Sacrificial Lens Hack: Self-amalgamating Tape

The problem presented here is how to secure a polycarbonate sacrificial lens to a tac light or optic lens when traditional methods don’t apply.

I’ve wanted to do this hack for a while, to protect the Inforce WMLx (reviewed here) on my Systema PTW L119A2 replica.

Reptile House contributor John D told me about the method, which involves self-amalgamating tape. It’s a type of tape I’d not heard of previously. John has been using his light protected in this way for months, which allayed any fears I had of the light overheating and melting the tape. (John also sourced the appropriately sized sacrificial lens – thanks John!)

Self-amalgamating tape is composed of silicone-rubber which – when stretched over joints – adheres to itself and forms a seamless, rubbery, waterproof, and electrically insulating layer (which is also is heat, UV and weather-resistant).

As luck would have it I was chatting to Ryan of Backcountry Workshop at a recent game, about sniper tape. He produced a roll of self-amalgamating tape and explained that nowadays it’s often used instead of sniper tape to secure webbing etc. Not only that, but it’s also used on weapon systems to secure cables.

That roll ended up going home with me (cheers Ryan!) which has made this hack a reality.

The hack is as easy as cutting a length of self-amalgamating tape, then cropping it to the appropriate width. When deciding on length, take into consideration that the tape must be stretched over the joint between the light and sacrificial lens.

I also wanted to make sure the WMLx’s cooling vents weren’t covered, but the tape was wide enough to partially enclose the sacrificial lens; and give good purchase on the sides of the light.

Because the tape must be stretched to leverage its full capabilities, it’s difficult to do a super neat job. You don’t want it looking all arts and crafts anyway. However, after binding the sacrificial lens, I finished with another layer of tape around the circumference of the light only.