Adhesive recommendation bonding aluminum to fiberglass - Liquid nails?

[KPC]

I've used 2 part epoxy in the past and it works well but often find that it is a bit runny & thin making it difficult to use on verticle surfaces (it runs out before setting up, plus because it is so thin it doesn't fill in voids (1/4") very well.

I need to bond an aluminum plate to the inside hull and was thinking of trying liquid nails. The local hardware store carries either general purpose or polyurethane formulas

It says on the polyurethane tube that it is good for bonding metal & plastic.

Does liquid nails work well? Is the polyurethane the right formula for bonding aluminum to fiberglass?

Need advice. thx.

 

[shaunsteezy]

i just bought blowsion sponsons with the easy install deal and i had to glue aluminum inserts into the hull and this is the glue they sent with the kit...

 

[KPC]

thanks for the reply. that looks like standard 2 part epoxy. I've used that stuff in the past and it bonds well, but i find that it is runny and it doesn't seal up gaps very well either. It should work perfect for what you are doing with the inserts.

I need to bond the aluminum driveshaft housing to the opening in the fiberglass hull. The fit of the aluminum housing isn't perfectly matched to the contour of the hull, it is close, but not perfect. So I need a thick adhesive that will act not only as an adhesive, but also as a sealant to make sure that no water or air leaks past. In this case, I don't think the 2 part epoxy is going to work well

Anyone ever try liquid nails? I'm leaning towards going that route, but sure would like to know if anyone else has ever tried it.

 

[stanton]

use filler in your epoxy. west systems 404, cabosil, microballons, ect. it will make the glue the right viscosity for your application and not some hackjob liquid nails lmao!
use the CORRECT EPOXY!

 

[stanton]

but what are you doing glassing aluminum to your hull anyways??????

 

[chriselmore_1]

I'm in the same boat. The midshaft I just bought for my new hull came with out the rubber seal on the back. Now I am just gonna 5200 the housing to the hull

 

[KPC]

but what are you doing glassing aluminum to your hull anyways??????

that is how it was put together from factory. there is the driveshaft bearing holder, then the driveshaft boot, then the aluminum driveshaft housing which covers the thru-hull hole for the driveshaft

It looks like they didn't scuff the fiberglass to give the glue something to bite to when they glued the aluminum driveshaft housing to the hull. The same problem happened with the rubber fuel filter mount that is glued to the inside of the hull. They didn't scuff the fiberglass and the rubber mount fell off the inside of the hull. The factory adhesive was well adhered to the aluminum piece but it peeled right off the hull. The same for the rubber fuel filter mount, the block of dried adhesive was firmly glued to the rubber, but it peeled right off the hull. It was almost like there was release film still on the hull, and the assembly line workers glued overtop the release film. Cause anywhere on the inside of the hull where a bracket is glued, I can just lightly pull on it, and it peels right off the hull.

So now, I'm going thru the ski finding anything that was glued to the inside of the hull, pulling it off, scuffing the fiberglass, and regluing it back on.

I don't think that finding an in store adhesive is hacking it just because it isn't advertised as being a marine product. Lots of products work in other applications.

liquid nails and 3m 5200 are both polyurethane based. they both claim to be waterproof and that they stay flexible even once cured. Considering the claims of both products being so similar, that is why I asked if anyone has ever tried it. 5200 in a caulking gun tube is $18 + shipping online (cause I can't get it local) vs liquid nails is $3.79 at the hardware store 2 blocks away.

I'm just asking if anyone has ever tried liquid nails or any other thick adhesive readily available at local hardware stores.

 

[SuperJETT]

There are plenty of materials that will do the job. Marine-tex, J-B Weld, epoxy resin with filler, etc.

 

[vitaly]

liquid nails and 3m 5200 are both polyurethane based. they both claim to be waterproof and that they stay flexible even once cured. Considering the claims of both products being so similar, that is why I asked if anyone has ever tried it. 5200 in a caulking gun tube is $18 + shipping online (cause I can't get it local) vs liquid nails is $3.79 at the hardware store 2 blocks away.

I haven't tried the Liquid Nails for the marine applications and I would not risk it.
The Liquid Nails is "somewhat" waterproof and works great to seal restroom counter tops where there is no water pressure (but silicone the top.)
The 5200 is a proven marine product.
Of course, you can try the LN and let us know how it worked out.

Check your local marinas, I remember buying a big plastic tube of white 5200 (not the caulking gun tube) for a few bucks from a marina store, but that was a couple of years ago.

 

[kevbo]

Epoxy has a lot less peel strength than softer urethane adhesives. A two part urethane like ScotchWeld is the best for secondary bonds that are subject to peeling force.

 

[stanton]

oh wow sounds minor, use whatever just prep properly

 

[crashnburn86]

marine-tex is awesome stuff i just used it a couple days ago.

 

[cdickski]

I'm not sure why by my local home depot stocks 5200 both standard and fast cure in a caulk gun size and I'm pretty sure it was less than $18 (definitely less than the marinas). They had it hiding in the paint section.

 

[227]

So wait- I don't think I'm not following you here, you need to bond the drive shaft housing to the hull? What do you mean by drive shaft housing? Do you mean the intermediate bearing Housing? Or does this hull have some sort of plate which the intermediate housing bolts to instead of hull inserts? Post pics, that'd be the most helpful.

 

[KPC]

So wait- I don't think I'm not following you here, you need to bond the drive shaft housing to the hull? What do you mean by drive shaft housing? Do you mean the intermediate bearing Housing? Or does this hull have some sort of plate which the intermediate housing bolts to instead of hull inserts? Post pics, that'd be the most helpful.

its for a 1/2 couch (ultra 150), I get better & faster replies on here vs pwctoday, so I post questions on here even if it isn't standup or blaster related.

That might be what is throwing you off with the design. I don't know how they do it with standups, as I never paid attention when I had standups.

The ultra 150 has the intermediate bearing housing, then a driveshaft boot, then a plate that is glued to the hull. it covers the opening in the fiberglass where the driveshaft goes thru the hull.

That aluminum plate that covers the thru-hull hole, needs to be reattached to the hull. When I disconnected the driveshaft boot, the aluminum housing that was factory glued to the hull, fell off (came unglued). Just like everything else in the hull that was factory glued to the inside of the hull, it is all coming unglued. Like I said in an earlier post, it is like they factory glued overtop of a release film used to pry the hull out of the mold. Even the little plastic 1x1 inch square zip tie holders that are glued to the inside of the hull are coming unglued. So I'm going thru the ski pulling everything off the inside of the hull that was originally factory glued, and scuffing the hull, and regluing the parts back in place.

I already did this with a few items using the 2 part epoxy last season and those items are holding up well. But as I said, for the aluminum piece that covers the hole where the driveshaft goes thru the hull, I need a glue that is very thick which will not only act as an adhesive to bond the aluminum plate to the hull, but it also needs to act as a sealant to keep water from entering the hull, or air entering the pump causing cavatation.

I had a bit of a cavatation issue with the ski and have been hunting down the problem (resealed the pump, resealed the ride plate, etc..) but right off the start, i sometimes got a little cavatation. I bet that aluminum plate was loose allowing air to be pulled from inside the hull, thru the driveshaft hole and into the pump.

 

[SuperJETT]

I assume you know about greenhulk.net? Those guys are the experts on sitdowns right now.

Marine-tex or J-B Weld would probably be your best bets on that.

 

[Speedfreak]

Auto glass urethane. It will need to be primer with the correct primer but the stuff it thick can be molded into shape it's so thick. And when it sits up it will never come off. I have glued footholds in with it no screws rivets or glass. And 5 years later when I changed holds they were still bonded perfect.

We use the 3M brand. And try to get u418 with the 5404 primer. It sticks to everything and if kept out of the sun light will never breakdown.

 

[KPC]

Auto glass urethane. It will need to be primer with the correct primer but the stuff it thick can be molded into shape it's so thick. And when it sits up it will never come off. I have glued footholds in with it no screws rivets or glass. And 5 years later when I changed holds they were still bonded perfect.

We use the 3M brand. And try to get u418 with the 5404 primer. It sticks to everything and if kept out of the sun light will never breakdown.

I spoke to the local autobody supply store and they said that u418 isn't made by 3m that the u418 cross references to a different brand. Regardless, they said that all windshield urethane is extremely flexible when cured. They said that elasticity is 700% for windshield urethane which allows the metal surrounding the windshield to easily flex so the windshield doesn't crack.

I've pulled glass out of cars before and noticed that the adhesive is extremely stringy, it comes off in a ribbon that will stretch out a good 3-4 feet long.

Are we on the same page with the windshield adhesives. Is this the stuff you used for gluing in the foot holds?

 

[Speedfreak]

Ummm no... That stringy stuff is butyl sealant that comes in a roll. It is like hot buble gum. The urethane is harder than that stuff... IT is technically made by 3M It is owned my Dow automotive and labled Essex

It has a 900 PSI tensile strength and 1400 psi lap shear strength. The urethane that holds a car window in is about 3/8 ths of an inch square and is built up to allow flex but when it is flattened out the strength is amazing. I have the racks in the back of my van glued to the walls with it... well everything is glued with it...my chest waders, fender flares on my old truck, SJ hood seal, handle grips, the rubber under the gas tank, scupper tube, well here is a picture of my one way install




Call a glass shop or if you know anyone that works at a car dealership or bodyshop they will know when the glass guys are there you won't need much. We'll do about anything for lunch money so you can get more than what you need for $10

 

[kraqus]

marine-tex or j-b weld would probably be your best bets on that.

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