TR2/3/3A Buffing out paint.

[PC]

Steve, two questions:

Do you have an air compressor? If so, how powerful?

Is the Finesse-It 39003 the only product you've been using with the buffer?



(OK, 's 2.5 questions...)

 

[PC]

It would also help if you post pix of the 20 year cat with one tooth.

 

[sp53]

Well the cat rarely shows her tooth, but I do have an air compressor. The finesse ll compound is a polish and I have that Black Ebony glazing I might try when I get the orange peel down enough and after I use the finesse ll. I guess there is new 3000 sound paper that kinda looks like a leather pad. I picked one a pad of it, but have just been using it by hand when I get buildup of paint from wet sanding. The 3000 stuff is supposed to provide a very high gloss, but I have not got the Velcro adapter for it yet plus I am not sure about using it. What I really want is the orange peel removed and a flat surface and some gloss.

 

[sp53]

Tex-N, I am so glad you posted your orange peel photos because we are both doing our first paint jobs. I thought that clear coat base coat did not orange peel because I did not know any better. Anyways, I hope this not too confusing, but when you were doing the "color sanding" and got to those little tiny low spots maybe 1/16 in diameter between the orange peel-- did you leave any of them shinny so the buffer would remove paint and come down to them. Or did the whole panel become dull in every angle of light before you started buffing. I mean like twisting the panel and looking super close, so that the whole galaxy was dull at any angle. They to me look like little bright stars in a galaxy. I was in high school in the sixties, but anyways-- all gone –dull-- before you buffed

 

[PC]

The reason I asked about the compressor is that pneumatic palm sanders are the workhorse of the refinishing world. If your compressor has the power to run one you may want to consider it. Everybody flinches when they first hear the idea of wet sanding with a power tool but the reality is that they are far more consistent than hand sanding and when used properly give far better results with way, way, way less work. They actually produce a less severe scratch than hand sanding.

... The finesse ll compound is a polish and I have that Black Ebony glazing I might try when I get the orange peel down enough and after I use the finesse ll. ….

Since 3M’s website is pretty useless, I called their tech support. They said Finesse-It II 39003 is a fine finishing polish. It will not remove sanding scratch. You will need to use a compound after sanding and before the 39003. (They also said 39003 is a discontinued product.)

…. I guess there is new 3000 sound paper that kinda looks like a leather pad. I picked one a pad of it, but have just been using it by hand when I get buildup of paint from wet sanding. The 3000 stuff is supposed to provide a very high gloss, ….

3000 paper does not provide high gloss. Nor does any other paper used in the auto finish industry.

What 3000 paper does is produce scratch that’s fine enough to remove easily with a compound. You will still need to compound.

… when you were doing the "color sanding" and got to those little tiny low spots maybe 1/16 in diameter between the orange peel-- did you leave any of them shinny so the buffer would remove paint and come down to them. ….

Buffing does not remove orange peel. Buffing makes the finish glossy. If you buff orange peel you get glossy orange peel.


The more or less “standard” process for sand, cut and buff is:

Coarse (“color”) sand to remove or reduce texture (orange peel) – abrasive sheets approximately P800 (ish)

Fine (“color”) sand to remove scratch leftover from coarse sanding – abrasive sheets, approximately P1200

Compound to remove sanding scratch leftover from fine sanding – heavy cutting compound, rotary buffer, wool pad

Polish to remove swirls and haze leftover from compounding – finishing polish, rotary or DA buffer, foam pad


That’s pretty much the "generic" (dare I say "universal?") process. Follow it and you maximize your chances of success.

It can be modified depending on the specifics of a given situation. Some may add extra fine sanding (P3000, P4000 or P5000) to reduce, modify or possibly eliminate one of the buffing steps. Some may use only foam pads, Some may use only DA buffers, etc. But just about everybody starts with the generic process and only makes changes as they develop a system to meet their specific needs.

 

[sp53]

Thanks for typing that out PC; I followed every word of it and understood what each step means now plus I have it in print for reference. When I talk to someone, it often goes in one ear and out the other. My concentration is in question. Yesterday I was behind this new black Mercedes SUV and noticed the orange peel from 10 feet away on a beautiful vehicle. So I can see now this paint world is the lunatic fringe and the color sanding would be at my level the only way to get that high quality because of my inexperience and equipment I have. I might stop fine tuning this paint job if I can stop myself before the asylum, but time will tell. In my next incarnation perhaps I will come back as painter for Maaco auto painting and spray a couple of cars a day, so I get a feel for everything and become one with the paint gun and stop this orange peel madness. In my missed spent youth I played a lot of pool and knew some really great pool players who would shot with a broom stick as an equalizer when the situation arose. So maybe I could get so good I could lay down perfect paint with HD paint gun.
Peace out

 

[PC]

.... Yesterday I was behind this new black Mercedes SUV and noticed the orange peel from 10 feet away on a beautiful vehicle. So I can see now this paint world is the lunatic fringe ...

