3M Marine high strength Repair Filler & hardware thru deck

[StanL]

Does anyone have experience with 3M's high strength Repair Filler 46012?

We're installing some pad eyes on the deck and thinking about using the product
to pack the oversized drilled holes for the mounting bolts, and to fill the gap
between the underside of the deck and a G10 backing plate.

We'd first drill oversize holes so the cored deck can be sealed off.
Then fill those bolt holes with wet epoxy and let it drain out after a few minutes, then pack the bolt holes with this filler and let cure. Then drill out holes just large enough for the bolts.

The G10 will have fender washers or aluminum backing plate in accordance
with hardware recommendations.

Not the kind of project we've done before, so any suggestions are appreciated. Is the 3M product appropriate for 1) filler between G10 plate & deck and 2) to seal off the core from the bolt hole?

[SaylorMade]

It might be ok, but the question is why?
Thickened epoxy seems to have proven it's qualities for this exact use?

[StanL]

Originally Posted by SaylorMade

It might be ok, but the question is why?
Thickened epoxy seems to have proven it's qualities for this exact use?

We havn't proven it LOL
That is to say, we have no experience with epoxy.

It's not just convenience, it's also eliminating a steps in assembling materials & mixing and possible errors. Also, with a fair amount of anticipated 3M product leftovers, it can be sued in other projects such fairing and other cosmetic fixes.

The 3M product is a fiberglass strengthened resin, polyester vs epoxy. I don't know enough about epoxy vs polyester, aren't both strong enough?

[xxxxx]

It's vinyl ester.

[StanL]

Originally Posted by xxxxx

It's vinyl ester.

Correction noted, and proving our need for help. LOL

Have you used it?
Do you have an opinion on its strength or appropriateness to these tasks?

[Jammer]

Originally Posted by StanL

Does anyone have experience with 3M's high strength Repair Filler 46012?

It's vinylester resin mixed with silica. They give you a tube of peroxide catalyst that you mix in.


Catalyzed products are less sensitive to thorough mixing than epoxy is, and so they are able to give you a product that is already thickened with silica. With epoxy, you have to mix the two parts first, then add the silica, or it won't cure properly.


I have used other, similar products, but not 46012.

Not the kind of project we've done before, so any suggestions are appreciated. Is the 3M product appropriate for 1) filler between G10 plate & deck and 2) to seal off the core from the bolt hole?

You're adding potential complications and bonding failure problems by using another product family. My suggestion is to stick with one system or another -- either all epoxy or all vinylester.


More specifically, I would recommend using any good marine epoxy (WEST, MAS, etc) and the corresponding silica filler from the same system. Wet out the inside of the repair as you propose then fill the hole with epoxy mixed with silica filler. The silica filler is easy to blend in and apply, and proportions aren't critical. If you work quickly in cool temperatures using a slower hardener you can mix enough epoxy for the wetout and the filler at once, wet out the hole, then add the silica to the pot, mix, and apply. Or you can mix epoxy twice to buy yourself some extra time.


You'll end up with less cost, a stronger repair, and fewer components to keep on hand.


One last fact to consider is that catalyzed polyester and vinylester products have a limited shelf life, especially in hot conditions, while epoxy does not (as a practical matter).

[xxxxx]

Originally Posted by StanL

Do you have an opinion on its strength or appropriateness to these tasks?

My opinion is that it's yet another another resin reinforced with short glass fibers and thickened with fumed silica powder (cabosil).

You plan to seal the core with epoxy. Mix up a batch of epoxy, brush the core. Then add chopped glass fibers and cabosil to the very same batch of epoxy, and fill the holes.

Also, G10 has excellent strength (like... 55,000 psi). If you use the right size hardware with washers, an aluminum backing plate is unnecessary.

[Jammer]

Originally Posted by StanL

I don't know enough about epoxy vs polyester, aren't both strong enough?

Epoxy, polyester, and vinylester resins are all "strong enough" and are widely used in new boat construction. Epoxy is perhaps less widely used because it is expensive.


The important differences in the products are not in strength but rather in bonding ability and water resistance. Epoxy is better for these, which is why it is more widely used for repairs.

[BigBeakie]

We are considering using 2 different approaches when bedding hardware. The first is, as per your plan, to use oversized hole filled with toughened epoxy and redrilled for the through bolt and then aluminium backing plate. Sealed using good butyl tape, countersunk holes etc.
This is our preferred method for high load applications eg winches, padeyes (high loads), jib tracks, etc.

The other approach to minimise deck penetrations is to drill small hole through top glass skin, de-core the foam using bent nail in drill down to bottom skin, then fill with toughened epoxy and high content of fibers, either glass or carbon fibers. Then drill & tap to use 316 helical fasteners such as helicoil or Recoil, to take stainless bolts/screws. These can be obtained in longer lengths to match the thickness of the deck core.

