Repaired-recreated my Bennett bottom mount trim tabs

Discussion in 'Powerboats' started by sdowney717, Jan 10, 2019.

  1. sdowney717
    Joined: Nov 2010
    Posts: 1,175
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    Location: Newport News VA

    sdowney717 Senior Member

    I have been planning for a long time to do this. The original 50 yr old tabs were badly rotten.
    I bought a piece of 316 SS of 2x4 feet to to make larger tabs of 42 by 12. Originals were 42 x 9" type 304 ss.
    The hardest part was cutting the SS sheet metal. Separated the big piece with a shear and bent the hook edge on a brake. The wing edge drop fins had to be bent at an angle as the transom is curved. Cut the old tab upright edge off to form the new backbone of the tab using my jigsaw and specialty SS blades. Regular metal cutting blades failed. That SS sheet metal is very hard to cut. I then coated the tab with Por15 silver. I simply sanded the sheet metal, but maybe next time will use their metal etcher, phosphoric acid. It is supposed to make them waterproof, so should help deal with corrosion. Por15 is just like paint except it becomes a very hard plastic surface. I looked at Rust Bullet and MasterSeries coatings, but the POR15 was cheaper and for this purpose is fine.

    I used SS 3/16 rivets to join the back to the plane. I heated the rivets red hot while in position and slammed them down with a 4 lb sledge. A piece of old iron for the otherside of the rivet gave it the support to do that.

    Then I re-coated another coat of Por15.

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