Rupes LHR 21ES Random Orbital Polisher - Features & Benefits

[Accumulator]

... There`s very limited cars I can`t finishes down perfect with... [the Flex 3401]..., I can think of 2 ever.. ..Currently I own, griots 6"...

Not to threadjack, but I`m surprised you can get the same finish with the Flex 3401 that you can achieve with the Griot`s. I can`t get my Flex to finish out *QUITE* as nicely as with my Cyclos or the Griot`s.



Back on topic, I do hear you on the Flex 3401 vs. Rupes question though...I`m kinda in the same position. I can understand the Rupes being great for people who either a) don`t have something like the Flex 3401 or b) don`t like it, but for those of us who are happy with the corrective abilities of the Flex I`m guessing that the Rupes offers *quicker* correction and a more user-friendly experience. Now just how much those diffs are worth, well, I guess that`s between the user and his wallet.

[Kevin Brown]

... Your analogy of an ice skater.... Does it actually apply?

Not literally, just a visual that came to mind at the time.

The original intent of the analogy was to relay how the abrupt motion might affect the finish.



For the analogy to be accurate, the skater would have to be towed along at a constant clip, his legs in casts or supports for rigidity; the skate blade would have to be shaped as a point, sphere, or an abrasive particle of some sort, and its up & down positioning would have to be controlled so as to eliminate pressure changes.

...I submit (with the full knowledge that I am likely wrong) that the point changes vs. curly changes are all the same depth of cut into the surface. Does that change anything for you if you would agree with it? Or are you saying this theoretical gouge is a horizontal dragging scar rather than a deeper one?

Pads do change shape as they work, which is no big surprise.



As the pad-face flexes while dragging across the paint (scuttling liquids and abrasives in the process), any single portion of the pad will likely have a varied pressure or force placed upon it. If the pad`s face has any sort of ability to conform and change shape via resiliency (foam) or the stacking of its fibers (wool & microfiber) or its design characteristics (Surbuf Microfingers), any particles in the vicinity will be under pressure. This pressure will force the abrasive particle against the paint, causing it to continually scrub the surface. If it so happens that an abrasive particle once again drags across a specific path (without changing its positioning), it`ll slice a deeper gouge into the paint on its return trip. This won`t happen if something limits the particles ability to conform or stay planted to the paint surface, but when it comes to polishing paint... we generally use pads that have some sort of "suspension" built in. I suppose this is why we see tick marks or pig-tails; these scratches or voids in the paint are likely deeper, wider, or both.



Let`s continue to use the ballpoint pen`s line of travel for a moment.



If the abrupt transition is not actually a "twist-point" that sees the ball momentarily spin in place, but instead is a path that creates what is essentially an extremely tight and small ovaloid circle... wouldn`t the marks on the paper appear to be wider? This assumes that the pen`s body is perfectly rigid, so too the backing plate. If either component had an ability to flex or distort, there`s a high probability that the ball would travel on its outbound trip in the valley it created as it traveled inwards (towards the mounting spindle). Perhaps the photo is not a true indicator of what typically occurs.



Interesting thought: if the slices in the paint were close enough to each other, wouldn`t the paint residing between the slices eventually be removed (via friction, pressure, pad motion, paint shifting & twisting, or whatever force), creating a void in the paint surface? To our eyes, would the void simply resemble a deeper or wider scratch?



Let`s remove the ballpoint of the pen, and replace it with a sharp metal cutting tip.



Immediately after running the ballpoint pens across the grid paper, I was thinking about how a single abrasive particle (perhaps attached to a sanding disc) might interact with the paint surface. Would the particle continue to move in a curlicue motion, albeit minute in size? Would the stress placed upon the particle (mostly due to speed & directional change) cause it to detach from the disc?

...Finally, your theories and the article on the Kevin Brown method contradict some of the things I do with my Flex 3401 particularly during the finishing stage. In other words I believe I keep the speed much higher than you but my final result is excellent even when studied under sunlight or led. Of course, products, pads and all are different so I know that changes everything.

I never claimed that the "KBM" is the end-all, be-all polishing method.



At least, I`ve scribbled down and posted up plenty of support material explaining why I believe certain sanding and polishing methodologies work. From what I`ve seen, there`s very little explanation as to why some guys have huge success polishing using high-speed settings, or short-stroke machines.



