The Rock Exotical Mini-8 - interesting...
A friend and climbing buddy was generous enough to loan me his Rock Exotica Mini-8 descender. It arrived in the mail yesterday and I did two rappels on it - didn't have time for vids - sorry, but they are in the works.
The first thing that struck me about it was its diminutive size as you can see here:
Notice in particular the slanted slot between the large 'ring' and the attachment 'ring' - that's what they call the belay slot. Notice in particular how thin it is at the upper left and lower right of this slot. BTW, here's what RE says about the belay slot:"The MiniEight has a belay slot that will fit up to 8 or 9mm rope. This is not intended to belay a leader fall. Only use in a low angle, low fall potential situation. Test First!"
Despite it's small size, it is rated for up to 13mm rope and as for the smaller sizes, RE states this:"The minimum rope size can be quite small because you can use a wrap with a lot of friction. If you do this, you must be sure your wrap never slips off into a lower friction configuration."
In addition to it's small size, it is also quite thin. That will be difficult to depict in photos but here's an attempt. first compared to a Petzl Pirana:
and compared to a Petzl Am'D carabiner,
The pics don't quite do the thinness justice - it's thin! As a result it only weighs 2.1 oz. Why that's 0.244 oz less than a Viridian weapon mounted light and green laser combo (WML weight includes battery) and the Mini 8 only costs a tenth as much!
The Mini 8 gave a great ride. Of course I used it on the best rope money can buy - 10mm PMI EzBend. I will be trying it on some lifeless, character-less, over-sized noodle rope as time and opportunity permits.
Both rappels were from about 50 feet, but the real test was after I cleared the lower limbs at about 30 feet. I could do just about anything I wanted to - go slow, turbo, and stop on a dime - well maybe a quarter. Very impressed by it's performance.
As for long rappels and I don't know what a 'long' rappel is, but here's what RE has to say about it:"Rappel devices can get hot & small 8’s get especially hot the longer the rappel. Use a bigger 8 for longer rappels."
Since RE makes a micro 8 and mini 8 I'm not sure if they mean you should use the Mini 8 for longer rappels or a F8 larger than the mini 8???
I think many are going to be by the Mini 8, especially if you could see it in person, as they are about 9mm rope. It's a psychological thing - it looks really small. While I'm comfortable as can be on 9mm PMI EzBend, the Mini 8 has the small effect on me; especially around the top and bottom of the belay slot - seems like that's where you need it to be pretty beefy.
Like most figure 8 devices, you have to remove it from the carabiner to install or remove it from the rope. I don't like that, but the same is true for a GG as well. The one F8 exception is the Pirana. The Pirana instruction sheet illustrates installing the rope behind the Pirana on the carabiner, but it has horns to prevent the rope from slipping from the back side of the Pirana to the front side which would decrease friction.
Higher friction configuration:
Lower friction configuration:
I want to experiment some with this approach with the Mini 8. The problem with doing this with the Mini 8 is the rope can slip over the ring into the lower friction configuration. That may be ok since you can re-gain the friction with wraps as shown here. BTW, this is the configuration I rappelled with EXCEPT I had the rope installed in the conventional way, i.e. around the F8, NOT around the biner as shown here:
While the horns make the Pirana and Mini 8 more versatile, all those wraps have to impart twist to the down rope. My down rope was short, only about 3 feet on the ground, so if it twisted, the rope wouldn't be long enough for the twist loops to form. I know it will though. I'll confirm this next time I climb.
Both the Pirana and Mini 8 have an interesting, and IMO, very useful feature. The connection hole for the carabiner has a friction mount to keep the device in place on the biner. RE does it with a rubber insert in the hole:
Petzl does it a bit differently but every bit as effective and seemingly a bit more robust:
And as Forest Gump says, "And that's all I have to say about that."