Author Topic: Sanding, Buffing & Polishing Plastic to a Mirror Finish  (Read 46767 times)

Offline HudValley

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Sanding, Buffing & Polishing Plastic to a Mirror Finish
« on: December 18, 2012, 07:05:20 PM »
I am new to this and I love the restoration process. I feel like I am having success; however, my finished product has thousand of light scratches from the sanding that are only visible if the phone is held up close in direct light. I am using Novus #2 as a finishing polish. My questions are these:

Are these sanding marks removable? In other words, can the plastic be smooth?

If so, should I continue to painstakingly polish with the Novus #2, or is my fault in the step-by-step sanding process earlier?

Are these sanding marks typical and just not apparent in the photos of the awesome work you guys do?

I am using 3M Micron polishing papers (6 steps from 30 microns to 1 micron "grit").

Any responses would go along way in alleviating my frustration.

I have included a photo of a side of a recent project to demonstrate what I'm talking about.
« Last Edit: December 24, 2012, 05:37:35 PM by AE_Collector »

Offline LarryInMichigan

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Re: Removing evidence of sanding
« Reply #1 on: December 18, 2012, 07:10:23 PM »
That is one of the most frustrating parts of restoring phones.  I usually just give up.  I did recently find a product which helps a bit, "Meguiar's Scratch X2.0".  I was looking for something else at Target when I noticed this on the shelf, so I bought a bottle.  It does a great job on various types of plastic, though it is intended for painted surfaces.

Larry

Offline JorgeAmely

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Re: Removing evidence of sanding
« Reply #2 on: December 18, 2012, 07:34:36 PM »
You need to go to 1200 or 2000 before jumping into Novus 2. And you need to get the polisher to warm up the surface of the plastic till it flows a bit to get rid of all blemishes. You should do your sanding with water.
Jorge

Offline Dennis Markham

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Re: Removing evidence of sanding
« Reply #3 on: December 18, 2012, 07:53:57 PM »
Welcome to the Forum, Hudvalley.  The product that has worked best for me is called Micro Mesh.  You can see it here:

http://tinyurl.com/ce8huc6


I buy the kit locally at the Woodcraft store simply because there is one located near me.  Search the Forum (from the home page) for "micro mesh" and you will find many posts discussing sanding tips.  Chensley@aol.com has had much success with this product.

Personally, I begin with 800 grit wet sandpaper and then progress to 1,000, 1,500 and 2,000 before switching to the micro mesh cloth sheets that move progressively up to 12,000 grit.  If there are deep scratches, it is sometimes necessary to go lower than 800 grit.

My experience has been that soft plastic (Tenite) is more difficult to remove all the sanding marks than the later ABS (hard) plastic.  It can be done with patience and a lot of work. 

Sand in straight lines, not circular.  With each change in the grit, change directions.  Once the plastic has dried, look under magnification.  If you can still see the previous sanding marks, then more sanding is needed on the second step.  Just keep going until you finish the 12,000.  You will have a mirror-like finish.  It takes some experience.  Lastly I polish with Novus2. 

Jorge's comment about the polisher/buffer warming the plastic is a good one.

Mileage may vary.

Check out the posts as I suggested and you should find more tips.

~Dennis

Offline AE_Collector

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Re: Removing evidence of sanding
« Reply #4 on: December 18, 2012, 08:04:39 PM »
The price of that kit blows me away! Nine 3" x 4" pieces of sand paper and a foam block for $23!

Terry

Offline Dennis Markham

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Re: Removing evidence of sanding
« Reply #5 on: December 18, 2012, 08:22:21 PM »
It is high Terry, but the sheets are cloth.  They can be used over and over again.  They've gone up since I bought my last set.  I think I paid about $21 for them.  I wore out one set and have just about worn out a second.  But they do last a long time.

Offline kleenax

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Re: Removing evidence of sanding
« Reply #6 on: December 18, 2012, 09:22:50 PM »
I am new to this and I love the restoration process. I feel like I am having success; however, my finished product has thousand of light scratches from the sanding that are only visible if the phone is held up close in direct light. I am using Novus #2 as a finishing polish. My questions are these:

Are these sanding marks removable? In other words, can the plastic be smooth?

