RF Welding - what does it mean? And what products is it used on?

You may have noticed that several Sea to Summit products include the term ‘RF-Welded’ in the description. Just what this means is a question that we get asked with some frequency…

Sorry about that pun. “RF” stands for “Radio Frequency”, and is a term used to describe a process for joining materials together. Here’s the best way to visualize how it works:

Imagine a radio transmission antenna, and a radio reception antenna. Put the two close to one another and switch on the transmitter: the high-frequency electromagnetic energy would stream from the transmitter to the receiver. Now imagine that we lay two pieces of material in between the two antennae. When we switch on the transmitter, it would cause the molecules in the material to become excited, and – if we calibrate the setup correctly – to melt and fuse together. The resultant bond can be stronger than the surrounding material.

Not all materials are ‘weldable’, by the way – it requires each piece of material to have a surface which will melt to the other material.

Some weldable materials are stiffer than a similar-weight coated face fabric. This is one of the primary reasons that Sea to Summit does not use RF welding for all of its dry sacks – the fabrics used for (for instance) Lightweight Dry Sacks and Big River Dry Bags are really pliable/flexible, and this allows them to be squished into spaces that conventional laminate dry sacks just will not go. The non-welded dry sacks in our range are sewn together, then seam taped.

For certain applications, weldable laminates can offer advantages in terms of strength-to weight; which is why we offer fully-welded products in the case of our Stopper and Clear Stopper Dry Bags and our Hydraulic Dry Bags and Dry Packs.

“There are differences in the quality of welding produced in different factories. There are also differences in the strength of the laminated materials being welded together. In other words, not all welded air mats are created equal.”

One product range which would be unthinkable without RF Welding is the Air Sprung Cell Mats. The genius of this design is the very large number of individual air-filled ‘springs’, which are formed by hundreds of dot welds (you can read about this here or here). As those other blog posts recount, Sea to Summit’s air mats are made in a factory which builds aeronautical and medical products. The manufacturing standards in this facility are second-to-none; which helps explain the very high quality of the welds (and thus the extremely small number of weld issues we have experienced). At this point, however, it is worth mentioning that not only are there differences in the quality of welding technology, but also in the strength of the laminated materials being welded together. In other words, not all welded air mats are created equal or have the same reliability record – as you can discover by reading through some online reviews. 

Some other items of gear which benefit from RF Welding: Aeros Pillows, TPU Accessory Cases, Phone and Map Cases, 210D Folding Buckets and the TPU Zip-Top Pouch. In addition, the new View Dry Sack and First Aid Dry Sack incorporate RF Welding to ensure the TPU window is completely water tight.

And – the award winning Pack Racks use the RF Welding technology as well.

B