The Rupes BIGFOOT LHR 21E is heading to the USA!!!

[Kevin Brown]

[QUOTE=CMJ`s DTL PZN;1531471]

Keep in mind that when you drop backing plate diameter, you are essentially shrinking the "platform" size.



Kevin can you clarify what you mean by platform size? I understand you cover more ground with a 6" pad, but isnt the main advantage the 21mm orbit compared to smaller orbits? Would having a 5" backing plate with 21mm out perform other 5" set ups including LHR15? Or am I not understanding this correctly?



I currently have the Flex 3401 with both backing plates and use 5" plates on my Griots,PC also. Just looking for clarification as I want to add the Rupes or rather replace other polishers with the Rupes if its that versatile.

Yes, the LHR21ES with a 5" pad will very likely outperform other 5" set-ups, and it will undoubtedly out perform the LHR15ES.



I`ve given a lot of thought to the LHR21ES. Here`s a fun question:



Will the LHR21ES cut faster using a 5" or 6" setup?



I suppose that the 21mm ø machine outfitted with a 5" plate & pad could or might cut paint faster versus the 6" pad, but I`d have a good argument against the assumption that it definitely would.



Although the machine`s polishing energy would be concentrated onto a smaller area (potentially causing anything abrasive to abrade paint more rapidly), it would also be loading with paint residue more quickly than a similar 6" pad, assuming the 6" pad was polishing the same exact-sized area. When pads and abrasives are coated in paint residue, speed of cut diminishes, whle scouring usually increases.



If using a 5" pad, you`d be losing some speed along the edge of the buffing pad (a larger diameter pad spinning at the same RPM rate is traveling a longer distance, hence more speed). So, if actual speed instead of pressure is increasing the speed of cut, then the 6" pad would have an advantage.



Then... if we instead focused on repetitive scrubbing of the surface for a given RPM (taking pressure and edge speed out of the equation), imagine if you will the following:



If we were able to line up abrasive particles side-by-side along the edge of a 5" buffing pad, our "ring" of abrasive would measure 15.7" in length (circumference). If we then did the same using a 6" pad, the "ring" of abrasive would measure 18.8" in diameter. See? The 6" pad would scrub a particular area of paint 19.745% more per revolution!



We`ve all been using 5" pads and discs with our PC`s, G110v2`s, and Griot`s machines because they don`t seem to be able to create ample centripetal force (the force that causes the backing plate to start and continue to rotate). Basically, 6" pads or discs don`t seem to rotate as quickly as their 5" counterparts.



In terms of the 21mm BigFoot, there`s so much orbital motion and backing plate rotation going on (especially if the spacer is installed that eliminates scrubbing of rotational speed), that it`s difficult to know whether we`re gaining or losing cut depending upon the size of the plate & pad.



What did I mean about the platform size?



When you shrink the diameter of the plate & pad, the platform or support of the machine is smaller. How does this potentially affect performance? Time to take our comparison to extremes, and out of the realm of paint polishing.



Imagine that you are sitting at a dinner table, and the tabletop is split so that an extension leaf can be placed into it. If you had a glass full of water (12" tall, 1" diameter) sitting on the table, and you decided to slide it across the table by pushing it along with your finger (and your finger was pushing the glass at its highest point), I suspect that the moment the glass hit the split in the table, it would tumble over, spilling its contents. However, if you did the same exact thing, but instead you were pushing a glass full of water that measured 12" tall, 12" diameter... the glass would be much more stable, and there`s a pretty good chance that it would not tip over.



Back to the backing plates & pads: When encountering hood bulges, fender flares, or any other panel shape that is not totally level to the entire pad, the edge of the pad is going to have to navigate its way against and then up & over or against and then down & level to the shape. A large diameter pad won`t transfer as abrupt a "kicking" or "karate-chopping" sensation as a smaller pad might, so the machine will be easier to control, and quite possibly feel "smoother" during use on complex surfaces.



Just as a panel`s shape might cause the smaller platform to feel less stable or choppy, so too will angling of the machine. Add some tilt to the machine (in any direction... anything other that totally level to the polishing surface), and the same sensation will occur.



