Clearcoat Strike Through- Rupes

[kdubski]

Hi guys,

In my 6 years of polishing paint I've had 1 incidence of burning through clear (rotary with wool).

Friday I was cleaning up a 2004 BMW m3 with a rupes 21, meguiars microfiber cutting pad and megs D300 compound. I made 2 sweeping passes over a 3 foot span on speed 4 and I think I struck through my clear coat.

Is this possible with a dual action polisher or was there no clearcoat here? I am losing sleep over this.https://uploads.tapatalk-cdn.com/20171128/cd1f1fee76089bf829b0bf2c14fb2a15.jpg

Sent from my SM-N950U using Tapatalk

[RaskyR1]

That is very possible with a DA, especially on an edge like that and on a 13+yr old paint. :(

[TTQ B4U]

Time for thickness gauge. Best money you'll ever spend. I wouldn't work on a vehicle I didn't own without one, let alone my own cars even.

[Rsurfer]

Time for thickness gauge. Best money you'll ever spend. I wouldn't work on a vehicle I didn't own without one, let alone my own cars even.
:iagree:No detailer should be without one, especially when doing correction work.

[parshisa]

What gauge at a reasonable for non-professional detailer would you recommend?

[Rsurfer]

What gauge at a reasonable for non-professional detailer would you recommend?
https://www.autogeek.net/highline-paint-gauge.html

[2black1s]

I'm not looking to start a debate over the usefulness of a paint thickness gauge as we all have, and are entitled to, our own personal opinions on such. That said, using a paint thickness gauge isn't going to do anything at all to prevent a strikethrough on an edge like shown here.

Strikethroughs on edges are caused by improper technique more than anything else. Next up would be a slip, which we are all capable of, across an edge inadvertently.

My personal belief is that an edge should never be touched with any kind of machine polisher. You can work up to an edge but not over the edge. And when doing so the polisher should be slightly tilted such that only the side of the pad that is rotating in the direction away from the edge is making contact. If you hold the pad flat, or tilted the wrong way, pad rotation into the edge can and will cause excessive abrasion across the edge and thereby increase the chance of a strikethrough. This is especially important when using a rotary polisher although the same precautions are prudent even when using a much more forgiving DA polisher.

Another thing to consider is that the paint thickness on an edge will always be thinner than the more flat surrounding areas. The sharper the edge is, the more pronounced the thinning effect is. The reason is that when paint is applied it tends to flow away from an edge. This is the primary reason for making my initial statement that a paint thickness gauge would do little, if anything, to prevent the kind of strikethrough described here.

[TMQ]

I'm not looking to start a debate over the usefulness of a paint thickness gauge as we all have, and are entitled to, our own personal opinions on such. That said, using a paint thickness gauge isn't going to do anything at all to prevent a strikethrough on an edge like shown here.

Strikethroughs on edges are caused by improper technique more than anything else. Next up would be a slip, which we are all capable of, across an edge inadvertently.

My personal belief is that an edge should never be touched with any kind of machine polisher. You can work up to an edge but not over the edge. And when doing so the polisher should be slightly tilted such that only the side of the pad that is rotating in the direction away from the edge is making contact. If you hold the pad flat, or tilted the wrong way, pad rotation into the edge can and will cause excessive abrasion across the edge and thereby increase the chance of a strikethrough. This is especially important when using a rotary polisher although the same precautions are prudent even when using a much more forgiving DA polisher.

Another thing to consider is that the paint thickness on an edge will always be thinner than the more flat surrounding areas. The sharper the edge is, the more pronounce the thinning effect is. The reason is that when paint is applied it tends to flow away from an edge. This is the primary reason for making my initial statement that a paint thickness gauge would do little, if anything, to prevent the kind of strikethrough described here.

I'm with him on this...PLUS microfiber pads on edge? That'll do it! If it was a foam pad you might have gotten away with it. It is really a sick feeling to do that. I've burned through a few in my day---not fun!

Tom

[Mike Phillips]

I cover this topic in all my classes.

Hang tight - I’m still at home, when I get to work and have the ability to use a keyboard I’ll share in this thread what I share in my classes.

