Cable penetrations through composite

[KeithB]

I have a lot of cable penetrations through the 15mm composite walls and floor on my build. I have special fittings to get the cables from the solar panels through the roof, but there are  alot of others, particularly through the floor.

The bulkhead cable fittings I have seen are designed for a solid surface and are a bit of a pain on a composite with just 1mm outset skins that won't take a screw.
So I am thinking of simply roughening up the cables or pipes concerned to give adhesion and them pumping Sikaflex in and around the hole.  Once it's gone off a bit, I'll add more Sikaflex either site to form a bit of a mound around the cable. As the Sika goes off it can be pressed into shape with a finger wetted with a bit of soapy water. There are no plans to undo this and pull the cable out once it's in.

Can anyone see any horrible downsides with this method?

Keith

[loanrangie]

Personally i hate doing something that is difficult to undo, if you are happy with what you plan to do then go for it.

[MrCruza]

Why not use a cable gland? No screws required. Can get them just about anywhere.

Cable Gland

[GBC]

Definitely a cable gland job. What you are proposing is literally their only purpose for being.

You need to know your cable diameter and purchase the relevant gland.

https://www.bunnings.com.au/epa-20mm-nylon-cable-gland_p4420403

[Johnnos3003]

I would be doing exactly what you purpose KeithB.

Not sure I would use Sikaflex, or at least a low grade that can be removed a bit easier than the stuff you would glue panels on with.

if the composite is 15mm trying use use glands would be a nightmare I recon.

[edz]

Piece of heater hose trimmed to poke out 5 or 10mm eiher side of the wall / bulkhead, sikaflexed in and  then a bit of silicone to seal inside gaps in between the wires / tubing that run through it

[Hoyks]

yes, composite with honeycomb or foam core doesn't like being crushed, so cable glands may work lose over time.

To prevent the core getting crushed you can use a potting compound so it has something solid to bare against. Drill the hole you want, strip the core out between the skins and then pack the gap with something hard like automotive bog and let it harden. You can either re-drill the hole, or shove the gland through and let it all harden up together.
Once its all set the fitting can be clamped down, it will seat against the skin and the core around the bearing surface is in-compressible.

Or just goop it in with polyurethane.

[gronk]

What is the overall thickness of the panel involved ?

[tryagain]

What is the overall thickness of the panel involved ?

I have a lot of cable penetrations through the 15mm composite

[KeithB]

Routering out and reinforcing the substrate for a cable gland is a heap of work and will still require a sealand to make it  truly watertight. I also worry about a plastic gland copping a rock.
So I will ditch the skiflex at this stage and try using a softer silicone, which can be removed down the track if needs be.
Thank you for the comments and I welcome any additional better or alternative ideas.
Keith

[GBC]

Routering out and reinforcing the substrate for a cable gland is a heap of work and will still require a sealand to make it  truly watertight. I also worry about a plastic gland copping a rock.
So I will ditch the skiflex at this stage and try using a softer silicone, which can be removed down the track if needs be.
Thank you for the comments and I welcome any additional better or alternative ideas.
Keith

My camper has 10 plus cable glands under it. Do not worry about a rock breaking one. They are strong. They have a rubber seals so compression forces don’t need to be strong. Nothing more than finger tight.