I believe this results in the strongest fastening into a blind hole in the deck, suitable for stanchion bases of a top rail system, solar array frames, etc. where high loads are not applicable.

The weakest aspect of drill & tap bedding is the shear strength of the bedding resin tapped threads, so the helical fasteners solve that issue from what I can research.

[Matt Johnson]

G10 is an epoxy laminated fiberglass sheet. If you're planning on bonding this with the filler, then you should use an epoxy resin mix. While vinyl ester will work better than most believe, it's bond to epoxy isn't that great compared to epoxy/epoxy. If you want to use vinyl ester, then buy standard FRP board instead of G10.... it will probably be more than fine.


Matt

[Flatswing]

[QUOTE=StanL;3395995]Does anyone have experience with 3M's high strength Repair Filler 46012?

We're installing some pad eyes on the deck and thinking about using the product
to pack the oversized drilled holes for the mounting bolts, and to fill the gap
between the underside of the deck and a G10 backing plate.

We'd first drill oversize /QUOTE]

I would minimize the over drilling part. Just need a hole big enough to use a keyhole bit, or if you prefer, a suitably bent nail to remove some core. If core is healthy plywood, bent mail May struggle.
Rod at Marinehowto.com covers this very nicely also. Then thickened epoxy works well & will not drip as much. Mix your own to peanut butter consistency & inject with a syringe to fill all the small gaps. If the deck hole is 3/8” or more, Thixo (flexible thickened epoxy from Jamestown Dist.) is a quick & easy albeit more $$ solution for this. Just gun it - in good for bedding the G10 as well as filling the hole prior to redrilling. Just be sure to use a caulk gun with added mechanical advantage, discard the initial 2” of Thixo and know that the cartridges hold 1/2 what a regular caulk cartridge contain. Catridges come with extra tips so can be reused in future.

[StanL]

Originally Posted by Matt Johnson

G10 is an epoxy laminated fiberglass sheet. If you're planning on bonding this with the filler, then you should use an epoxy resin mix. While vinyl ester will work better than most believe, it's bond to epoxy isn't that great compared to epoxy/epoxy. If you want to use vinyl ester, then buy standard FRP board instead of G10.... it will probably be more than fine.


Matt

Didn't know that about G10, just heard it was very strong and stiff. There is so much more to "fiberglass" than we realized.



Our understanding for this application is as follows:



The purpose of the G10 is to spread the load as wide as possible, and the G10 will be the last piece under the deck before the washer and nut. Our assumption is that the strength of bond between the G10 and it's support is not critical, and will be held in place by the stainless hardware anyway. If water made it that far, we've already lost. Perhaps more important is having a proper base for the G10 to rest against that is completely flat on the G10 side and that conforms and completely fills the gaps on the under deck side.

[Matt Johnson]

Originally Posted by StanL

Our understanding for this application is as follows:



The purpose of the G10 is to spread the load as wide as possible, and the G10 will be the last piece under the deck before the washer and nut. Our assumption is that the strength of bond between the G10 and it's support is not critical, and will be held in place by the stainless hardware anyway. If water made it that far, we've already lost. Perhaps more important is having a proper base for the G10 to rest against that is completely flat on the G10 side and that conforms and completely fills the gaps on the under deck side.

That's all true and accurate. Spreading the load over a larger surface area just requires a stiff backing plate - it could be plywood, metal or fiberglass. The backing plate does not need to be bonded (but can be), but once you mentioned leveling the surface -- which is the correct way to do this -- I was concerned that you were looking to bond this in. In reality, bonding this in with VE would be fine, but if you were looking for the best practices, then epoxy to epoxy should be used.

Matt

[xxxxx]

Originally Posted by StanL

Didn't know that about G10, just heard it was very strong and stiff. There is so much more to "fiberglass" than we realized.



Our understanding for this application is as follows:



The purpose of the G10 is to spread the load as wide as possible, and the G10 will be the last piece under the deck before the washer and nut. Our assumption is that the strength of bond between the G10 and it's support is not critical, and will be held in place by the stainless hardware anyway. If water made it that far, we've already lost. Perhaps more important is having a proper base for the G10 to rest against that is completely flat on the G10 side and that conforms and completely fills the gaps on the under deck side.

A urethane adhesive would be another good way to bond the G10 backing plate to the underside of the deck. It has great gap-filling qualities, a tenacious bond, it is impervious to water, and it is fast and easy to work with.


Example: 3M 5200, LePage PL Premium, etc.

[Matt Johnson]

Originally Posted by xxxxx

A urethane adhesive would be another good way to bond the G10 backing plate to the underside of the deck. It has great gap-filling qualities, a tenacious bond, it is impervious to water, and it is fast and easy to work with.


Example: 3M 5200, LePage PL Premium, etc.

But don't UAs compress easily? This would allow the backing plate to point load any high spots you're trying to fair and make level.

Matt