Here’s a great [UK] alternative to ‘Coax-Seal’

Here’s a great alternative to ‘Coax-Seal’

About 15 years ago, I managed to get my hands on some small reals of ‘Coax-Seal’ whilst in the USA. These very quickly ran out as I normally dispatched a length with each antenna build.

Coax-Seal is manufactured in the USA and was pretty well impossible to find in the UK apart from one outlet who was selling a single 5-foot roll [less than 2m] for £10.00 which didn’t include delivery. To think, I was getting through about 10m of the stuff each week.

This wasn’t really a very good solution, given the amount that I used and dispatched to buyers – so I needed to find an alternative, preferably manufactured here in the UK.

Easy to find in North America, but not so here in the UK.
It’s good – but overly expensive at around £12 for 1.75m

Whilst casually chatting to a builder friend who was installing a new window for me, I noticed a real of what looked like a similar product that he was using to secure the glass. An idea shot through my head. Could this be an acceptable alternative to Coax-Seal.

The product is ‘Hodgson Flexistrip Butyl Tape‘ and is extensively used in the fitting of windows, double glazing and glass. It’s also manufactured right here in the UK. At 15mm wide, it’s wider than ‘Coax-Seal’ and is substantially thicker at 2.5mm – so you get much more product for your money.

Here’s the chemistry for the techies.

Butyl rubber is the only known elastomer that is impervious to gases. The material is flexible, with good room temperature damping characteristics. The material is biocompatible, resists many acidic and alkaline chemicals, ozone, heat, and weathering, and has good aging properties. It resists attack by phosphate ester hydraulic fluids and ketones and has excellent UV resistance and electrical insulating properties. Butyl rubber is usable between -50 and 250°F

As a replacement for ‘Coax-Seal’, Flexistrip looks to make a good alternative. In addition, it’s mega cheap in comparison. Since 2007 I’ve been using this on all my antenna projects and even after many years out in the elements in all seasons [and running QRO], all the coax connectors are still in prime A1 condition – so it does the job for sure.

Hodgson’s Flexistrip makes an excellent replacement. At 2.5mm thick, it’s twice the thickness of Coax-Seal

Grab yourself a 30m real [yes that’s about 100 feet of the stuff] for around £13 – that should be enough to last for many projects. Check out the manufacturer’s data sheet here.

We found many outlets here in the UK. In particular, here the guys at ‘Reddiseals’ were just one outlet. It’s also in abundance on EBay and Amazon.

Tell your mates – here’s another great tip from us here on