Reinforcing fiberglass to mount a TV

[mattman]

Hopefully I don't get too much grief for putting a small TV in our sailboat. It gets dark pretty early this time of year.

I've attached some photos of the current temporary setup, which is thru bolted with rubber gasket on each side to help with the rotational forces. I'm hoping that if I sandwich and glass in some marine plywood on the back it'll be sturdy enough for this little 24" TV permanently.

Fiberglassing is an area that's new to me, but I was thinking I could just round off the corners of the plywood and epoxy it to the current fiberglass to make sure it's fully bonded to the current surface area. Then I would wet the top and sides with polyester resin, use "peanut butter" to get a smoothish radius at the joints, and just add a few layers at a time. Maybe 3-4? Essentially following what Boatworks Today did:

https://www.youtube.com/watch?v=9jHUI0CiYbs

Does that seem like it would give this enough enough structure to support this application? Should I get more creative to fix the plywood/glass to the top and bottom to give it additional structure? Am I going to regret this entirely?

Thanks!

[Fore and Aft]

Matthidinger we have the same TV mount. It is a pity you used the spare mount as a backing plate as we have one bracket in the saloon and one at the end of our bed. The biggest hassle was wiring in a new cigarette lighter for the TV when we move it to the end of the bed.
Anyway why not forget the plywood fibre glassing thing as there is not much load on these brackets. Then replace the raw plywood with a piece of plastic like in the link below.
Our bracket is just screwed into a 18mm plywood bulkhead and has held in fine for years.
Cheers
Drew
https://www.kingplastic.com/products/king-starboard/

[Chotu]

What Fore and Aft said. It’s completely unnecessary to go through all that grief. You just need a doubler/backing plate. If there is torsion you’re worried about, maybe glue the doubler to the fiberglass using almost anything (epoxy, 5200, etc).

Even if you did use plywood, get some marine ply and forget about all the glass work.

To me, it sounds like you are looking to play with these materials for fun because they are new to you. I get it. I did the same when I first started. However, this is a ton of unnecessary work if you’re just trying to get the job done.

If you do decide to do all this work just for something to practice on, make absolutely sure you glass over the wood WHILE IT IS COOLING and not in the early morning while it is warming up for the day. As wood warms, it off gasses and will make bubbles and voids in your glass job as the gas escapes. If you do it at the hottest point of the day, the wood sucks air (resin) in as it cools and seals off much better.

[GordMay]

Originally Posted by Chotu

... If you do decide to do all this work just for something to practice on, make absolutely sure you glass over the wood WHILE IT IS COOLING and not in the early morning while it is warming up for the day. As wood warms, it off gasses and will make bubbles and voids in your glass job as the gas escapes. If you do it at the hottest point of the day, the wood sucks air (resin) in as it cools and seals off much better.

The details, that a 'pro' knows!

[Spot]

I would glass the existing plywood board off the boat, 2 layers plain cloth plain resin, and re-install with construction adhesive, bolts, fender washers, and lock nuts. Use the spare mount somewhere else. Save the epoxy and fillets and 3-4 layers of fiber glassing in a tight space for a structural repair that really needs it.

Doing the project in the shade or late afternoon, prime coating the wood with resin before glassing it-all things that will help with the 'bubbles'.

[mattman]

Thanks all. One thing I should mention is that fiberglass it's mounted to right now doesn't seem like it was meant to support anywhere near these loads, even with a backing plate. It's a very thin and flexible glass+gelcoat layer, e.g., when I press center of that panel with my hand it deflects quite a bit, since it's really just for decorative lining. That's why I think glassing in the wood will add structure to the whole area beyond just the 2 bolt holes.

[OS2Dude]

Our 1985 Catalina 30 has a doored enclosure on the hull in the saloon. We put our 12v 24" TV there. Sanded a spot to bare glass and glassed in a small wood block. We don't have a swing arm. Works great.