The lack of information pertaining to machine stroke in general is the reason I started to write about machine stroke and machine speed in the first place. As an example, I just could not accept without verifying why short stroke machines were always considered as being best for fine sanding, while large stroke machines were supposedly best for coarse sanding. While there is some validity to these set-in-stone recommendations, I never was able to locate any reasoning behind the premise. After much thought and discussion, I now absolutely understand why the recommendations do and do not hold merit.



By the way... a group of us recently used the Rupes® LHR75 Mini-Random Orbital (15mm diameter stroke on a 3" machine) outfitted with 3000 grade sanding discs with no drama whatsoever. We watched for edge-digging, kept our speed low, kept things clean while we worked.

Getting to the point... Your writings are based on smat tech specifically. Is that correct? I almost always finish with diminishing abrasives and wonder if the tool, polishes, and pads I use would change the rules to some of your theories.

Regarding clumped and non-clumped abrasives... a lot depends upon the things already discussed.



Regardless the structure or design of the abrasive particle (diminishing or clumped, non-diminishing or non-clumped)... if the particle has attached itself to the pad or it is rolling between the pad and paint, it makes a difference. If the pad is apt to allow particles to attach to it or not, it makes a difference. If the abraded paint residue inherently ties or binds strings together or not, it makes a difference. If the pad generates a tremendous amount of heat via dragging action (increasing evaporation of buffing liquids, or causing gumminess, or advancing heat build-up in the paint), it makes a difference.



In my mind, if you`re using ANY abrasive-laden compound, maximum cut is likely if the particle is traveling at maximum speed (the speed of the pad via attachment or scuttling). If abrasive particles and pads become overly-laden with paint residue, cutting speed and ability will diminish. If the goal is final-polishing, in my mind optimal polishing is accomplished if the abrasive particles can continuously roll about, cleansing themselves as they roll, adjusting positioning all the while.



Things get a bit complicated when we`re dealing like a material such as microfiber, because in my mind I don`t want the microfiber material to be inconsistently coated with abrasive. This is why I`ll generally prime a fresh pad, them blow it clean using compressed air, or run the primed pad against a microfiber towel. The goal is to have every portion of every microfiber string coated with a single abrasive particle, so that the cut will be consistent in depth and width. I don`t "work" or "jewel" the area. I cut it slow and steady, using consistent pressure, with an eye towards keeping the fibers planted but separated.



Knowing all of this, how do things differ when using larger, clumped abrasives versus small and non-clumped abrasives?



I suppose that for clumped abrasive to work optimally, they`ve got to continuously break down to their smallest point. Even if they don`t, the pad being used will dictate the depth of cut to some degree. After all, if you were to fully coat a foam pad with clumped abrasives, then place the pad onto the paint surface, the larger particles would not automatically dig into the paint. Instead, they would push into the pad for the most part, correct? Once you started polishing, THEN you would likely see inconsistent cutting of the surface, which hopefully would end up consistently cut after the diminishing cycle had run its course.



In the end, do we even need abrasives to cut away paint if the pad can supply ample friction? I think I know where you`d stand on this idea; SVR15 Matt in Australia is a big proponent of using buffing liquids featuring no abrasive (claimed, I have no data on the subject), and you sell the same pads (or pads very similar) to the type he uses.



I`ve used Meguiar`s Ultimate Paste Wax for cutting via random orbital and microfiber disc. Sure, I know that there`s tremendous masking ability with this product, but nonetheless, I was able to eliminate some pretty serious scratching and haziness from a particularly finicky paint job. To confirm, I simply had to wax the area, then polish only a portion of it. Where I polished, no visible marring remained. Again... pretty confident that under all the wax, there was some micro-marring. But this paint was so finicky that it could not be stripped using diluted Glass Cleaner or IPA, otherwise etching would occur. Yup, ultra sensitive paint!





Polishing theories destroyed?



In the end, you are correct that tools, polishes, and pads make a difference, but I don`t feel that there are any holes blasted through my "polishing theories". All along I`ve tried to be fair-minded when considering stroke size, machine speed and type, applied pressure, pad diameter & type, abrasive design, backing plates, and all sorts of other parameter, for several years now.



I will say that microfiber has offered up some interesting twists; whereas I basically considered foam pads to play second fiddle to them, the experience gained with the latest slough of large stroke machines has proven that foam can be a hero when paint cutting and polishing are accomplished at a rapid clip. These large stroke machines work quickly, and are for the moment at least... a blast to use.



I appreciate a good polishing conversation, CEE DOG.

Let`s keep it up..! Great for autopia.org.



