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Gear Test

Rubbaweld tape

Rubbaweld tape

Rubbaweld is billed as a “self-amalgamating marine tape” that welds itself into a solid, waterproof skin. Ideally, the product should be able to seal moisture from splices and connections, repair leaky fuel and water hoses, whip rope ends, and enhance grips on tools, to name a few potential applications.

The self-amalgamating properties of Rubbaweld allow the tape to bond to itself without adhesive, creating a solid elastomeric tape whose thickness is dependant on the number of layers applied. The tape should not attack the substrate or leave residue behind after removal.

To confirm the manufacturer’s claims and determine the practicality of Rubbaweld, I started with a length of No. 2 battery cable and removed an inch-long section of its insulation from the center, leaving some of the paper liner intact on the exposed conductors. If moisture penetrated the Rubbaweld seal to the cable, the paper liner would certainly be affected.

Following the guidelines provided, I removed the thin protective liner from the tape and began a tight wrap around the cable, stretching the tape to at least twice its length, which decreased its width and thickness. Making one full turn to start and then working my way down the cable at an angle, I overlapped each wrap by 50 percent. I started and ended about an inch on both sides of the bare conductor. I do a good amount of splicing and taping in this fashion, so I was able to make three passes over the area without stopping or piecing the tape. However, the process could take some time and patience without prior experience. It is important that each wrap be overlapped by the following, and that even tension is kept on the tape to assure proper stretch.

Following the application, I submerged the taped section of cable under water and left it for several days. After removing and drying the test cable, I attempted to peal the Rubbaweld from itself much in the way that it was applied. I was successful only in splintering tiny chunks from the edge. The only method of removing the tape was to slice it lengthwise along the cable with a razor blade. Only then was I able to peel the Rubbaweld from the cable and bare conductor.

Examining a cross section of the removed product revealed that it seamlessly bonded to itself and formed a solid layer of rubber. In fact, it formed around the bare cable so well that I could see individual conductor strands imprinted on the inside of the rubber, as if in a mold. The section of paper liner that had remained on the cable showed no signs of water migrating into the taped area.

From a waterproofing standpoint, Rubbaweld works well, and I will find many uses for it both on board and at home. Caution should be observed though, as I was unable to confirm its rating as an electrical insulator. I would use the product as an overcoating on properly insulated splices and terminals.

The hose-repair process would be similar, but I would apply layers of Rubbaweld on top of a different, more structurally reinforced wrapping that would be able to withstand the internal pressure associated with cooling systems and similar applications. I should note that Rubbaweld will only bond when dry and, as such, cannot be used directly on hose that is actively leaking. It has a temperature range of -40 F to 212 F.

Rubbaweld is available in black and white, in widths of 1, 2 and 4 inches, as well as other packaged lengths. The price for a 1-inch-by-15-foot roll is $13.95. It is available exclusively in the United States from marine hardware manufacturer C. Sherman Johnson Co. in East Haddam, Conn. Phone: (800) 874-7455.