# Interesting Great Stuff conversations with DOW



## Blort (Feb 5, 2005)

I am always dubious of household chemicals since their use is often put under much less scrutiny than commercial applications governed by OSHA. So, I decided to call Dow about great stuff and find out if they had any polyurethane foams that were either (1) food grade or (2) had a high hydrolytic stability (don't break down in water). According to the tech people, there is nothing in the literature that they know of talking about how Great Stuff holds up in water, but that generally they thought it would be hydrolitically stable since it is a closed cell plastic. What I could find said that depending on the type of foam you could expect between 5-10 years of stability from the foam.

I asked them about the polyurethane foam used in breast implants and other medical applications, and they referred me to Dow Corning who I will probably call next week. Dow Corning had problems with TDI foams (toluene diisocyanate) a couple years ago leaching from breast implants. Great Stuff is MDI foam, so that may not be a problem here.

On a funny note, I asked them if they had recommended sealants that were non reactive with MDI foam and they said that you could pretty much use anything but silicone because it wouldn't stick. I thought this was pretty funny and informed them of the long tradition of using silicone and coco fibers (which he seemed to find curious) in the hobby.

At any rate, I am still not convinced that the fire retardant additives in Great Stuff are hydrolytically stable and given the nasty toxicity of some of those compounds the jury is still out for me. I contacted the Polyurethane Foam Association and they said that what I was talking about was a rigid foam application and to contact the Spray Polyurethane Foam Alliance who I will call later today. I also sent an email to some rigid foam manufacturers specializing in underwater applications.

At any rate, I thought some might find this interesting.

Best,

Marcos


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## Rain_Frog (Apr 27, 2004)

Jason Hupp is the one I asked before I decided to use it. I have experienced no problems with Great Stuff, however.

Jason has a vast knowledge of chemistry, so he'd be somebody you might want to talk to.

The question is, what makes Great Stuff different than Dr. Foster/ Smith's Black Pond foam?


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## Guest (Mar 8, 2005)

It's yellow  


I know I'm a smartass


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## Rain_Frog (Apr 27, 2004)

I think I will go back and smear more silicone down in places on my new vivarium before I let my tinc live in there. Some of it comes into contact with water from the false bottom.

Personally I believe it is safe... as long as it doesn't come into contact with ultraviolet light. 

Another thing to consider is the amount of fish people that have been using it...but it is COATED. 

Consider the effects though. In a tank of mostly substrate, there is probably little chance enough of this stuff will accumulate in the substrate if one changes it seasonally and changes the water. I don't know the effects if a drip wall is running, but the majority of my Great Stuff has been sealed behind cork bark or coated with silicone.

But with Marco's views, I am thinking twice now about using it again, or at least give it some epoxy coating. Epoxy will only work if you cover it from UV, or be prepared to redo it within 7 years... saltwater will also corrode epoxy about that length of time.

Jason Hupp's argument that Great Stuff is inert as it cures with water. He sent me once some information in an email about the chemical composition (polymers, etc.), but I believe I deleted the message when I was asking him, due to his background in chemistry.


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## bbrock (May 20, 2004)

Marcos,

Just wanted to say thanks for taking the time to track down information and report on this. Like most of us, I've taken the "nothing bad has happened to me" approach but obviously this isn't the most reliable indicator. Thanks again for tracking down real information.


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## Rain_Frog (Apr 27, 2004)

What should I do now? My tank already has Great Stuff in it with silicone?


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## Arklier (Mar 1, 2004)

These are the products I see advertised on most pond sites for plugging holes in waterfalls and stuff:



















There's one other, but I haven't been able to find a good picture. I'm pretty sure that the first one is not meant specifically for ponds. The stuff is expensive too. Cheapest I've been able to find quickly is $10 a can.


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## Rain_Frog (Apr 27, 2004)

I think I'm going to hunt around myself, like I did for information about epoxy.


BTW guys, I really asked West System originally about their pigment, as I know specifically that latex paint underneath undermines epoxy's strength and bonding to a surface.

Apparently the white pigment is safe, made of titanium oxide, while the gray pigment is mostly graphite, but he never gave me a definite answer. IT IS NOT aluminum though.

So, if you ever want to color up your backgrounds, get some of it. I have it, and I'm ready to use it for my Xenopus tank.

I just may have to save face and buy some Becker's Foam. I still have like two weeks before Paul sends me the acrylic for my doors. I can't use epoxy in this situation because it could damage the glass from the heat output and I refuse to move the tank to the basement again for work...


