Raychem History: GRS

 Tiptoeing Through History: Raychem’s GRS Sleeve in Stockton, CA (1975)

This week’s opportunity to tiptoe through history takes us back to Stockton, California, in 1975—a time when Raychem was grappling with a problem that was equal parts challenging and dangerous.

The issue? A leaking bell-and-spigot natural gas line.

That alone is serious enough. But this leak wasn’t out in the middle of nowhere. It was downtown—surrounded by buildings, roads, and plenty of traffic. Shutting everything down and replacing the line wasn’t always an option, so the question became: How do you safely stop a gas leak and permanently repair it in place?

Somewhere inside Raychem’s R&D group, a solution began to take shape. Looking back today, it’s a fascinating mix of caution, ingenuity, and confidence in their technology.

Here’s how the process worked.

First, crews would excavate and expose the leaking gas line. No shortcuts here—you had to clearly see what you were dealing with.

Next came the delicate part. Using a brass hammer and lead wool (chosen specifically to avoid sparks), the crew would carefully hammer the lead wool into the leaking area in an attempt to temporarily stop the gas flow.

Once that was done, soapy water was sprayed on the area to confirm the leak had been stymied. No bubbles meant it was time to move forward.

Cleaning the pipe was next—but again, safety was paramount. Surface preparation had to be done without introducing sparks. That meant sand blasting or using air-driven tools, such as a brass needle descaler.

With the surface as clean as conditions allowed, the GRS shrink sleeve was wrapped into place and secured using Raychem’s rail and channel system.

And then came the part that still makes people raise an eyebrow today…

Open flame.
Once everything was in position, the torch came out and the sleeve was shrunk down onto the pipe, forming a tight, sealed repair.

It sounds a little crazy when you read it now—open flame on a gas line in a busy downtown area—but the reality is this: GRS was an extremely successful product. Over its lifetime, it generated multi-millions of dollars in sales and was widely accepted as a reliable solution for this exact problem.

If memory serves, the GRS product line began to fade out in the late 1980s or early 1990s, giving it a solid 15+ year run in the field. That’s no small achievement, especially considering the demanding and hazardous applications it was designed to address.

Next week, we’ll revisit GRS once again—but this time, we’ll be heading to Puerto Rico for another chapter in its story.