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Carl Klamut
05-13-2006, 06:04 PM
I just finished a project made of aluminum plate. It turned out quite well and I would like to shine up the surface with those brite circles you see on fine instruments. I tried using steel wool on a wood dowel, but that didn't work too well. I would appreciate if anyone can provide a reference, sketch,or just a written description.
Thanks.

Powerpooche
05-13-2006, 06:18 PM
If you're talking about "Engine turning" try a pencil eraser and valve grinding compound or rubbing compound. Be very systematic with your pattern because one little error will really stand out. Brownell's might offer some kind of kit to do this.

P.O.

Tin Falcon
05-13-2006, 10:51 PM
Carl:
There are several variations on this. The article in projects in metal book suggests using createx sticks. These are rubber sicks embeded with abrasive and come in variouse diameters and grits. These are available from MSC, enco McMastercarr etc. The other method is a wooden dowel with somesort of abrasive paste such as lapping compound.I have had decent results using metal polish. There are probly some other favorite methods as well.
TIN

greywynd
05-13-2006, 11:48 PM
With aluminum I would be cautious using real hard abrasives, they may embed and turn the surface dark grey. I would be tempted to get some fine sandpaper (3-400 grit, maybe finer?) and glue a disc of that to your dowel. I would use a piece of scrap to experiment though before you go at the finished part.

Let us know waht ends up working best, I'd be interested in knowing for sure. (Pics are always welcome too!!!)

Mark

SGW
05-14-2006, 08:52 AM
Brownell's www.brownells.com has -- or at least had, several years ago -- a couple of ways of doing this. Besides the ones already mentioned, they also sold small steel bristle brushes on an arbor, with a small O-ring to put around the bristles to stiffen them. The idea was to apply some lapping compound of suitable grit, and bring the rotating brush down on the workpiece.

Powerpooche
05-14-2006, 12:20 PM
Eastwoods (www.eastwoodco.com) also has a kit. Search "engine turning"


P.O.

DancingBear
05-17-2006, 08:58 PM
Coincidentally I've been experimenting with engine turning aluminum recently myself. I found that fine abrasives work much better than coarse. So far fine-grade Clover compound seems to work well, but there may very well be even better choices I haven't come across yet. My initial luck with a Cratex stick wasn't very good, but I may try again sometime.
I used a dowel, but the end tended to mushroom out pretty quickly. A good hardwood dowel (rather than the big-box store wonder I had) would be a worthwhile investment.
Use consistent feed pressure, and as Powerpooche noted, place your spots accurately and consistently, as variation of any of these show right up. I did find that if you catch an error before you finish the row you can go back and redo the row.
Whatever abrasive you use be sure to thoroughly clean your machine up after you finish. It will get flung a lot further than you might expect.

There's probably nothing like practicing on some scrap for awhile to find what works for you. I spent about a week of evenings trying before I was really happy with the results, and there's still room for improvement.

HTH

Walt

HWooldridge
05-18-2006, 12:07 AM
We finish a lot of aluminum where I work with random orbital sanders and 220 grit garnet paper, then wash down with alcohol. The orbital action makes a nice pattern - it's not engine turned or jeweled but looks good to the eye.

bagbalm
05-29-2006, 05:57 PM
Nonwoven abrasive - Scotshbrite works well. You can buy them in discs that mount on rubber backing wheels. For this sort of mark you want to run them slow and lubricate with spray WD40 or something similar.
You work in a pattern so that the newest circle overlaps the previous work and lends a scalloped pattern. That can be in lines or archs - whatever makes sense for the surface - I can picture working out in a spirol.

Fasttrack
05-31-2006, 06:15 PM
Check out http://www.homeshopmachinist.net/bbs/showthread.php?t=19336&highlight=engine+turning for a great thread on engine turning - lots of pictures to help out

ShopDawg
05-31-2006, 08:59 PM
We do a lot of fabrication in stainless steel and we use the ScotchBrite pads to not only clean and polish the welds, but to also "pattern" an area. To pattern and area we use a 4" brown pad (They come in different abrasive grades designated by different colors. Brown = course, Green = meduim, White = extra fine, and I think there are a few more grades, but I can't remember what they are). For polishing out welds, we use a 90 degree die grinder with the pad, and for patterning, we use a 90 degree drill at a lower RPM.