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## Darks!de (Nov 16, 2004)

Yeah, they usually run $10-15. RainFrog, both the greatstuff and silicone are non-toxic (well we'll be able to prove that in the next week or so thanks to blort) and most everybody on this board has some in their tanks, so i wouldn't worry about it. The DOW reps thought that silicone would not stick to great stuff, and thus would not make a good sealing agent. Obviously they never made vivs 

Luke


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## Rain_Frog (Apr 27, 2004)

I will say this though:

I only use the flexible, blue can. I don't know the difference in properties, but will say this...

I was pretty unhappy with the effects after a while in a mantella tank for a few months. The stuff eventually is easy to peal off, and you can peal the silicone off of it as well. I have told myself not to use it again except for small spots, not the majority of the background. 

So, I do agree from experience (as far as the blue can goes) that it will break down...and it occured after about 6 months. But whether or not "noxious chemicals" leach from it when it breaks up, that is something Marc will verify us.

I only used it THIS time to fill gaps behind the cork bark, as I knew no other way to keep the cork stuck to the background. The entire back is cork, with maybe a few spots of covered with silicone Great stuff blue can. 

If I can find another way to get my cork to stick, all I gotta do is get a knife and cut it all out behind it, that's it. I just gotta fill up the space with something to keep Kole and a future girlfriend (hehe :lol: ) from getting stuck back there...

In the meantime, does anybody want me to contact Handi Foam? I'm starting to believe what makes Great Stuff different is, like Marc said, additives of fire retardants.


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## mydumname (Dec 24, 2004)

I think your problem came because of the can you used, blue. The red and yellow can is what I believe everyone else uses. It's what I used and I had no problems.


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## Blort (Feb 5, 2005)

Interesting stuff  Thanks everyone for chiming in. I enjoy calling DOW; it is how I take breaks at my home office to keep from going crazy.

As I understand it, Becketts Pond Foam is the same stuff as Fomo One-Component Handi-Foam. My reference for this is the MSDS I got from Beckett. You can visit the Fomo website and peruse all their MSDS. I think the straw foam is a good basis for comparison as the Beckett one says it is the same product and the hazardous components are the same. You can compare this with the Great Stuff MSDS here.

Now, it seems that the big difference is the pre-polymer in that Fomo claims that it is non-toxic while DOW makes no such claim regarding the CAS number used. A general note of caution about MSDS sheets and using them as the final word, is that they are designed for the manufacturing sector and generally talk about the product in its raw form and in its transition form, but rarely in its final or cured form. So, where that is applicable here is that from what I understand prepolymers of urethane are nasty things. However, they are used up in the chemical reaction. In my opinion, the argument is about trace elements and additives. Another thing to keep in mind is what is considered toxic is defined by OSHA whose standards most MSDS are designed to meet (you may find the EPA using different definitions for example). They face stiff, stiff opposition from industry in adding chemicals to their toxic lists. Don't remember off the top of my head, but the list of OSHA carcinogens hasn't been updated in over a decade and neither have the PEL (permissible exposure levels) of most chemicals. According to the institution where I received my authorized OSHA instructor certification, this is due to pressure from industry.

However, the state of California has their own rules and sometimes you will see two MSDS one for everybody else and one for California. Unlike the feds, they have updated their PEL and list of carcinogens, and they also have rules about other things to be listed in MSDS.

So where does that leave us? Well, to guess about what else may be in those compounds. Like I posted earlier, my biggest concern is with the things that were added to most polyurethane compounds to decrease their flammability. Some of you may remember lawsuits about couches, beds, etc., catching on fire and going up in a matter of seconds. Well, it turns out polyurethane foam gives just the right mix of fuel and oxygen to cause one hell of a blaze. For this reason, it was mandated that certain things be added to make polyurethane foams more fire resistant. If you peruse the DOW Great Stuff website you will see lots and lots of claims about the fire-retardant properties of Great Stuff. In my understanding, this is not a natural thing for polyurethane foam to do. Some of the chemicals that were used for years were PBDE's. Recently some of this was phased out in the US, link here, by some manufacturers. So, to really know what is in this stuff, we really need to see not only what is required by the MSDS, but other additives. Furthermore, we need to examine what happens after the material cures and even when it is a stable plastic like fully cured polyurethane foam, how it stands up to light, water, silicone, etc. What makes me cautious is that if this stuff was hydroliticaly stable and didn't degrade or leach chemicals, you would probably see it in biomedicine and other applications. That is why I plan on calling DOW Corning and seeing what they have to say about polyurethane foams.

