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  1. #1

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    Newbie question: Are rotary polishers supposed to wobble?

    I bought a Drillmaster 69474 7-inch sander/polisher from Harbor Freight this morning. When I run it, it takes a little while to get to full speed, which I understand is normal. The disc also wobbles quite a bit, and the whole thing seems to run a bit unevenly. Is this intentional, or should I take it back? I have the unlimited replacement plan, so exchanging it would not be a problem. This is not a DA btw.

  2. #2
    dansautodetailing.com Stokdgs's Avatar
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    Re: Newbie question: Are rotary polishers supposed to wobble?

    When you have no backing plate or anything else on the rotary and you run it, what happens ??
    If it runs smooth, at all speeds, then you add the backing plate and repeat the process, what happens ??
    If you put a pad on the backing plate and run it through the speeds, what happens ??
    No Rotary should wobble, and actually, a Rotary runs smoother than anything else..
    Dan F
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    Re: Newbie question: Are rotary polishers supposed to wobble?

    Quote Originally Posted by Stokdgs View Post
    When you have no backing plate or anything else on the rotary and you run it, what happens ??
    If it runs smooth, at all speeds, then you add the backing plate and repeat the process, what happens ??
    If you put a pad on the backing plate and run it through the speeds, what happens ??
    No Rotary should wobble, and actually, a Rotary runs smoother than anything else..
    Dan F
    Thanks, Dan! The machine did a lot of rattling even with the back plate off (no wobbling obviously since there was nothing left that could wobble). It ate itself through a layer of clear coat and messed up the paint, which was probably more my fault than the machines, but I decided to return it for a DA polisher.

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    Re: Newbie question: Are rotary polishers supposed to wobble?

    Quote Originally Posted by D. Tail View Post
    It ate itself through a layer of clear coat and messed up the paint, which was probably more my fault than the machines, but I decided to return it for a DA polisher.

    I don`t think there`s any "probably" involved that it`s not the machines fault.

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    Re: Newbie question: Are rotary polishers supposed to wobble?

    Just because I messed up doesn`t mean the machine didn`t have a problem.

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    dansautodetailing.com Stokdgs's Avatar
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    Re: Newbie question: Are rotary polishers supposed to wobble?

    D.Tail,
    Sorry this had to happen to you and your vehicle..
    Dan F
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    Re: Newbie question: Are rotary polishers supposed to wobble?

    Quote Originally Posted by D. Tail View Post
    Just because I messed up doesn`t mean the machine didn`t have a problem.
    True, but that (perceived) problem didn`t burn through the clear coat. For the sake of that person googling "drillmaster polisher issue" next week lets be clear, it was never determined that the unit had an issue, and the outcome wasn`t the units fault either. If you thought it did have an issue you should never have put pad to paint to begin with.

    I`m not trying to rub your nose in what you did, you`re not the first person to do it and years ago I did wetsanding a very valuable car, but we need a perspective here and that perspective is let`s not blame the tool because there`s a high probability that wasn`t the issue here. Take it as a learning experience. .
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  8. #8
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    Re: Newbie question: Are rotary polishers supposed to wobble?

    There are instances where we mean well, but have no business making the attempt. I can tell you Rotary polishing should not be taken lightly. Learn on a "junk car" that means nothing to you or the owner. Lots of material here to read and learn. Good luck!
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  9. #9

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    Re: Newbie question: Are rotary polishers supposed to wobble?

    Thanks for your replies, everyone! I have certainly learned my lesson and won`t go back to rotary polishing anytime soon. I also won`t buy HF power tools again. I know a lot of people have good luck with them, but here is the thing: If I know the tool is good, then I can focus on my mistakes and on correcting them. Here is another example: I took back the HF sander and replaced it with one of their DA polishers. The thing works, but it vibrates like crazy, and below level 4, it stops spinning literally when you just look at it. I know poor technique, saturation of the pad, too much pressure, etc. can all cause this, but this seems extreme. Could an accomplished detailer still get the job done with the polisher? Probably, but I`ll return it and get a Porter-Cable instead. That way, I know that if I do my job right (at some point... ), the machine will too.

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    dansautodetailing.com Stokdgs's Avatar
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    Re: Newbie question: Are rotary polishers supposed to wobble?

    D. Tail -
    All D/A Random Orbital machines need speed to keep the pad rotation going.
    If I ever use one like with a 3" pad on badly water stained glass, I run it full speed to get as much pad rotation as possible to break down the glass compound.

    The Porter Cable Sander/Polisher machine is not going to rotate all that great either, but fortunately, there have been a few good advancements in compounds and polishes, so that supposedly, one can use a machine like this and get pretty darn good results.

