PC 7424 Meltdown!!

Discussion in 'Tools - Machine Polishers, Pressure Washers, Detai' started by floraneg, Aug 14, 2010.

  1. floraneg

    floraneg Birth of a Detailer

    Has this happened to anyone, or has anyone ever seen this before? I was using my PC7424 on my Vette this evening and the backing plate fell apart and scratched the crap out of the car. I had just finished the hood and was moving to the front quarter panel of the passenger side when I noticed some small yellowish debris. I thought it was the SHR and moved the PC upward toward the hood to turn it off when all of a sudden all hell broke loose.The pad shifted and the backing plate, or what was left of it came in contact with the car. The yellowish debris is very sticky and feels like warm marshmallows. I pulled out the 4" spot pads and it took me over an hour to get the scratch out!





  2. mrd0t

    mrd0t Obsessive Detailer

    :yikes: Not good..thankgod it was your car and not a customers.
  3. Asphalt Rocket

    Asphalt Rocket Nuba Guru

    This happens when the PC gets to hot and transfers that heat to your pad. I a couple things that will help in the future. I see a white cord in your picture, if that is your extension cord it is too small, do you have the brown washer in between the backing plate and the pc itself. The washer came with pc in the plastic bag with your wrench. Lastly excessive pressure being applied to the pc will cause it to get very hot and melt a backing plate. You will have some say it is a defective backing plate if it is the original style. I have an original style backing plate and mine has not broken when using the pc, this is from using the pc correctly and I am not saying you are not. Those would be the reasons you have had this problem. Good luck on finishng your vette, from one vette owner to another.:thumb:
  4. floraneg

    floraneg Birth of a Detailer

    The white extension cord was not used with the PC. I was using an orange one with the unit. As for the pressure, I really wasn't applying any pressure at all. I was just holding the unit sideways on the panel. I was wondering if it had something to do with priming the pad to much causing the glue to break down or something to that effect.

    The plate is the original that came with the unit. I purchased it about 4 years ago and have only used it about 5 or 6 times. Looks like I'll be geting a new plate to finish the car. It's a killer trying to do the Vette with the 4" pads.

  5. eyezack87

    eyezack87 Guest

    I melted 3 of those before sending one back by request to Lake Country for analysis. Then melted the new version and sent that back too. The one you see for sale on Detailed Image is the newest one. I have yet to melt it LOL
  6. supercharged

    supercharged DB Forum Supporter

    4 words of wisdom - upgrade to Flex VRG3401!!!
  7. supercharged

    supercharged DB Forum Supporter

    That's because PC simply doesn't have the power you need! And even new XP7424 still needs MORE POWER! The difference between PC and Flex is like a difference beween 328 and M3. And trust me, there is a BIG difference!
    take a look at this - YouTube - Flex XC 3401 VRG vs. Porter Cable 7424
  8. eyezack87

    eyezack87 Guest

    Late post but I was in NY so don't blame me :p. It had plenty of power for me. It just took longer thats all. I was doing the "KBM" before it popped up. I just didn't brag about it or anything thats all
  9. Kevin Brown

    Kevin Brown Buff Daddy

    Hmmm... that's strange... :shrug:

    My little G100 had plenty o' power to pull some 1500 grit sanding marks just the other day.
    Then I used it on a E63 AMG , an SL500, a '56 Bel Air Wagon, an ML430... about 70 hours of detailing & polishing. No busted plate... nothing but shiny paint!

    Maybe I got a good one? :gidiup:

    FWIW- my little G100 can outspin the Flex 3401 VRG on the top end! :headbang:
    Plus, it features a maxumim of 6,800 OPM versus 4,800 OPM for the Flex.

    Product, pad, procedure.

    Wouldn't trade my one G100 for FIVE 3401 VRG's. Never liked the Flex. LOVE the Festool Rotex RO150 FEQ, however. A bad Mamma Jamma.

