Leveling surface for backing plates

[SVNeko]

We've used a thick piece of G10 as a backing plate. You can sand this to roughly the shape you need, then fill in gaps and glue with thickened epoxy. This way you're relying on more backing plate and less thickened epoxy.

[toddedger]

G10 is great if you can afford it, but i would recommend 3m high strength premium filler instead of epoxy. While I love epoxy, the High Strength Filler will be much easier to work with. It's thick like peanut butter and has glass fibers mixed in it, and it sets in 15 minutes.

I would wax the bolts and assemble them through the backing plate, and filler, giving a little squeeze to make sure the angles form correctly.

[Stumble]

Originally Posted by toddedger

G10 is great if you can afford it, but i would recommend 3m high strength premium filler instead of epoxy. While I love epoxy, the High Strength Filler will be much easier to work with. It's thick like peanut butter and has glass fibers mixed in it, and it sets in 15 minutes.

I would wax the bolts and assemble them through the backing plate, and filler, giving a little squeeze to make sure the angles form correctly.

Filler is not a backing plate, if you go this route replace the g10 with an aluminium or stainless plate.

[alctel]

if you can get hold of old road signs, they are amazing backing plates. Easy to cut as well.

[toddedger]

Yes i agree, use metal for backing plate followed by G10 over 3m high strength premium filler.

[oleman]

I would build up a plate using g10 (some machine shops will not machine fiber because of the mess it creates) or marine aluminum and take it to a machine shop and have it machined to the correct angles for the proper fit.
With correct measurements for accuracy, it could become an addition to the vessel to be proud of.
I would make up a model from wood first prior to investing in the expensive final materials and machining.
Yes, it will be costly, goes along with every thing on our vessels.

[thinwater]

You don't need G10! Pure internet myth that will never die, like propylene glycol AF being better for the environment.

Structural grade fiberglass plate is available from all the same places for less than 1/2 the cost, has the same stiffness, and will do all the same things. It is still going to be much stronger than the underlying laminate, which is all that matters. G10 is just as wrong for this as carbon fiber.

Stiffness is the same. Tensile strength is 24 ksi vs 32 ksi, but since tensile failure is impossible if properly sized (they are sized for distribution and thickness), it makes no difference.

https://www.mcmaster.com/#grade-g-10-garolite/=16eaoe4
$38 for 1/4 x 12 x 12
https://www.mcmaster.com/#standard-f...heets/=16eao5u
$16 for 1/4 x 12 x 12

[Suijin]

If it were me I would cut backing plates out of 1/8" G10, drill my hole pattern, butter up the bolts and plate, mix epoxy with 404 filler (for structural applications), bolt it together, getting the plate level/perpendicular to the bolts, let it kick, pull it apart, seal with 4200 and reassemble and tighten. If I was sure I'd never be taking it apart, I'd use 5200, which should last you essentially forever.

Don't use wood. Even though it might seem that the area is dry, water finds a way. G10 is the superior choice.

[ErBrown]

Originally Posted by Suijin

If it were me I would cut backing plates out of 1/8" G10, drill my hole pattern, butter up the bolts and plate, mix epoxy with 404 filler (for structural applications), bolt it together, getting the plate level/perpendicular to the bolts, let it kick, pull it apart, seal with 4200 and reassemble and tighten. If I was sure I'd never be taking it apart, I'd use 5200, which should last you essentially forever.

Don't use wood. Even though it might seem that the area is dry, water finds a way. G10 is the superior choice.

Thanks everybody for the help and suggestions. Suijin, you just outlined my exact plan with this post. I appreciate the comments on other options to G10 for the backing plate but had been working with a local rigging shop and they hooked me up with a few G10 backing plates. They've actually been nice to work with since they cut fairly easily, unlike the stainless I was originally planning to use. This came in handy since I had a few obstacle to work around with the second bracket (not pictured in this thread).

I'm using very thick Peanut Butter like epoxy but two of the area need enough build up that each is a multi-day project, otherwise it starts to sag. All in all it's working out pretty well so far. I buttered the bolts with vaseline and and expect them all to be ready to bolt-up tomorrow. Once it's all cured and ready to go, I'll disassemble and seal it all up with 4200.

