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View Full Version : Tested Out Unigrit on Rear 1/4 Panel and Bumper!!!



the_invisible
Aug 21st, 2009, 10:50 PM
Hi guys!

Today I started wetsanding the passenger side rear quarter panel and the rear bumper of my G35. I used Unigrit Sandpaper for the entire job. I soaked three varieties of papers in separate buckets to reduce contamination. The grades I used were 2000, 2500, and 3000.

For the bumper, I started with 2000 grit to remove the orange peel. Then I worked down to 2500 and then 3000 grit to refine the finish to a mirror gloss.

For the rear quarter panel, I used 2500 and 3000 as the orange peel was minimal. I was trying to enhance gloss rather than removing orange peel.

For the OEM paint, I was able to completely remove all sanding marks with just one pass using LC 5.5" orange CCS Pad KBM'd with M105 and the 7424XP at full speed. All tracers and sanding marks were removed completely with just one pass (Don't flame me :( ) . I did a second pass for good measure.

Here are the results after compounding, no LSP or M205 Just one pass of patient compounding:

http://i6.photobucket.com/albums/y250/the_invisible/P1050464.jpg

http://i6.photobucket.com/albums/y250/the_invisible/P1050467.jpg


I am fairly satisfied with the rear bumper and the quarter panel. The job took about two hours. With some time left, I proceeded to the hood (AGAIN). I started with 2000 and worked my way to 2500 and 3000. I should also mention that the hood is recently repainted with the Sikkens Ceramic Clear Coat. After two passes with an orange pad and one pass with the yellow pad using M105, I am still seeing some tracers that I am unable to remove. I also have some swirls induced by the orange and yellow pads.

Needless to say, however, tracers is significantly reduced using Unigrit compared to 3M. I honestly thought that tracers would be eliminated by switching to Unigrit. However, tracers still rear its ugly head whenever I sand the hood. What is the best course of action to remove tracers from Ceramic clear coats? Feathersanding? Or hitting it with a wool pad?

PorscheGuy997
Aug 21st, 2009, 11:14 PM
Did you mist the surface while sanding? It's very important to mix some M00 and water for lubricating the surface. Also, do not apply pressure when sanding; let the paper do the work.

If you are sanding correctly, you should have no problem removing the 3000 grit marks. However, I would suggest using a rotary to remove the sanding marks. It takes a bit of sanding to remove the orange peel, so the chance of tracers is greater.

Instead of using a yellow LC pad, pick up a Surbuf pad and give that a try.

the_invisible
Aug 21st, 2009, 11:22 PM
Yes, I sprayed a lot of clean water mixed with a lot of Deep Crystal Wash to the surface during sanding. I am not sure how much to use, as there is no specified ratio. But I did use a lot of soap.

I have some purple foam wool pad on my way, do you think those will do the trick? I am putting off any more compounding on the hood to remove tracers until I have received the purple foam wool pads. I understand that the PFW pads do not work as well on the DA as on the rotary, I still want to give it a try first.

Where can I buy Surbuf for a reasonable price?

The ceramic clear coat takes forever to sand, and even longer to remove defects. What a nightmare.

PorscheGuy997
Aug 21st, 2009, 11:34 PM
How many strokes were you using? Eight is about the norm. After that, dry the area and check your work.

You might also try switching to a new paper often.

Ceramic paints are very hard (well, they're ceramic). It's easy to sand the paint, but hard to remove the marks. That's why it's important to use a rotary to pull out the sanding marks.

I have used the PFW pads and got rid of them. The Surbuf pads are much, much better. Some woodworking stores stock them or you might try Surbuf.com.

the_invisible
Aug 21st, 2009, 11:45 PM
Alright, thanks. I have a feeling that PFW may work.

I think the reason for my tracers is because I did not switch paper often. By switching paper, do you mean putting it back into the bucket and use another one, and keep rotating them? Or by switching paper, you mean discrading the old one and start using a completely new one??

Thanks!

the_invisible
Aug 22nd, 2009, 03:27 AM
lol just cancelled my PFW order and ordered some Surbuf.

Is Surbuf a little too aggressive? Should I only focus on using it only on tracers?

Also, is it still safer to remove the tracers on my hood by means of feathersanding + DA Foam buffing than to use Surbuf???

Eddie6th
Aug 22nd, 2009, 11:08 AM
hi invisible.

nice work you've done there.

I'd agree with what porscheguy is saying. I think you should step up to a rotary for this kind of work. Although you have successfully done this with your PC,it's taking a bit more time and effort. I think that is more the case than it being the paper,although the unigrit is a better choice. I also find that the wool is good for sanding marks. I tried a cutting pad,but prefered the wool,followed by the foam.

Have you got any model in mind yet?

the_invisible
Aug 22nd, 2009, 02:17 PM
Thanks Eddie!!!

I am really contemplating on a rotary. Trust me, I know it's a fun tool to use. But currently I want to get the best out of the DA before moving on.

Kevin Brown had posted about the Surbuf Series R pad on Autopia and apparently he was able to remove some 1500 grit sanding marks with it using a DA. That is the pad I want to try first. Because I have been able to completely remove sanding marks out of OEM paint with my orange pad, I want to stick with the DA for now. But sooner or later, in a matter of months, I will be getting a rotary. I just upgraded my DA less than a month ago and I don't want to spoil that.

