SS finishing

E L Iverson

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I recently stripped a 66 for a complete tuneup. While apart (being a knifemaker) I sanded from 600 down to 2000 then buffed with Brownells 555. At this point I had a mirror finish but also had random scratches that sanded out with 2000 grit. I then rebuffed with a new wheel and compound and had more of the scratches appear. It seems after sanding I have produced a surface that is extremely fragile. Could I have sanded through some type of work hardened top layer? Now whatever I do seems to look less than attractive. Any ideas how to fix this?
 
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If your scratches are reappearing its most likely the grit of the polish, or the force you are applying at the wheel.

Try an unstitched (soft) cotton buff, green rouge, and light pressure (preferably low speed)...AFTER you have it to 2000g.

Your probably trying to hard with something a little to aggressive, 2000g will buff out with a car buffer(wool pad) and compound. Assuming you have the previous grits completely out....
 
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One other thing you should be aware of is that any deep scratches from the original finishing operation will "print through" when you go to a full polish. If you are sanding the 2000 grit in the same direction as the original finish, it will mask the deeper scratches and you won't see them until you go to a full polish.

If you want a quicker way of cutting the deeper scratches, diamond lapping compound on a felt wheel in a Dremel is very fast cutting. However, it is so fast cutting that care has to be taken to not apply too much force and to make sure you keep the wheel moving in steady even strokes. Otherwise, if you hit one spot too hard it will leave a "divot" in the finish that is apparent when lighted form certain angles. If you don't want to rish the Dremel, diamond lapping compond applied to a cotton rag and doing it by hand is a much safer approach and still fairly quick cutting. BTW, lapping compound on a cotton rag by hand is probably the safest approach to use around any laser etching or engraving. That way you can stop as soon as the area is cleaned up just enough and not risk removing the engraving. I've also found that a very light touch with the Dremel around the roll stampings will reduce the rounding of the impression that occurs when a stand polisher is used.

As for a source for diamond lapping compound, I get mine from Production Tool. Production Tool Supply

Finally, fully polished stainless steels are somewhat "fragile". It's the nature of the material. Stainless steel is very hard on any abrasive used to refine the finish (meaning it wears out sandpaper quickly) because of the chromium content, but when fully polished can scratch easily if you look cross eyed at it. The good news is that it doesn't take much work to clean it up if you only have a light maring of the polish.

BTW, I learned the hard lessons about polishing stainless doing a set of headers for a Riddler candidate show car. After the individual tubes were returned from the polisher, and the headers assembled, it took another 80 hours of work with a very fine polishing compound on a cotton rag and hand stroking each tube to remove the "haze" left by the rouge used by the polisher. By the time I was finished, I had a real hatred for that set, however the end result was a 100% flawless finish that could stand up to the scrutiny of a Riddler judge and his damned magnifying glass.
 
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