Deck fittings - backing plates

[kloudie1]

I have used these guys and have been happy. They have lots of different stuff.. This page is 1/4" aluminum plate, 2.5" wide .. easy to work, and cheap.. They have lots of other stuff, including stainless..
http://www.speedymetals.com/pc-2248-8351-14-x-2-12-6061-t6511-aluminum-extruded.aspx

 

[Ross]

Re: Cherry and a hand grip

Cherry, walnut, oak, locust, eastern red cedar all hard enough and durable enough for backing plates. Bevel all of the exposed edges use acorn nuts.

 

[Sail123]

I take whatever I need a backing plate for, to Rivers Metals, and they make me an exact plate to match out of 316. The wood, would cost a lot less, and last quite well, if you choose the proper wood, and or treated it properly.

Also, look at a pair of scissors. How to you think two pieces of stainless bolted to your deck, over time, is any different than scissors? All edges of stainless, should have the edges against the boat, rounded off.

 

[Ross]

Scissors only work if the blades move. I would be much more concerned about cut fingers than fiber glass.

 

[Sail123]

Scissors only work if the blades move. I would be much more concerned about cut fingers than fiber glass.

Pushing scissors along cuts very well. First lesson I learned in kindergarten. Taking the edge off the backing plate is a favor to your boat.

 

[rickbarr]

I'm a bit late on this thread, but I hope I'm in time.
I would NOT recommend using 5200 as a bedding compound; it is NOT a bedding compound, it is an adhesive, period. And it is a damn good one at that. Do not use 5200 on anything which one day may need to be removed, like a window, a cleat or a stanchion.
Things get broken on boats, like a window, a cleat or a stanchion; so use a good bedding compound, not an adhesive.

I agree to disagree with you on the 5200 I agree because as of late I've reverted to 3m 4000 for most of my bedding needs it's just nicer to work with and advertises U.V. Resistance (we'll see in a few years) But 5200 isn't all that permanent.
The amount of times I've easy removed it and broken the so called permanent seal of the dreaded 5200 makes me wonder.. I could be wrong maybe it was applied wrong or the bonding surfaces weren't prepped right. It brittle's and cracks with time, and gets destroyed by sunlight. Maybe it's not the greatest bedding compound but in this application it's being used to adhere a backing plate to the inside of the hull...Why would you want to remove it ? And if you did trust me a flat stiff scraper a hammer and a little sweat & you could remove the backing plate or hardware or what have you. I reseal my chain plates every few years, have tried quite a few different compounds for the job and nothing works as good and as bad as 5200...

 

[Maine Sail]

but in this application it's being used to adhere a backing plate to the inside of the hull...Why would you want to remove it ?

1- 5200 makes a pretty poor choice for distributing backing plate loads evenly along the underside of the deck. The best bet is to wax the backing plate, mix some polyester or epoxy resin into a thick peanut butter consistency with milled fibers and cabosil then draw it up to the underside of the cleaned & prepped deck with waxed bolts.

Now let it cure then remove the plate and clean up the bolts. This process distributes the loads of the backing plate evenly over the plates entire surface and reduces point loading in a few small spots. 5200 compresses easily and thus does little to nothing to minimize point loading of the backing plate. Unfortunately the underside of decks, especially when close to transition points like a deck flange, are anything but even. You ideally want a backing plate to sit evenly on the underside of the deck and to be well supported for even load distribution.

2- Deck hardware should NOT be sealed inside the boat. The only seal should be on the outside. Why? Because when, not if, the deck hardware eventually leaks you need to know about it. We have HUNDREDS OF THOUSANDS of boats bedded with 5200 & similar with sopping wet decks. Sealing the inside only makes this worse and can lead to a failure of the bolts themselves..

Sealing the inside only serves to trap water from an exterior leak in "no mans land" which can;

A) force water into the core rather than allowing it to drip out so you can see it and address the problem. I recognize most people ignore deck drips but if you are reading this thread you probably are not one of the hundreds of thousands of boat owners who ignore these issues..

B) cause crevice or pitting corrosion of the bolts where you can't see it. This can lead to the failure of a stanchion or other deck fitting which can then become a safety issue..


