Backing Plates
 

I am completely rebuilding my anchor windless and re-installing it correctly. (so much was wrong with it I don't want to get into it here) So, I have it all rebuilt and tested and I am now re-installing . Upon removal I notice there was no backing plate, it was bolted to the deck using SS hardware and washers. My deck is cored so there is no way I am putting this on without a backing plate, the windless can exert some real force so I want this load distributed over an area much larger than the washer area . So, I went down and cut/drilled some 1/4" AL plate to match all the holes in the unit...it all looks good... but.... now I am thinking AL is probably not the right metal in an anchor locker in contact with SS hardware. SO, now I am thinking either making a "plate" out of 5/8" marine plywood or maybe some SS plate (expensive and hard to cut).

What are your thoughts?

G10

Wander down to the boat yard in Vineyardhaven and ask the yard guys if they have any scraps.

I had 5/8 aluminum 12x12 put in my boat for the t top legs jim. It's not failed yet.

That G10 stuff is insanely tough...How do you machine it? I heard it eats up carbide tipped tools within a few inches.

Its not that bad as long as you don't go too thick.

Diamond table saw blade will do it fine. It will chew up teeth on everything else.

Make sure to bed with 4200 on BOTH sides (around the bolts).

If you really wanna make sure you have no core penetration, oversize the holes, fill with epoxy, redrill.

Plywood will rot over time. I agree with Ted.
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Jim:
Put a capstan on the research boat for hauling samples. used 1/4" Aluminum as the backing plate, 4200 on it, and then put SS fender washers.

Haven't had a problem with corrosion and it is very exposed.

Don't you mean 5200 hound?
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You could use the Al and add a sacrifical zinc to it, watch the Al and replace it in a few years if need be. I agree anchor locker is a tough place high humidity/corrosive environment.

Likwid...You think 1/4" G10 is the right thickness? I am going to order some 12X12" sheets and give it a try. I think if I can cut/drill it, it would be an ideal backing plate. That stuff is bulletproof, stiff, strong and non corrosive. I just don't think I can cut and drill it but I will give it a go.
My other thought was some 3/4" King Starboard but that stuff is kind of flexable.

1/4" is more than enough.
Just go nice and slow drilling it, I bet depending on the space you could get away with an entire 12x12 square to back.

We use it for backing plates for winches.

There's no difference between drilling your fiberglass hull and G10. :)

Jim, if you UPS it to me, i will drill it for you...

This is my slow time of year at the studio

MAS the crap out of some good quality 3/4" plywood is more than enough backing for the cored deck over an area.

What is this G10 you guys are talking about????

heated/compressed fiberglass & resin.
stuff is tougher than tough and makes amazing backing plates.
well worth the money if you just wanna do it once and do it right.

Likwid,
Where is this G10 carried. I used Stainless 6" x 6" plates for all my rod holders as backing plates. And some 5200.

Jamestown Distributors

The problem with 5200 is if its something you MAY someday remove, you're gonna be in for a nightmare.

Rod holders are fine to bed with it since the only time you'd ever need to remove them is if something bad happened to the hull around them.
I'd leave them as is since they don't particularly see high loads and probably the 5200 alone will keep them in place forever. :hihi:

No, 4200 E
1/2 the strength of 5200. less permanant for the reasons Ted mentioned.

I do think some resined/sealed 5/8" marine ply would suffice w/ SS fender washers, lock washer and nut.

g10 is pricey. I looked at it for the r/v, but I had some 1/4" Aluminum on hand, so went with that.

Chiseling 5200 is fun... :smash:

AL is fine. Coat your bolts and washers with 42 hundo .

yeah. like root canal.

I was thinking more like trying to get in a NYYC waitress's pants while still in a drysuit.

I use a heat gun when removing spray rails bedded with 5200, helps a great deal.

well, I'm part of the population from Newport that is never invited to NYYC

Consider yourself lucky.

That being said.... I never noticed the Irish girl bartender from the NYYC who used to nude sunbathe next to my house every Sunday afternoon. :angel:
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Pretty sure her panties are forever mounted up in the forepeak of a certain IMS machine at a certain home of sleds. :hihi:


amongst others. :devil2:

Panties aside...I found one of those multi-master tools with a sharp chisel bid cuts old 5200 off OK. 4200 is even softer (yet plenty strong) my rule of thumb is if it sees water pressure below the waterline then use 5200, if it is above the waterline and someday you may have to remove it then use 4200. Both create are very strong bond and should last the life of the boat.
good stuff.

I found you can order lots of sizes and shapes of G10 from Mcmaster carr but basic sizes are available off amazon.

That G10 stuff is some hard and stiff stuff! I was able to cut it with my chop and table saw (albeit slowly) but after drilling a few holes on the drill press the shavings caught fire as they were sucked up by the vac. (It has a nasty smell when you machine that stuff) I had to check the vac to make sure I didn't start a fire in the vac.

It will make a great backing plate though. You can really crank on it with a bolt and it will not rust/warp/corrode or interact with anything. Uuber strong stuff.

I gotta get some more .. Thanks for the tip.

How much does this g10 cost?

About 20 bucks for a 12X12X 1/8 sheet, I picked up a few 6 X 12 X 1/4" sheets (for cleat backing plates) and they were about 12 bucks a pop.
Not cheap but will do the job and last longer than the boat.

These guys have a ton of it up to big sheets but it is costly

McMaster-Carr

That G10 stuff is the berries. Yes it does STINK when cutting.
We have plenty at work, and I used a piece to go over my anchor locker, mount a winlass and roller. I painted it white and it is still like the day I put it on. Never corrodes, never fades and stronger than steel. It is a resin filled and fiberglass reinforced. Not epoxy though.

I used carbide to cut it, and did it outdoors.