The long term answer is where I am at a bit of a loss. I think three things should continue (1) a ongoing effort to find out what chemicals we are putting into our tanks and (2) some long term toxicity studies, and (3) suppliers to the hobby should be open about what they are selling. I know the last recommendation may be an emotional one but (a) providing MSDS upon request is the law and (b) there is more to be lost by using terms like "proprietary blend" and perhaps making a little more money than by contributing to the husbandry of animals and our understanding of these chemicals as a whole through transperency. I think how fruit fly media is sold by suppliers and made by individuals goes to show that it is possible for a continued dialog about what the pros use and for them to still maintain a viable market for their product through the fact that they can buy in bulk, etc.

What I would like to see is some sort of comparison of tissue and/or blood toxicity from samples taken from captive bred PDFs that have been exposed to these conditions for years. I know that without a proper control group, etc., we would be stabbing in the dark for a while, but there may be interesting results or the opportunity to collaborate with the scientific community.

Looking forward to this ongoing discussion. Thanks for bearing through this message 

Best,

Marcos


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## Rain_Frog (Apr 27, 2004)

Yes, thank you Marc. And like you said, I just checked Fomo's website, and Arklier did prove a point. The kind many pond places sell is Fomo 1. I went to Fomo's website, and it has fire retardant properties too....


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## Arklier (Mar 1, 2004)

I've got a red can of Great Stuff here with me, so I'll put what's on the can down here. Any typos are mine.

Front:

<DOW>
GREAT STUFF (TM)

Saves Energy
INSULATING FOAM SEALANT

GAPS & CRACKS

Fills, Seals & Insulates
#1 Selling Foam Sealant in the World

* Airtight & Waterproof
* Bonds to Most Materials
* Cures Rigid & Trims Easily
* Sandable & Paintable
* For Interior & Exterior Use

*DANGER! FLAMMABLE GAS.* VAPOR MAY CAUSE FLASH FIRE. CONTENTS UNDER PRESSURE. Read caution on side panel.

NET WT. 16 OZ. (484g)

On the back:

*HANDLE RESPONSIBLY*

*WARNING/DANGER:*
* Extremely Flammable. Keep away from sources of ignition.
* Cured foam is combustible and may present a fire hazard if exposed to flame or temperatures above 240 degrees F (116 degrees C).
* Contents under pressure. Do not place in hot water. Do not puncture, incinerate or store at temp over 120 degrees F (49 degrees C).
* Can may burst if left in areas susceptible to high temperatures such as motor vehicles or near radiators, stoves or other sources of heat.
* KEEP AWAY FROM CHILDREN.
* Use in a well ventilated area or with proper respiratory protection.
* May cause sensitization by inhalation and/or skin contact.
* Product is extremely sticky and difficult to remove from skin, clothing and surfaces.

*FIRST AID MEASURES*
* EYE: Flush with running water for 15 minutes.
* SKIN: Wash skin with soap and water.
* INHALATION: Remove to fresh air. If breathing has stopped, administer artificial respiration.
* INGESTION: Give large quantities of fluids. DO NOT induce vomiting. Consult a physician in all cases (show label when possible).

_GREAT STUFF is a polyurethane intermediate which is made up of polymeric diisocyants, polyols and hydrocarbon gas mixture. Refer to Material Saftey Data Sheet._

*GREAT STUFF* Gaps & Cracks Insulating Foam Sealant expands to take the shape of cracks and voids forming a permanent, airtight and waterproof bond to wood, metal, masonry, glass and most plastics. *GREAT STUFF* Gaps & Cracks Insulating Foam Sealant is tack free in 15 minutes and cures in 8 hours. Cured foam dries rigid and can be trimmed, shaped, sanded, painted or stained. CAUTION: Cured foam will discolor if expoed to sunlight. Foam must be painted or coated. Extremely cold temperatures can adversly effect performance. *GREAT STUFF* is an adhesive sealant and will seal itself shut if allowed to sit unused for over two hours One time use should be expected. Overfilling can buckle substrates. Use *GREAT STUFF* Window & Door Insulating Foam Sealant for applications that require use of a low pressure or flexible foam sealant. Foam is extremely sticky. Protect skin, eyes and surfaces.

*SHAKE WELL*

*INSTRUCTIONS:*
* Plan ahead for safety and best results.
* This product is extremely FLAMMABLE during dispensing. Do not smoke or use near open flame. Shut off pilot lights and sources of ignition until tack free.
* Extremely sticky. Prevent skin & eye contact. Wear gloves & protective eyewear.
* SHAKE CAN VIGOROUSLY FOR 30 SECONDS AND BETWEEN USES.
* Screw threaded end of straw assembly securely onto valve. Dispense SLOWLY.
* Fill openings less than 50% full. Large voids or low humidity, mist water to speed cure.
* If product does not flow easily, do not force product from can.