I hope others will chime in to keep the discussion rolling.

[Chris Lasrson]

Mine is on its way.

[Paul Sparks]

Just a couple of laymen questions 1. Is there a limit on the stroke of a da where it would be of no additional benefit ? How much stroke is considered the optimum for paint correction. 2. Will this stroke requirment change with the onslaught of new materials being brought out for da paint correction ? Denim ,rayon and the orange peel removal pads come to mind.

I have no idea how you find the time to research all of the information that you share with the detailing community plus your day to day detailing supply business and other numerous activities. I am very thankful you take the time to share with us your findings.

[Kevin Brown]

Is there a limit on the stroke of a da where it would be of no additional benefit?

I think it comes down to whether or not the stroke is too large to reasonably use on a particular polishing project.



If the task at hand requires you to polish scratches from a rare pair of eyeglasses, and the lenses are not to be removed from the frames, we would likely not reach for a 21mm BigFoot with a 6" pad! If such a tool existed and you wanted to use it for this task, a 1mm-stroke random orbital outfitted with a 12mm diameter pad might be best. It would have to be a high RPM unit in order to generate an ample amount of random backing plate rotation.



If you had the need to polish the side of a cruise ship, I suppose a random orbital could be designed to be held by two guys; it might feature an ultra-lightweight chassis, use a 6-foot diameter pad and feature a 2-foot diameter stroke. This machine would require very low RPM capability (by comparison), as that amount of throw would create a LOT of centripetal force.



Then again... if you were hired to polish a very delicate antique trinket of some sort, you might not want to use a machine that featured a large stroke because if you happened to hook an edge or a protrusion, the object might be torn to pieces!



It`s also important to realize that if held in place, a rotary machine focuses all of its polishing energy and motion onto an area the size of its buffing pad, whereas the random orbital can polish an area exceeding the pad size (dependent upon its stroke):







Why is this relevant? Well, if you happen to be polishing a car panel that requires a lot of edge work, and there`s not a whole lot of paint thickness left on that panel, you`d really need to focus all of the polishing only on the exact areas needing polishing attention. In this case, a rotary machine might be the optimal machine. If not a rotary, then a small stroke random orbital would be the next best bet. A large stroke machine would only polish the outlying areas part of the time. I hope this makes sense.

How much stroke is considered the optimum for paint correction?

A lot could be written about this topic (I`ve written my fair share here). In short and other things being equal (everything about the machine except for its stroke, pad type and size, buffing liquid, machine speed, backing plate, applied pressure, etc.), some points to consider:





• A short stroke machine will focus its polishing energy onto a more confined area.

This has been covered, see above diagram.





• A short stroke machine will move everything attached to its backing plate mounting pad at a slower pace.

The RPM that it is spinning will remain the same, but since everything is whirling around along a smaller circular path, it`ll be traveling at a slower rate of speed (MPH).











• A short stroke machine will create less centripetal force and consequently, less backing plate rotation.

Since everything mounted to the motor shaft (counterbalance, bearings, backing plate mounting spindle, backing plate, buffing pad) is moving at a slower rate of travel (just covered this point, see above diagram) it will create less rotational or centripetal force, consequently creating less backing plate rotation. Don`t be confused: the motor speed will remain the same (remember, we are not changing any parameters other than stroke size, for simplicity sake), but random rotation will slow. This means that you`ll not only see less rotation of the backing plate, but less measured speed of motion along the edge of the buffing pad. This means you may see a loss of cutting power along the edge of the pad.





• A short stroke machine will not maintain its backing plate rotation as well as a large stroke machine.

Since it`s common to see manufacturers using lighter weight counterbalances with short stroke machines, there`s less mass spinning along. So, if the buffing pad encounters an obstacle or added friction or pressure (causing drag), rotation of all the spinning parts will slow more rapidly. I noticed this exact thing happen while comparing two Mirka CEROS machines (5" and 6" machine 6mm diameter-stroke models). The only variable between the two units was the weight of the counterbalance (one optimized for the weight of a 5" backing plate, the other for a 6" backing plate). The difference was dramatic.



• A short stroke machine moves pads and buffing liquids less distance per rotation.

This is a big deal. With less motion per rotation comes less speed, less rolling about of abrasive particles, and less potential cleaning of the buffing pad, as particulate, debris, and paint residue are more apt to stay attached to or remain underneath the face of the pad. Anyone that has used the Rupes® LHR75 3" 15mm-diameter stroke Mini-Random Orbital can attest to the fact that foam pads stay cleaner longer, and very little scouring occurs (comapred to when a small stroke 3" machine is used).

