Mount seat base plates

[longjohn119]

Mount seat base plates are always problematic in existing aluminum seats, sheet metal screws don't hold very well, especially if you are using a post and toggle bolts never seem to get good and tight.

I was wondering if anyone has tried 'well nuts' https://www.emhart.com/products/pop/wellnut.asp which are like trolling motor vibration mounts, to fasten base plates to aluminum seats? They aren't cheap ($1.39 each at Lowes for 1/4") but if they work it would be worth it

 

[longjohn119]

In case anyone cares I went with 1/4" rivets nuts recommended to my by several people on another site

 

[rellis1962]

Considering riv-nuts myself. Did you use the aluminum or yellowish steel riv-nuts. I think the steel riv-nuts are parkerized or something to help prevent rusting.

 

[Froggy]

You still got the problem of getting the rubber end under the sheet metal no?

 

[rellis1962]

Well nuts and riv-nuts are all one piece. The back end (part below the surface) of well nuts expands as you tighten the bolt. Riv-nuts need to be installed with a special tool. This tool sort-a mushrooms the back side of the riv-nut. I have used riv-nuts to do other things on my project. Think I may use the 1/4" steel riv-nuts to install my ped seat plates. If that doesn't work then it would not be a problem to change over to toggle bolts or make some sort of access so I can do traditional nuts and bolts.

 

[Troutman3000]

Well nuts and riv-nuts are all one piece. The back end (part below the surface) of well nuts expands as you tighten the bolt. Riv-nuts need to be installed with a special tool. This tool sort-a mushrooms the back side of the riv-nut. I have used riv-nuts to do other things on my project. Think I may use the 1/4" steel riv-nuts to install my ped seat plates. If that doesn't work then it would not be a problem to change over to toggle bolts or make some sort of access so I can do traditional nuts and bolts.

I havn't had any trouble with just using screws through the wood and then through the aluminum, however without the wood I think there would be a problem.

 

[Froggy]

That is why I carpeted a 9x9 square of Ply on top of my carpeted floor, over 1 inch of solid ply, no toggle needed.

 

[perchin]

That is why I carpeted a 9x9 square of Ply on top of my carpeted floor, over 1 inch of solid ply, no toggle needed.

Also what I'll be doing on mine.

 

[rellis1962]

Wood plate between the aluminum bench seat and mounting plate sounds like a good idea. My boat is made of .10" thick Al - almost 1/8" so it may hold the bolts/screws a little better. I am sure the wood would help distribute the forces over a larger area and maybe result in less stress on the mounting bolts/holes. :?:

 

[Troutman3000]

Wood plate between the aluminum bench seat and mounting plate sounds like a good idea. My boat is made of .10" thick Al - almost 1/8" so it may hold the bolts/screws a little better. I am sure the wood would help distribute the forces over a larger area and maybe result in less stress on the mounting bolts/holes. :?:

Thats right. Mine hasnt moved but i have a much larger deck. Yours should be fine.

 

[crazymanme2]

I tried riv-nuts & wasn't happy.They loosened up after a while & they make noise now when I move in the seat.

 

[Oddagus]

I have had good luck on several boats by using sheet metal screws and a marine sealant like 3M 5200 or the 3M 4200. The stuff makes a very strong bond with the aluminum. Rough up the area, clean with alcohol or acetone, put down the sealant, and screw the mount down with Stainless #12 or # 14 screws.

 

[fishfast41]

What I did on my last build was to use a piece of plywood on the bottom side of the seat, then I ran long carriage bolts thru the seat mount, the aluminum bench, and the plywood. It held up great for a very long time.

 

[perchin]

I was originally going to build a wood box to connect to, but I found a good deal on 1/4" aluminum plates for my flooring and decking, which should hold up just fine :mrgreen: