Pits in Stainless trim-Help!

[japr]

Hi All-

I'm hoping that the combined wisdom on this forum can help me out.

I'm in the process of polishing all of the stainless trim on my 55 chevy wit ha 3/4 HP (3600 rpm) buffing motor, using 10 in wheels. I've gotten pretty good with removing scratches and leveling by working up through abrasive grades to 600 grit and then removing these scratches with an emery/sissal, followed by an emery/spiral sewn wheel. The emory/spiral sewn combo removes all of the sissal scratches and leaves a nice dull shine.

My problem is that after I move to the stainless/spiral sewn combo, my pieces have very small pits that suddenly appear (and get more noticable after coloring w/ white and a canton flannel wheel). The pittting is only visible from at about 8 inches in the right light, but it's not a mirror finish.

I'm beginning to think that this is a result of poor technique, since I took a piece that was professionally polished (but still had some minor buffing scratches) and did not have visible pitting and applied the stainless/spiral sewn and rouge/flannel combination- voila- the scratches were gone, but the pits appeared.

Is there something that I am do wrong or not doing that would cause pitting to occur during the final stages of polishing?

Thanks in advance!

John

[sswee]

Just a few questions first. Are you talking about exterior molding trim? Is the trim press formed or cast. It sounds like tiny air bubbles commonly found in cast or possibly oxidation pits. Have you tried sanding the pits out and repolishing? Pitting can't be caused by buffing, but buffing can sure bring them to light.

[japr]

The stainless I'm working on now is the exterior trim, which I assume is press formed and not cast. I've tried sanding down smooth with 600 grit, but the pits reappear after the stainless and coloring wheels.

My initial thoughts were oxidation pits, however, working on the piece that was already very straight and nearly miror-like causes me to think it might be something else.

[pickleboy]

can you please post pics so we can make a better assessment? this forum is full of experience but visual is best to diagnose. thanks

[japr]

I'll take some pics tonight and post- hopefully the pitting will show up OK, since it's very fine.

[mpierich]

The pits are kind of mysterious if it's rolled steel, like the other fella said.

But, I just tried Caswell's reccommendation of using emery then the green stainless compound (on a motocycle brake disc), and was very impressed with the results. Apparently the green is specifically for stainless and it may give you a better shine than white.

[japr]

Thanks for all of the comments. I tried to take a picture, but the pits are too fine to show up in the photos. I did get a very nice reflection of my self, though!

I ordered the White Lighting Stainless Rouge and will give that a try.

I'll also send out a piece or two to a reputable polisher to see if there is something an experianced person can do.

[thesound]

You said that things were okay after you had done the initial buff with the spiral/emery, but did you take note of which wheel the pits actually started to show up with? I'll just say this: I'm in the process of polishing a cast iron Chevy 400 block, and after I had spent approx. 100 hours going from 36 grit all the way through 2000, and then began buffing using a felt bob with the brown compound, I noticed the same thing happen on the surface of my block as what you're describing with your parts. You know what it turned out to be? At some point I must've layed my die grinder on a surface that had dirt or grit on it, because upon closer inspection of the felt bob I was using I found one, yes ONE particle of sand stuck in the compound. Basically what it was doing was spinning around and "chunking" the surface of the block with each revolution. (Total frustration, as this was set to be the crowning moment of all those hours of sanding.) If I were you, I'd check the wheels you're using. Make absolutely sure they're as clean as possible. Make a habit of raking them out on a regular basis. For as much time as we spend sanding, it's a small insurance policy against having to do ALOT of useless rework. Hope that helps.

-Rob-

[japr]

Thanks Rob-

Your experiance sounds like it could be similar to my situation. I was also wondering if contaminated wheels could be the problem and have since ordered a new set of spiral sewn, loose and flannel wheels. The pits always seemed to appear after the stainless/spiral combo, so this could be it.

I'll have a go with the new wheels and see what happens. In the meantime, I've sent off two pieces to another polishing company, which guarantees a concours/show finish- I'll see what they can do!

John