Archive for November 14th, 2009

14
Nov
09

The “New Deal”: An Alumacraft “FDR” restoration part three: Polishing aluminum…

When we parted company last we were working to prepare our little vessel for a good buffing.  To make a nice finish, some small items must be dealt with.  Aluminum “warts”.

Alumacraft FDR 11-10-09-003

This is a "wart". See the little aluminum nodule at the end of the scrape? This needs to be removed.

A “wart” is formed by scraping the aluminum hull hard enough that the soft metal is dragged and reformed into a lump at the end of a scrape.  The problem is they are very unsightly, they tend to collect polishing compound and snag your wool polishing bonnets.  To get rid of these you can wet sand the area with 600 grit wet/dry sand paper.  I wanted this boat to look nice so I actually sanded the entire bottom of the hull.

Okay, some might think this is extreme…as do I.  However, this will make the hull very smooth (albeit not perfect) and allow us to actually save some time when buffing since all the little bumps or “warts” will be done away with on the front side of the buffing work.

Alumacraft FDR 11-10-09-001

The tools for prepping the hull. An orbital sander, a pad sander, a 7" angle grinder, fine and coarse wool bonnets, and a Cyclo orbital buffer.

To begin with the hull will be sanded with 240 grit sanding discs on the orbital sander.  Don’t obsess about the rivet heads too much as they will buff out.  However…don’t linger on the rivets too long either.  Sand the hull working in manageable areas.  For instance I work from one vertical rivet line to the next, finish sanding and buffing, then move on.

Alumacraft FDR 11-10-09-005

After sanding with the orbital sander and 240 grit sanding disc, the aluminum should be fairly dull and you should be able to get rid of the "warts" and other imperfections. Some folks will feather and buff out every scratch. I'm too lazy for that!

Next, using the pad sander loaded with 600 grit wet dry sand paper, sand the same area again to finish getting rid of scratches and “warts”, as well as softening the effects of the previous sanding work.

Alumacraft FDR 11-10-09-007

After re-sanding using 600 grit wet/dry sand paper and the pad sander, the aluminum is already showing a shine.

Alumacraft FDR 11-10-09-008

Here is a comparison of the cleaned aluminum (right) and the sanded aluminum (left).

After all this sanding, you may want to move to 1000 grit or even work your way toward 1500 or 2000 grit paper.  I am not going to obsess about the bottom of the hull too much.  The sides are where the money is for me.

Now lets move on to the buffing.  To begin you’ll need an angle grinder/buffer of some type.  The one I used is a relatively cheap 7 inch size.  It is a variable speed so that as we work with different compounds we can adjust the speed as needed.  We also need a coarse wool bonnet.  In fact several are a good idea since they can get loaded up with compound.  The good news is you can wash them out and reuse them.

Alumacraft FDR 11-10-09-002

For both the Feather Craft and the Alumacraft, 3M Heavy Duty Buffing Compound was used. It is fairly abrasive, but gets out a lot of little nicks and scrapes. It also prepares the aluminum for finer polishing compounds for the mirror finish.

A little dab will do you!  Keep this old axiom in mind.  DO NOT use too much compound as it will load up in the wool bonnet and eventually the wool will become ineffective at buffing….PERIOD.  Use a little bit at a time.  Spread it out with the pad, then turn on the buffer at the lowest possible RPM’s and work in a small area of about 12 to 16 inches by 6 inches high.

The work is slow, but good results will follow!

Alumacraft FDR 11-10-09-009

Now we're gettin' somewhere! The old shine is coming through. On the left is the area we just buffed as described, and the right is what we sanded earlier.

Alumacraft FDR 11-10-09-010

After buffing about half the length of the port side, I still found areas of scratches that were objectionable. No problem. Just sand them again, and buff as we have been. You can see in the middle and right part of the photo the area that was re-sanded.

Alumacraft FDR 11-14-09-003

After more buffing, we are left with a nice shiny, smooth surface.

Alumacraft FDR 11-14-09-001

A shot of the bow.

Alumacraft FDR 11-14-09-004

The side shot above shows the progress from the aluminum brightener (bottom of hull in the photo) to the buffed area. (Top of hull in the photo)

Alumacraft FDR 11-14-09-002

And finally a stern shot. Yes we have swirls from the coarse wool bonnet, but those can be buffed with a fine bonnet or the Cyclo orbital buffer and micro-fiber cloth. You can also get rid of a lot of those swirls by hand buffing.

Hopefully before winter gets a real hold on NW Ohio, I will be able to finish the other half of the hull.  Then in the spring time, we’ll revisit the project and work on the topsides and deck.  Then we can begin to work on adding hardware, seat, repairing the old cracked steering wheel, and getting this boat ready for boating season.