chris.olson
Petty Officer 2nd Class
- Joined
- Mar 15, 2009
- Messages
- 173
The skeg on our '85 Force 50 had been cracked for quite awhile and it broke yesterday afternoon and ended up in the bottom of the lake someplace. I could not find a replacement stainless steel one online to fit the lower unit on the 40/50. It was broke almost to the lower bolt hole on the bearing cage, which would be tricky to weld on a new homemade aluminum one. So when you can't get parts, make your own.
I formed one up out of .080" 6061 T6 sheet, welded the back seam. Welded a small skid shoe on the bottom of it. Left a hole on the bottom to let the water out. Riveted it to remainder of the skeg that was still there with 3/16" aircraft rivets.
The replacement is actually stronger than the original since it's a tempered alloy instead of a casting. The process of forming it and welding the seams makes it very strong. If it hits something substantial it will still protect the gearcase from breakage by shearing the rivets instead of breaking at the stress relief holes that are cast into the original one. T6 must be heated to 700-800 deg F to form it. The way I did it is to clamp a 1/4" piece of steel in the vice, heat the piece of steel to red color with a torch. Place your cutout over the steel and wait about 30 seconds for the heat to transfer to the T6, then form it by hand over the steel plate, folding it 180 deg to form the leading edge of the skeg. Make sure the cutout is slightly oversized because the likelyhood of bending it perfectly to get the trailing and bottom edges to line up exactly are very low. Those have to be trimmed before welding the seams.
Thought I would show the repair since these older outboards are getting hard to find parts for. Forming up a replacement skeg is not that hard, and much cheaper than spending $200+ at a welding shop to have a new one welded on. You can make your own out of a $12 piece of T6 sheet that you can buy in pre-cut sizes like 12" x 12" online.
I formed one up out of .080" 6061 T6 sheet, welded the back seam. Welded a small skid shoe on the bottom of it. Left a hole on the bottom to let the water out. Riveted it to remainder of the skeg that was still there with 3/16" aircraft rivets.
The replacement is actually stronger than the original since it's a tempered alloy instead of a casting. The process of forming it and welding the seams makes it very strong. If it hits something substantial it will still protect the gearcase from breakage by shearing the rivets instead of breaking at the stress relief holes that are cast into the original one. T6 must be heated to 700-800 deg F to form it. The way I did it is to clamp a 1/4" piece of steel in the vice, heat the piece of steel to red color with a torch. Place your cutout over the steel and wait about 30 seconds for the heat to transfer to the T6, then form it by hand over the steel plate, folding it 180 deg to form the leading edge of the skeg. Make sure the cutout is slightly oversized because the likelyhood of bending it perfectly to get the trailing and bottom edges to line up exactly are very low. Those have to be trimmed before welding the seams.
Thought I would show the repair since these older outboards are getting hard to find parts for. Forming up a replacement skeg is not that hard, and much cheaper than spending $200+ at a welding shop to have a new one welded on. You can make your own out of a $12 piece of T6 sheet that you can buy in pre-cut sizes like 12" x 12" online.