Will this stroke requirment change with the onslaught of new materials being brought out for da paint correction (denim, rayon, and the orange peel removal pads come to mind)?

Large stroke machines tend to roll the edges of buffing pads under the pad itself. Use of a backing plate that supports the full width of the pad helps control this. If very tall or pliable pads are used, the outer edges will roll under more readily when using a large stroke machine. I`ve also noticed that very short or firm pads become "jittery" or "darty" as they glide along. Basically, there`s not a lot of built in suspension travel if the pad is overly rigid or short. I think these issues could be controlled to a large degree by simply designing pads that have a rolled edge (or a backing plate that was curved upwards at its edge, and Velcro held the pads so that they rolled at the edge).

I have no idea how you find the time to research all of the information that you share with the detailing community plus your day to day detailing supply business and other numerous activities. I am very thankful you take the time to share with us your findings.

All I can say is thanks, and I hope it all makes sense.

[Concours.John]

I was rotary for many years. I would have never thought a perfect finish could be acheived with a DA. Until a couple years ago and MF pads my mind has been changed. Im seeing near LSP ready finishes with MF compound pads/M105 and a 7424 XP. Technology has changed. There was a little learning curve but can now only count a few time the rotary came out. I know this will be my next machine over a Flex. Just need to talk some with the "Buff Daddy"

[Junebug]

What about the Cyclo? It`s got a long stoke and the limiting factor (IMHO) is that no one makes a 4" MF pad........WHY? I have a white Suburban coming in this weekend and the Cyclo with orange pads using a mix of M101 (BIG THANKS to Mike Napoli) and D300. I`m using this combo over my PC`s with MF and my rotary cause this beast is big, but just needs a good 1 step. I figure I`m covering 8" or more with each pass, plus my hands just can`t take the vibes from the PC for the amount of time required to do this thing.

I am interested in your new machine, hope to see some vids on YouTube about it.

[RaskyR1]

What about the Cyclo? It`s got a long stoke and the limiting factor (IMHO) is that no one makes a 4" MF pad........WHY? I have a white Suburban coming in this weekend and the Cyclo with orange pads using a mix of M101 (BIG THANKS to Mike Napoli) and D300. I`m using this combo over my PC`s with MF and my rotary cause this beast is big, but just needs a good 1 step. I figure I`m covering 8" or more with each pass, plus my hands just can`t take the vibes from the PC for the amount of time required to do this thing.

I am interested in your new machine, hope to see some vids on YouTube about it.

Optimum Microfiber Cutting Pad - 4.25" | Free Shipping Available - Detailed Image

[Junebug]

I think it needs to be 4" to work.

[RaskyR1]

I think it needs to be 4" to work.

O-well....I tried.

[Accumulator]

What about the Cyclo?

IF you`re a fan of SurBuf pads, you can get them in 4".

[Junebug]

Tried Surbuf and didn`t care for them.

[Accumulator]

Tried Surbuf and didn`t care for them.

Same here...but I did want to mention them for use via Cyclo.



So *nobody* sells a 4" MF cutting pad?!? Seems odd since you can get `em in 3", which I`d consider more of an oddball size. Eh, guess there are a lot of 3" polishers in the Pro realm...

[drew935]

Same here...but I did want to mention them for use via Cyclo.



So *nobody* sells a 4" MF cutting pad?!? Seems odd since you can get `em in 3", which I`d consider more of an oddball size. Eh, guess there are a lot of 3" polishers in the Pro realm...

How about these?

I have a few but let`s not steer away from the OT



Optimum Microfiber Cutting Pad - 4.25" | Free Shipping Available - Detailed Image



Optimum Microfiber Polishing Pad, 4.25" : Amazon.com : Automotive

[miracledetail]

This is just how easy it is to use the LHR21e, my friend came down a few days ago and wanted some Bigfoot training, so I gave him hard Audi paint and the LHR21 with a green Rupes pad and Rupes Zephir and he produced some awesome results, and this guy has NEVER picked up any type of polishing machine in his life! He now wants to polish more paint, he couldn`t believe how easy it was and that the machine has no vibration at all even with a 21mm throw at full speed!



For reference Im using the LHR15e.



Miracle Detail Training Day using the Rupes Bigfoot System - YouTube



Kind Regards

Paul Dalton



Miracle Detail.

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