If so, should I continue to painstakingly polish with the Novus #2, or is my fault in the step-by-step sanding process earlier?

Are these sanding marks typical and just not apparent in the photos of the awesome work you guys do?

I am using 3M Micron polishing papers (6 steps from 30 microns to 1 micron "grit").

Any responses would go along way in alleviating my frustration.

I have included a photo of a side of a recent project to demonstrate what I'm talking about.

Wish I knew who I was addressing here, but there was no signature :-(

First, you didn't say whether you were trying to finish bakelite or plastic; it makes a big difference. Generally, it was covered pretty well in the previous answers, but I didn't see anything mentioned about WET SANDING. This is pretty important.

Anyway, what you did is just not go far enough in the sanding process; you should finish up the sanding (before the Novus), by working up to wet-sanding with 2000 grit. You need to figure out a way to cross-match your "micron" paper grit with the universally utilized grit-sizes.

On bakelite, you can usually get by without using sandpaper at all if you have a buffing wheel system. In fact, you can pretty easily ruin a nice bakelite set with too much sanding. Hard plastic (ABS) is the easiest, and can quite often be finished off without conventional sanding as well if you know what you're doing and practice, since "buffing" is really the lazy-man's way to sand your phones! All you do is change the buffing compounds.
Ray Kotke
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Offline Dennis Markham

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Re: Removing evidence of sanding
« Reply #7 on: December 18, 2012, 09:30:39 PM »
You're right Ray, I didn't mention plastic vs Bakelite.  I did mention "wet sandpaper" but didn't say to use it with water.  There are quite a few posts on the Forum about the technique I think.  I was talking about plastic, not Bakelite.

Offline HudValley

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Re: Removing evidence of sanding
« Reply #8 on: December 19, 2012, 06:35:23 PM »
Thank you all for your replies. So many things to consider, but I love the challenge. I will take your advice under consideration. I know there are threads about polishing, buffing, and determining hard and soft plastic types, so I will reread those.

I still have three questions (addressing any of the three will be helpful):

1) What are the advantages of wet sanding plastic, other than keeping dust down?
2) Is a perfectly completed phone completely scratch free, even of minor surface scratches?
3) Jorge, you wrote: "warm up the surface of the plastic till it flows a bit to get rid of all blemishes." What do you mean by "flows a bit"?

Thanks again. You guys are great. I can't wait to share my results with you all.

Rob

Offline JorgeAmely

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Re: Removing evidence of sanding
« Reply #9 on: December 20, 2012, 12:05:53 AM »
Novus 2 on the polisher head and then applied against the plastic surface remains wet until friction causes the Novus to dry (3-5 minutes). The orbital polisher (my tool of preference is the Ryobi RB60) action causes the Novus paste on the pad to warm up the plastic until the point that the plastic layer immediately below the pad flows a bit to fill the minute scratches left by sanding paper and other tools.

The rise in temperature is not too high: you can touch the pad or the phone with the back of your hand and notice the heat coming off the surface, but if I was going to guess, I would say the temperature goes up by 10-20 degrees. I have done a few soft plastic phones and those are the hardest to sand. Usually, the micro-mesh tools mentioned by Dennis leave a very nice finish, but in addition to that, I always finish it off with Novus 2 and then a coat of Turtle Wax F-21 Sun Protectant.

I always do wet sanding with very warm water. Sandpaper lasts longer.

There are some areas of WE500 phones that are difficult to leave scratch free because of various surfaces meeting at 90 degrees. When to stop is a matter of deciding when good enough is enough. Sometimes if you push your luck too much, you may get in a corner where it is difficult to fix a scratch. Or you create a scratch you can't fix. With practice you gain confidence and you'll know when to stop.

 
« Last Edit: December 20, 2012, 12:14:47 AM by JorgeAmely »
Jorge

Offline Bill

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Re: Removing evidence of sanding
« Reply #10 on: December 20, 2012, 12:16:36 PM »
Perhaps this post should start a new thread, titled something Finishing Tools Needed. Moderator?

