Urethane Glue to Mount Frag Plugs

[AKReefing]

So I had a thought. Dangerous, I know. Has anyone tried to mount frag plugs onto/into rock using Gorilla Glue (the urethane stuff)? I've done a test with a plug in a jar of saltwater and it cures just as it would in freshwater. It foams slightly, expanding to fill the hole and secure the plug. It's really no different than Great Stuff, except it barely foams up as it cures. My next experiment is to actually mount a plug in a hole in a rock in the tank.

 

[AKReefing]

So here's the experiment. I drilled a cavity in a piece of dry rock, then submerged it in a Ziploc bag of saltwater. I smeared the urethane Gorilla glue on the stem of the plug, then applied it to the rock cavity UNDERWATER. Now to wait for the cure.

 

[AKReefing]

Looks good. Will try one in the display.

 

[MnFish1]

I would think that after curing it MIGHT be fine. I'm not sure that there is any advantage to using it as compared to super glue, and without contacting the company I'm not sure I would use it since there are other good options that we already know are safe?

 

[JayM]

I’m no expert, but reading the SDS would make me think twice about using it.

 

[AKReefing]

I would think that after curing it MIGHT be fine. I'm not sure that there is any advantage to using it as compared to super glue, and without contacting the company I'm not sure I would use it since there are other good options that we already know are safe?

It's just an experiment.

After curing? That's already been done many times. How many people use the expanding polyurethane in a can when making fake rock on a aquarium wall?

Superglue skins over immediately on contact with water. Kneadable epoxy would be better when trying to fit a plug into a drilled hole.

 

[AKReefing]

I’m no expert, but reading the SDS would make me think twice about using it.

Yeah, lots of possible effects from uncured polyurethane glue. As far as cured: "Once fully cured, PUR adhesives are generally considered to be non-toxic and safe for most applications, including those in which the adhesive comes into indirect contact with food or is used in the construction of household furniture."

 

[JayM]

Yeah, lots of possible effects from uncured polyurethane glue. As far as cured: "Once fully cured, PUR adhesives are generally considered to be non-toxic and safe for most applications, including those in which the adhesive comes into indirect contact with food or is used in the construction of household furniture."

I understand that, but unless I’m mistaken, you’re experimenting with curing it underwater which might be bad if there’s livestock present.

 

[AKReefing]

I understand that, but unless I’m mistaken, you’re experimenting with curing it underwater which might be bad if there’s livestock present.

Could be.

 

[taricha]

I’m no expert, but reading the SDS would make me think twice about using it.

Just for curiosity, could you link or share the SDS you're looking at. Just wondering if we know what specifically we expect to be released.

(As a general position, if something smells while curing, it's releasing volatile stuff. And if you don't know what those things are, and know they are safe, best to avoid. )

 

[JayM]

Just for curiosity, could you link or share the SDS you're looking at. Just wondering if we know what specifically we expect to be released.

(As a general position, if something smells while curing, it's releasing volatile stuff. And if you don't know what those things are, and know they are safe, best to avoid. )

Gorilla Glue SDS

 

[MnFish1]

It's just an experiment.

After curing? That's already been dine many times. How many people use the expanding polyurethane in a can when making fake rock on a aquarium wall?

Superglue skins over immediately on contact with water. Kneadable epoxy would be better when trying to fit a plug into a drilled hole.

The question/comment related to whether it makes sense to use gorilla glue - my answer - no

 

[AKReefing]

Ok, bottom line after testing is that the glue liquefies immediately on contact with the water, which left no usable glue on the plug. I tried gluing the plug stem, then wrapping it in a wet paper towel strip, and it was less messy and most survived insertion into the hole. I finally got two frags in place, but the mess was more than I wanted. Ultimately, the excess foamed and floated to the top for easy removal. There was no reaction by anything in the tank.
My tank is 34" deep, so I needed tongs, which didn't help a lot. Would I use it in a shallower tank? Yes.

 

[BeanAnimal]

Just for curiosity, could you link or share the SDS you're looking at. Just wondering if we know what specifically we expect to be released.

(As a general position, if something smells while curing, it's releasing volatile stuff. And if you don't know what those things are, and know they are safe, best to avoid. )

In a prior life I pumped millions of pound of single and plural component polyurethanes.

Without getting into the weeds - it is all pretty much the same stuff. There is an isocyanate based component and a polyol component. Moisture is a catalyst - the more moisture, the more "foam". The polyol (typically mostly a vegetable oil) and moisture dictate what type of polyurethane (hard plastic to light air foam) are the end product. In the case of gorilla glue, the isocyanate is MDI. These are generalizations, but hold mostly true. The off-gas is going to be TDIs and MDIs (and other isocyanate compounds) and a lot of carbon dioxide. The stuff is bad news to breath - even if somebody tells you that it is not.

I was not allergic to the off-gas -- I am now after so much exposure. I have not been around the stuff for almost 2 decades. Now if I breath isocyanates in any capacity I feel ill. If I work around it at length, I get hives, etc.

 

[BeanAnimal]

PS the ether blown stuff (now pretty much non existent) was - well fun... especially in a confined space :zany-face:
But wow did it smell good when curing... kinda like cookies and ether

 

[AKReefing]

The off-gas is going to be TDIs and MDIs (and other isocyanate compounds) and a lot of carbon dioxide. The stuff is bad news to breath - even if somebody tells you that it is not.

Which? The off-gas from the urethane or isocyanate?

 

[BeanAnimal]

Which? The off-gas from the urethane or isocyanate?

Urethane is a complex polymer that is fairly inert once cured. The off-gassing is a product of the curing process and what is dangerous.

 

[AKReefing]

So the urethane off-gases isocyanate.

 

[JayM]

So the urethane off-gases isocyanate.

I think most, if not all urethane glues contain isocyanate, so I’d imagine that they all will off-gas it.

 

[MnFish1]

Yeah, lots of possible effects from uncured polyurethane glue. As far as cured: "Once fully cured, PUR adhesives are generally considered to be non-toxic and safe for most applications, including those in which the adhesive comes into indirect contact with food or is used in the construction of household furniture."

If you already knew the answer - just curious - and not trying to be a jerk - why ask? Just use it....? Multiple people have said - there are other things that are known safe to use...?