Faulty 7424, or is me?

A

apoirier594

New member
I just got my first polisher. Got the 7424XP and the Megs. MF kit(5") from autogeek. The polisher seems pretty weak on speed 3, I have no idea how I could use a polish for that. Four is almost the same then 5 picks up, 3 and 4 seem to stop rotating rather easily but then 6 can take twice as much as 5 can.



I used D300 and the MF polishing pad on my mom's Camaro's back window. It had really bad etching or oxidization, never seen this before on a window. Anyways I had it on speed five and after 6 passes it got some of it out, but only certain spots. Then I maxed her out to 6 and it was really working, why is their such a big difference?



I was frustrated because I was using the Aqua Brush attachment to try to shampoo and as soon as it touches the caret it won't spin, just seems like it gets caught. I put it up to 6, it was spinning fine while in air then touched carpet with PC weight only and no spinning. I used the gray soft one and it spun but did noting to carpet.



Sorry for such long post but I want to make sure its fine before I correct my truck, and I was REALLY looking forward to not having to shampoo by hand anymore, a few members here said the attachment was great for them.



Before



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After



DSC_0667.jpg
 
apoirier594 said:
I just got my first polisher. Got the 7424XP and the Megs. MF kit(5") from autogeek...
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Noting that I've never used the XP model....



What you're experiencing sounds like the typical "why isn't my PC more powerful?!?" query.



As you've noticed, speed 6 is a whole lot more effective when doing significant correction. I'd stick with that for anything where a lower speed is not specifically desirable.



Aw gee...I really don't know what to say that'll really be of much help. I'm biting my tongue Re what does come to mind, namely "this is why some of us aren't big fans of the PC" :o
 
The tool was never designed to handle the "amp draw" that a brush attachment puts on it.

It was originally developed as an alternative to an air DA, for sanding wood, finish sanding and smoothing out of bondo, high build primers etc.

It was not until 89 that Mequiars found a way to use it in place of the old big orbitals to do finish polishing.

My suggestion is that if one is going to use a brush attachment for carpet, they move on to an air DA and have a compressor with at least 12CFM and 125PSI.

Grumpy
 
I haven't used brush attachments for my PC, but the lack of rotation sounds pretty normal. I don't think I've ever used mine at anything less than a 4. Speed 6 is definitely more powerful, but the vibration makes it uncomfortable for long jobs. I find speed 5 or 5.5 gets nearly the same results without causing fatigue so quickly. Speed 4 I use for spreading sealants. A few tips: Keep the pad level on the surface. Any angle will stop the rotation much more easily. Also, with the MF pads and D300 you will likely find it more efficient with less pressure. I often use D300 and M105 together for a little more cut when necessary.



There are some good threads about the MF system. You might find some other great tips for getting the most out of it with a little research.
 
The carpet brush works great on GG6". PC just doesn't have the power to spin a 6" pad or a carpet brush.
 
Thanks for the replies. Today was my first time ever using a PC and D300, I did half my hood on speed 5 but it took a bit over a hour for D300 then D301. That took out all the swirls, then I did the other half with D300 then D301 in 30 minutes and their are still some swirls. I do about 3 passes heavier and 3 with PC weight on speed 5. Should I bump it up to speed 6 or as Nth said just keep it at 5? Thanks!!



And whats the best way for me to shampoo carpet now? A lot of friends and future customers want me to shampoo their interior. I have D103+ and a hand brush with a shop vac. That takes forever tho
 
Get a Griot and use the PC for waxing.
apoirier594 said:
Thanks for the replies. Today was my first time ever using a PC and D300, I did half my hood on speed 5 but it took a bit over a hour for D300 then D301. That took out all the swirls, then I did the other half with D300 then D301 in 30 minutes and their are still some swirls. I do about 3 passes heavier and 3 with PC weight on speed 5. Should I bump it up to speed 6 or as Nth said just keep it at 5? Thanks!!



