My take on Diminishing Abrasives

[budman3]

I’m not sure if anyone else is confused about diminishing abrasives, but here is my take on the subject. Let’s start off with and example- sand paper comes in different sizes of grits and a quality piece of sandpaper will always maintain that same grit throughout the entire process. Since the grit is the same when you begin and finish, it has constant abrasives. In detailing, many companies have developed polishes with diminishing abrasives. These polishes start off aggressive to cut through damage and then the abrasives break down into smaller particles to create a smooth surface again.

Since you want to save as much clear coat as possible, do a test spot to find the least abrasive method which will remove the damage. You do not want to use a compound that is too aggressive – it will remove the swirling and marring BUT it will also remove clear coat that doesn’t have to be removed. This is why it is key to do a test spot to find a polish and pad combo that will remove the marks but nothing more. Once you become familiar with different polishes and pads, finding a combination will become easier. Many “hack detailers” simply grab a rubbing compound, a wool pad, and a rotary and go at it. Sure the marring will be removed but the clear coat will be as well. Also, if you do not let the polishes break down, you can be left with buffer swirls. Always use the least aggressive method as possible!

Once you find a polish, pad and even machine combo, it is time to work that polish into the paint. Different polishes ‘flash’ or work into the paint for different amounts of times. Experience with the products you are using will useful so you know how long to work it in.

Below are simplified and magnified versions of what is going on when you are polishing with diminishing abrasives in a two step manner. Polishing may definitely take more than two steps, but for simplicity I left it to only two. Possible examples of this type of combo are, and not limited to:
Menzerna Powergloss followed by Nano 106ff
Poorboy’s SSR2.5 followed by SSR1
Pinnacle XMT3 followed by XMT1
Meguiar’s #83 followed by #9
Etc.

http://i124.photobucket.com/albums/p39/kmford8/dim-ab.jpg


http://i124.photobucket.com/albums/p39/kmford8/dim-ab-fp.jpg

So, let me try and explain this a little more. As you see above in step one, the abrasives start off large but when friction occurs, the abrasives begin to get smaller and smaller. If you stop before the abrasives have had a chance to break down, you will be left with micro marring, which could have been removed if you kept on polishing. It is possible to finish a compound off in just one step if you use a soft pad with proper techniques. However, it is likely there are some light marks or marring still left, which is easily removed with a final polish.

The final polish diminishing abrasives (in an ideal world) will start off close to the same size as the broken down abrasive from the compound. Once the final polish has broken down, the abrasives will be very very small. This will remove any marring left from before and will finish off to near perfection.

Again, this is just my personal take on the subject at hand. Let me know if you read anything out of line or if you have anything to add. This isn’t meant to be a tutorial on how to polish rather just some background on something that can get a little confusing.

[makdaddy626]

To add some more "personal point of view" thoughts...

I don't think it's necessarily possible to finish without marring when using a strong compound, why? Because, and I'm just "guessing" here, not every particle will break down at the same rate, and/or, the speed at which particles break as a whole may change based on their state.

In scenerio 1, all particles do not break down at the same rate, some particles, due to difference amounts of heat and friction around the pad, break down to a "finishing" size, but others, are still to large and continue to create marring.

In scenerio 2, it may be that as particles break down, that the rate at which the break down occurs, speed up. So, a particle taken from PG that had diminished down to the starting point of a particle from Nano may not have the same working time, and correcting abilities that the particle from Nano has.

Hope that makes some sense to someone besides me... ;)

[Brian_Brice]

Very good thread, and well put posts by both.

There are a few compounds out there where the abrasives break down after a few passes almost completely, so really what you are left with after a few passes, provided the product has plenty of lubrication is technically a final polish, ohc is one that fits this description,(although I'm not fond of the new formula). Even still, the compounds aggressiveness still leaves unwanted finish behind, even after multiple minutes of polishing. Yes the product will allow you to continue polishing for a very long time, but the abrasive size itself was not designed to finish down perfect, that's where the final and mid level abrasives come into play.

[makdaddy626]

I think that is one of the big difference in many of the inexpesive compounds/polishes compared to the more expensive ones. The uniformity of particle size and the speed at which the break down.

[Jimmie]

:goodpost: vote here for "sticky"

[ScottB]

a diminishing abrasive could also be contributed to a marketing term. But I agree in general its the ability of a polish to break down into smaller abrasive particles.

[Todd@RUPES]

To add some more "personal point of view" thoughts...

