Friction Testing with Painter's and UHMW Tape on Smooth Chrome Top Cap

Discussion in 'Double Edged Razors' started by ShavingByTheNumbers, Feb 21, 2017.

    Smooth Chrome Top Cap Causes More Friction


    A few weeks ago (link), I wrote about how I had started using the Edwin Jagger Kelvin, which has the standard EJ DE89 head, and how I was experiencing what I considered to be a lot of friction with the shiny smooth chrome of the EJ DE89 head. I was used to the textured satin finish and double open comb of the PAA DOC Satin, my first DE razor, and when I switched to the EJ Kelvin, I was really surprised and disappointed by the friction and sticking that I was getting, even when using the same high-quality soaps as before.

    As previously discussed, I conducted a simple experiment with gliding razors (without blades) against dry and wet skin (from water) on the inside of my wrist. It was confirmed that friction with the smooth EJ DE89 head significantly increased in wet conditions, much more than with the PAA DOC Satin. Also, I confirmed that the smooth plastic top cap of the Dorco PL602 produced a lot of friction on wet skin, similar to the friction from smooth chrome on wet skin. In the past, I couldn't figure out why I was experiencing such friction and stick-slip issues with the Dorco PL602, so I quickly gave up on that inexpensive razor.

    Lather Has Improved, but Some Friction Remains


    My friction problem with the EJ Kelvin led some B&B brothers to suggest that my lather might be lacking water, and sure enough, they were right! It turns out that with the PAA DOC Satin, I could get away with less hydrated lather, but with the EJ Kelvin, I have to use more water in my lather to cut down on the inherently higher friction from the EJ DE89 head. In a way, I was forced to improve my lather building skills. It's been working pretty well, but there is still an overall level of friction that I don't like from the smooth chrome on my skin.

    I've theorized here that while there is POTENTIAL for much more friction from a smooth chrome top cap, what friction a guy experiences ACTUALLY DEPENDS ON HIS SKIN. It is possible that smooth, more elastic skin with smooth chrome under wet conditions should produce much more friction than rougher, less elastic skin with smooth chrome, which has some roughness there to prevent the friction from manifesting so badly. One guy might notice friction, while another guy might not notice a friction problem using the same setup. This could explain why some guys experience undesirable friction with smooth chrome razors.

    Painter's Tape and UHMW Tape Didn't Really Help


    The thought crossed my mind that adding tape to the top cap could reduce friction, so I studied the use of blue painter's tape and ultra-high-molecular-weight (UHMW) tape, the latter being shown below.

    [​IMG]

    Painter's tape has a textured surface, while UHMW tape has a low coefficient of friction and is used for applications with sliding surfaces. I wouldn't want to use tape on a regular basis, but I'm not completely against such a thing if the cost is reasonable. Theoretically, if it worked, a little painter's or UHMW tape could make shaving less expensive and better if it allowed for less expensive, lower performing soaps to be used, offsetting the cost of the tape, while producing better shaves with more slickness, lower friction due to the tape. It was a fascinating idea!

    Well, it was a fascinating idea, but that was about all it was. In practice, painter's tape and UHMW tape didn't help reduce friction much if anything at all. I shaved with different combinations of tape on the EJ DE89 top cap, making sure that the Astra Superior Platinum blade exposure was approximately the same on both sides of the head when I had different conditions on each side. Two examples are shown below, the first with the EJ DE89 top cap covered with UHMW tape and the second with the EJ DE89 top cap covered with blue painter's tape on one side and UHMW tape on the other side.

    [​IMG]

    [​IMG]

    Here are some shave results:
    • Covering the top cap with UHMW tape and wrapping it underneath the top cap edges made the blade exposure too negative and the razor too inefficient
    • UHMW tape on top only did not seem to help, maybe not at all. A problem with the tape was that near the end of the shave, the edge or corner of the tape, at least on one side, started to unstick and cause sharp irritation during some strokes. That was not good.
    • With blue painter's tape on top of one side and UHMW tape on top of the other side, the friction with both tapes was very similar, too similar to call which was better. It was a wash. What was noticeable was that there was an overall friction present, as I was experiencing without any tape.

    Conclusion


    Painter's tape and UHMW tape did not seem to help reduce friction from the smooth chrome of my EJ Kelvin (DE89) head, but at least in the process of trying to solve the friction problem, I got help from fellow B&B members on making better lather and significantly reduced the friction that I was getting. Thanks for the help!

    There's more to come on my adventure with the EJ Kelvin! :001_smile
     
    Last edited: Feb 21, 2017
  1. Try using some Johnson's Paste Wax on the cap. It should add no appreciable thickness to the cap, yet should theoretically reduce friction. You could also try liquid car wax.
     
