7 replies to this topic

[camper101]

I know Silaprene is supposed to be a good sealant, but how good is it as an adhesive?

 

I'd like to stick one of these on my roof and I've got a brand new tube of Silaprene. Will it hold up to years of road vibration, snow/ice, and the occasional tree branch?

 

I realize others like Sikaflex can do the job, but I'd prefer to do it all with what I already have (assuming it works).

 

FYI I'll probably use lots of butyl tape and sealant around the hole in the roof, but the product above is mainly to keep the wires flat and low (for a solar installation). I've decided I don't want the wires coming straight up through the roof through a cable gland - I'd have to give them a sharp bend which I'm not comfortable about.

 

Thank you.

 

Edited to say: OK, forget the part about the tree branch - that's my problem, not the adhesive's...

As a comparison to Sikaflex, I assume I'd use something in the 221 or 252 (?) range. I don't know that I want anything completely bombproof up there. And I also prefer not to deal with primer, etc.

Edited by camper101, 03 September 2014 - 07:39 PM.

[Lighthawk]

You have a good idea:  keep those solar wires flat and low!

 

Whether silaprene will hold up long term?  Who knows    I used up a tube doing various repairs, including a hole in my roof!  Impressive stuff.  I even caulked my kayak bulkhead with it (no leaks!).

 

I would prefer to see a mechanical anchor,  i.e. a screw rather than depend upon spooging a bunch of high tech caulk and hoping to stick the unit.  

 

My solar install did come through the roof directly, but I sleeved the wires and sent them under the panel with less than six inches of exposure to errant branches and the like.  

 

I'm not familiar with Sikaflex.  Sounds like a stain product (Sikkens)  that was removed from CA market after CARB regs.  Another point to consider:  you are likely sticking to the paint job on aluminum roof panel.  Again, I would use a few screws plus high quality caulking.  

 

Does your unit allow for the wiring to pull through, or is it a junction box of a sorts.  The least amount of junctions, the better.

Edited by Lighthawk, 04 September 2014 - 06:28 AM.

[camper101]

...

 

Does your unit allow for the wiring to pull through, or is it a junction box of a sorts.  The least amount of junctions, the better.

Thanks, that product on Amazon is a relatively recent idea while I figure all this out (fortunately haven't drilled the hole yet...).

 

It is a pull-through thing - it's basically hollow inside. So the solar panel wire would come in through the holes, go through the roof, and get butt spliced to my FWC solar pre-wiring.

 

I have the one-piece aluminum roof, but I see you had a different version (and looks like you sanded/Scotchbrite-ed the paint before applying the sticky stuff, which I'm also torn on).

 

Any chance you have a picture of the wires coming out of your roof and how you strapped them down?  I couldn't find one in your gallery -- it's mostly pictures of beautiful places.

 

I was originally thinking of using one of these, which would be easier and cleaner, but the wires would stick straight up and I'm not sure how sharp of a bend you can put in PV wire without it cracking someday.

[Lighthawk]

Here is a shot of my roof penetration for solar, before final completion. I used a "below waterline" 3M sealant, since my tube of Silaprene was used up from previous projects.  

 

I later added a wire loom wrapped with 3M black electricians tape to protect the wires.  You can see that my wiring is exposed for less than six inches.  There's a zip tie under the panel that cinched the wiring up tight.  My main fear was tree branches.  So far, so good!  

 

Suggestion:  try to locate the panel and penetration as close to each other as possible. 

 

 

 

[camper101]

That's helpful, thanks again.

 

I also have one of those solar plugs and am trying to find a creative alternative that keeps everything lower (the panel is a thin stick-on panel). But maybe there's a reason everybody uses the solar plug... it works.

[photohc]

Would be nice if we could find a source of 90 deg SAE plug. Looked a few months ago on the internet and didn't find any. 

[camper101]

Would be nice if we could find a source of 90 deg SAE plug. Looked a few months ago on the internet and didn't find any. 

No kidding - I also looked more recently. Not sure if you saw this thread but they're out there - you just need to find out where and order a bunch. I know people on this forum would use them, and motorcyclists seem to be interested as well.

 

Could be a micro business opportunity for somebody. Get a couple thousand of them at 10 cents apiece (I have no idea what they cost or how many you need to order...) and sell them on eBay or Amazon FBA. I'd pay over $5 for one of those right now.

[billharr]

Would be nice if we could find a source of 90 deg SAE plug. Looked a few months ago on the internet and didn't find any. 

 

 

No kidding - I also looked more recently. Not sure if you saw this thread but they're out there - you just need to find out where and order a bunch. I know people on this forum would use them, and motorcyclists seem to be interested as well.

 

Could be a micro business opportunity for somebody. Get a couple thousand of them at 10 cents apiece (I have no idea what they cost or how many you need to order...) and sell them on eBay or Amazon FBA. I'd pay over $5 for one of those right now.

 

I have looked long and hard for a 90 degree plug. No luck, only have seen one in a old picture of a FWC. Someone made them at one time. I would pay $10.00 for one.