• If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Announcement

Collapse
No announcement yet.

Strike Through Demonstration

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Strike Through Demonstration

    The paint on a car with a clearcoat is made of usually of two or three stages: primer, colour coat and lacquer. When polishing, either by hand or machine, we are abbradding away a very small layer of the lacquer/clear coat in order to remove the paint defects.

    If you polish too far using to aggressive a compund, then it is possible to remove all of the lacquer coat and end up through to the colour coat - this is known as "striking through",and I'll demonstrate that here.

    First of all, start with a three-stage painted panel - this has just been polished with Farecla G3 to an excellent finish:





    Now, paint thickness readings were taken and revealed paint to be around 85 - 90um. This is very low thickness, and on a detail if you were to measure this thickness of paint then you wouldn't take any aggressive compounds to the paint... and this is why! I polishes the area by rotary polisher, Meguiars polishing pad and Farecla G3. One set of passes to thorighly break down the product, lift up the machine and here's the "yellow" pad:



    This is a big indicator that you have struck through the clearcoat as you are no polishing colored paint and the pigment is dying the pad... Looking at the area polished now, we can see what a struck through area looks like:









    Note that the area struck thorugh looks slighly lighter and lacks any of the gloss of the surrounding paint... This lack of gloss can be clearly seen under the Brinkmann light:

    normal area:


    struck through area:


    half and half:


    A check of the struck-through area reveladed a paint thickness consistently between 75 and 80um:





    So... there we have it, strike through.

    Clearly, if this was a genuine car and a genuine detail, if you measures paint thickness to be around 85 - 90um then you would rotary polish the paint with G3, as you would get strike through with the above... The moral of the story here being that if you are going to machine polish your car, its always much safer to check the paint thickness before using any abbrassive polishes, especially harsh compounds.
    "A thing of beauty is a joy for ever: Its loveliness increases; it will never pass into nothingness; .... "

  • #2
    Re: Strike Through Demonstration

    Very interesting.... you can really see it in the 'half and half' photo.
    Brandon

    2007 Black Chevy Avalanche

    My Albums: Avalanche
    Meguiars Online Acronyms - Meguiars Product List....

    Comment


    • #3
      Re: Strike Through Demonstration

      great write-up!! I'm sticking to an orbital on my baby, I'd cry if I damaged the paint in any way

      Comment


      • #4
        Re: Strike Through Demonstration

        Dang! I just wanna know whos car that was....hopefully not a customers...

        Comment


        • #5
          Re: Strike Through Demonstration

          Originally posted by SL1CK View Post
          Dang! I just wanna know whos car that was....hopefully not a customers...
          LOL, no - not a customers. Its a scrap door off of an old Peugeot 307 I use for testing products and doing demonstrations like this. Also have an old bonnet, and an old front wing for this too.
          "A thing of beauty is a joy for ever: Its loveliness increases; it will never pass into nothingness; .... "

          Comment


          • #6
            Re: Strike Through Demonstration

            Nice write up! Very interesting.

            I do have some questions though. What is an "um" exactly? And do you measure the three layers (primer, paint and clear coat) or just the top layer?

            Hope you can answer them.

            Ricardo

            Comment


            • #7
              Re: Strike Through Demonstration

              "um" is actually µm, which means micrometer or micron. The µ is the Greek letter mu.

              A micrometer is equal to one thousandth of a millimeter or one 25-thousandths of an inch. That just goes to show how thin the paint on our vehicles really is.
              2004 Ford F250 SuperDuty Crew 6.0L Diesel - Black
              2003 Ford Mustang Mach 1 - Dark Shadow Gray

              Comment


              • #8
                Re: Strike Through Demonstration

                You are measuring the thickness of al three layers with the gauge. Very expensive gauges exist that will differentiate (to ranging degrees of accuracy) between the three layers, but most gauges dont.
                "A thing of beauty is a joy for ever: Its loveliness increases; it will never pass into nothingness; .... "

                Comment


                • #9
                  Re: Strike Through Demonstration

                  Thanks guys for the replies.

                  Comment

                  Your Privacy Choices
                  Working...
                  X