Thanks, Ray. I think the amount of abrasion needed for a mirror polish is in the other direction, getting out the stubborn scratches rather than cornstarch, which would be minimal abrasion. I've found that the higher a luster I give to what's there, the more the unresolved imperfections show up. But to Ray and others, I'm actually excited about how the Prestina will look with a tight swirl pattern because this will add dimensionality. Otherwise it's a pretty ugly duckling, and the reason they're so rare -- last year Warrior372 wrote on CG that he knew of only three in North America. Then mine showed up and I know there's one at Allann Brothers Coffee. What's nice about my current cosmetic choice is if I ever want to make it closer to the original look, I can spring for chrome plating the panels, which come off pretty easily.

drgary wrote:For a Great Mirror Polish, Use Chrome Plating

That's what I decided after working on a panel for three hours today. Instead, I want to do the turned finish that Adam (aka ANeat) suggested on page 12 of this thread here with this image he grabbed off the web. I'll skip the decal, though. But I believe that finish will be very decorative on this machine with all of its square and boxy angles.

DOH!!! I was so hoping for success in getting a mirror finish. I looked at a video on YouTube for this swirling business - certainly no easy way out or shortcut.

-phillip

drgary wrote:Thanks, Ray. I think the amount of abrasion needed for a mirror polish is in the other direction, getting out the stubborn scratches rather than cornstarch, which would be minimal abrasion. I've found that the higher a luster I give to what's there, the more the unresolved imperfections show up.

Keep in mind, there's polishing and then there's buffing.

Polishing is where you remove the scratches, etc. In that case, its a process of using finer and finer grid sand paper or rouges, etc.

Producing the mirror finish is buffing, which is the final stages and is usually a very light process. For SS you use green rouge (which is designed specifically for stainless). The cornstarch is more for final buffing I believe (although I have never tried it myself).

Ray

I'll experiment with the swirl pattern on the back of one of my panels to see if that's the way I want to go. I have a Craftsman rotary tool and the sanding bits are easily available. I realized last night that there is precedent for using that type of finish on espresso machines. I'm sure lots of us have been considering this dream machine! (Kees van der Westen Mirage Idrocompresso with Veloce bodywork) http://www.keesvanderwesten.com/mirage- ... resso.html. If anyone in the Bay Area wants to sample shots from one of these they have one without the fancy duds at Blue Bottle in the San Francisco Ferry Building.



And no, I don't think I'll quite achieve that look, but the Prestina group is one of the best ever so the shots should be "Ma'velous"!

Also see Paul Pratts' site
http://www.espresso-restorations.com/metal.html

drgary wrote:I'll experiment with the swirl pattern on the back of one of my panels to see if that's the way I want to go. I have a Craftsman rotary tool and the sanding bits are easily available.

The pattern process you are talking about is known as Engine Turning (also sometimes called Engine Jeweling - or just "jeweling", such as on rifle bolts, etc.). Doing it by hand is probably going to be a bit tricky, because you need the same amount of pressure and the same duration, etc. in order to make it look uniform.

Google "Engine Turning" or "Bolt Jeweling", etc. and you should be able to find plenty of information.

Here's an example of doing it on a machine:
I'll be interested to see the sort of results you get. I think to have it super uniform, you might consider having someone with a CNC mill or something help you out. Or maybe rig up a jig on a drill press or something.

Also, try some testing using a wooden dowel and maybe some valve grinding compound or something (available at most auto parts stores). I think for the largest circles, people use dowels, because you need even pressure against the surface. You can also use rubber pads I think. I've even heard of people using stuff like pencil erasers, etc.

I was going to do this pattern on my lathe bed (in the areas where the carriage bed ways don't touch anything. A couple of months ago I put two nasty scratches into the bed while milling out that heat sink for my La Pavoni PID relay, so I was thinking I might try jeweling the center of the bed to help cover up the scratches (and if everything goes to hell, a new bed is only about $100).

Anyway, on my drill press I have an X/Y table, but I think if I were doing a large panel, I would rig up a jig using wooden blocks maybe. That would allow you to control the X axis along one block of wood. Then if you laid a ruler along your working area, you could just inch the panel along 1/4 or 1/2 inch at a time. Anyway, just a few thoughts

You do have a drill press by now right?

Ray

Hi Ray,

I'm thinking of doing this more simply -- no drill press at the moment. I picked up an extension for my Dremel tool (Craftsman brand) and am looking into ordering a 1/8 to 1/4 inch collet adaptor to hold some 1 inch Scotchguard abrasive disks with a 1/4 inch shaft. To lay out the pattern, I'll use a ruler and draw marks on a grid for centering each swirl and will be careful to apply similar pressure. I'll test this, of course, on the inside of a panel to see if it looks good. If the Scotchguard swirl doesn't look right, I can get sanding disks the same size of different grits.

Unexpected Polishing Breakthrough

Before giving up on a mirror polish, I thought I'd make one last try and attempted something Lucio Del Piccolo (aka LVX) had suggested for polishing my Microcimbali. I combined very fine steel wool and car buffing compound. About 20 minutes of elbow grease did the trick, and the stuff washed off with soap and water. This was the middle range of abrasion I was seeking and effectively smoothed the shadowing in the panel for this result. The next steps for a high luster are white rouge and then Blue Magic or Mother's metal polish. I used those final two steps for the back of the Amica shown earlier that still has slight shadowing and scratch marks because this intermediate step wasn't taken. This is hard to photograph, so to give you a sense of what I'm seeing the finish is now much more even but the mirror isn't clear enough to use for fine details, like shaving. All of this suggests to me a step before buffing of hand touch-up to eliminate remaining scratches and shadows because the DeWalt polisher is too hard to aim into the corners and slight indentations.

Funny ... on the way home before trying this, my wife and I stopped at our local frozen yogurt place and I noticed that the tables were swirled. Some of the swirl placement was imprecise and the surface had been scratched since. It seems there's no perfect solution.

Hey Gary, this is for aluminium, but it's probably a similar technique for stainless steel.

-phillip

I do a lot of buffing, a mirror finish on high carbon steel is difficult and very time consuming. But if you really want to do it, here is what you will need to do.

Hand sand starting with 400 grit (you could also use geeseless compounds on a buffer which is what I use). Sand in a uniform direction until you can only see the scratch pattern for the 400 grit. Then go to 600 grit, change the sanding pattern to 90 degrees of the 400 grit and sand until you no longer see any of the striations from the 400 grit. Keep repeating but you are now wet sanding, 800, 1000, 1500, 2000 grit. Now you have to go to micro mesh and sand up through 24,000 grit. At that point you will have a near mirror finish. Now you need a bench buffer and some buffing wheels, use a slow speed buffer, not a grinder with a buffing wheel. Use white rogue, then chromium oxide, then a metal polish like MAAS. You need a different wheel for each compound, do not mix compounds on wheels. With a 100 hours or so of sanding and buffing you will have a mirror finish. There is no shortcut but the results are super.