Pedestal Base Screws pulled out of deck

[Rodd]

Again, this is for the Grady White, not the Pearson! My seats are on pedestals, and the bases have screws that have been somewhat stripped. I am thinking of drilling large holes and putting in snap toggles that will accept a 1/4-20 bolt. (There are 6 holes in the pedestal base). One problem I may have is that the space under the deck is filled with foam, so I'm not sure I'll be able to get those toggles to open up after I drill the hole.

Anyone have ideas or a different suggestion on how to re-fasten the seat bases into stripped fiberglass holes?

Thanks!

 

[Michael Davis]

Are they swivel chairs? Could you fill the old holes with epoxy and turn the base 30 degrees?

 

[SG]

Put a base plate down then attach the base plate to the deck, then screw the seats into the base plate?
There may be some standard marine grade aluminum plates -- or even seat bases. You might try a fiberglass "plate", if you can find one.

The other option is to create a raised base plate using fiberglass, then attach the seats to that glassed-in "plinth". You might even glass-in the screws with washers so that you use "nuts and lock washers" on the topsides.

 

[Rodd]

Thanks guys for the responses! Yes, they are swivel chairs, and I have already rotated them and used new holes. I want to be able to fasten them down from underneath the deck. SG's idea about installing a base plate is good, but then I face the same dilemma as to how to firmly attach the base plate to the deck. Again I would want to attach it using a fastener from below the deck, rather than screwing into the deck. I have used epoxy, redrilled the holes, and screwed into the epoxy, but that didn't last either! My best idea so far is to use these snap toggles so that the bolt will attach to a "nut" that is under the deck.

 

[SG]

I suppose you can’t get below the deck to attach a backing plate?

 

[jssailem]

@Rodd when you did the epoxy screw in fix, where did it fail? The epoxy cracked or the epoxy plug pulled out?

 

[JimInPB]

Backing plates are best, if you can get to the underside of the deck. Having a glass shop put glass plugs in the stripped holes is a second best option that is probably on or just below structural par with adding an oversized top plate for reinforcement. If you want a quick & dirty solution, you might try epoxying in a few of these - https://www.lowes.com/pd/Hillman-3-8-in-Brass-Standard-SAE-Wood-Insert-Lock-Nut/3012578

 

[Rodd]

negative as to getting below the deck-- I tried, but it is foam filled. John, it was the epoxy that cracked.
Jim- those look interesting too, but so far I am leaning towards using the Snap-Toggles I mentioned earlier.

 

[JimInPB]

If the epoxy cracked and failed, then I will assume that you used just epoxy, without any fiberglass mixed in?

If you are dead set on installing toggles, you might choose to use a hole saw & cut an opening for a 4" pie hatch in the center of where the pedestal mounts. That would give you access to get to the back side of the deck. You could even dig out a little foam if you had to. If I was going to go that far, I would probably choose to use some 3/8"-16 T-heads, rather than toggles though. https://www.boatoutfitters.com/stai...T2wIVBFmGCh3meQr5EAYYAiABEgI2g_D_BwE#215=1281

 

[jssailem]

@Rodd I would suggest, retrying the epoxy. To use thickening in the epoxy to give it a bit of flex and density. Wax the screws and set them in the epoxy before kicking. The epoxy will harden and the screws will be backed out leaving a threaded hole. Then set the base and inserts the screws into the holes.
One of the problems is the epoxy if not threaded will crack.

 

[jssailem]

Here are a couple of ideas.

Epoxy Bonding Studs

1. Bond threaded rods or studs into the substrate (instead of bolts or screws) and attach the hardware with nuts. This variation is appropriate for many engine, motor or machine installations. Coat the base with wax /mold release to make the hardware removable. Although the hardware is not “bonded” to the substrate, the epoxy still provides a bearing surface that perfectly matches and supports the base of the hardware.
2. Prepare the studs/threaded rods by waxing the upper ends (above the surface) and cleaning the lower ends (below the surface). Place a nut on the stud positioned with the top of the nut slightly above the surface.nd washer on the studs, wet out the lower ends and push them into the epoxy filled holes. Allow the epoxy to cure thoroughly before tightening the nuts.
3. Fill the hole 2/3 full with epoxy. Allow the epoxy to penetrate, and refill as necessary.
4. Wet out the lower end of the stud and push it into the epoxy-filled hole. Top off the hole or clean away excess epoxy as necessary. Allow the epoxy to cure thoroughly before attaching hardware and tightening the nut.

Advanced Fastener Epoxy Bonding

Drill oversized holes to increase the exposed substrate area and the amount of epoxy around the fastener
For greater strength and stability, drill oversized holes to increase the exposed substrate area and the amount of epoxy around the fastener.

1. Drill oversized holes 2/3-3/4 the depth of the fastener. The diameter may be up to twice the fastener diameter (Figure 16a).
2. Drill a normal sized pilot hole at the bottom of the oversized hole to the full length of the fastener. The normal sized pilot hole serves to hold or clamp the hardware in position until the epoxy cures. If the fastener hardware can be clamped by other means, the oversized hold can be extended to the end of the fastener.
3. Wet out the holes and the fastener with epoxy. Allow the epoxy to thoroughly soak into the exposed substrate
4. Fill the hole with thickened epoxy/adhesive filler. Use 404 High-density (preferred) or 406 Colloidal Silica.
5. Install the fasteners with just enough force to hold the hardware in place. Allow the epoxy to cure thoroughly before applying loads to the hardware.
   

Coat the hardware bottom and the fastener threads with thickened epoxy.

 

[Maine Sail]

Thanks guys for the responses! Yes, they are swivel chairs, and I have already rotated them and used new holes. I want to be able to fasten them down from underneath the deck. SG's idea about installing a base plate is good, but then I face the same dilemma as to how to firmly attach the base plate to the deck. Again I would want to attach it using a fastener from below the deck, rather than screwing into the deck. I have used epoxy, redrilled the holes, and screwed into the epoxy, but that didn't last either! My best idea so far is to use these snap toggles so that the bolt will attach to a "nut" that is under the deck.

You will need to excavate the foam and install backing plates. Some 4" or 5" Beckson access ports work well for hiding this access.