    But it will still take longer than a good Rotary ( DeWalt, Makita, 3M), and there will be Vibration, which may or may not be a good thing to deal with long term..
    Your hands and arms will have to absorb the vibration through the handles and I think that over time, it cannot be good to your body to a certain degree..
    Now, if you only do this once and awhile, then it might not be as bad..

    I dont know the pricing but a lot of people over a decade+ have gone to the Griot machine and had good results with the power and I guess pad rotation of it.. And they have or used to have a Lifetime warranty, and many have had to use that because they break down with hard use apparently..

    There are more expensive machines in that line like the Flex 3401VRG which is more forced rotation random orbital, but still not a true Rotary, and the Rupes machines which everyone really likes around here..

    Like I have said before, pad rotation is what helps break down the product with the pad and clean, level, and polish the paintwork to a great place..
    The Random Orbital machines all do this, some better than others, but you need to run it full speed and make sure its still rotating.. Draw a straight line with a Sharpie on the top of the backing plate so you can observe it going around and the speed it is rotating..

    So yes, an accomplished Detailer and about everyone else who wants to put in the time and effort, really pay attention, be really innovative and try new things until you find the best process for that paintwork that day, and work at this a lot can do some pretty darn good things out there if you want.. You just really have to want to... It all comes down to that...
    Good luck !
    Dan F
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  11. #11

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    Re: Newbie question: Are rotary polishers supposed to wobble?

    Quote Originally Posted by D. Tail View Post
    Here is another example: I took back the HF sander and replaced it with one of their DA polishers. The thing works, but it vibrates like crazy, and below level 4, it stops spinning literally when you just look at it. I know poor technique, saturation of the pad, too much pressure, etc. can all cause this, but this seems extreme. Could an accomplished detailer still get the job done with the polisher? Probably, but I`ll return it and get a Porter-Cable instead.
    The HF DA is a decent machine--certainly not the best, but decent and there are allot of people out there using it with great success. Certainly a capable machine for someone just starting out--then later it can always be dedicated to 3" or 4" pads for polishing tight areas when you step up to a better polisher. However, the 6" backing plate that comes with the HF DA is not of great quality and if you used the HF backing plate with HF pads that is most likely the source of the excessive vibration and the stalling on speed 4. Replace the backing plate with a quality 5" backing plate and quality 5.5" pads and you`ll see considerable improvement. Also, make sure you are using proper technique as improper technique will stall most any standard DA.

    If you think the PC is going to solve the stalling issue you`re in for a big surprise as the PC has less power than the HF and again proper technique will stall the PC just as it will the HF DA.

    Here`s a collection of articles and video`s by Mike Phillips that may help you--pick and choose those that apply to your situation--Car detailing articles by Mike Phillips - Auto Geek Online Auto Detailing Forum
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    Re: Newbie question: Are rotary polishers supposed to wobble?

    Thanks, guys! Yes, the PC doesn`t necessarily seem to spin a lot better, but I just spend an hour with it on the car, and the results I am getting are a lot better than with the HF machine, so I am very happy. I have been using the machine with Meguiars Ultimate Compound to get the clear coat nice and smooth and then worked on the stubborn areas with a more aggressive, hand application-only compound. It`s becoming clear (no pun intended) that the shine I am getting isn`t on par with the high-gloss factory coat, but it`s looking a lot better than the rusty scratches. I think with a bit more work, I can get it to a point where the casual observer won`t notice the work. This is the hood - the other parts are farther down and will be easier.
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  13. #13
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    Re: Newbie question: Are rotary polishers supposed to wobble?

    Its very important to realize that while "Rotary polishing" can be challenging, it is best performed by those who have gained the "knack" and "feel" for the surfaces being "corrected". It can take years to gain Rotary expertise. Some NEVER do, not through any fault of their own. If you don`t trust yourself, that is being very smart, then don`t try it. I have also said in this forum before, its hard to refer to yourself as a "detailer" without "Rotary Skills". Its kind of like calling yourself a Dr. without a degree. "Rotary" expertise SAVES you money in the time it takes to "perfect" panels. One of the only reasons I stayed in detailing for 42 years is God blessed me with the ability to use a "Rotary" I have made the "Flex" and the "Makita" some of my favorite tools. Good Luck! Paintxpert

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    Re: Newbie question: Are rotary polishers supposed to wobble?

    Consider this, I do more BLACK cars than any other color. I don`t even use my new Flex da, even though it is a "stunning" tool. But time is $$$$$! So I take on the correction with my Rotary. Black Maserati Sport yesterday, car wash beat. 125,000 dollar car, you had better know what your doing! I "meditate" while concentrating on unfolding the curves on the vehicles surface. All conditions have to be right for a Superior job.

 

 

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