*CLEAN UP:* Solid surfaces, uncured foam dissoves with acetone. For skin and solid surfaces, cured foam must be mechanically removed or allowed to wear off in time.

*OVERFILLING:* Overfilling the gap is common but easy to remedy. Once dry, trim excess foam wiht any sharp knife or serrated knife.

This lable is intended to meet the requirements of the United States. If you are reading this lable in a locatino other than the United States, please refer to the lable intended for your location.


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## Rain_Frog (Apr 27, 2004)

Any more word on this?


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## Blort (Feb 5, 2005)

Rain_Frog said:


> Any more word on this?


Well, I talked to Dow Corning, and here is what they said. Yes, polyurethane foams are hyrdophobic and hydrolyticaly stable, but do have a permeability of %.025. While that sounds like a small number, it isn't if there is something in the compound aside from plastics, such as a fire-retardant additive, that can leach into the enclosure where parts per million can be the measure of too much.

I tried to articulate what we try to do with Great Stuff, and their recommendation is making molds instead of trying to fill holes. They offered a food grade alternative to using epoxy which is Selastic (sp?), or S-RTV, which is a elastomer like silicone, but from what I understand cures much harder (more like hard rubber than soft silicone). From what I got, you can slop in over a rock and use it as a positive to fill an area or as a negative to make a mold. It is a two part mixture that uses platinum to cure in a 10:1 mix.

However, it won't cure completely if in contact with numerous things which may or may not be in a vivarium. A full list of what these things are (sulfures, urethane, etc) is available on their website if anybody is interested in experimenting with it. They also shed some light on full curing of RTV silicone and that the DOW rep was right in saying that when using silicone to coat polyurethane foam (Great Stuff), it won't fully cure. It might be a small amount, but that means that some of the unstable chemicals in the mix are still in their raw form. If this poses a risk to animals, I don't know, and until somebody has data on toxicity in the animals, I don't want to hazard much of a guess.

My take in short:
*GS is not designed for and has not be tested in this application
* it does break down on a very small scale (%0.025)
* that small scale could result in contaminants
* it wasn't designed to mix with RTV silicone
* there is no data either way about the potential contamination from additives
* there is no data on toxicity in the animals themselves
* even if hydroliticaly stable, there is still UV, and possible biological attacks from microbes resulting in new chemicals derived from precursors in the foam

All that amounts to not worth it for me, but I can understand if other's continue to use it. However, I don't think GS is much different than Beckett's or the rest of the Polyurethane Foam family. Alternatives such as clays, densely packet coco-fiber, are probably how I will go. If I do need something more complex, I will mold it from food-grade epoxy or food grade rubber.

For what it is worth,

Marcos


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## bbrock (May 20, 2004)

Blort said:


> Well, I talked to Dow Corning, and here is what they said. Yes, polyurethane foams are hyrdophobic and hydrolyticaly stable, but do have a permeability of %.025. While that sounds like a small number, it isn't if there is something in the compound aside from plastics, such as a fire-retardant additive, that can leach into the enclosure where parts per million can be the measure of too much.


Once again, thank you! One thing that is worth mentioning is that the risk of this stuff needs to be placed in the context of the vivarium system. For starters a vivarium with a misting system and overflow drain has a self flushing mechanism that will help to dilute and eliminate contaminants. Also, a vivarium is a very bioactive system. As you've mentioned, their may be potential for bacterial decay, although I would bet that the decay rate is extremely slow. But there is also the potential that contaminants that do leach out could also biodegrade into harmless compounds.

I know these are generalities but I do think it is worth remembering that a living vivarium does have some built-in safety mechanisms that MIGHT offset low levels of contaminant leaching. It might also be worth mentioning that natural wood contains a lot of really nasty carcinogens, tars, etc. No vivarium that contains natural organic materials is 100% free of toxic compounds in the system. I'm still willing to bet that GS is very safe for our frogs but there is no way to be certain it seems. Thanks to Marcos we can narrow the liklihood that it is dangerous but cannot not eliminate the idea completely. This is all very good information to have.


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## Rain_Frog (Apr 27, 2004)

Marc, excellent analysis. Marc, did you get my 2 PMs?

My 2 cents:

Great Stuff should never be used bare submerged underwater. I know of a few folks that neglected to cover the foam with anything in constant submersion under water.

The level of minerals and bacteria in a false bottom could rapidly degrade the foam, and without proper siphoning, the tank could definitely become too toxic.

I would never use Great Stuff in any running water feature unless I had epoxy to cover it. It does seem to go bad after a while, and without proper protection, aethetically it will become unpleasing real fast.