I have a 6-inch orbital buffer, and it is great for large flat (or nearly flat) surfaces. But I would like to find a small buffer - maybe 3-inch or even 2-inch, as it would be better in small areas that are hard to access with a big buffer pad. Think the inside surface of a handset handle, up against the cups, for example. Or the hangup area between the ears of a 302.

Beyond that, it would be nice to be able to turn the "orbital" part off and make it a straight circular buffer. When buffing a flat area near an inside corner (think either of the above examples), I find that the pad on an orbital buffer slams into the adjoining surface with every revolution.

Any ideas?

I also have a mental picture of a cylindrical sponge sanding pad (replacable paper if possible), with a shaft on one end to chuck in a drill or drill press. Kind of like a lint roller, where the sandpaper instead of lint adheres to the sticky surface. Probably need a softer surface, though. Anyway, with a slow RPM, this could make sanding some curved surfaces easier.

Again, any ideas?

Bill
« Last Edit: December 21, 2012, 12:04:36 PM by Bill »

Offline kleenax

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Re: Removing evidence of sanding
« Reply #11 on: December 20, 2012, 09:50:34 PM »
Perhaps this should be a new thread, titled something Finishing Tools Needed. Moderator?

Any ideas?

Bill

Bill;

I have a 3/4 HP buffing wheel set-up with the long shafts on both ends. On one end, I have a 6" loose-cotton wheel, and on the other end, a spiral-sewn (kind of hard) 6" wheel for polishing brass. Oh, and it's 3,450 RPM. It came with 8" wheels on it, but I like using a 6" that is 1" wide for phone buffing. A 6" with long-shafts on your motor works fine for buffing handsets. All you have to remember is to use buffing compound often, and KEEP MOVING! You NEVER want to stop in one place while buffing a plastic phone, or it will melt/burn instantly. With a powerful enough buffing system, and the right buffing compound, you don't even have to do ANY sanding; just buffing. You can actually buff out just about any scratch, scuff or most discoloration in phone plastics.

If you prefer something smaller, you might try another buffing/polishing tool that I use for polishing my castings: it is a flexible-shaft (4 ft) that has a collet on the end. I simply mount a mandrel with a 3" loose-cotton wheel attached to it. For power, I run it from my drill press. I utilize this tool for my castings because they have to be polished at a MUCH slower RPM; around 400-600. As mentioned in wet-sanding, I start at 400-grit, working up to 2000, then finish off with 3M Buffing compound on the 3" wheel. This set-up imparts the "water-clear" castings with their glossy transparency. Incidentally, this exact set-up works great on just about all other buffing/polishing of phones as well. It's messy (that 3M stuff goes everywhere!), but works wonders. You do need a respirator while doing it however.

Posted some photos of a good example of "buffing-only" instead of sanding. Trying to put together a nice article for Singing Wires on buffing.
Ray Kotke
Recumbent Casting, LLC

Offline Bill

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Re: How to Sand Plastic to a Mirror Finish?
« Reply #12 on: December 21, 2012, 12:03:58 PM »
Ray -

All I can say is "Wowsers!", which translates loosely to "Holy cow!" I'm unlikely to get a long-shaft buffer - lack of space to put it. But a 4-foot flex shaft is now on my list of gotta-have stuff since I have drill press.

Bill
« Last Edit: November 18, 2016, 10:56:52 PM by AE_Collector »

Offline kleenax

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Re: How to Sand Plastic to a Mirror Finish?
« Reply #13 on: December 21, 2012, 07:38:35 PM »
I neglected to post a photo of the finished product! Here is the phone in all of it's splendor ;-)
Ray Kotke
Recumbent Casting, LLC

Offline Dennis Markham

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Re: How to Sand Plastic to a Mirror Finish?
« Reply #14 on: December 21, 2012, 10:13:51 PM »
Beautiful, Ray!  Thanks for posting this information and photos.