Need HELP Color Sanding and Buffing - SPI UV Clear

[BobS531]

Need Help ColorSanding and Buffing – SPI Clear
Products Used:
Silver Metallic Base Coat
SPI –UV Clear Fresh- 1 week old, air dried, no bake
Norton Black Ice P1000, P1500, P2000 all wet by hand
Tried one piece of 3M Trizact 3000 wet by hand also on atest
M105 on 8” 3M Wool Compounding Pad05719 (recommended for Perfect-it step 1)
Makita 7”Grinder/Sander Variablespeed rotary. Running at slowspeed. Trying for about 1500 rpm
M205 on 8” yellow foam pad
5000K LED Tube lights in the booth. Look similar to a fluorescent tube

Hi All,
I am new to color sanding and buffing and need help. I am seeing what I believe are 2000 grit sanding scratch texture / pattern afterI buff. M105 appears to round them andproduce a nice shine, but does not flatten them. I expected flattening, not rounding andsmoothing, maybe my expectations are off….
A little back ground. I have a 2001 F150 that I completely re built from the frame up. Sand blasted, painted every nook andcranny. (I am practicing for the classic63 caddy convertible I plan to rebuild). Cut out a lot of rust, welded in new metal (getting pretty good formingmetal and tig welding). Did all the bodywork and painted myself. (My body workis as straight as an arrow, took me 30 years to learn to sand properly J). It is a silver metallic with 3 coats (about 4mils) of SPI UV Clear. Paint is a little over a week old at this point.
I had dirt, lint and fibers in it even after building asimple paint booth with filtered, pressurized air (surprised me, thought mybooth would keep that out). So I decidedto color sand to remove the dirt and orange peel. I started with 1000 grit wet and a E-7200 padby hand, then 1500 and then 2000. Wetsanding by hand took a week.. Whew.. Then used a wool pad on a rotary buffer andM105. With in 10 to 15 secs, a glossdevelops and it looks good from a distance.
Picture of hood: Notethat it was dark outside, so the reflection of the window is black.
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However, on close inspection, I can see the “lay”/ “Grain”/“Texture” of the 2000 grit sanding scratch pattern. i.e, I can see the direction that it wassanded. I know it is the 2000 grit,because as a test, I sanded again in a different direction and rebuffed and thetexture / grain / whatever, was in thenew direction. I can only see it in thereflection of the LED tube light bulbs along the edges that are in thebooth. Under any other light source, Ihave not been able to see it.
It is very difficult to take a picture of, but here is amagnified view (about 8X).. note thefuzzy angled lines (all angled the same way) along the periphery of the bulb. Notice that it is glossy, but the texture /pattern of the sanding marks are there. s
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Here is another picture magnified (8X). I put a piece of blue tape near by to focusthe camera.

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So I guess my questions are:
1. I am newto buffing, I guess since the M105 is supposed to remove 1200 grit scratches, Iexpected it to completely remove these 2000 grit pattern marks. Do I need to use a more aggressive compound? Would M100 be a better choice?

2. Do I need to buff longer, I am buffing for about30 sec to 1 min until the compound dries and is wiped off by the pad. If you go any longer, it can leave a littleburn residue.. I have re-buffed someareas 4 or five times and have not seen any real change in the scratchpattern. It seems like the first 20seconds does the trick and there is no more improvement after that.

3. Do I just not know how to buff? I have read a lot and can’t figure out what Iam doing wrong.. Maybe I got the wrong wool pad or Compound?

4. I have also tried the M205 and the yellow foampad and not seen any real change in the gloss. I know it is supposed to remove swirls and buffer trails. Which I have not actually seen anyhow. But tried it anyways.

5. Do I need to sand with finer than 2000 gritbefore buffing? I did buy a sheet of the3M Trizact in 3000 grit and re-sanded by hand, an area that had been previously buffed inthe cross direction to the original scratch pattern and the resulting patternmay have been less, but I could still see the direction how the 3000 grit wassanded.