Seal the deck side only and try your best to make the backing plate evenly distributed over its entire surface area...

 

[rickbarr]

I agree to disagree with you on the 5200 I agree because as of late I've reverted to 3m 4000 for most of my bedding needs it's just nicer to work with and advertises U.V. Resistance (we'll see in a few years) But 5200 isn't all that permanent.
The amount of times I've easy removed it and broken the so called permanent seal of the dreaded 5200 makes me wonder.. I could be wrong maybe it was applied wrong or the bonding surfaces weren't prepped right. It brittle's and cracks with time, and gets destroyed by sunlight. Maybe it's not the greatest bedding compound but in this application it's being used to adhere a backing plate to the inside of the hull...Why would you want to remove it ? And if you did trust me a flat stiff scraper a hammer and a little sweat & you could remove the backing plate or hardware or what have you. I reseal my chain plates every few years, have tried quite a few different compounds for the job and nothing works as good and as bad as 5200...

I agree with you completely on useing an epoxy based or poly based filler to bed the plate to the cabin liner.Not that many people do as the process is a long one and it takes two people to do it. I use the same method for thru hull installations useing FBG backing plates. But I did mention in my first posting the key element is to seal the actual hole it all begins and ends there !!
Place some plastic below decks under where your going to be replacing or adding hardware I made a mess of my cabin sole because I forgot to lay plastic down before starting the project.
Drill the mechanical fastener holes larger than the thru bolt. Then take an Allen Key and cut it so it will fit in the hole. Attach it to a drill and rout out the core inside the hole. Clean it out with a hoover or compressed air. Place tape under the hole and pour in epoxy. (I usually pour in a little zylene to thin the epoxy out for better saturation but people here will raise hell about the dangers of Zylene so use it at your own risk)Then go inside the boat bring a pin and a plastic cup or something to that effect. Poke a hole in the tape and let the epoxy drain out into your cup. Re tape the hole go back up on deck. Mix filler into the epoxy you've just gathered and using a syringe fill the hole with the thickened epoxy (on a hot sunny day use a slow setting hardner and work fast) After the epoxy kicks use your hardware to mark where your thru bolts need to go and re drill your holes using the correct sized corresponding bit. It's a pain in the arse and takes time but if you skip this step doesn't matter how or what you bed the plate or hardware with water will seep into the core eventually. P.s. Just buy Don Caseys " This old boat" He'll set you straight on how to correctly install hardware...I read the book years ago and have been following his methods ever since. (with slight variations)

 

[michellepinto]

HDPE is very widely used now. Though some may not be very confident with the idea of using a plastic hull, HDPE is seen to be harder than steel but also flexible. So incase of a collision or anything, it does not crack.

 

[Maine Sail]

P.s. Just buy Don Caseys " This old boat" He'll set you straight on how to correctly install hardware...I read the book years ago and have been following his methods ever since. (with slight variations)

I like lots of what Mr. Casey has written however his ideas on bedding deck hardware are lacking to say the least. The "create a gasket" / "tighten twice" method has perhaps lead to more wet decks than any other single method other than perhaps the actual gaskets used by Pearson et. al.... Mr. Casey also totally ignores the absolute best protection against a leak and that is a slight counter sinking or chamfer of each hole. Hinckley and other quality builders have known about this for decades, even before that book was written, yet this critical step was completely left out of his description on bedding deck hardware...

Here's some more info folks might find interesting with more detail on the why's and how's...

Re-Bedding Deck Hardware

Sealing Deck Penetrations To Prevent Core Rot

 

[sandpiper10471]

You can also thin epoxy with alcohol, but WEST system does not recommend any thinning.

 

[bffatcat]

backing plates

I had my boat completely reconditioned last winter. The yard gave me the choice either 1/8"
stainless or 1/4 " aluminum The stainless cost more. Reasons: costs and more labor intensive. for the difference I went with the stainless. I would not object to aluminum. Either is suitable. (my opinion) I would not use wood or fiberglass. The previous owner bedded stancions and deck hardware with 3/8 marine plywood which was showing serious wear at the time of my refit