Heh, heh. Wait till you start seeing buffer trails (a.k.a. swirls, holograms...) from a block away....

 

[Alfred E. Neuman]

Yesterday I was behind this new black Mercedes SUV and noticed the orange peel from 10 feet away on a beautiful vehicle.

Every Mercedes I've worked on that's newer than about 2010 has a level or orange peel that I would find unacceptable from any collision shop fender repair. I'm not sure if it's the way the clear is applied or a byproduct of the paint they're using.

 

[CJD]

We just test drove Jaguars. They have a large amount of orange peel too. The Cadi’s we tested were factory buffed.

The circle has come round and the US cars have improved!

 

[Alfred E. Neuman]

Without a doubt the best factory paint I've seen lately is on Japanese cars. We went and drove the Subaru BRZ and ND Miata last weekend. Both of those had flawless paint.

Miata FTW! Now I'm just waiting for the 2019 with 181hp to get here in the fall and it's MINE!

 

[sp53]

So I am going to start using some 2000 and or 1500 wet sand paper, do I want to stand with a block in a straight line or do I want to use a block and sand in circular motions?

 

[CJD]

I was taught to use circular motions, the idea being to minimize the depth of any scratches. If you go in one direction then the depth of scratches compounds. In circular motion you never repeat the same exact pattern, so the depth of scratches is minimized.

I also know the marine shops recommend straight sanding patterns, always the lengthwise direction of the boat.

Is that clear as mud?!? Using 1500 grit there won’t be many visible scratches however your sand it.

 

[PC]

I was taught to never sand in circular motions. The scratch is harder to buff out.

With any finishing process consistency and uniformity are the biggest determining factors in quality. Circular hand motions are extremely inconsistent and produce the least uniform pattern.

I don't believe the theory that straight sanding would make the scratch deeper. Scratch depth is determined by the grit size of the abrasive. The first pass removes some material and leaves scratch. Subsequent passes will take down any high spots and the remaining scratch will be the same depth (but the total film thickness will be reduced).

Uniformity and consistency are why power sanders produce better results than hand sanding. It's impossible for a human to make identical motions thousands of times in a row. It's easy for the machine and it never gets tired. If you examine scratch closely you'll find that power sanding leaves scratch that's typically 500 points finer than from hand sanding with the exact same grit paper.

See my earlier post regarding sanding direction. https://www.britishcarforum.com/bcf...ng-out-paint&p=1088663&viewfull=1#post1088663

 

[CJD]

I don't believe you have more control with a machine than your hand. After all, your hand is controlling the machine. You can tell in an instant if a bit of dirt is under your paper using your hand. Not so with a machine...and as for direction, the buffer works in a circular motion, doesn't it? Wouldn't there be linear buffers if straight was better? Sorry, just what I was taught!


I am not saying to never sand straight, as many areas , like along the top of the doors or the trough on the sides of the bonnet, must be done with straight strokes. But in general a shine is a combination of many tiny microscopic scratches oriented in many different directions. On large flatish panels circular sanding and buffing produces the best shine from any viewing angle. If all the scratches align, then the finish will appear different from different angles.

 

[PC]

I think we'll have to agree to disagree.

I don't believe you have more control with a machine than your hand. After all, your hand is controlling the machine. ….

With the DA you only need to control overall pressure (light) and placement. When hand sanding you need to control those plus direction, angle, pressure at each point in the arc, etc. And again, there is no way a human being can replicate exact motions thousands of time in a row.

…. You can tell in an instant if a bit of dirt is under your paper using your hand. Not so with a machine.......

If you work clean you won't get chunks big enough to feel, especially if you’re using a block. A human hand will never be able to feel a few 800 grit particles while sanding with 1200 paper. But you will be able to see the resulting deep scratches. That means going back and re-sanding or spending way too much time buffing.

...and as for direction, the buffer works in a circular motion, doesn't it? Wouldn't there be linear buffers if straight was better? ….