And whats the best way for me to shampoo carpet now? A lot of friends and future customers want me to shampoo their interior. I have D103+ and a hand brush with a shop vac. That takes forever tho
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Do you have the little spacer washer in between the backing plate and the PC??? Also more speed does not mean more cutting being done.
 
addr6 said:
Do you have the little spacer washer in between the backing plate and the PC??? Also more speed does not mean more cutting being done.
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Its obvious you never used the Dynabrade attchment on a dewalt at 3500 rpms. More rotations from the machine will in fact get more cutting done.



To the OP. I won't comment on them Porter Cables, but research hard enough you'll find my opionions on them! :tape:
 
apoirier594 said:
Thanks for the replies. Today was my first time ever using a PC and D300, I did half my hood on speed 5 but it took a bit over a hour for D300 then D301. That took out all the swirls..
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That isn't all that long to correct a panel via PC. Some of us have spent many times that!



then I did the other half with D300 then D301 in 30 minutes and their are still some swirls.
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Well, sounds like you just can't get it done in that amount of time. Doesn't surprise me at all.



I do about 3 passes heavier and 3 with PC weight on speed 5. Should I bump it up to speed 6 or as Nth said just keep it at 5?
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I'd be doing all the significant correction at speed 6 and I'd be applying pressure. And I don't consider six passes (3 with pressure/3 without) to be all that many depending on what you're trying to do and what kind of results your getting. You don't want to keep cutting paint for hours on end and overthin the clear, but if you're trying to remove not-too-deep marring (that's safe to correct) then it simply takes as long as it takes. Which can be a long time if you're using a machine that doesn't have a lot of oomph.



And whats the best way for me to shampoo carpet now? A lot of friends and future customers want me to shampoo their interior. I have D103+ and a hand brush with a shop vac. That takes forever tho
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There are places you can't get to with a brush on the machine anyhow, just gotta do those by hand and maybe you'll have to do it all that way if the PC isn't up to the job of scrubbing.



Make sure you're using the right cleaning chemicals for the job. Not every situation can be handled 100% with just some regular APC.



As with the polishing, yeah, it does take forever. Even when I use the steamer, the hot water extractor, my Cyclo with brushes, and any other time-saver I have on hand, sometimes this stuff just takes a lot of time.



When you consider doing cars for others and/or for pay, you need to give some thought to how much time and effort it takes you. Emphasis on *YOU*, not somebody here how posts how he can turn a beater into a showcar in two hours or somesuch ;)
 
addr6 said:
Do you have the little spacer washer in between the backing plate and the PC??? Also more speed does not mean more cutting being done.
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Yes I use the little washer. I took it out and it seemed faster but wouldn't spin at all when it touched paint, seemed like backing plate would screw in on a weird angle. Need less to say I put it back on.



Accumulator said:
I'd be doing all the significant correction at speed 6 and I'd be applying pressure. And I don't consider six passes (3 with pressure/3 without) to be all that many depending on what you're trying to do and what kind of results your getting. You don't want to keep cutting paint for hours on end and overthin the clear, but if you're trying to remove not-too-deep marring (that's safe to correct) then it simply takes as long as it takes. Which can be a long time if you're using a machine that doesn't have a lot of oomph.
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Well 6 won't work for me. haha, deft. much more comfortable at speed 5. I changed my passes to just 5 with pressure, but still a bit of swirls, so guess I'll try to up that to 8 or so when needed.



So what do you recommend? Flex DA? It looks great, just can't afford it now. Anyways the PC will eventually finish my car but if I'm doing customers I'm sure I'd need the flex.



What are some good pad and polish combos? Something I could use with the PC for more cutting power. I have heard the MF kit and D300 is good on a flex with all the power, I like it also on the PC just want a little more cut
 
apoirier594 said:
Well 6 won't work for me. haha, deft. much more comfortable at speed 5. I changed my passes to just 5 with pressure, but still a bit of swirls, so guess I'll try to up that to 8 or so when needed...
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OK, I understand and won't :nono: you about speed 6; preventing nerve damage from the vibration is a lot more important than polishing your car IMO.