6. All my sanding is by hand, I am aware that if Isanded with a finishing DA, that the effect is that of using about 2 gradeshigher grit and the marks would be short and small and harder to see. Is that the problem, that I really need touse a DA?

7. Is my light source (5000K daylight LED) creatinga special situation where this pattern is visible when in the real world, itwould not be visible?

8. I have never actually looked this closely in a“SHOW CAR” finish. Would I see the samething? In other words is this normal?

9. In thinking about this, since compounding is a“free” abrasive, it does make sense that it would tend to smooth out thesanding scratches verse flatten them like a sanding block would.. So maybe this is normal? And I am just looking too critically..

All comments and input are welcome…

Thanks and look forward to hearing from the professionalsand amateurs alike.

[BobS531]

I know there has to be perfectionists out there that have color sanded and buffed paint successfully that can give me pointers?

I even called the Meguiars tech line. For every question I asked I got the exact same answer "If you are not getting the results you want, adjust your technique". Yeah.. I was really hooping for advice that would prove useful... So I turned to this forum...

My best guess at this point is that the M105 is not the right compound for this job. Since it is the SMAT technology, that means that it has very fine abrasives that do not break down. The abrasives are sized for finishing and are thus very small. That therefore means that they act like fine sandpaper and smooth vs flatten. sort of like trying to sand orange peel with 2000 grit. It will simply not flatten.

So if that is the case, what compound should I use? Anything I buy will have to be bought online and shipped, so will take several days. I would like top know I am buying the right stuff..

[GSKR]

2000 grit sand marks.fg 400 works great I wet sanded a 13 vette top to bottom for etched water spots using buff and shine pads.This is not advice for you.promblematic promblems that you have are simply trial and errors and a lot of test spots.A majority of advice is speculation.maybe Mike Phillips will see this and help you out.sorry I couldn't be much help,but I'm not gonna give you speculation advice.mike Phillips has more years experience than me.

[BobS531]

Thanks, I am interested in hearing all opinions. I did notice the FG400 is listed as being more aggressive than the M105.

I hesitate to call the sanding marks "scratches" since they do not catch the light the way a scratch would. it is more of a "pattern" or "texture".

Yesterday, I did another test on one of the paint test coupons I did a couple of months ago. In this test, I only used 2000 grit over an entire area. (to eliminate the possibility of it being the 1000 or 1500 that had not been fully removed). I then divided the area in half and sanded with the trizac 3000 at 90 degrees.

After buffing with wool and M105, I could see the 2000 grit texture in one side and the 3000 grit in the other. the 3000 had completely removed the 2000. the 3000 was also about the same pattern as the 2000, not really any noticeable difference.

Now I have to say that when I put the truck out in the sun, it looked pretty damn good, easily the best paint job i have every done.

Thanks again.

[Crispy]

How many passes are you making with the wool pad and rotary?

It should take about 10 minutes to do a 2 foot square test spot.

When compounding with DA and coarse foam pads, it takes me about 10 minutes for 4-6 passes.

After compound I polish with polishing foam pad 4 passes.

[LEDetailing]

How about moving up to 4000 then 5000 grit sand paper. I know exactly what you are describing as the texture. I think you are just being a perfectionist, which is exactly the way you have to be to get perfect paint. If you have enough clear I would just wetsand two more steps 4 and 5k. Maybe try a fender or door panel per day to save your sanity.

I wetsanded spots on the hood of my Lexus with 2000 grit and have the same very light texture/pattern. I should try my 3000 and 5000k unigrit paper from Meguiar's and see if it removes the texture.

[BobS531]

How many passes are you making with the wool pad and rotary?

It should take about 10 minutes to do a 2 foot square test spot.

When compounding with DA and coarse foam pads, it takes me about 10 minutes for 4-6 passes.

After compound I polish with polishing foam pad 4 passes.