:)

[Mike Phillips]

Ahh..... it's good to be back at work after a week off on vacation and a week almost completely offline...


About burning through edges and raised body lines...

Tom you may or may not remember what I'm going to type below but I covered this topic in the 3-day class you attended here but then I covered hundreds of topics and I'm confident most people do not remember every topic I cover.


Here's the real-world deal...


Anytime you're buffing out a car, new or old, you have KNOW IDEA



Who has buffed the car out before you and their skills and abilities?
How many people have buffed the car out before you?
What they used for tools, pads and products?



There's a HUGE difference between the skills and abilities of a hack detailer and a knowledgeable detailer.

There's a HUGE difference when it come to paint thickness on edges and raised body lines on cars that have been buffed out multiple multiple times over the years and a new car that's never seen a buffer.

There's a SUPER HUGE difference between tools and pads but most important --> abrasive technology, that is the quality of the compounds, polishes and cleaner/waxes used by a person.


The above are all VARIABLES that you cannot control. Think about the above three key variables when standing in front of a car you're about to detail. And then know and understand that paint is naturally thinner on edges and raised body lines AND paint is naturally thinner on edges and raised body lines if the car has already been buffed out by hack detailers using low quality products.

Also keep in mind that it's EASY to stand next to a car and buff out the easy panels, you know, panels like the hood, tops portions of the fenders, top portions of the doors and trunk lids. For most detailers, especially without a lift, it requires more work and less glory to sit your butt on the ground and buff out the lower panels.

So what portions of a car do think are at the most risk for having thin paint? The lower portions or the higher easy to buff portions?

Where do you think the paint will be thinnest? the middle of a door panel or the middle of the hood? The edges or any raised body lines?


The above are the things I think of when I look at a car to size it up before buffing it out. The above are things everyone should know and understand when standing in front of any car and sizing it up before buffing it out.


Also....

People ask me all the time if it's possible for an orbital polisher, (any brand), to burn through the paint on a car.

The answer is of course "yes". My answer is always, you can burn through paint by HAND if it's already whisper thin....


Whisper Thin Paint on Classic Cars by Mike Phillips - Be Careful! (http://www.autogeekonline.net/forum/ask-mike-phillips-your-detailing-questions/104788-whisper-thin-paint-classic-cars-mike-phillips-careful.html)


:)

[kdubski]

My technique is sloppy in that case. I use the above mentioned technique when compounding with a rotary, hence my limited clear coat strike through's. I never imaged this to happen with a rupes that I recently purchased.

Time to take the Rupes more seriously!

[TMQ]

Thanks Mike...

The information you just provided is just What I needed to hear---(again). As one buffs out more and more cars---the information/concepts becomes even clearer!

Yeah...I needed that!!!

Tom

[kdubski]

Do you guys recommend 3" pads for the sections with a lot of body lines? There are a good amount on the M3...

[Calendyr]

While I agree edges are more sensitive and all, I would never do a compound without mesuring the paint first. Yes edges are more vulnerable and have less clear coat, but if the paint is already super thin, the difference may very well be a strike through on the first pass over an edge compared to no strike through.

For me it' very simple. Anything under 100 microns I will not use a compound on. When that happens I tell the client I can polish the paint, it will remove some of the swirls but will not affect the scratches and it will remove any oxydation and will make the paint shinier. Then it's their decision.

Some brands have ridiculously thin paint now, the worst has to be Mazda. I came across a brand new Mazda SUV with paint thickness ranging from 50 to 70 microns this summer. This is borderline idiotic.

As for pads, 3 inch pads are not very good for correction work. I think the issue is that most of the correction is done on the edge of the pad or something. You can tape the edges if you can't avoid going over them. Otherwise you can lift the machine at an angle when close to an edge so no pressure is applied on the edge. Mostly you want to simply leave a little bit of room close to the edge.

With a Rupes 21, curvy cars are definatelly a challenge. You might want to invest in a second polisher with a smaller throw for those cars. Something like a Boss 15 or Rupes 15. I use 5 inch pads on a Bigfoot 21 and always manage to work my way on pretty much any car shape, but some are a lot more difficult than others (Porshes are a good exemple).