But note that it's kinda a "threshold of effectiveness" issue, where that switch up to speed 6 makes for exponentially better results.



Be sure you don't overwork the product, but otherwise yeah..just do the number of passes you need to do in order to correct things. Eh, the good news is that if you're not taking out the marring then you're probably not overthinning the clear.



So what do you recommend? Flex DA? It looks great, just can't afford it now. Anyways the PC will eventually finish my car but if I'm doing customers I'm sure I'd need the flex.
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The Flex 3401 *is* a nice unit, and I do like mine. The Griot's Garage 6" RO is also nice, and does suprisingly well compared to the Flex considering that the Griot's doesn't have forced rotation.



And the Flex has a somewhat unique "recoil" that some people don't like. Not the same as the PC's vibration, but, well..it makes the Flex something that's not right for everybody.



What are some good pad and polish combos? Something I could use with the PC for more cutting power. I have heard the MF kit and D300 is good on a flex with all the power, I like it also on the PC just want a little more cut
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Although I hear they're not all that different, I'd switch to the MF cutting pad. For the product, you could try M105 or Uno, both of which have worked well for me on hard clear, even via PC. The smaller MF cutting pad, with either product, was great for spot-correction on my Audi, and that's via PC at speed 5 (I don't like high speeds with small pads). In fact, I've been keeping my one PC set up for 3" pads just so I can do this sort of spot-repair without messing around setting things up.



But the 6" MF cutting pad, with Uno, on the Griot's polisher at speed 6 *really* got the job done. No, not in just one pass or anything, but it still made a tough job go OK. I didn't even consider getting out the Flex because it was going OK with the more user-friendly Griot's.
 
Thanks Accumulator. Well my truck is still full of swirls except for my hood now. I have to re-wash before I polish and haven't had time. So this week I'll try it agin, with speed six to. I'll let yall know
 
Barry Theal said:
Its obvious you never used the Dynabrade attchment on a dewalt at 3500 rpms. More rotations from the machine will in fact get more cutting done.



To the OP. I won't comment on them Porter Cables, but research hard enough you'll find my opionions on them! :tape:
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Nope, never used the Dynabrade attachment. I was not aware thats what we were talking about.
 
Since this is your first time with the MF pads on a PC I wonder if your are cleaning the pad after each pass or two? If you have an air compressor try blowing the pad clean frequently. A clean pad rotates better and cuts many times better. A loaded pad even on speed six won't cut worth a damn. A pad that isn't rotating will also not cut well so mark the pad with a magic marker so you can see it rotate and don't apply so much pressure that stops the rotation. The MF pads cut surprisingly quickly, especially with #105 but the 300/301combo work fine for pumping out volume as long you keep the pad clean and rotating. Just a suggestion. Also, several have reported MF pad failure at speed six so be alert to any symptoms so you don't damage the paint.
 
addr6 said:
...Also more speed does not mean more cutting being done.
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Factors that increase abrasion ability

• Increased speed (Velocity)

• Increased pressure (Compression)

• Use smaller pad(Reduced surface Area)

• Using a slower panel transition speed (Increased surface contact time)

• Reduce the working area



The key to the polishing process is to know how the paint will react with each pad / polish combination you consider using. You must know your product and what its capabilities are before using it. This is why a ‘test’ spot is so important.

The factors that affect the outcome -speed, friction (kinetic energy) applied pressure, foam pad actual surface contact area, pad grit number (abrasive ability) amount of surface lubrication available, the surface area and heat conductivity of material
 
Hmm, I was told numerous times on these and he ag forums to not use speed 6 with the mf discs. Is that not true? Weren't there a lot of pad failures at those speeds? I use mine at the click above speed 5 and get decent correction, though I wouldn't say better than an Orange pad and SIP on the flex. I guess I should try it on speed 6 since I haven't been as impressed as everyone on here with the mf discs?
 
4-5 with the PC and the MF discs...vary your pressure!



perhaps your camaro has hard paint and you just arent strong enough (combo) D300 and MF isnt the strongest out there...try 105 and a surbuf to get more cut from the PC.
 
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