silicon sealer reacts with copper

**Isetech** · 28-Dec-22, 01:08 PM

Anyone had this issue? I have never noticed it before.

I drilled the holes for the walls plugs, put a dab of silicon on the back of the box and pushed it against the wall, fitted the cove rand walked away. A couple days later I had to open the IP 65 box and pull in another wire and that is when I noticed the reaction. I noticed that all the copper parts had a blue film of stuff on it. You could still smell the sealer in the box.

I need to change the silicon sealer or leave the cover off until the sealer to set.

**SCW** · 28-Dec-22, 02:12 PM

Silicone releases acid as it cures (acetoxy curing, I think ??), so this will react with the copper. The more humid the environment, the faster the acid is drawn off, so leaving the boxes open will help.

**Justloadit** · 28-Dec-22, 08:55 PM

Another point I noted with silicon sealers, is that they shrink over time, compromising the seal. Not good at all.
Also do not use silicone sealer on the back of any PV panels, as it reacts with the panel film and damages the cells.

I have found other sealer which is far superior to silicone sealer, not cheap, about 3 times the price of silicone, but has no acetic acid in it, nor does it shrink over time.
Can't remember the name of it right now, but when I remember I will post it here.

I know ACDC has some as well, it is listed in the Solar section, and can be used on solar panels if the case required.
Have a look at this one Aqua-Flex MS-Polymer, not the one I am thinking off. Look at the specs to see how it fares.

**Isetech** · 29-Dec-22, 05:12 AM

I have found that sika and Fisher have the best products

I have found the fischer contractors adhesive works the best for securing and sealing enclosures to wall.

The trick is to find products that are water based and to apply the sealer to the back of the enclosure, not the around the top and sides, or just enclosures with the correct screw holes so that no sealer is required.

**Derlyn** · 29-Dec-22, 06:36 AM

I use Alcolin Contractors Acrylic for just about everything.

Inside and outside, works like a bomb and it's the cheapest.

We prefer sealing surface enclosures all around the edges, so we use a lot of the stuff
but it makes for a very neat finish and serves 2 purposes, weatherproofing and cosmetics.

Every inch of trunking that we install gets sealed on both sides in it's entire length, not for waterproofing,
but for cosmetic purposes. It makes a huge difference.