As with all things boat related, this original "1-day project" turned into about 4 days, but the end result is going to be solid and I'm really looking forward to getting out and playing with the new vane.

Thanks again,
EB

[JPA Cate]

For ease in removing our windvane, Jim designed the backing plates with the threaded part coming out the transom, so that he did not have to get all the way back in there when we wanted to remove the windvane. Simply undid the 4 nuts per bolt. Hope you can use this concept.

Ann

[Stumble]

Originally Posted by Ann T. Cate

For ease in removing our windvane, Jim designed the backing plates with the threaded part coming out the transom, so that he did not have to get all the way back in there when we wanted to remove the windvane. Simply undid the 4 nuts per bolt. Hope you can use this concept.

Ann

One of the advantages of using g10 is that it can accept being tapped if it's thick enough. So you don't need nuts at all.

[daletournier]

I literally this week finished fitting my Hydrovane. I used the hydrovane on my last boat for over 7 years with no problems so I've fitted it to this boat exactly the same way.
Timber pads on the outside and 12mm ply heavily glassed and expoxied for backing plates. I used epoxy and micro balloons to bed the backing plates for a perfect fit.
I would not use something like 5200 as you want this to be ridget, its under a great deal of load in certain conditions.



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[ScottMeilicke]

Originally Posted by Stumble

One of the advantages of using g10 is that it can accept being tapped if it's thick enough. So you don't need nuts at all.

I like the idea of bolting from the outside into a threaded backing plate. Myself I would use ⅜ stainless, but I have no experience with threading G10. If you then decide to pop off the wind vane, you could replace the thickness of the vane mount with equivalent thickness rubber washers to provide a water tight seal when the cane is not in place.

[ErBrown]

Looking good Dale.

I just finished the last layer of epoxy and am waiting on it to set, so I can do the final mount.

This is likely a question for another thread but will try here.

Due to the angle of our transom and the need to gain a little clearance we're using about 4 inches of teak pads between the transom and top bracket of the vane. Think (4) 1" pads stacked and through bolted. My question comes to the final fit. I'll be sanding and cetol'ing the completed spacer. I'm assuming I should use a sealant between teak layers to prevent water intrusion?

My plan is to seal the base of the spacer and bolt holes with 4200 UV. Should I use the same for the surface between pads? Seems like this might look odd. I was thinking maybe butyl here but not sure of the best option. I guess there is also the chance that I could just seal it with Cetol. The rest of the teak on the boat is 3 coats of natural teak and 3 coats of gloss. Seems to do a pretty good job of sealing small gaps...

Here's a quick pic. The bolts are just set in the holes currently (coated in vaseline) while the epoxy cures. They fit together much nicer when actually bolted in place.

[daletournier]

Originally Posted by ErBrown

Looking good Dale.

I just finished the last layer of epoxy and am waiting on it to set, so I can do the final mount.

This is likely a question for another thread but will try here.

Due to the angle of our transom and the need to gain a little clearance we're using about 4 inches of teak pads between the transom and top bracket of the vane. Think (4) 1" pads stacked and through bolted. My question comes to the final fit. I'll be sanding and cetol'ing the completed spacer. I'm assuming I should use a sealant between teak layers to prevent water intrusion?

My plan is to seal the base of the spacer and bolt holes with 4200 UV. Should I use the same for the surface between pads? Seems like this might look odd. I was thinking maybe butyl here but not sure of the best option. I guess there is also the chance that I could just seal it with Cetol. The rest of the teak on the boat is 3 coats of natural teak and 3 coats of gloss. Seems to do a pretty good job of sealing small gaps...

Here's a quick pic. The bolts are just set in the holes currently (coated in vaseline) while the epoxy cures. They fit together much nicer when actually bolted in place.

I'm certainly no expert but in your case I would epoxy all four teak pieces together so it's one big permanent block. I would then use the 4200 or equivalent to mate it to transom.

For my bottom bracket I used a wood pad but mated it using a epoxy putty to get a perfect fit. For the upper brackets I taped sand paper to the hull and rubbed the timber pads in it to get the right contour, the curves in the top pads were minimal.

As mentioned I mixed up a brew of epoxy filler quite thick and added it to backing plates as I tightened them in place, once again to get a perfect non flexing fit.


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