Hot Melt Adhesive as an Electrical Insulator

Bertramdriver

Bertramdriver

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Just been talking to a German guy working on his boat in the boatyard. He claims to be an aeronautical engineer but I can't confirm that. We were discussing the pros and cons of various types of electrical connections including chocolate boxes and screw fix end terminations. He claims that anytime a screw is used in securing a wire he coats the join with high temp hot melt adhesive to provide extra strength and corrosion resistance. It seems odd but for the life of me I can't find any reason not to try it. Any thoughts?
 
Bertramdriver said:
Just been talking to a German guy working on his boat in the boatyard. He claims to be an aeronautical engineer but I can't confirm that. We were discussing the pros and cons of various types of electrical connections including chocolate boxes and screw fix end terminations. He claims that anytime a screw is used in securing a wire he coats the join with high temp hot melt adhesive to provide extra strength and corrosion resistance. It seems odd but for the life of me I can't find any reason not to try it. Any thoughts?
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Sounds like a good idea provided the glue is added after the connection has been made. I'm sure it will be a good insulator.

Richard
 
If it re-melts at the same temperature it will be the weak point in a fire, If it does not re-melt then the join is un mintainable or changeable.
Corosion should be addressed by suitable materials and strength should not be an issue with properly made connections.
 
To stop corrosion I used put Vaseline on electrical terminals it worked well. I'm not sure why you would need extra strength unless a wire connection was under tension which it shouldn't be.
 
For the occasions that a properly made termination using appropriate hardware warrants extra protection I like liquid neoprene, normally decent insulation boots or sleeves / heat shrink and the aforementioned correct materials / workmanship will suffice quite nicely. If he's an aerospace tech I'm surprised he was even prepared to discuss choc blocks.
 
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David2452 said:
For the occasions that a properly made termination using appropriate hardware warrants extra protection I like liquid neoprene, normally decent insulation boots or sleeves / heat shrink and the aforementioned correct materials / workmanship will suffice quite nicely. If he's an aerospace tech I'm surprised he was even prepared to discuss choc blocks.
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Choc blocks on any boat are non starters as far as I'm concerned.
 
Hot melt adhesives are used extensively in electrical manufacture notably for stabilising large components on circuit boards. It's obviously an insulator and will seal against moisture, its use on boats will be limited by the fact that removal and access will be difficult. I have used a glue gun to tack wiring into place.
 
there's a problem that such adhesives are not generically consistent in their properties.

Some, for example, are acceptable to the food industry, some are not. Others are stretchy, some are rigid.

Dielectric values vary, ranging from >1300 V/mil (http://www.ellsworthadhesives.co.uk/loctite-1x-hysol-hot-melt-adhesive-83358-40lb-carton.html) to ≥ 25 kV/mm (http://www.sesp.de/en/search/Dual Wall Polyolefin.html)

Unless, therefore you have the tech specification, it would be unwise to assume that the adhesive is safe to use when overlying a material passing an electric current.



EDIT Found it. Hot melt adhesive which is designed to be electrically conducting. :)

http://www.sciencedirect.com/science/article/pii/S0379677999000612
 
Dougal Tolan said:
If it re-melts at the same temperature it will be the weak point in a fire, If it does not re-melt then the join is un mintainable or changeable.
Corosion should be addressed by suitable materials and strength should not be an issue with properly made connections.
Click to expand...

FYI once hot glue gun glue has melted it goes through a chemical process meaning it will not melt at that same point again (I looked it up when I was using hot glue to secure a jig in place when making up my Corian worktop and was concerned about getting the jig back off!)
 
BERT T said:
Choc blocks on any boat are non starters as far as I'm concerned.
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I have used some choc blocks in dry bridgedeck areas where they can be easily checked and for non-critical applications.

Not the very best technical solution but easy to use without soldering and my cat has dusty bilges.

I don't wrap them with PVC tape as that makes them harder to check by eye. I've never had to change any corrosion.

After all, the boat builders master control connections are like a giant choc block behind the switch panel so they can't be that bad.

Of course, some may disagree but when you've done something for 40 years without a problem you can probably infer that it's reasonably sound! :)

Richard
 
Most sailors are familiar with the rusty blobs and disintegrating screws that have got choc blocs a bad name but occasionally it's convenient and expedient to use them if made from suitable materials. I usually use them dry but often use Vaseline against corrosion. I wouldn't use any sort of glue as it would make them un dismantleable.
 
sarabande said:
there's a problem that such adhesives are not generically consistent in their properties.

Some, for example, are acceptable to the food industry, some are not. Others are stretchy, some are rigid.

Dielectric values vary, ranging from >1300 V/mil (http://www.ellsworthadhesives.co.uk/loctite-1x-hysol-hot-melt-adhesive-83358-40lb-carton.html) to ≥ 25 kV/mm (http://www.sesp.de/en/search/Dual Wall Polyolefin.html)

Unless, therefore you have the tech specification, it would be unwise to assume that the adhesive is safe to use when overlying a material passing an electric current.



EDIT Found it. Hot melt adhesive which is designed to be electrically conducting. :)

http://www.sciencedirect.com/science/article/pii/S0379677999000612
Click to expand...

Yes, we use some conductive hot melt glue.
But it's rare and expensive stuff, you are unlikely to come across it by accident. For that matter, I also have conductive epoxy to hand.

Hot melt covers a wide range of products. Most of it is perfectly Ok as an insulator at low voltages, I'd take care if you need ultra-low leakage or voltages above say 50V.
Securing wires against vibration is possibly the second biggest improvement you can make to reliability, after keeping the metal bits dry.
I've used hot melt on a few bikes to seal the backs of connectors, I prefer it to Vaseline as that collects dirt.
Some hot melt can be re-melted without too much problem, some is more permanent.
 
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