wow!
this thread really took off.
You guys should know some history.
We also considered the RDM, as we used to be Rotovac users (and still keep it on the truck for the occasional nasty) But when we bought a quality wand and had a teflon wand glide made for it, it was a much better cleaning tool all around.
As you may already know, not all wands are created equal. I was actually quite surprised when I first came to this realization, as I kind of thought a wand was a wand, but once someone shows you the light, it's pretty obvious and you ask yourself why didn't I see this before?
We started with a lightweight 1.5" tubed 12" wide 2 jet wand and fitted a NON-teflon glide to it, it was easier to push as you would imagine plastic to be vs: steel lips, and it did seem to dry the carpet a little better, but it chipped and scratched and eventually tore carpet fiber, and became harder to push. We tried a few designs that varied in material and slot shape and configuration.
In the end 100% teflon(although expensive in comparison), proved to be the material of choice for many reasons which we explain on our website(GreenGlides.com look under "Learn about glides"), mostly the low coefficient of friction and self healing ability from scratches and nicks.
We came to some conclusions on slot designs as well, a series of holes pulled up much more water than a continous slot therefore cleaned better, but not just any hole, the size was critical to the vacuum source, and the placement of said holes in proximity to each other was also important not to close and not to far.
Even the slot size was critical, although the slot doesn't glide as smoothly in comparison as the holes it was still much better than a conventional steel wand lip, and as long as the size of the slot was limited there was indeed a drying decrease and a little more water was picked up. If you consider the average slot width of about 3/16" any decrease will be a little easier to push and dry a little better as slot velocity is increased at the carpet.
Any larger than 3/16" would be just the opposite.
Our preferred slot size is 1/8". The slot doesn't dry or glide as well as the hole, but it does permit larger debris to pass and this may be worth the compromise, and as we have learned from end users like Glynn, some wool carpets respond better to the slot.
The next consideration is fit, the glide absolutley must fit snugly, this is what prevented me from making them myself in the garage, I use a machinist for this reason. Each must be fitted to the shape of the lips and vacuum slot precisely. I have tried to help many make them but it's costly to do in small quanties, and not practical for a good fit, I started off just making a few for myself and friends, because I couldn't go abck to cleaning without one, but word spreads and now we make them in volume.
Another tid bit worth mentioning is the glide makes streaking from multi-jet wands an issue of the past, this proved to be big deal, as some of the best wands ever made fell out of favor due to this little detail. the glide completely reversed this, and now those very wands are in demand again.
Ideally you want to use a quality wand like a PC or HM cast head low profile with a 1.75" or larger tube. They are a bit heavier, but that is compensated with the addition of a glide. The perfect scenario would be to have a wand that you could quickly swap out the glide and yet seal well. This can be accomplished but requires a notch to be cut into the side splash fin of said wands, so you can slide the glide on an off without distorting the teflon channel. But that is another animal, this is not as big of a deal with the cheaper lighter weight welded wands as the glide pops on and off more readily(but still do some damamge to the sealing surfaces with reptitive use) and they vary more in design tolerance as they are not cast heads from a mold.
