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Old 05-07-2004, 09:51 AM   #15
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Questions that take us back to science...

I have been trying to figure some of this stuff out...

Polishing, according to the research I've done in some textbooks on the subject, is the process of using finer and finer grades of abrasives to grind a surface smooth. Generally, these abrasives are suspended in a liquid or creme substance, known as lap. In use, the process cuts very small grooves into the material, eliminating the layer of material that has oxidized into a patina. In this process, it is important to avoid creating any degree of friction that generates sufficient heat to melt the surface of the metal, since the idea is to cut it.

A second process may also be used--buffing. In the buffing process, very fine abrasives are used with a very soft cloth at high speeds to create sufficient friction to melt down the surface of the grooves cut by the abrasives. Buffing is not appropriate for every material.

So, in sum, polishing cuts off a bit of the material, while buffing melts down a fine layer.

Based on this, I have a couple of questions, which I think would require a high understanding of metal properties:

- First, it is apparent that some of these polishing approaches use buffing while others do not. Is there any research on whether buffing is harmful to the structure of aluminum?

- What lap is most appropriate for polish? Sandpaper is a lapless way of applying abrasive. What are the comparative benefits of using lap?

- How do we know what abrasives are used in polish? What are the comparative merits of different abrasive materials (diamonds, garnets, grit are some of the more common ones I know of)?

- Is there any material benefit to polishing? How many times can you polish before compromising the metal structure?

- Finally, in the back of Aviation Maintenance magazine, I see ads for coating materials. They promise easy application and removal--and greater protection to the skin. Has anyone ever looked into if new coating materials could give greater durability to a polish job?

In looking over the tenor of this discussion, I see argument stemming from concern over the cost and effectiveness of different polishing systems. It seems to me that the likely difference is chemical. The tradeoff elements are clear: different grades of lap and abrasive--and the effect of buffing on the chemical composition of aluminum. This is a subject for very detailed research in materials engineering (as it is a critical concern for the computer chip industry). I may be going on a limb here--but I don't think conventional wisdom of any sort (or even trial and error accounts) are going to resolve this--it's a question for science.
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Old 05-07-2004, 04:17 PM   #16
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Stephanie,
Was'nt your trailer polished already? You should not need more than a fresh up? Am I mistaking your jewel for someone else's?
Yes, mine was polished using the Nuvite by the previous owner. I haven't done anything to it but wash it since. It has suffered pitting on the front from roadrash, and tiny little pinhead size dots of corrosion, which is worse towards the front. There is also water marks and such giving it an overall haze. It would be nice if it was shiney again. Here's a pic:
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Old 05-07-2004, 04:32 PM   #17
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So I did some experimenting with polishing today. I had at my disposal some SS, some Eagle One Aluminum Wheel Polish, and some Meguires Polish for Clear Coats. Thought I'd give them all a try here and there. I also had some 1200 grit sandpaper, which is pretty fine, from the auto body supply store, and my brand new variable speed buffer with 3m pads which I bought just for this occasion.

I took the side compartment door, and started out by hand polishing a spot about the size of my hand with the SS. It took a few minutes, but it finally cut through the corrosion dots and left a very nice shine.

Wanting to experiment further, I got out the hose and carefully wetsanded the other end of the door. The sandpaper cut right through the corrosion in a couple passes. I didn't press down on the sandpaper at all, but it still did the job. It left very fine scratches in the rest of the metal though. I ended up polishing it several times with the SS by hand to get it back to a nice shine, and it still wasn't as nice as the shine I got totally by hand.

Thinking that maybe I was being too easy on it, and needed to sand a little more in order to even it all up, I went ahead and sanded the rest of the door, only a little more thouroughly. The result was a smooth hazy finish with very fine scratches again. I'm attaching a picture of it at that stage.

I then experimented with the newly sanded area. I used SS and the buffer on it, and wasn't really happy with the results. I thought I had to use a lot more SS than by hand and still ended up buffing it clean by hand because the buffer got to a certain point where the black stuff was all over the panel, and that's as far as it took it.

I tried the Eagle One, and didn't see much difference between it and the SS. I thought it worked better with the buffer, maybe because it's a paste. I tried some by hand as well.

Finally, I tried going over the whole thing with the Meguires. It was hard to buff off, but I did think it made it shine a little finer than before. Probably the same concept as using progressivly finer polishes like the nuvite system.

Overall though the door still had a slight haze of fine scratches. I probably could go back and get finer sandpaper and work those out, then finish up with polish to get a nice shine on, but overall I think in my case it would be more work than just doing it by hand. The original shine is pretty nice, it just needs the corrosion knocked off, and I don't think the sandpaper really adds any benefit in my case.

The last picture is of the finished door, which still looks pretty good once I stepped back from it.
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Old 05-07-2004, 04:46 PM   #18
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Stephanie,

I don't think you need to sand. I believe that you can get away with a good polish.
Oh, and never put your buffer face down on the ground - it will pick up dirt and make nasty swirls.
Good Luck!
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Old 05-07-2004, 05:25 PM   #19
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Oops! I didn't even notice I had until I got the picture uploaded. I'll be cleaning that mitt before using it again.

I'm going to go try some polishing by hand on the body and see how it goes. It does suffer from a lot of little chips and nicks on the front, probably from all those trips to Alaska. Unfortunately when I polish those areas the black stuff gets in the chinks and makes them stand out even worse.

Dosen't bother me too much though. It's not perfect, but it comes by it honestly
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Old 05-07-2004, 05:40 PM   #20
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Quote:
Originally Posted by Stefrobrts
Unfortunately when I polish those areas the black stuff gets in the chinks and makes them stand out even worse.

Dosen't bother me too much though. It's not perfect, but it comes by it honestly
Stephanie,

The black stuff comes off with mineral spirits on a rag.
Use a rag with the spirits, and a dry one to wipe after it immediately.
It might work with other solvents also, mineral spirits was just what was sitting around here. Let me know if you find something that works better.
Read the thread "finally got started" it has great info to share.
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Old 05-07-2004, 06:52 PM   #21
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A perfect polishing solution (almost)

After reading all this stuff, I decided the only correct way to polish my Airstream is to take all the skin off, turn the sheets over, and rivet them back on with the shiny insides pointed out. So now I need to determine whether to switch the panels left for right, or flip them end to end.

In the first instance, my entry door would end up on the street side. In the other, I will end up with the coveted 'rear entry' door location.

Which would be more practical?
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Old 05-07-2004, 07:31 PM   #22
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Quote:
Originally Posted by uwe
Stephanie,

The black stuff comes off with mineral spirits on a rag.
Use a rag with the spirits, and a dry one to wipe after it immediately.
It might work with other solvents also, mineral spirits was just what was sitting around here. Let me know if you find something that works better.
Read the thread "finally got started" it has great info to share.
Glass Wax works really well for removing the black residue too...unfortunately, it's no longer made. I bought out all that I could find when it was discontinued. It also leaves a water resistant finish...

Shari
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Old 05-07-2004, 07:31 PM   #23
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Quote:
Originally Posted by markdoane
After reading all this stuff, I decided the only correct way to polish my Airstream is to take all the skin off, turn the sheets over, and rivet them back on with the shiny insides pointed out. So now I need to determine whether to switch the panels left for right, or flip them end to end.

In the first instance, my entry door would end up on the street side. In the other, I will end up with the coveted 'rear entry' door location.

Which would be more practical?
Turn it upside down, polish the belly and make it look like you're towing a clawfoot bathtub.
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Old 05-07-2004, 11:19 PM   #24
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Glass Wax works really well for removing the black residue too...unfortunately, it's no longer made. I bought out all that I could find when it was discontinued. It also leaves a water resistant finish...

Shari
Oh, fine! You're a LOT of help!
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Old 05-07-2004, 11:51 PM   #25
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I've started trying to polish my 61 Overlander .I was using Met-All polish with an air powered buffer.I was surprised at how little I knew after watching the cleaners polish airplanes at work for the last 25 years.Read up on process at perfectpolish.com and am having better results now. I tried some wet sanding to remove some deeper scratch first 600 and then some 1500.I am reluctant to wet sand much or use a coarser compound as the alclad is less than one thousandth of an inch thick.The air polisher I bought will fry my old compressor if I polish too much so I ordered one of those Chicago-electric polishers from harborfreight.The guys at work get great results using the Met-All .They were using Met-All when I started in the industry(with cyclo polishers) and I have seen many salesmen demonstrating all kinds of processes,but we still use the Met-All.
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Old 05-08-2004, 02:53 AM   #26
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I agree~

Quote:
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Oh, fine! You're a LOT of help!
lol, I agree~!
I was able to find a can but..to be honest, it's so old..I don't even think it's close to the original formula~!!!
Oh well..
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Old 05-08-2004, 07:06 AM   #27
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I wetsanded my trailer as well in scratched areas however I used 1200 and 2000 grit paper. Met-all does a fine job. Airstream even sells it on there site.
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Old 05-08-2004, 09:10 AM   #28
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Bumper Polish

Kind of a cruddy pic I'll take more. This is the pass side front bumper. You can see the old (original) and the new. I went over this with 600 for about five minutes and then 1200 for another five then with a 9" variable speed buffer with a little Blue Magic on a wool pad. I'm headed over there today so I'll get a body and front grill pic also.
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