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Tuesday, November 24, 2009
Removing scratches/scrapes from Stainless Steel
I guess I can say I've put my own share of road rash on a
bike - and my body, too, at times!
Sorry to say that the only method to remove the scrapes in Stainless Steel is
sanding, then polishing, unless the scrape cannot be felt when you drag your fingernails across the area. My gut feel
is that if the weight of the bike was on the pipe and it was moving at all, you've got what we term as "gouges"
on the polished surfaces. "Gouges" are removed by progressive sanding with Micro-Mesh (Debbie can help
you with that) start with 600 grade then 1000, 1200, 1500,1800,2000 and 2400 grades- I think Micro-Surface makes a sample
pack with those grades as part of it - use fluid so that you are wet sanding. After the 2400 grit, start polishing
with our NuShine II Grade F9 metal polish, using a wool compounding pad (be sure it is a compounding pad
- not a loose wool pad - which is used on paint). Compounding pads have the wool fibers twisted up into a tuft, like
cut pile carpet. Use about 2000 rpm & keep the pad moving so as not to overheat one spot. After the surface
has a good reflecting image, -usually there are buffing swirls, but they come out later -then change to a new wool compounding
pad, and go over it with NuShine II Grade G6. Finally, cosmetic polishing can either
be performed by hand or with a random orbital buffer with cotton flannel over the face of the buffer. To
get that clear mirror image and depth of shine always finish with NuShine II Grade S.
If you are so lucky that
the scratches are so minor that your fingernail can't catch on the scratch, then just start with the NuShine II
Grade F9, then G6 and final finish with Grade S. This is the procedure
when polishing stainless steel sheet metal, and will give you a mirror surface.
What Grade of Nuvite polish (NuShine II) should I use?
The real question is, what is the current condition
of the aluminum skin on the plane/Airstream/boat or whatever?
So here's
the start point options:
1. Normal, dull, but non-corroded skin = NuShine II, Grade G6, followed by a final finish
with NuShine II grade S.
2. Already polished skin, but cloudy, otherwise slick = NuShine II Grade C if it has been polished
regularly, NuShine II grade G6 if it has been cloudy a long time, followed by final finish with Grade S.
3. Corroded, rough skin - first pass NuShine II grade
F9, followed by Grade G6, then a final finish with grade S. If the first pass with F9 does not clean up
the corrosion pitting, more passes will be necessary.
As
you can see, there are options. Also, all polishing except the final finish should be done with a circular
("car buffer") buffer with a wool COMPOUNDING pad, running no more than 1500 to 2500 rpm. Standard
wool polishing pads don't work for metal. Clean residue around panel lines, rivets, etc. with long
nap microfiber (i.e.: not the glass cleaning type) or polishing cloth. Use mineral
spirits if the residue has had time to dry.
Final
finish with cotton flannel sheet material wrapped over the head of a random orbital buffer.
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