A number of people have experienced temperature problems with mini irons like the Clover Mini Iron II and the Dritz Petite Press, so I am designing future DIY Packrafts to be easier to make using larger hobby irons like the Coverite Black Baron sealing iron, pictured above.
Irons like this are designed for heat sealing the plastic skin onto radio controlled airplanes, and they’re available in every hobby shop that sells RC airplane kits (and many places online, of course). They’re inexpensive (generally $20-$30 USD), robustly built, and unlike the mini irons, which have limited temperature control, model airplane irons typically feature a rheostat for controlling the temperature, allowing you to dial in an exact temperature. (They don’t have accurate temperature gauges built in, so finding the right temperature must be done by trial and error, but once you’ve found the right setting you can set the dial and forget it.)
When I built my first RC airplane in the mid-1990s, a friend gave me his old Top Flite Sealing Iron. I don’t know when he bought it, but it was at least several years old then and it still works perfectly more than two decades later. Top Flite is still making an iron that looks exactly the same (pictured below). I can’t recommend it though, because it has an annoying design flaw: the metal top plate (held on by four screws) overhangs the vertical sides just enough to prevent you from being able to use the sides of the iron for heat sealing.
That’s why I recently bought a Coverite Black Baron heat sealing iron. You can see in the picture below how the sides of the Black Baron protrude far beyond the top plate; the rounded side design isn’t ideal for making packrafts, but it works pretty well, and most of the ironing is done with the bottom of the iron anyway.
I’ve been using the Black Baron for a while now and I’m quite happy with it. The ideal temperature for heat sealing the DIY Packraft fabrics is towards the high end of the range, but it’s not maxed out, and the non-stick coating allows it to slide nicely over the fabric even when applying pressure.
There are other brands of model airplane heat sealing irons too, and they’re probably just as good, so if you’re struggling to find a heat sealing iron that works for you, visit your local hobby shop and pick one up.
Note that a few manufacturers of these model airplane irons also make “trim” sealing irons with smaller feet designed for heat sealing small areas. These do not get hot enough to seal TPU coated fabric so should be avoided.