Solar panel adhesive

[Trainop]

Hi, I put this topic in the new members forum by mistake, doh, but in short does anybody know if it's OK to use unibond extreme repair sealant to seal a solar panel cable cowl onto my caravan roof, thanks.

 

[Parksy]

I moved your query to the Technical message board to attract more replies
The bonding agent for your cable cowl needs to be flexible and waterproof. Click Here for some info from a similar topic, I used the same bonding that fastened my solar panel bracket to my caravan roof.

 

[Trainop]

Thanks Parksy,, appreciate it

 

[Trainop]

Also I read on another forum that polyurethane should be used,, and not silicone, why not, and would silicone damage the paintwork or something?

 

[JTQ]

Also I read on another forum that polyurethane should be used,, and not silicone, why not, and would silicone damage the paintwork or something?

"Why not", basically because it will not IMO do anything like as good job of it, however it is paramount with either that the surfaces are really clean. The bond with polyurethane base sealants will have a very much higher tear off resistance than silicone based products. So strong that it will require cutting to get free, whereas the silicone will probably peel in service letting the damp in.

 

[Trainop]

Thanks JTQ,, I may have not explained it clear enough,,, I recently had a solar panel fitted which has been stuck with sikafix, also the cable cowl,, but I had rain entering the van down the hole. I assume the plastic nuts were either not tight enough or the rain was leaking between the cowl and the roof, so I put silicone Sealant around the base edge and over the nuts and cable where it enters the cowl, it's stopped the leak, but I wondered if the silicone on the van roof might harm it.

 

[JTQ]

IMO the silicone will not harm the paint, it releases the vinegar acid as it cures but that is well over by now.
However it is IMO likely to fail some time in the future; you have identified where the leak is, I would get rid of the silicone and use a PU sealant if I wanted a permanent seal..

 

[Trainop]

Mmmm, could be a job getting the silicone off without scratching the roof, I might have to keep my eye on it, and as it starts to peel, I'll put some pu on

 

[Damian]

You cannot apply a polyurethane sealer on top of a silicone sealer(or the other way around), it simply will not stick .
There are several specific sealants /adhesives for use on caravans, Sikaflex, Soudall Fixall to name two.
The likes of B&Q silicone are a waste of time and money , they are just not up to the job required on caravans.

Removal of PU or Silicone from a caravan is best done with a Plastic Scraper followed by a thorough clean of the area to be resealed with white spirit and a final prep with Meths.

 

[Trainop]

Thanks Damian