I ended up doing was removing my heat shrink with the grease under it, which was super easy to do. I cleaned all the grease off. I had 5 "T" splices that I did in the same style I mentioned above, I cut the primary so I had three wires, I twisted them together and soldered. I also had 6 traditional end to end splices...

I did them all the same way and it seemed to work well:
I put two layers of that liquid electrical tape all over the splices.
Then I put heat shrink over all of the splices. On the T's, that means the end of the shrink had nothing coming out of it.
Then I put one final layer of liquid electrical tape all over the heat shrink, with extra focus on the ends of all of the heat shrink.

Between that and the sheer mass of the soldering joints, this should last somewhere between 15 years, and forever It will most likely outlive these harbor freight LED tail lights anyway.

My favorite part of this whole job is that theres a full ground wire, no grounding to body. Every light is properly grounded. I'm going to hook up the trailer, plug in the lights, and the lights are going to work. Every time. Year after year.

 

[tdf-texas]

People like to read titles but not posts. This post is about sealing T-splices. Simply throwing heat shrink over them is either not an option, or will not seal it fully, depending on which kind of T splice you do.

So what I ended up doing was removing my heat shrink with the grease under it, which was super easy to do. I cleaned all the grease off. I had 5 "T" splices that I did in the same style I mentioned above, I cut the primary so I had three wires, I twisted them together and soldered. I also had 6 traditional end to end splices...

I did them all the same way and it seemed to work well:
I put two layers of that liquid electrical tape all over the splices.
Then I put heat shrink over all of the splices. On the T's, that means the end of the shrink had nothing coming out of it.
Then I put one final layer of liquid electrical tape all over the heat shrink, with extra focus on the ends of all of the heat shrink.

Between that and the sheer mass of the soldering joints, this should last somewhere between 15 years, and forever It will most likely outlive these harbor freight LED tail lights anyway.

My favorite part of this whole job is that theres a full ground wire, no grounding to body. Every light is properly grounded. I'm going to hook up the trailer, plug in the lights, and the lights are going to work. Every time. Year after year.

Sorry if you misunderstood the post. I do "T" splices on a regular basis as shown in the video - one wire on one side and two on the other. The wires are twisted together, soldered, then covered with a sealed heat shrink. You don't have to make the splice look like a "T", just have the three wires connected together in line such that the heat shrink will cover the entire splice.

 

[poconojoe]

Sorry if you misunderstood the post. I do "T" splices on a regular basis as shown in the video - one wire on one side and two on the other. The wires are twisted together, soldered, then covered with a sealed heat shrink. You don't have to make the splice look like a "T", just have the three wires connected together in line such that the heat shrink will cover the entire splice.

Yep, two on one side of the heat shrink, one coming out the other side.
With the higher quality heat shrink which has the incorporated adhesive, it should seal fine. If you are paranoid, cover the ends with liquid electrical tape or silicone.
I think this is better than having all three on one side.

 

[dingbat]

Twisted, soldered, and heat shrinked with sealant connections last the lifetime of the wire.

Typical Goggle U "quality" instructions....lets seal the connection without cleaning the acid (flux) from the wires.......big no, no. Immediate failure of soldering test administered prior to hire.

 

[mike_i]

They probably assume that one knows you don't use acid flux on this type of job, save that for metal radiators. Also It's easier to use resin core solder then you don't have to worry about applying the flux.

Typical Goggle U "quality" instructions....lets seal the connection without cleaning the acid (flux) from the wires.......big no, no. Immediate failure of soldering test administered prior to hire.

 

[dingbat]

Also It's easier to use resin core solder then you don't have to worry about applying the flux.

Rosin, Resin = Soldering Flux.........just a milder version.

Rosin leaves a residue on the board (clearly visible in video) that can contaminate manufacturing equipment which is the main motivator to cleaning flux from circuit boards but.....rosin residues can also lead to failures in harsh environments. Been there, done that.

Don't get me started on cold solder joints...lol

 

[mike_i]

I meant rosin core, thanks spell check.

Rosin, Resin = Soldering Flux.........just a milder version.

Rosin leaves a residue on the board (clearly visible in video) that can contaminate manufacturing equipment which is the main motivator to cleaning flux from circuit boards but.....rosin residues can also lead to failures in harsh environments. Been there, done that.

Don't get me started on cold solder joints...lol