The plastic of the stem, the upper housing rails and their slits are getting oxidized by age, wear and moisture, i.e. they get abraded. The plastic stem gets abraded but so are the upper housing rails too. Those abrasions are not any small matter, you can actually feel them just by running your... fingernail along the edges and the surface of the stem. That is what makes the switch harsh and binding, not any dirt. I mean what kind of dirt would be that big and strong?mode1ace wrote: ↑25 Aug 2021, 08:22I'm very skeptical of this, it's not about literally being as smooth as possible, completely flat surfaces can be highly frictional. It's about reducing friction. NOS alps sliders have a leathered appearance, but the switch housing itself is smooth, one slide leathered and the other smooth has less contact area, and no meshing of rough surfaces.NeK wrote: ↑25 Aug 2021, 08:18Tbh dirt is the least of the issues. The whole point is it to make the plastic stem surfaces as smooth and polished as possible. I use a dremel with felt tip to polish them one by one. Also the metal leafs need to be polished as well. And all of that before adding any kind of lube.
My worst condition blue sliders have seen so much use they have worn smooth, unlubircated this binds horribly.
Just boil and wax your switches, it works amazingly. This problem has now been solved and everyone just has to try this method.
Therefore I find it difficult to see how two abraded surfaces have no friction when slide together. As you pointed out, only one surface maybe be "leathered" but the other must be smooth, for mininal friction, however this is clearly not the case for worn/aged switches which both are degraded.
IMO for a proper restoration there is no getting away from actually polishing the surfaces of the plastics that make contact, to remove their abrasions.
Also I find it difficult to understand what is the point in the boil "cleaning" step, because you are still going to boil them in wax again right afterwards. What does that contribute to the end result? I think most likely the candle wax, which was known for months now, is the only thing that actually makes the switch smooth in the end. Has anyone tried to "wax-boil" step without the cleaning first? I have a feeling that it will have the same result.
And lastly, I would refrain to refer this problem as "solved", without other people with verified NOS switches have actually tested them side by side and verified that everything is near identical.