There are linear sanders. But the machine of choice for finish work is the dual action sander, which makes an orbital motion, not a circular motion. And since the machine is controlling the orbit, not human muscle, the scratch produced is extremely controlled and consistent.

…. But in general a shine is a combination of many tiny microscopic scratches oriented in many different directions. On large flatish panels circular sanding and buffing produces the best shine from any viewing angle. If all the scratches align, then the finish will appear different from different angles.

The best shine is produced by the reduction and elimination of microscopic scratches. When all the scratches are aligned a process that removes one will remove them all. Scratches that are randomly distributed will also be randomly removed and randomly left behind, making for more work buffing.

The point of multi step process is for each step to completely remove residual defects imparted by the previous step.



Luckily, nobody has to take my word for any of this. It's easy to try it for yourself, see how the results look to you, and decide what works for you.




Here's a guy showing the basics of using the DA (The sanding part comes at about 5:32 in.)

 

[CJD]

That’s a circular sander...am I missing something?? I thought the discussion was linear strokes vs circular.

Oh, just sitting here thinking. I forgot that I used a pneumatic sander just like in the utube vid on a Cadi back in ‘86. I watched a film and a shop was using those to crank out the pre-paint sanding, so I thought that was the “bomb” and bought one. Granted, I may have used it all wrong, but the finish came out horrible. The sander cut lows and highs in a finish that was straight before I started. It was the second worst finish I ever sprayed.

I chucked the sander. Since the dawn of time all the best finishes have been “hand rubbed”. You can do it faster, but not any better. The last bodywork I had done by a shop was a Jag about 2 years ago. I sent it back 4 times until they got it right! I wasted more time driving back and forth than if I sprayed the bumper myself in the end. Shops are interested in cranking a profit. They are not always the best source for “best” way...they are for “fastest”.

 

[PC]

That’s a circular sander...am I missing something?? I thought the discussion was linear strokes vs circular.....

The machine is dual action sander. Its motion is orbital, not circular. But if you want to think of it as a compound combination of modified arcs, that’s reasonable.

The point I’m trying to make is comparing linear sanding by hand to circular sanding by hand to orbital sanding by machine.

It’s pretty easy to compare circular and linear hand sanding. You do patches with each and compare the results. Then buff each with the same buffer at the same speed using the same compound, pressure and time. Then compare the results again.

You can’t equate circular hand sanding to orbital machine sanding. It’s impossible for human hands to replicate the motion of a DA. But you can compare results. Circular hand sanding, even with fine papers, produces visually circular scratch that’s difficult to buff out. DA sanding with the same paper produces a uniform haze with no visible scratch lines that is easy to buff out.

...Oh, just sitting here thinking. I forgot that I used a pneumatic sander just like in the utube vid on a Cadi back in ‘86. I watched a film and a shop was using those to crank out the pre-paint sanding, so I thought that was the “bomb” and bought one. Granted, I may have used it all wrong, but the finish came out horrible. The sander cut lows and highs in a finish that was straight before I started. It was the second worst finish I ever sprayed.

I chucked the sander. ....

Could have been a lot of things. Thirty years after the fact it’s impossible to say what went wrong. but I believe that if you had gotten good advice and instruction you would have had a much different experience.

.... Since the dawn of time all the best finishes have been “hand rubbed”. You can do it faster, but not any better. ...

Like I said earlier, I’ll have to agree to disagree. I believe the opposite. I believe you can do it better and faster.

“Hand rubbed” was the thing back in the day when soft lacquers were common and high performance machine abrasives weren’t. Times have changed. Paints have changed. Abrasives have changed.

.... The last bodywork I had done by a shop was a Jag about 2 years ago. I sent it back 4 times until they got it right! I wasted more time driving back and forth than if I sprayed the bumper myself in the end. Shops are interested in cranking a profit. They are not always the best source for “best” way...they are for “fastest”.

Any tool can be misused. And it’s certainly common enough for these particular tools to be horribly misused by body shops that don’t care about quality and are only interested in minimizing costs. But that says nothing about the tool and everything about the user. And these tools aren’t used exclusively by bottom feeders.

Chip isn’t just a paid endorser. He uses these tools. As do other top tier custom builders and restoration shops.

Shops putting hundred thousand dollar paint jobs on million dollar show cars aren’t looking to cut corners.