I am making in the range of 4 section passes. depends how much compound I use. I am laying a couple of strings of compound out.. But I am going until it is pretty much dried up. A couple of times I went a little too long and actually left some burned residue. I had to sand it off with 2000 and rebuff that area. I have also buffed everything twice.

I am also cleaning the wool pad after just about every panel. usually spray a little water on it, scrub with my hand to loosen the dried residue, and then drying it my turning the rotary on for a few seconds. I have spurred the pad a couple of times, but in general that just seems to tear it up and make fluff bunnies go everywhere..

thanks

[Eric@CherryOnTop]

I would imagine that since the paint is only a week old, the 2000 is doing it's job very very well. I would also imagine that following that up with 3000 and then 5000 would make the sanding scratches so minuscule that the rotary/wool/105 would handle it no problem. Working by hand, that's a tall order. The compound is capable of pulling out 1200 grit sanding marks under only the best of conditions but it's not always the best approach and it does take awhile. I always found M101 to be a better compound in every way to M105 and it can be used on a rotary with a wool pad even though it's specifically designed for foam pads.

I'm also not sure if your light source is really bringing out the worst in the paint. The color temperature might be bit cool compared to direct overhead sunlight, but I'm sure it's very intense when it's concentrated against the paint like that. I've found that defects that show up in my LED lighting setup don't always show up when I pull the car outside to inspect it.

If I were you, I would do a test spot with 3000 grit, then 5000 grit, then compound and see what it looks like. If you're seeing 2000 grit marks one way and 3000 the other way as you described in the test on your paint coupon you might need to modify your technique to a crosshatch pattern with each. You want the 3000 to fully remove the 2000 marks. Try moving the light farther away from the panel if you have it up close so it isn't as intense and concentrated. If you compound with a wool pad on a rotary you're also going to want to follow up with a dual action polisher with a softer foam pad with the M205 so you don't have buffer trails on the paint.

[BobS531]

How about moving up to 4000 then 5000 grit sand paper. I know exactly what you are describing as the texture. I think you are just being a perfectionist, which is exactly the way you have to be to get perfect paint. If you have enough clear I would just wetsand two more steps 4 and 5k. Maybe try a fender or door panel per day to save your sanity.

I wetsanded spots on the hood of my Lexus with 2000 grit and have the same very light texture/pattern. I should try my 3000 and 5000k unigrit paper from Meguiar's and see if it removes the texture.

My test with 3000 by hand showed that the texture was still there. (by the way, the 3M Trizact 3000 only took a few strokes to completely remove the 2000. Fairly impressive). I am sure it was lighter than the 2000, but you really could not notice the difference. Trying some 5000 might be the next test. sanding in a cross hatch might help as well (as mentioned). that way you would have a "diamond" shaped pattern which might be easier to obliterate. Along this same thought, a DA probably has the same type of effect.

I know they cut and buffed show cars before 5000 grit and DA's were available, but they probably used heavier compounds and more compound steps...

[BobS531]

I would imagine that since the paint is only a week old, the 2000 is doing it's job very very well. I would also imagine that following that up with 3000 and then 5000 would make the sanding scratches so minuscule that the rotary/wool/105 would handle it no problem. Working by hand, that's a tall order. The compound is capable of pulling out 1200 grit sanding marks under only the best of conditions but it's not always the best approach and it does take awhile. I always found M101 to be a better compound in every way to M105 and it can be used on a rotary with a wool pad even though it's specifically designed for foam pads.

I'm also not sure if your light source is really bringing out the worst in the paint. The color temperature might be bit cool compared to direct overhead sunlight, but I'm sure it's very intense when it's concentrated against the paint like that. I've found that defects that show up in my LED lighting setup don't always show up when I pull the car outside to inspect it.