Eddie6th
Aug 22nd, 2009, 06:05 PM
Good idea. It sounds like a good combo with that pad,to cut out 1500.

Let us know how you get on..

Michael Stoops
Aug 27th, 2009, 11:31 AM
Looks like you're getting pretty darn good at this process - and you are a brave man indeed to "learn" on such a nice car! While we wouldn't recommend this approach for everyone, it seems to be working for you.



For the OEM paint, I was able to completely remove all sanding marks with just one pass using LC 5.5" orange CCS Pad KBM'd with M105 and the 7424XP at full speed. All tracers and sanding marks were removed completely with just one pass (Don't flame me :( ) . What's to flame about? If you're removing tracers and sanding marks to your satisfaction (and you do seem to be rather particular about these things :D) then it's tough for anyone to say anything negative about it. Out of curiosity, how much pressure are you using during this process?


Needless to say, however, tracers is significantly reduced using Unigrit compared to 3M. I honestly thought that tracers would be eliminated by switching to Unigrit. However, tracers still rear its ugly head whenever I sand the hood. What is the best course of action to remove tracers from Ceramic clear coats? Feathersanding? Or hitting it with a wool pad?You can still end up with tracers if you aren't flushing/cleaning the work area and the surface of the paper on a regular basis. You can pick up errant bits of debris and trap them, grinding them against the surface and creating the odd tracer here and there. This is where you're likely to find the rotary buffer to be a huge benefit. Once you get that Makita 9227C in (same rotary yours truly uses) you'll find some of these processes go much more quickly.

Of course, with the rotary you will need to adjust to techniques that are quite different from D/A use, and the associated holograms that can result from improper use. Of course, you've got the D/A pretty well wired, so removal of any holograms you may create should be a piece of cake for you.

the_invisible
Aug 29th, 2009, 02:56 PM
Thanks Michael, I refrained from commenting on the results until I am able take some more pictures of the work on a sunny day. For the rear quarter panel, I was trying to level the surface very lightly and to reduce a small amount of orange peel. The goal was not to completely eliminate orange peel, but to reduce it to a visually appealing level. There are some doubts about the work... However, after some very thorough inspections under different lighting conditions, I think the process was a success.

Here are some more pictures I took 15min ago... again, this is after M105 and UC, no Polish, no LSP yet:
http://i6.photobucket.com/albums/y250/the_invisible/P1050493.jpg

http://i6.photobucket.com/albums/y250/the_invisible/P1050496.jpg

http://i6.photobucket.com/albums/y250/the_invisible/P1050497.jpg

For the rear quarter panel, I do not see any tracers, hazes, or other sanding related defects. I am able to confirm this by comparing the adjacent panels (door and trunk lid) for hazes or marring. You can still see some orange peel, but they look worse in the pictures than they are in real life. I could really see the taller orange peel being shaved off during the sanding process. As you can tell in the first picture, I put most emphasis on the C-Pillar because that is where I look at the most. The rest of the quarter panel, I did not put a lot of effort into sanding because light is rarely reflected off that part of the car, and thus orange peel is not too obvious in that area. The point of sanding the rear quarter panel was to blend in the sanded C-Pillar. Again, although the rear quarter still exhibits some orange peel, it is much better than before it was sanded. That's how bad the orange peel was in the beginning!!!

With M105 and the orange pad, I used moderate pressure of around 10-15lbs. The goal was to allow the pad to rotate as freely as possible, while maintaining adequate pressure to allow the foam pad to cut into the paint. I cleaned up the area by hand using light pressure with Ultimate Compound.

I just did a wetsand touch up and finished the area by hand using Ultimate Compound... Will post pictures in another thread :D

bullitt21
Sep 17th, 2009, 06:10 PM
I don't mean to bump this thread to the top, but I've been busy and just recently started looking at this site again. I see the pictures the OP is posting and they look good, no doubt. My question is what does the paintwork look like under halogens, sun-gun, etc. I see the pics but there all in the shade. The reason I ask is because I've completed many, many corrections over the years, and a great deal of my work comes from dealers installing defects and then using fillers. For instance, I have a MB E-350 at my shop right now and when in a small amount of sunlight or the shade it looks magnificent,(a little dull), but looks great. But get it out in the direct sunlight or shine some halogens on it and it will give you nightmares and a headache with all the Buffer trails, holograms, swirls, and scratches the dealer left. Just wondering if you have any pics of it under strict lighting. Not questioning your work, I would just like to see it under the sun.

Here's what the car looks like in the shade.

Even after washing and claying in a a little sunlight

Under the lghts.

Mark Kleis
Sep 17th, 2009, 08:23 PM
Hey bullitt21,

Just so you know, the links were not working that you posted, so I removed them.

Can you try hosting the pictures directly here on MOL? We have free hosting and then we can help walk you through the process.

Thanks!

Mark

Kevin Brown
Nov 8th, 2009, 05:16 PM
Where have ALL your pictures gone? :dunno

Must be a problem with your Photobucket account because other threads are missing pics, too.

Good posts with pics... messed up with blank squares! :poke