Which product for sealing cable holes through rubber grommets?

[gregmacc Junior Member Find all posts View Profile Close gregmacc]

I'm running battery charging cables to the rear jack storage area. I need to cut a slot in an existing rubber grommet. What's the best product to seal around the cables? I'm pretty sure normal silicone won't be successful long term.

[LeighW Avid PP Poster! Find all posts View Profile Close LeighW]

Make small hole pull cable through to correct length and then for example
pull a bit more through, say 30mm, apply neutral cure silicon to the 30mm of cable
and pull back through the grommet, as you pull the cable back the silicon will form a
nice donut seal.

[gregmacc Junior Member Find all posts View Profile Close gregmacc]

Thanks LeighW ... Any specific examples of "neutral cure silicon"? ... Would that necessarily be printed on the tube?

[gregmacc Junior Member Find all posts View Profile Close gregmacc]

Oops ... Just looked at my Selleys stuff ... It's neutral cure ... whatever that means

[gregmacc Junior Member Find all posts View Profile Close gregmacc]

What's the black stuff you see under caravans that gets used wherever the floor is holed for passing pipes etc.? Sets too hard maybe for grommets?

[Rob L Junior Member Find all posts View Profile Close Rob L]

Melt hole through with a small soldering iron. Gives a nice round hole with reinforced ring around it. Then seal as suggested by LeighW. Will prevent tearing along a cut.

[LeighW Avid PP Poster! Find all posts View Profile Close LeighW]

Plumbing silicon for doing colorbond, metal etc, will be written on tube.

[humungusmon Junior Member Find all posts View Profile Close humungusmon]

Sikaflex is the go. It goes off like normal silicone. It's the stuff that holds the plastic dust sheeting on under your door skin. Panel beaters use it all the time. You can get it in a cartridge from bearing / bolt suppliers or car paint joints. Leigh W , my booster diode is a beauty and still going strong! Cheers Chris.

[gregmacc Junior Member Find all posts View Profile Close gregmacc]

Thanks Rob and humungusmon ... tuns out laying on my back and attempting to get any sort of sealant up and into that dark and dingy cave where the grommet lives was going to be a real PITA ... I ended up cutting a small slit and poking through the main 12V cables (16mm double insulated twin), some sensing cables for future solar changeover input into the Redarc BCDC, and a chassis earth cable. Were it not for the slender, petit fingers of my lady working away on retrieving said cables from inside that cable infested cavern of a jack compartment, we may have needed to rely on an ice box to keep the beer cool. The grommet is one of those that sort of hangs down like a cows tit (for want of a more sophisticated description) so I just cable tied the bunch of cables together and wrapped a seriously large wad of insulation tape around the whole shamozzle ... I'll keep a close eye out for any grommet splitting and/or dust/moisture ingress and respond accordingly.
Thanks again for all the helpful advice.

[RanJ Avid PP Poster! Find all posts View Profile Close RanJ]

I tend to steer clear of Sikaflex for sealing up holes in grommets. Sometimes I need to be able to remove the silicone to gain access again. With Sikaflex... its just so much harder lol. That stuff is amazing! two years ago i glued down two 80w solar panels to the roof of a van with that stuff Using the mount corners so there is a 3" gap between the panels and the roof. While dubious at first I thought the panels would almost act as a wing and try to lift off. ... 150000 kms later and sustained speed in excess of 100kmh and they've shown no signs of moving apparently. Mind you... each corner of the panels has half a tube under it!