Painting PEX pipe gives your orange plastic loop antenna an aluminum appearance. I experimented with Krylon Fusion as well as ordinary 100% acrylic latex.
Aluminum core PEX is a wonderful material for building loop antennas. PEX-AL-PEX contains a welded aluminum tube sandwiched between two layers of cross-linked high density polyethylene. I found that the aluminum core has enough skin depth to support radio signals down to low frequencies. Probably even thick enough to lower power transmission.
But the biggest challenge with using PEX for an antenna is sunlight. Normal PEX will deteriorate quickly when exposed to ultra-violet rays. Manufacturers only specify PEX for indoor use only and not exposed to direct sunlight.
So, what to do? I gave some thought to placing the loop inside some pipe insulation, but in the end, painting PEX pipe seemed the better idea. But how? Plastic is notoriously hard to paint. Also, PEX manufacturers warned against a petroleum-based paint, recommending only 100% acrylic latex. Acrylic will block UV and it will expand and contract with weather changes.
My best solution appeared to be Krylon with Fusion for Plastic, a paint designed specifically to bond with many types of plastic. My biggest challenge was finding any in Calgary. Rust-Oleum seems to have taken over our market. Everywhere I went were tons of Rust-Oleum for Plastic spray paints, but no Krylon. Trouble is, Rust-Oleum paints are petroleum-based and not what I wanted for PEX.
On a hunch, I went to our local Sherwin-Williams paint store. I remembered reading that Sherwin-Williams had purchased Krylon recently. Sure enough, although not advertised, I discovered a selection of Krylon with Fusion for Plastic. Unfortunately, only black or white. For $8, I bought a can of black.
Painting PEX Pipe – Experiments
It took two coats, but the end result was a black loop antenna. Krylon Fusion sticks to PEX quite well without any preparation, other than a quick wipe with alcohol to remove mold release. So, if you can find a color you like, you can use Krylon Fusion spray paint to turn your orange PEX-AL-PEX into a good looking loop.
My second option was just to paint the PEX with ordinary 100% acrylic paint. I went to Home Depot and bought a small can, colored dolphin gray (see right). For this approach, I had to prepare the plastic by roughing it up with some 120 grit sandpaper. After cleaning, the ordinary acrylic latex went on easily. With two coats, I have a plastic loop antenna that looks like it made from aluminum tube.
Time will tell how well painting PEX pipe with either Fusion or plain acrylic latex will hold up. For now, though, it looks like an easy and cheap solution. My small can of latex should be good for many years of touch up.