Hope this helps and doesn`t instead confuse things even more! Abbreviated a bit for simplicity.

[David Fermani]

Wow....This is turning into a pretty EPIC thread! Kudos to Kevin Brown!

[Kevin Brown]

Kevin, just a thought on the Rupes. Does anybody change the electrical cord and plug on the Rupes.. Seems to me like it very rigid and doesn`t have the suppleness of comparable cords on all others.

No doubt it has a RIGID cord! I haven`t seen anyone do it yet, but I suspect you may end up being the first.

Anyone in super cold climates probably despise the cord.

[LilJayV10]

My experience is limited to the PC using 5.5 pads. I will definitely be picking up the Rupes from Kevin later this spring but still on the fence to go with the 21 using the larger pads. I obviously want the most powerful polisher i can get but I`m afraid the 21 w/ the larger pads will be too cumbersome when using it on curved panels. Maybe I need to put my purse down and up my technique.

[C. Charles Hahn]

My experience is limited to the PC using 5.5 pads. I will definitely be picking up the Rupes from Kevin later this spring but still on the fence to go with the 21 using the larger pads. I obviously want the most powerful polisher i can get but I`m afraid the 21 w/ the larger pads will be too cumbersome when using it on curved panels. Maybe I need to put my purse down and up my technique.

Just get the 21 and a 5" backing plate; you can still use your 5.5" pads that way.

[LilJayV10]

Just get the 21 and a 5" backing plate; you can still use your 5.5" pads that way.

That`s probably what I will do. That way I can use the 6 inch pads on hoods, flat doors, etc and use the smaller pads on curvy panels. I saw that Rupes sells 7 inch pads. Damn!

[pwaug]

Mike P over on AG is doing a test--half the car with a 15, the other half with a 21, both on the clock. Everything else--pads, products, etc the same. Should be interesting.

[LilJayV10]

Mike P over on AG is doing a test--half the car with a 15, the other half with a 21, both on the clock. Everything else--pads, products, etc the same. Should be interesting.

That is interesting. Thanks for the info.

[autoconcierge]

Mike P over on AG is doing a test--half the car with a 15, the other half with a 21, both on the clock. Everything else--pads, products, etc the same. Should be interesting.

The 21 will win, put money on it.

[LilJayV10]

Any idea when he is going to post the results?

[ls7drew]

What 5" backing plate can be used on the 21 Rupes? On AG they say you can`t use the 5" Rupes backing plate on the 21. But I`d prefer to hear from Kevin and if you can use it, do you have any?

[pwaug]

Any idea when he is going to post the results?

Some time early this week.

[Kevin Brown]

What 5" backing plate can be used on the 21 Rupes? On AG they say you can`t use the 5" Rupes backing plate on the 21. But I`d prefer to hear from Kevin and if you can use it, do you have any?

Yes, it can be done! More about it here:



http://www.autopia.org/forum/machine...ml#post1525660



Yes, it is "legal" to do so (it won`t invalidate the warranty)!

To date, I have sold over (50) plates to guys using them on LHR21ES machines. Read about it here:



http://www.autopia.org/forum/machine...s-lhr21es.html



Yes, I have them in stock ($40.45 + $5 shipping via Priority Mail).

If you want one, e-mail me a request at iamwaxman@aol.com , and I`ll fire off a Paypal invoice your way.

[ls7drew]

Thanks Kevin! Very nice to know, ya just send an invoice over PayPal to 49erdrew@gmail.com

Yes, it can be done! More about it here:



http://www.autopia.org/forum/machine...ml#post1525660



Yes, it is "legal" to do so (it won`t invalidate the warranty)!

To date, I have sold over (50) plates to guys using them on LHR21ES machines. Read about it here:



http://www.autopia.org/forum/machine...s-lhr21es.html



Yes, I have them in stock ($40.45 + $5 shipping via Priority Mail).

If you want one, e-mail me a request at iamwaxman@aol.com , and I`ll fire off a Paypal invoice your way.