Glue for foam boat build?

W

Wilson

New member
Hello. New guy here from WI.

I am planning a foam duck boat build and wondering what kind of glue to use. Yesterday I did an experiment with wood glue, loctite foam glue and silicone. My doubts were confirmed when I broke open the foam this morning. Each edge held firm but the interiors were still wet except for the silicone which was mostly set up. I've never been too impressed with silicone's sticking abilities to a smooth surface so not sure I would trust it though it was by far the most difficult to get apart. Because closed cell foam is essentially a vapor barrier it didn't allow the glue to cure on the inside. So if everybody is building these boats with glue, how are they confirming the sandwiched glue isn't still wet a year later? I see that gorilla glue is popular but again, will it actually dry inside the glue sandwich? I am trying craft spray glue right now just because I remembered I had it.

Thanks for any input.
 
HI,
I've used gorilla glue when laminating pink foam insulation sheets for making decoys and been very happy with the results. You might try that. Would definitely want to test it out a boat falling apart is a lot more critical than a decoy.

v/r
Bill
 
Best advice I can give you is to make use of the technical data sheets provided by the makers of each product. They WANT you to be successful and be happy with your results. I've included a couple examples of the typical data provided. (click on the thumbnails for readable full size images)

An adhesive which "cures" rather than "dries" is probably a better choice to laminate two non-porous surfaces.



View attachment adhesive.jpg



View attachment adhesive2.jpg
 
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Well I'm a moron because I didn't notice on the tube of loctite it says not recommended for two nonporous surfaces. Usually I do read.

Is the LN polyurethane adhesive a "curing" adhesive? I see it says works on foamboard and nonporous surfaces but what about two nonporous surfaces?

Thanks
 
Wilson said:
Well I'm a moron because I didn't notice on the tube of loctite it says not recommended for two nonporous surfaces. Usually I do read.

Is the LN polyurethane adhesive a "curing" adhesive? I see it says works on foamboard and nonporous surfaces but what about two nonporous surfaces?

Thanks
Click to expand...

Your best source for accurate answers would be the maker of the product. The tech sheets shown were only an example of the information available. At no time was it a recommendation either for or against. The contact number for the Liquid Nails product is Please call us at 1-800-729-9029.
 
Thanks for the info. Right now I'm trying some por15 between two pieces of foam. Not sure if it's the same as a two part epoxy but we'll see. I know it dries rock hard.
 
Bill Burruss said:
HI,
I've used gorilla glue when laminating pink foam insulation sheets for making decoys and been very happy with the results. You might try that. Would definitely want to test it out a boat falling apart is a lot more critical than a decoy.

v/r
Bill
Click to expand...

I might have to try out some gorilla glue since everyone raves about it. I'll call them too tomorrow to see what they say.

I have been thinking about making some decoys. I'll have some foam left over so might have to give it a shot.
 
Wilson~


I am unfamiliar with a "foam boat". I am guessing from the context of this thread that it is a vessel that uses foam insulation boards for structure and hull sheathing - is this correct? Got a link that would tell me - or show me - more?


That said, I have used marine epoxy successfully for laminating and coating both polystyrene and urethane foams for decoys. It cures rather than dries.



I would think Gorilla Glue would be very expensive. I use it mostly for wood-to-wood joint that need to be permanent and watertight.


All the best,


SJS

 
Here's a video of one version. Of course the possibilities are endless and mine isn't going to be too much like this. I'm not using wood in mine except for the transom for mounting a trolling motor. Google "foam duck boat build" and you should get some other versions. Making layout boats is popular.

https://www.youtube.com/watch?time_continue=30&v=6s4nSsSO7bE&feature=emb_title

I'm trying some epoxy paint right now so we'll see how that goes. I figured epoxy would work but was looking for other cheaper sources.

I don't plan on using gorilla glue on the boat. Yes, I would have to spend way too much on it but might give it a try for decoys.
 
Wilson said:
Well I'm a moron because I didn't notice on the tube of loctite it says not recommended for two nonporous surfaces. Usually I do read.

Is the LN polyurethane adhesive a "curing" adhesive? I see it says works on foamboard and nonporous surfaces but what about two nonporous surfaces?

Thanks
Click to expand...

Wilson,
The Liquid Nails product would be a "moisture cured" adhesive. According to the data, it is designed to join two, nonporous surfaces. "Moisture cure" adhesives (such as this product) react to the moisture in the air. In very low humidity conditions, it has been recommended to apply the adhesive to one surface and LIGHTY spritz to other surface before joining the two surfaces together. It only takes a very very light spritz to provide the moisture need for proper cure. One does not need or want, large beads of water trapped between the glue up. Again, under most conditions there is sufficient humidity in the air to generate a full cure.

This link has probably more than you want to know about all different kinds of adhesives. Of the "curing" adhesives, moisture cure and two part adhesives are probably the most common that one will encounter at a big box store.

Again, as to any particular application, the maker of the product will be your best resource for accurate information.
 
So I grabbed some titebond polyurethane glue, same as gorilla but only a dollar more for 8 oz vs 4 oz of gorilla, and tested it. On one piece I didn't add any moisture but the other I did. The piece without moisture was cured around the edges but not on the inside and was actually still very tacky. This was after 12 hours which is 8 more than called for on the bottle. The piece that did have moisture was fully cured throughout. I had to pry it apart with a screw driver.

On the piece that didn't have moisture I added perforations for the glue to sink into on one half. This side came apart, with much straining on my part, in many pieces rather than in two clean pieces like the other half but the glue still wasn't fully cured.

None of the test pieces came apart easily. My 6' 2" 210 lb frame was straining pretty good vs some 6" pieces of foam. But my findings are that you should definitely add moisture and adding some perforations on each side to add bite for the glue certainly isn't a bad idea considering the composition of foam. I have found that any kind of glue easily peels off of foam board when not given extra bite.

Earlier in the day I called Gorilla and was strongly advised that none of their glues were recommended for this application even with the moisture method I described even though they themselves recommend adding moisture to very dry surfaces. I know I used titebond but they are both polyurethane glues and fundamentally the same. It just goes to show that even though they are well intentioned, they aren't necessarily correct all of the time. I also contacted DAP and was advised to use a particular glue for this application but upon reading the tech. data found it wasn't recommended for two non porous surfaces. He apologized but I'm sure was just reading off of a list, saw foamboard and really had no clue.

The takeaway is that sometimes you just have to test for yourself.

I have some loctite polyurethane caulking drying yet and I did add extra moisture as advised. We'll see.
 
Thanks for the pics. Yeah, the gorilla glue definitely works even if they don't recommend it. I have mine glued right now. I ended up using the loctite polyurethane glue in a tube. It was only $8 for a 28 oz. tube and dries nice with some moisture added.

How long is your boat and what type of plywood did you use on top?

Thanks
 
Just over 11? and used three full sheets of blue foam - have a spreadsheet somewhere with dimensions

Just used normal luan and is why I need to replace it - other wood is cedar

Can make it another year or so - worked great for early Teal
 
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