Sunday, September 9, 2012

Dimplin’ In The Rain

Saturday was a rainy day at DOG Aviation and was spent dimpling the fuselage tail cone skins for the flush rivets that are being used on the RV-12 project. Once the dimpling is completed, the tail cone skins will be ready for final metal prep and primer. The first tail cone skins that were dimpled using the C-frame were the left and right F-1281 skins and they proved to be slightly challenging in that they are curved. Because of the curve, they required a little extra work to make sure the rivet holes were square to the dimple dies before whacking the C-frame with the mallet to create the dimples.
                                    Once again the two different sized pool noodles proved to be useful for keeping
                                    both the F-1281 skins at the right height and angle for the C-frame.
                                        A level was used to help keep the skin aligned square to the dimple dies
                                        to insure the dimples would be perpendicular to the rivet the holes.

A note of caution for those also dimpling their RV-12 skins … both the F-1280 left and right skins have a lone hole sitting just forward of a row of holes. These two holes are for the static ports and are NOT to be dimpled. Suggest placing a piece of tape over the holes as a reminder to skip them during the mind numbing process of dimple mania.

                       The static port on both the left and right F-1280 tail cone skins do not get dimpled.

All nine of the tail cone skins are nine feet long and there are lots and lots of rivet holes to dimple, so it takes roughly an hour to dimple each skin … with nine skins to do, this will be a two day process.
                          Passin’ the time away on a rainy day dimpling one of the tail cone’s two F-1282 bottom skins.

I have been removing the blue plastic film in preparation for priming and also doing a little final sanding of all of the skin’s edges with a foam sanding block. For a long time now I’ve wanted to mention the sanding blocks the DOG Aviation procurement department picked up a while ago, but keep forgetting to mention them. Have been using some extra fine foam sanding blocks made by 3M and have to say, they do a great job. Because they are made of foam and have a rather thin outer abrasive coating, I was not holding much hope for their longevity. However, I have to admit, they really do a great job of final smoothing on edges and last and last. I have been using one for a long time now and only have one little tear in it where it caught a really sharp burr I missed during initial filing. Amazingly, they will quickly smooth a sharp edge without getting torn up but obviously are not made for jagged edges.
                                                 The 3M extra fine sanding block procured from Home Depot and
                                                 aircraft supply does a great job of final smoothing aluminum edges.