    BTW- please don't take offense to this, supercharged... just happy to be revisiting the forum. been gone a while. Wheeeeeeeee!!!! :afro:
  10. daveinsweethome

    daveinsweethome DB Forum Supporter

    i also love my meg polishers. with different backing plates i use the flex for bigger jobs but the size, feel and performance of megs is it for me too.
  11. Kevin Brown

    Kevin Brown Buff Daddy

    Uh-oh... :thud:

    Don't know if you primed the pad thoroughly, but you'd have to rub the compound in pretty darned hard to rip a molded urethane backing plate apart like that.

    Don't know how much product you were using, but I doubt it was heavy enough to cause a backing plate to fail.

    Don't know how fast the backing plate was a' spinning, but since those plates are typically good for 12,000 RPM...
    I doubt it blew to smithereens like kiddies flying off a small-block powered merry go round.

    This leaves TWO possibilities.

    Either the backing plate was DEFECTIVE... which is not common, but DOES happen.

    Or, you were using TOO MUCH PRESSURE! :yikes:

    Since I was not there, I cannot say with certainty.
    But, I have seen pics of your backing plate, and another on MOL just yesterday failing while using Surbuf pads.
    Typically, guys are using the Surbuf at very high speed with very little pressure.

    Too much pressure and the plates heat up, then BREAK or SHEAR.

    Too little pressure and the machine is essentially trying to violently shake the plate off the spindle (kitty kat, tape stuck to paw, violent paw dance).

    Here is some DB posted info from awhile back regarding the "KBM":



    Best of luck, and if you see smoke billowing from the urethane backing plate.... BACK OFF!! :gasp:
  12. Legacy99

    Legacy99 Wax on..Wax off

    Some of the older LC backing plates were defective. I had one go bad and seen 4 brand new, still in the package just crumble.
  13. Kevin Brown

    Kevin Brown Buff Daddy

    That's a relief.... sort of. :shrug:
  14. mujjuman

    mujjuman Virgin Detailer

    damn it! right when i bought a 7424!!
  15. CU2MIKE

    CU2MIKE Guest

    Actually, I have used to the Flex VRG, and I did not like it one bit (no offense supercharged, as everyone is entitled to their own opinion)
    But the VRG fights me too much, much more than my Makita fights me at times. When I say it fights me, I mean that it wants to go and do its own thing, although by doing the figure 8 method lessen that dramatically, I'd still prefer my trusty Griot's (and if the deeper RIDS laugh at my Griot's, I simply pull out my Makita)
  16. Kaban

    Kaban Welcome to Detailing

    For the record the VRG3401 has a max obit rate of 9600.... not 4800 as you claimed.

    What kind of backing plate were you using on the PC? Looks like the Lake Country DA plate.
  17. Misha

    Misha Nuba Guru

    does look like lake country. once phil has are not like that, even though they are harder at least they dont separate
  18. supercharged

    supercharged DB Forum Supporter

    It probably has to do with experience you have with it...honestly, I remember polishing my car with PC 7424, it took all effing day, results were WAY from satisfying, and as a matter of fact it literally shook the heck out of me, and mayde me dehydrated...I felt like I was polishing myself insead of a car...and I wasn't even half way done...I was so pissed, I upgraded to Flex immeditely and never experienced that problem...But even with that I still wished for a more powerful machine, and upgraded to Makita rotary...I still have my old 7424 that I use from time to time to apply sealant/wax, but it's VERY WEAK for serious paint corrections which will take an etternity to complete...and I HATE how it shakes the f*** out of you, instead of correcting defects...maybe it's just me, maybe not...
  19. morgan_w

    morgan_w Virgin Detailer

    What's your definition of a "serious" paint correction? I have completed many (what I would think) are "serious" paint corrections with my 7424xp in a timely manner, as well have many others.
    Like Kevin Brown said, removing 1500 sandingmarks isn't serious I don't know what is. The fact that you are getting shaken to death, sounds like user error. Don't get me wrong, use a D/A for a constant stretch of time it puts off some good vibration for sure, but then again how much strength does it take to control a rotary as well. To each their own. But I think upgrading to a rotary because it's taking to long or not enough POWER is the wrong reasons because as many have proved D/A's can hold their own with proper techniques/procedures and products. This doesn't mean, I don't think the rotary has it's spot in a good detailer's arsenal!

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