And yes, it doesn't really stick to silicone very well. You can peal it right off. Try it.

I would like to comment: Many of us folks use standard tapwater. NOTHING that we use is as loaded in lead, minerals, arsenic, cadmium, etc. as it is. But many of us have used it just fine, as long as we occasionally flush it to avoid build up of minerals. 

Additionally, how do we know the chemical composition in our soil mixes? And how many of us out there are using GE silicone 2 that deliberately says "Not recommended for aquariums."

About "food grade epoxy," I have never heard about this. Interesting Marc. If you could find me a place that sells it, that would be interesting.

Personally I am quite confident in marine grade epoxy because many saltwater fish people (which are more sensitive) have been using epoxy built tanks for years. AS LONG AS IT IS CURED PROPERLY. That paper verifies that it is safe for human consumption.

However, people still forget that epoxy will need to be recoated in about a decade or more.

This is one thing all of us choosing to work with epoxy must do. I believe I will call West System Monday and verify this. There is no point in making a very nice artificial background when you must tear it up or redo it when your animals have much longer to live! 

P.S: The antithesis of Marc's argument will be posted hopefully soon. Jason Hupp, who I listened to religiously about chemicals, hopefully will add a reply as soon as he returns to Florida, he tells me in a PM.


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## Blort (Feb 5, 2005)

Rain_Frog said:


> P.S: The antithesis of Marc's argument will be posted hopefully soon. Jason Hupp, who I listened to religiously about chemicals, hopefully will add a reply as soon as he returns to Florida, he tells me in a PM.


Thanks for goading me on  I'm really looking forward to Jason joining the fray, since I have a bunch of questions to ask him. I hope it will be more of a synthesis than an antithesis though :wink:

I agree that at least the industry literature points to coating spray polyurethane foams (SPF) in general and almost without fail all the applications that use a SPF core for flotation, insulation, etc., have the foam surrounded by some sort of polymer. I have found also many, many manufacturers who recommend sealing the foam to prevent UV degredation, most of those references come from the roofing industry.

Something that is somewhat encouraging is a study about the breakdown of rigid polyurethane foams which I believe use similar prepolymers, MDI, etc., as SPF. 


> After a period of 700 days, no aromatic amines were detected using gas chromatography mass spectroscopy, according to William E. Brown, who headed the study. Nor was any physical breakdown of the polyurethane foam cubes evident from visual inspection after the buckets were taken apart following the experiment.


http://www.memagazine.org/backissues/ju ... dfill.html

My biggest unresolved question is the fire retardant chemicals or as they are called in the industry "combustion modifying additives". There are a whole bunch of these that are used from the PBDE that are now being phased out for being toxic to many others. Most studies seemt to be about their release during a fire except for the Carneige Mellon study cited in the preceding paragraph. For a good primer on combustion of TDI and MDI foams (see section 9: COMBUSTION MODIFYING ADDITIVES):
http://www.pfa.org/stone.txt

I"m going to call DOW back about this now that I know the lingo and ask them if any of that is in GS. Also, I am going to ask clarificaiton about the following from their MSDS:


> HAZARDOUS DECOMPOSITION PRODUCTS: Hazardous decomposition products depend upon temperature, air supply and the presence of other materials. Gases are
> released during decomposition.
> HAZARDOUS POLYMERIZATION: Can occur. Polymerization can be catalyzed by: strong bases and water. Can react with itself at temperatures above 320F (160C).


I"m pretty sure they are referring to the precursor chemicals not the stabilized product, but I will ask and see if they have any data on the decomposition gasses at "normal" household temperatures.

There is also a toxicological and environmental section that I won't quote because it is very long, that I believe applies to the raw materials not to the set foam. I am going to verify this.

Regarding the epoxies, I don't really know off the top of my head, but I think many of the marine grade ones are also food grade.

I hope Jason can clarify some of this 

Marcos

PS. I did get your PM and sent a couple back, let me know if you didn't get them.


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## Rain_Frog (Apr 27, 2004)

Marc, I got several PMs, but I sent two subsequent ones after you sent me two. Perhaps you didn't receive them?

As for the epoxy article I posted, Rsines never got back to me. So, I will be posting a message in the feedback section.

I will be contacting West System tomorrow about using latex paint underneath epoxy (to color backgrounds), and how long will it last in a freshwater environment. (to give y'all heads up when you'll need to recoat again).

Marc, you might want to add a post there too requesting your Great Stuff article to be sticky, i think it is something all newbies should be aware of before they even attempt it.

BTW: For all you DIY freaks out there, I will be taking a few pics of a step by step process of making epoxy backgrounds.


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