Mine isn't really portable yet but I can step outside with it. Still got the remote battery pack but the unit is palm sized. Open frame is an over-statement. But it really is simple if you forgo the electronic switch.
I use the coil provided with the unit and I compacted it without trimming or bending wire. I reverse the power-in connector and removed the 3-pin coil connector. Made sure all solder joints were solid on both sides of the PCB (optional; I stripped the larger components and remounted them back where they were).
With a 10V input (line losses for me, 9V is the battery-low level) you may see 8 amps but typically at 10V it is only 6 amps. 16 awg throughout is perfect. You need a momentary switch that you can rely on. I use this one:
...rated to 10 amps or 1/3 HP. You want at least 8 amps capable and you want momentary!
This is the layout. The switch is wired into the negative lead:
Seriously, a mild bend in the coil wires and solder them along the board. you can see the leg of the coil at 9:00 at the left edge of the board. Nice long solder bead. It has a small Z-bend at the solder pad to clear the leads of the black capacitors. you can see the slight rake in the horizontal section of the coil-wire.
I stabilized the chokes with a bit of Shoe-Go and this is how I carry it. A 5.1mm plug on the end of a short cord, and 3x 18650 power source keeps thing warm for a couple days.
I looked at Digikey for instance and they have momentary at 8 amps with a good side knob for convenience for not too much money. The one I chose is on eBay for a ten-lot. too much for me but these particular switches have a defeat if you pull them. Not very useful but I thought I'd put that out there that yes, this unit has a full-on bypass.
The glass vile is something I had and find useful. If you have a cylinder that fits, you will need to fashion a bottom. A wooden tongue depressor cut short in between the coil will work. Just remember it gets hot. I also centered the vile using crushed Teflon tubes which where subsequently stitched together. Works great for adjustable depth.
And yes, this switch is just Shoe-Go'd to the side. Also a handy feature. You may need some structure... and you'll probably want a box. Haven't found a need for one. Don't get shocked either. Don't put it in your mouth!
Performance stats: 10 seconds at 10V and 6 amps [60 watts]; Standard cap set to 'hot' [deep soak w/ cap at 4mm from the far end of the coil] going from room temp to drawing at the second click.
