grease wire to wire shrink tube splice?

[coppercone2]

If you make a wire splice by fusing two wires inline, do you put dielectric grease on the joint before heat shrinking it?

It's something new I saw and I wonder if one should bother. Does the heat shrink still work properly?

[floobydust]

I think it's more of a psychological pacifier, seen it done for extra protection against oxidation. It doesn't always work, if the silicone grease can get washed out.
Some heatshrink needs around 260°C which I think melts the grease and it dribbles out. It's just messy.

I prefer to use thick-walled heatshrink which has hot glue inside. That seals up against water too.
It all depends on what you are sealing against- temperature, pressure, abrasion etc.

[coppercone2]

yea the idea I think is for moisture resistance but do you get any significant ingress into a solder joint through a heat shrink and does the grease react with the sleeve material since its not really ideal? I thought it might cause it to decay by diffusion or something.

With crimp to crimp or butt splice crimp I understand because the tension varies with temperature cycles and it walks mechanically so you can imagine oxide creep in, since it will expand and show a bit of exposed skin, oxidize, then it won't be able to contract as well and then it might abrade and re oxidize and so on but I don't think the process is similar for solder joints.

How long does the grease last? Can't it act like a sponge to absorb hydrocarbons which make the plastic vulnerable?
I know some hot glues can absorb moisture and it begs the question, are the electronics grade hot glues/premade glue filled heat shrinks totally different or just better the normal hot glue?

To this point I have been using regular heatshrink twice over for that kind of joint. For commercial joints I used the solder thats built into heat shrink you attach with a hot air gun for speed (no glue in this).

Can the grease or phase change glue (or is it just viscosity change) actually make a connection worse over a LONG time scale?

Electronics grade silicones are different I think because they chemically cure to a tighter molecular structure (I think?)

Say you are using teflon wire.