I don't think it's necessarily possible to finish without marring when using a strong compound, why? Because, and I'm just "guessing" here, not every particle will break down at the same rate, and/or, the speed at which particles break as a whole may change based on their state.

In scenerio 1, all particles do not break down at the same rate, some particles, due to difference amounts of heat and friction around the pad, break down to a "finishing" size, but others, are still to large and continue to create marring.

In scenerio 2, it may be that as particles break down, that the rate at which the break down occurs, speed up. So, a particle taken from PG that had diminished down to the starting point of a particle from Nano may not have the same working time, and correcting abilities that the particle from Nano has.

Hope that makes some sense to someone besides me... ;)

You are very correct on both terms. The larger/sharper/harder the initial abrasive (specifically larger) the greater the difference in the way the abrasives breaks down, and the more marring that can occur, however...

As they breakdown, there comes a point, where the breakdown occurs faster (and faster) and the abrasive quickly looses the ability to polish out the marks it left behind. The reason that has been explained why this occurs to me is because as the pieces fracture, they multiply in number, so the begin to act against themselves and quickly "breakdown" other pieces at a faster and faster rate. This is why "most" heavier cut compounds also tend to cut very fast..

[ASPHALT ROCKET]

Great post, glad to see a few of these popping up lately.

[gary26]

So what happens when you use a product like XMT360 and you use it until it dissappears. Are the abrasives in this product so light it doesn't have any effect on the clear cloat. Hope this isn't a dumb question, still learning.

[Mr Dream Machines]

[I don't think it's necessarily possible to finish without marring when using a strong compound, why? Because, and I'm just "guessing" here, not every particle will break down at the same rate, and/or, the speed at which particles break as a whole may change based on their state.

You certainly can. Yellow pad and 800 to 1000 grit can be worked down so fine that you don't get marring
The better products have uniform aluminium oxide particles that from my experience all break down at the same rate. I keep the pads flat on the surface and have had no drama's there.

[TOGWT]

Diminishing abrasives require friction, not heat (that is just a by-product of friction) to activate and progressively reduce there size until they become a finite milled dust; they are buffered or cushioned in a lubricating water-based oil film emulsion, usually in a semi-liquid paste. Some very abrasive compound polishes don’t feel abrasive to the touch because the particles are formulated in a solvent or polymer oils in a water-based emulsion and are not released without friction. The abrasive start off as large particles, which remove the most paint, they are then reduced in size into finer and finer particles, removing progressively less of the paint surface, by the friction caused by the foam pads contact with the paint surface. By varying the size of the abrasive a differing cut is obtained, so the more the abrasives are reduced in size the finer the resultant finish until the particles are reduced to a very fine powder, which in turn produces a burnished surface shine.

The amount of size reduction (diminishing) can be adjusted by the type of abrasive material used allowing some polishes to used for the removal of surface scratches only, but if required can then followed up with a finishing type polish that contains smaller abrasives. Were as some polishes will remove surface scratches and by changing the abrasive ability of the foam pad will then go on to buff the surface to a shine ready for the application of a last step product (LSP)

Extracted from- Diminishing Abrasives- - Detail University - Auto Detailing Forum (http://www.detailuniversity.com/forums/school-exterior-detailing/1865-diminishing-abrasives.html)

[YankeeFan]

The question that comes to mind is, why does damage occur when you go past the point of the polish becoming translucent? If all the abrasives are gone why the damage?

Howard

[budman3]

Howard- once the product flashes and is broken down there's a good chance that it'll dry out shortly there after. So essentially you'll be dry buffing, the lubricants from the polish won't be there and the dried up polish and pad will likely cause micromarring. I'm not sure if that is the damage you are talking about though.

[TOGWT]

Howard- once the product flashes and is broken down there's a good chance that it'll dry out shortly there after. So essentially you'll be dry buffing, the lubricants from the polish won't be there and the dried up polish and pad will likely cause micromarring. I'm not sure if that is the damage you are talking about though.

Agreed- you may or may not have surface lubricaton left from the polish but either way you will have the abrasive ability of the foam, which will cause micro marring or worse if 'dry' polishing

[fenderbender]

Diminishing should be out of the question today.
We now have non diminishing polish w/nano construction which means you can stay on the panel longer.without damage.good example of this .The jeweler used a diminishing product of varied sizes had to have a recovery system to reclaim gold ,now they use a non diminishing nano construction have hardly any to recover. The same goes for your paint. In an effort to cut cost emission waste the manufacture is cutting paint total millage.some are down to three mills from bare metal.Not much clear to cut into. Remove to much clear delamination starts.