 

[CJD]

I think we both have different definitions of "difficult to buff out". I assure you I can beat any machine sanded surface by hand. You will beat me in the time it takes, though. Shops use power tools to save time and money...but the finish does not improve. A professional hand rubbed finish is as close to perfection as you can get...so how can you improve on that? 9 times out of 10 I can study a repaired surface and tell you if the shop used power tools to prep the final primer, and usually what type sander they used. That is because power tools are easy to control on large panels, but difficult on the corners and crevices. I read an entire book in the edges! On the 10th time I bet there was some hand sanding envolved to clean up the tool marks. Watch the Smithsonian show on the Bentley and Rolls finishes...they are still hand rubbing them. I think that pretty much says it all...when time and money are not a factor (like our hobby painting) Bentley still hand sands every car.

Last time I checked an "orbit" is circular. I still do not understand how a circular arc by a power tool is different than a circular arc by hand and block. Are you saying the size of the circles makes a difference? I look at it from the opposite perspective, in that it is not impossible for one's hand to duplicate the power tool, but rather the power tool can never entirely duplicate one's hand.

 

[smaceng]

So I had never painted a car, but wanted to. I took a class at the local JC. I bought a TR6 that had been media blasted and primed. I decided on a two stage BRG. So I got the big compressor, proper filters and desecants. Added a house fan, filters and lots of lights to the garage. I first sealed the panels to avoid an interaction with the unknown primer sprayed by the media blaster. I then sprayed on a high build primer, sanded, and then another coat of sealer. This was followed by 3 coats of base and three coats of clear. I cut using 3m wet/dry paper starting with 1000 (wet) then 1500, 2000, 2500 and final 3000. After that I used the variable speed buffer (3M), with their system, first wool, and three pads of foam (black, white, and blue). I used Meguiars buffing compound 105, 205, and 7. It didn't turn out perfect, but I have gotten a number of comments that it looks like a professional spray. It is a lot of work, and I'm not sure I will do it again. Good luck, Cheers, Scott in CA

 

[PC]

…Last time I checked an "orbit" is circular. I still do not understand how a circular arc by a power tool is different than a circular arc by hand and block. Are you saying the size of the circles makes a difference? I look at it from the opposite perspective, in that it is not impossible for one's hand to duplicate the power tool, but rather the power tool can never entirely duplicate one's hand.

Maybe I’m confusing things a little with the way I use the term “circular.” Being sort of OCD I think of textbook mathematical circles, very round things with a single, constant radius, or at least something very close to that.

Pointless side note: (sorry if this just adds confusion, but I can’t help myself) planetary orbits are elliptical. They have two radii. They are only circular in then special case where the radii are identical (which doesn’t happen in nature).

Anyway, the DA’s “orbit” is a spirograph pattern. If you consider the flowers generated by a spirograph to be circles, that’s OK. But whatever you call them, when you make them with sandpaper they aren’t just planform patterns. They’re 3D structures.

The whole point is consistency. A uniform structure can be removed with a uniform process. If the structure is uneven the removal process will need to cover a greater range of structures. With a buffing process, having to cover a wider range of structures means more work and more opportunities to miss deeper defects. You get a cycle of work, inspection and re-work with more instances of residual defects.

A human hand can’t replicate its own motion from one movement to the next, let alone thousands in a row. The resulting scratch pattern is far less consistent than produced by the machine.

One of the worst side effects of circular hand sanding is that the scratch left by subsequent sanding steps looks the same as the previous steps’ that were supposed to be removed. You can’t really tell if you’ve successfully removed the defects from earlier sanding steps until you start buffing and find the scratches aren’t coming out as fast as you expect (or at all).

With linear hand sanding in alternating directions you can see when you’ve removed the previous steps’ defects. Machine sanding produces a pattern that is so consistent that you can also see if the previous steps were removed. But most importantly, due to the uniformity of pressure throughout the entire arc, machine sanding produces a shallower structure that’s easier to remove.

I think we both have different definitions of "difficult to buff out". I assure you I can beat any machine sanded surface by hand. You will beat me in the time it takes, ...

I obviously think otherwise. But since there’s no way to put it to the test though our keyboards we’ll just have to continue to disagree.

... A professional hand rubbed finish is as close to perfection as you can get...

I’d say this is the core of our disagreement. Unless we meet in a garage somewhere and play with it all on paint with our own hands (and machines ;-) ) we will continue to disagree.

.... Watch the Smithsonian show on the Bentley and Rolls finishes...they are still hand rubbing them. I think that pretty much says it all...when time and money are not a factor (like our hobby painting) Bentley still hand sands every car….

Bentley factory. Primer sanding at 1:25.

Bentley factory. Finish sanding at 16:56