  2. Thanks for the suggestions, but those things probably shouldn't be in contact with the skin and mouth. Still, something could theoretically be wiped on the cap to reduce friction, but it would probably come off during shaving.
     
  3. Most of the waxes aren't toxic; I wouldn't use them on my cutting board, but I doubt you're going to suck the razor blade :) (Carnuba wax, for example, is used on candy)
     
  4. :laugh: No sucking on razor blades here, too. A wax would be okay to me if it were safe for food contact and such. Has anyone tried a wax product? Wouldn't it come off during the shave?
     
  5. Why not get a better cream? It's obvious to me that the cream your using is not producing the right slickness for the razor. There are lots of other great creams and soaps that may be a fix.

    You can't be shaving with water only, and if the top cap is sticking then you need a different cream or a different lather making process.
     
  6. As I explained in the OP, I am using high-quality soaps and, thanks to you guys, I've improved my lather-making skills, using more water. I had to do this to adjust to the naturally higher friction from the EJ DE89 head. I'm still getting some overall friction. It's not bad anymore, but it's there, which is different compared to what I was used to with the PAA DOC Satin, even with less hydrated lather.
     
  7. As I wax my old enameled cast iron sink (due to the wear), and it lasts a reasonable amount of time, it should last a few shaves. and the rinses will be EASY.
     
  8. Interesting. Maybe wax would hold a while on the razor, but maybe not. My guess is that the repeated contact would wear off the wax fairly quickly. I could be wrong, though. It wouldn't be the first time. :001_smile
     
  9. I have no idea. I haven't tried it yet, but I probably will on the OLD I picked up. 99 percent of the chrome is _gone_.
     
  10. I did some searching on B&B and couldn't find anybody doing any testing on waxing the top cap to reduce friction and increase slickness. If you do some scientific testing going back and forth between shaving with the razor as it is and shaving with the razor with the top cap waxed, please start a thread about it with your results, okay? You might have something there.
     
  11. I just wanted to add that UHMW tape is a lot like PTFE/Teflon tape. UHMW tape is made of UHMWPE (ultra-high-molecular-weight polyethylene) with an adhesive. PTFE has a lower static coefficient of friction than UHMWPE, but UHMWPE is more cost-effective, which is why I purchased UHMW tape instead of PTFE/Teflon tape for the experiment. Similar to Teflon, UHMWPE is apparently FDA and USDA approved for direct contact with food products.
     
  12. My theory is that a smooth chrome finish doesn't allow any soap film to build between the cap and your skin.
    Without that soap film, the razor feels "sticky" and doesn't glide as well.
    Satin finishes don't look as good as shiny chrome, but I believe they perform better in terms of glide.
     
  13. That's a good theory. I was wondering about that. I think that the theory is right. It seems that lather gets in the small crevices of a satin finish, cutting down on friction. I'm sure that this happens because the difference in soap scum buildup on my PAA DOC Satin is significantly more than on my EJ Kelvin. I think that you've hit the nail on the head! :thumbup:
     
  14. I'm going to play with it a bit. I have smooth finished cowhide for strops, so I'm going to take a piece of it, damp it as a synthetic skin, and use three otherwise identical superspeeds on it. One with liquid car wax, one with paste wax, and one simply clean and polished.

    It may be this weekend before I get to it.
     
  15. Cool! Make sure to test friction before and after adding product. Are you planning on test shaving with the "winner"?
     
  16. I hadn't thought about it, but sure.

    The reason for using three of the same SS's is so that I don't have to worry about remembering "what was the friction like on this one to start, vs this one, and this one.."
     
  17. This shouldn't apply that much, really simply because the surface area of head that actually contacts your skin should be absolutely minute. Well, unless you're screaming "Cut, you misbegotten son of a bowdlerizer!" and pushing as hard as you can, having forgotten to put in the blade.
     
  18. Oh, yeah, you're thinking about using multiple SSs is right on. You have to go back and forth between them to make sure of the differences between the waxes. I reread what you originally wrote and I think that I misunderstood you. You said that one of the three razors would be "clean and polished", so that's your control without any wax. Just forget what I said about testing friction before and after adding product. If you don't find any difference between the control and the waxes when using a wetted surface with water, what about testing with a good lather? If you find a difference, then a test shave would be worth it.
     
  19. I avoided talking about the frictional dependence on surface area here because it is complicated. For rigid surfaces, the effect of surface area is small. Usually, you don't even have to consider it. For surfaces sliding against each other, you usually just need the kinetic coefficient of friction and the normal force to figure out the tangential force from friction. However, for this case with a small rigid area (razor) that can dig into an elastic surface (skin), it's not so simple as when considering rigid flat surfaces. "[T]he coefficient of friction increases because the object may begin to dig into the surface" (How Surface Area Affects the Force of Friction - dummies). You touched on this issue. The applied pressure changes the surface area and the geometry. It's complicated.
     

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