Rupes 21 -vs- Rupes 21 Mark II

Is it just me or does it sound different too? Sounds torquier. Almost like the difference between a base model Mercury Sable v.s. the Duratech Mercury Sable with the beefier 24V DOHC engine.
 
Yep, I definitely want one. I noticed how they added the rubber piece on the back side of the polisher as well. Nice touch.
 
Vega@Autopia said:
Is it just me or does it sound different too? Sounds torquier. Almost like the difference between a base model Mercury Sable v.s. the Duratech Mercury Sable with the beefier 24V DOHC engine.
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Its funny you mention it, b/c I hadn't noticed the sound difference until watching Larry's vid. I've logged a fair amount of time with the MKII, but hadn't noticed it, then again it would be hard to detect unless you were switching rapidly between the two.
 
Potentially, but you'll also substantially increase vibration. A fact many overlook is that the pad on the BF system, more than any other system before it, acts as a counterweight. Its been shown before, run a RUPES in free air with no pad, note the vibration, then attach a properly weighted pad and do the same. Its virtually vibration free when mated with the correct weight pad. While we can't say not to run a smaller pad, it really isn't the intended design for optimal performance.

Would make more sense to simply go with a LHR15 if you find yourself needing a smaller pad. Personally the 15 is my favorite tool in the line anyways.
 
I guess when you were at the Adams event you showed Adams pads etc. whats your thoughts on that? Or how does that work? Does Rupes bark at you guys about something like that?
To be honest, not really sure where im going with this......
 
Its well documented that RUPES endorses the use of their pads for the BigFoot tools due to their part in balancing the tool. I knew this going into the project with Adam's. RUPES foams didn't necessarily align with AP compounds, so new pads had to be selected. Knowing that we contacted RUPES, asked for spec weights on their pads and did everything we could match weights and densities (the Adam's pads are not just off the shelf LC pads). All that being said, I did my best on my final project with Adam's, to honor the RUPES philosophy of matching pad weights to tools.... are they a perfect 1:1 for RUPES factory foams? No... but they're the closest I'm aware of.

As far as demoing, Jason and I only gave a talk on the concepts of random orbital polishing and specifically efficiency and what the BigFoot line does that no other tools do. The actual paint correction demo was handled by Adam and his team.
 
I have the 15 and 21.
What I'm not understanding is when the pad stalls , are we losing oscillation and/or just the rotation?
It looks to me like just rotation stops.
With a free floating spindle how does a more powerful motor in the Mark 2 keep the pad rotating? Dont both the new and old machines oscillate at the same RPM?
 
Larry is now part of the marketing effort by Rupes more so than any other product I have seen him discuss.
 
ShawnF350 said:
I have the 15 and 21.
What I'm not understanding is when the pad stalls , are we losing oscillation and/or just the rotation?
It looks to me like just rotation stops.
With a free floating spindle how does a more powerful motor in the Mark 2 keep the pad rotating? Dont both the new and old machines oscillate at the same RPM?
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It would also be nice if Rupes was able to offer an upgrade for a reasonable price to convert a Mark 1 to a Mark 2. If it uses the same outer shell.

Will they consider selling the front piece with the newly added bumper as an accessory for the Mach 1 models?

I'm just thinking back when they had those Kirby and Electrolux vacuums. So many upgrades in the 70s.
 
ShawnF350 said:
I have the 15 and 21.
What I'm not understanding is when the pad stalls , are we losing oscillation and/or just the rotation?
It looks to me like just rotation stops.
With a free floating spindle how does a more powerful motor in the Mark 2 keep the pad rotating? Dont both the new and old machines oscillate at the same RPM?
Click to expand...

Shawn you are touching on a subject that many people do not understand, kudos.

When the pad stalls you are losing rotation, but in some cases you can loose oscillation (bogging). It really depends on why the pad is stalling in the first place.

This is fairly complex question to answer but I will do my best given that I am not an engineer.

There are multiple factors that "drive" the pad to rotate. One of the most important is the speed (and distance) of the oscillation. This creates the inertia that spins the pad (in simplest terms - its actually far more involved). By operating at a higher OPM, the force that spins the pad is increased.

However, even the OPM is subjected to load. If you hold the pad completely flat and press down as a hard as you can, then the OPM can bog. So now the pad's rotation is slowed by two things - the increased friction of loading the pad as well as the fact that the tool is no longer generating the same force that spins the pad.

With a more powerful motor (torque), the tool is more resistant to loosing OPMs, and thus the pad will resist stalling more (the force creating the spin remains higher). With a higher RPM motor that resists loosing OPM under load, you have another factor that resists bogging and thus keeps the pad spinning better.

The Mark II spins at a faster rate than the Mark I (4700 RPM/OPM vs. 4200 RPM/OPM) max. This is true - not advertised - RPM. However, this is a small part in the rotation, it is the ability the Mark II to spin faster under load that creates the faster pad spin. If we had a tool that had 20k RPM, but dropped to 3K with the slightest load, the pad rotation would suffer considerably.

One thing that really impressed people at SEMA was how they couldn't really stall the pad, even at speed 3. This isn't so much of a factor of the RPM, as it is the machines ability to maintain the RPM under load. That is, even on speed 3 it is very difficult to bog the motor because of the increase in torque.

When you encounter a significant curve in the body line that forces the pad to engage the surface at an angle, the pad is far more likely to stall. This is the nature of a random orbital tool. The higher RPM of the motor (again combined with a host of other changes) and the increase in torque does provide more inertia for the pad to spin, so it may drive through this better, but even so a 21mm random orbital will provide 80-90% of its cutting action form the orbital movement alone (provided the pad can transfer the movement to the paint). With the Mark II, far more power is available in the orbital action, so even on the rare occurrence that a pad will stall, it will still deliver far more cutting power to the paint.

Hope this helps.
 
Thanks Todd,
That's the best explanation I never expected..lol
I'm sold
I would think being a hobbyist it's fine having the Mark 1 models.
Did they improve the motor on the mini as well? Though I've never experienced that stalling on me.
 
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