If I were you, I would do a test spot with 3000 grit, then 5000 grit, then compound and see what it looks like. If you're seeing 2000 grit marks one way and 3000 the other way as you described in the test on your paint coupon you might need to modify your technique to a crosshatch pattern with each. You want the 3000 to fully remove the 2000 marks. Try moving the light farther away from the panel if you have it up close so it isn't as intense and concentrated. If you compound with a wool pad on a rotary you're also going to want to follow up with a dual action polisher with a softer foam pad with the M205 so you don't have buffer trails on the paint.


Thanks for comments

Have you used M100 as well? Agree regarding the LED light source. I think that it is the fact that it is a straight line along the tubes. Yesterdays test was under fluorescent. I did notice that since my two sand scratch patterns were at 90 degrees to each other, that I had to rotate the coupon 90 degrees to see the scratch pattern in both samples. in other words, I could only see the scratch pattern when it was aligned with the direction of the tube. So when one pattern was aligned and visible, the other was at 90 degrees and was not visible...

I did notice a few swirls when I had it outside a couple of days ago... I am also aware that silver does not show swirls much because of the flakes and it being a light color, thus reflecting quite a bit of light that tends to mask / camouflage the swirls..

I appreciate everyone's input!!

[57BORNTORUN]

You could also call Kevin at Southern Polyurethane Inc. (SPI) It`s his formula of clear coat and nobody knows better his products than he.Easy guy to talk to as well.

[GSKR]

You could also call Kevin at Southern Polyurethane Inc. (SPI) It`s his formula of clear coat and nobody knows better his products than he.Easy guy to talk to as well.

Agree go to the source for info.Like I said if no one is present with you,everything is just speculation and ideas.call the people who make the stuff.

[BobS531]

Agree go to the source for info.Like I said if no one is present with you,everything is just speculation and ideas.call the people who make the stuff.


Thanks 57borntorun and GSKR, I have spoken with Barry multiple times and he has been very helpful. However, he did tell me that he does not do a lot of compounding. Also as you mentioned, it is difficult with out someone in person.

[Mantilgh]

I don't know if I should be giving advice on this because I have little experience with a rotary, but you would think 105 and a wool pad would clear that up.

I've only done minor scratch removal with 1500 and 2000 grit and it usually levels out pretty quick with a compound and an aggressive foam pad on a DA polisher.

I wonder if your pad cleaning technique has anything to do with it?

Maybe leftover moisture making the compound less effective.

[BobS531]

Hi All,
By way of an update, I finished buffing out with the M205 and removed all the masking. I had been leaving the masking on to help with the clean up. Enclosed are a couple of pictures showing the truck outside in the sunshine today. It looks great outside and way more than adequate for a daily driver. The texture is not visible in normal lighting with out a straight edge type light to see it (ie tube light). And even then, you have to look extremely close. It is not visible with any kind of point light source like what would be used to see swirls.

As I said earlier, this is the best paint job I have ever done. (I have done a half dozen since I was 16 yrs old, but this is the first base clear). But I am a perfectionist and on a classic car which will be my next project, I would strive to do even better. I think the path to get there is to sand with even higher grits like up to 5000 grit. (Hey, there is a reason they make it). I also believe that an air powered finishing DA would provide an even better finish, because of the more random and less straight line sanding pattern.

The other thing I have noticed is that the 1000 grit removed the orange peel, but now with the peel gone, you can see the urethane wave. I have read of people starting with 600 grit to remove the wave and truly flatten the surface. (Obviously you would need enough clear to allow for that).

And for those who wonder why someone would put so much work into a truck like this? Good question, I always loved this truck, and I hated to lose it to the rust bugs. I am confident that my work will last longer than the original. I put paint in all the spots that the manufacturer does not (inside the rockers, inside doors, inside and out of the frame, underneath the cab and box, etc…. all the places that really matter when it comes to rust… And it turned out to be a lot more work than I thought (4 years so far). I probably would not have done it if I had known it would be this much work.

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If any restoration types run across this thread, I am still interested in the details of how to do a show car quality cut and buff..