Mounting Pedestal Seats

[scottzfx]

I have just installed a new deck and want to use pedestal seats instead of the old lounge seats. I am going with the posts that do not require a hole through the deck as I am trying to avoid any holes into the deck. Here is what I was thinking and would like your opinions. Sandwich two 3/4" sealed, 12 x 12, plywood sheets together with PL. Drill the holes for the mount and attach capture nuts to the underside so I can bolt mount down, but not go through the deck.

Why, you ask? I figure this will spread the load out over a wider area and provide plenty of strength no matter what size my passenger is (I'm 215 lbs). However, here is where I need major advice. I was actually thinking of "gluing the plywood sandwich to the deck with PL, or some other substance. Again, I really don't want to punch holes in my "new" deck. I'm not sure this will be sufficient to hold adults while underway. Does anyone have any advice on how to attach such a build without punching through the floor?

 

[Mark42]

Re: Mounting Pedestal Seats

I'm guessing you used the common 1/2" CDX for the decking? Did you do glass and resin on top of the new deck?

I think a single 3/4" ply square about 18" should transfer the weight evenly enough. The pl might work right on top of the glass/resin of the new deck, but would work better if the glass and resin were ground off the new deck so there is wood on wood contact.

To keep the old deck sealed, use epoxy to apply the new ply square directly to the new deck surface. Just rough up the deck with some 80 grit first. And buy some stainless steel 'T" nuts and epoxy them into the base of the ply square before installing. Then the bases can be bolted directly through the ply and into the T nuts and no holes were made in the new deck.

 

[foodfisher]

Re: Mounting Pedestal Seats

The higher the seat/longer pole, the bigger the foot/seatbase should be. I can invision a captain w/his feet in the air and the boat digging trenches on some beach.

 

[scottzfx]

Re: Mounting Pedestal Seats

Thanks! I went with 5/8" CDX with three coats of resin thinned out with acetone to coat the deck. The plywood base is 3/4" coated the same way. I actually have not laid the glass yet, as I have been waiting for the PL in a couple of seams to set and then a final hit with the sander. I'm hoping to finish that tomorrow and tape the seams, then start laying the glass.

I'm using polyester resin and mat, and before you all start yelling at me, I used this on the recommendation of Steve at US Composites. He said to use this because I had gone with a thicker decking material. I don't care to sand the resin coat off the deck where I'll be placing the base support.

When you say epoxy, I'm guessing you mean if I had used epoxy resin, I could just mix some resin and use that to "glue" the base down? I can see if the one marine shop around here has any epoxy resin I can get my hands on.

The post is 13 inches tall and its a 4 inch post with a 7" inch diameter base. I was going to sandwich two ply to get a little extra height. It'll put the top of the bottom cushion at 19" off the deck.

 

[dude11]

Re: Mounting Pedestal Seats

For my infomation,if no one else--What is "pl" you plan to use for glue between wood ply??dude11

 

[scottzfx]

Re: Mounting Pedestal Seats

Its waterproof, weather proof, polyurethane construction adhesive. PL is actually its name. I didn't know what it was either till I started reading all the posts on here when I started to replace a portion of my deck. Think of it like LiquidNails on steroids.

 

[dude11]

Re: Mounting Pedestal Seats

Got ya! thax,dude11

 

[Mark42]

Re: Mounting Pedestal Seats

Regarding the use of epoxy with the poly resin finished deck; epoxy will stick to the poly resign very well. Just rough up the poly with 80 grit and apply the epoxy.

If you don't want to buy the epoxy (yes it is pricey) then grind off the poly resin where you want to use the PL adhesive. PL is a good adhesive, and it will stick to the poly, but it will stick to bare wood better.

BTW, when gluing up bare wood, I find that the best adhesive is a water proof "carpenters" glue. I think its better than the construction adhesives.

 

[scottzfx]

Re: Mounting Pedestal Seats

Thanks! I'll post some pics when I'm done.

 

[scottzfx]

Re: Mounting Pedestal Seats

Finally finished the project. Sorry the pic is not that great, but you'll get the idea. I finally decided to epoxy the bases to the deck. After it dried, I used 8 2" screws for additional holding power. I had pre-drilled the holes in the deck and filled them with sealant. After that, I covered with two layers of glass. I did use the t-nuts and bolted the pedestals to the bases. I also used sealant in those holes. Hopefully the water will stay out and I will stay upright. Its really nice to have all the extra room without those lounge seats. All of this was probably way overkill for a trailer queen that lives under a cover when she's at home.

Thanks for the help!

 

[Ced]

Re: Mounting Pedestal Seats

Nice job there scottzfx! Underway of a very similar project for my 1971 glastron. Taking my time to ensure it turns out as well as yours. I have the same apprehention as you with regards to the new deck. This helps greatly. Thanks for the posts & pic.Enjoy!

 

[Woodonglass]

Re: Mounting Pedestal Seats

Here's a better pic for your review. Hope it helps.

(click the pic to enlarge)

 

[Ced]

Re: Mounting Pedestal Seats

Sweet! Thanks Woodenglass & everyone out there with the pics & knowledge. Time to get crackin',Spring is here.