Sanding / Polishing Center Mount Exhaust
07-13-2013, 03:23 PM
#1
Sanding / Polishing Center Mount Exhaust So my CME has been looking kind of crappy for a few years now so I decided it was time to try and polish it up.
As you can see it was covered in slag from a sloppy welding job and had no luster whatsoever.
First off: you're going to want to wear safety glasses and a mask. This creates a ton of metal dust and flying debris. I did the serious grinding outside.
I started with an angle grinder with an 80 grit disk sander. I then switched to a 120 grit disk sander. In hindsight I should have probably started with the 120. The 80 was very aggressive and in the end I was not able to remove all the grind marks with polish. The areas I had trouble getting to I used a dremel tool with a cone style stone grinder. It wasn't real pretty but it was better than doing it by hand.
After the grinding with the angle grinder I switched to the palm sander with the 220 grit paper. I ended up having trouble getting it to look even so I ended up going back to a 120 grit with the palm sander. From there I went to 150 then back to the 220 grit, then 320, 600 and finally 1600 grit. You may want to experiment with something like 1000 grit as 1600 may not have been abrasive enough. Once I was down to this level I just did it by hand and I also wet sanded it with the 1600.
To polish I used a mothers cone style foam polisher and White Diamond Metal polish. Both are available at Advance Auto. I just used a standard power drill for the polisher.
All in all I think it turned out pretty good when compared to how it used to look. I will say be very careful using the grinding disk. Anywhere you accidentally get in too deep will not polish out. I was trying to get to a mirror finish which did not happen. But I think the way I have it now hides the imperfections better. I mean you really don't even see anything except the actual outlet tip so it's up to you how detailed you want to get. I spent probably three days off and on working on this so it is tedious. I'm sure experienced metal polishers could do it much faster but I'm pretty new to it.
As you can see it was covered in slag from a sloppy welding job and had no luster whatsoever.
First off: you're going to want to wear safety glasses and a mask. This creates a ton of metal dust and flying debris. I did the serious grinding outside.
I started with an angle grinder with an 80 grit disk sander. I then switched to a 120 grit disk sander. In hindsight I should have probably started with the 120. The 80 was very aggressive and in the end I was not able to remove all the grind marks with polish. The areas I had trouble getting to I used a dremel tool with a cone style stone grinder. It wasn't real pretty but it was better than doing it by hand.
After the grinding with the angle grinder I switched to the palm sander with the 220 grit paper. I ended up having trouble getting it to look even so I ended up going back to a 120 grit with the palm sander. From there I went to 150 then back to the 220 grit, then 320, 600 and finally 1600 grit. You may want to experiment with something like 1000 grit as 1600 may not have been abrasive enough. Once I was down to this level I just did it by hand and I also wet sanded it with the 1600.
To polish I used a mothers cone style foam polisher and White Diamond Metal polish. Both are available at Advance Auto. I just used a standard power drill for the polisher.
All in all I think it turned out pretty good when compared to how it used to look. I will say be very careful using the grinding disk. Anywhere you accidentally get in too deep will not polish out. I was trying to get to a mirror finish which did not happen. But I think the way I have it now hides the imperfections better. I mean you really don't even see anything except the actual outlet tip so it's up to you how detailed you want to get. I spent probably three days off and on working on this so it is tedious. I'm sure experienced metal polishers could do it much faster but I'm pretty new to it.
Last edited by Ace111799; 07-14-2013 at 11:20 AM.
07-17-2013, 08:18 AM
#5
Im doing a quad tip i just got now,not going that crazy though,sand smooth,polish tips,paint the cast color back on n call it a day,good work though its not easy polishing cast whatsoever,i have done a few cast items and geting it to a polishable surface isnt easy
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07-17-2013, 10:23 PM
#8
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Good job. Just a tip though, most of the time I see guys doing similar polish jobs, they do way more sanding than needed. You probably could have started out with just 220, possibly even 320, but I can't tell how porous the metal is from the picture. Generally exhaust pieces do not need sanding quite that aggressive.
08-02-2013, 03:16 PM
#10
I was unhappy with the way the interior of the exhaust looked so I went a step further and did the inside. I found these little sanding wheels for the Dremel tool and went to work. They fit in there perfectly. I mainly focused on the areas that you could see. Not so much on the under side of the top. I then hand sanded with a 300 grit and 600 grit and finally polished with the white diamond polish as before.
I'm curious to see how long it takes to tarnish back up being that it is right in the exhaust path. The spots you see in the picture were after one day of driving. I may have created a monster.
I'm curious to see how long it takes to tarnish back up being that it is right in the exhaust path. The spots you see in the picture were after one day of driving. I may have created a monster.
08-03-2013, 02:24 AM
#11
TECH Enthusiast
Cool payoff for your effort. For heavy cast parts , a stationary buffer with course, then finer compounds& wheels would have cut through faster without the finer sanding, course not everybody has all that. I do like the white diamond for a final cleanup or a maintenance cleanup on something dirty but originally smooth.
As nasty as your parts were, I also would have hit it some with 80 or even 60 initially. The trick with rough sanding is to stop with the coarse paper a little sooner, before you get as deep as you need to go. That way you get the quick start without taking off more material than you need to.
The problem you may have with keeping a shine is that the more porus metals aren't as dense. You will most likely prefer a product other than white diamond for their maintenance cleaning.
As nasty as your parts were, I also would have hit it some with 80 or even 60 initially. The trick with rough sanding is to stop with the coarse paper a little sooner, before you get as deep as you need to go. That way you get the quick start without taking off more material than you need to.
The problem you may have with keeping a shine is that the more porus metals aren't as dense. You will most likely prefer a product other than white diamond for their maintenance cleaning.
Last edited by jlcustomz; 08-03-2013 at 02:35 AM.
08-03-2013, 09:43 PM
#14
TECH Fanatic
Came out awesome, might have to give this a shot one weekend when I have the time. Mines look just like yours did or maybe even a little worse and my car only has about 16k miles on it. I wonder what makes them so cruddy like that so quick, are these CME tips like cast aluminum or something?
08-04-2013, 08:24 AM
#15
Came out awesome, might have to give this a shot one weekend when I have the time. Mines look just like yours did or maybe even a little worse and my car only has about 16k miles on it. I wonder what makes them so cruddy like that so quick, are these CME tips like cast aluminum or something?
