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Smells like... Great Stuff?

9K views 33 replies 8 participants last post by  EntoCraig 
#1 ·
I set a tank up about a month ago. It sat cured for one week, then I added silicone and coco. It sat for another week just like that, then last week I had a fan on it all week. The silicon smell is long gone, but it still smells great stuff.

I didn't use a lot of GS, plus I made sure it was cured before moving forward. It had been dry for 2 weeks before I started lightly misting.

Any thoughts?

The smell is not strong, or alarming, but it is noticeable. I have 3 frogs that are waiting to go in the tank. Should I be worried or are they good to go?
 
#5 · (Edited)
The propellant is propane. This will have dissipated a long time ago. If there is a residual smell then you have a uncured zone. This could be due to the improperly mixed/shaken can before use, or it could be due to being insufficiently air cured due to the moisture in the air not being enough when it first began curing, or it could be an improperly mixed ratio/batch from the get go. Expired can, bad batch, who knows.

If it still gives off a detectable aroma there is uncured product. This will only be an issue however, if it is allowed to come into contact with water AND it is not one of the water cured proponents. (If it is the water will cure it.) If so it could get into your water and potentially cause issues.

Your call. I'd say a greater than 60% chance you'll be ok. Any uncured area is sealed over with cured product, and silicone. But there is always a chance.

I've had this happen a few times over the years (bad batches mostly)and as I sell my work, I can't risk it and had to toss it or use it as a display/experimentation tank. Just one of the unfortunate issues with mass produced single component polyurethane foams. I switched to a professional two part PUR foam system with better faster results, but its a LOT more temperamental and requires getting fully suited up.
 
#9 ·
If it still gives off a detectable aroma there is uncured product. This will only be an issue however, if it is allowed to come into contact with water AND it is not one of the water cured proponents. (If it is the water will cure it.) If so it could get into your water and potentially cause issues.

Your call. I'd say a greater than 60% chance you'll be ok. Any uncured area is sealed over with cured product, and silicone. But there is always a chance.
I'd say this sums up the answer you're searching for
 
#7 ·
Did you black out the sides/back? If you didn't, you will probably be able to see the uncured part(s) from the outside. You could poke some holes to let some air get back there. Better yet, you could carve it out and re-do it...yeah that will suck but sometimes its better to play it safe.
 
#10 ·
Thanks for the additional clarification. Im going to point 2 fans down the vent hols that go to the drainage level for a bit and see if some air flow down under will help cure any GS that hasnt cured.\

Im also going to poke some holes all through the GS and see if I can get some air down to any uncured sections.

If this doesnt work, Im going to remove the plants and carve out some larger hole to search for uncured areas. (I can patch these up much easier, and cheaper, then a complete rebuild)

At this point if I cannot find anything I'll let it sit in the garage for a while While I wait.

If then nothing, I will probably break something around the house, swear a bit, and rebuild the thing.

F
 
#20 ·
Here is something. Did you make this in your garage? What temperature and humidity did you use it in? I see you live in Utah and I imagine its a lot colder than here. I live in San Antonio, Texas and I build vivs year around (part-time). THE single biggest issue I've noticed regarding the proper cure of the literally 100's of different materials I've worked with, designed, and experimented with, is the ambient temperature/humidity. I live/work at night just to combat this single issue as the only time temperatures ever stabilize around here is from about 10pm-5am during the summer. During the winter I keep the garage closed and use heaters.

Possible reasons you are having issues with this:

1. Your temperature/humidity levels are not in the appropriate ranges for the foam to cure. The fastest cure I've ever had with GS foam was in a rainstorm in Hawaii. 100% humidity, 85F. Full cure in less than 20 minutes. (I was using it as a mother-molding material for some molds I was taking off banyan tree roots.)

The colder the temperature and less moisture in the air, the less C02 is produced and less expansion you get, resulting in a higher density foam and an sort of pudding/frothy/melted ice-cream look.

The problem this can cause is that if the amount of moisture that comes in contact with the material is not enough by the time the outer layer skins, the areas underneath do not have enough moisture to fully react. Adding to that the skin prevents almost all air/water movement.
This is dramatically exacerbated if coupled with spraying large volumes as this creates deeper areas.

2. The cans you are buying are bad. The batch/source/handling/shipping whatever is not correct. One of the biggest issues with polymers in general is their freeze/thaw stability. Some are no longer stable or in the same configuration after a freezing event. Sometimes its just as simple as shaking the can to mix it again, but other times it has permanently deteriorated the polymer. PUR foam, I think is one of the later, but as you are seeing at least partial cures, this could be ruled out to a point.

3. User error. You are not shaking the cans for 2-3 minutes like they say and/or you are using too large of volumes for the ambient conditions to allow for.

4. Your sense of smell is 50-100X greater than the rest of us.

My guess is its too cold, too dry, and you are using too much at a time. Also check the expiration dates of each can EVERY time. This is a HUGE issue with GE silicone too.

As for the GAS being toxic I've got varying degrees of agreement with that. An animal in contact with air that has that gas in it will likely not kill/damage it. Too dilute. However what the gas originates from, could be an issue IF it is allowed to come in contact with water and THEN that water comes into contact with the animal. Assuming it is not a water-cured material that would become inert after reacting with the water.

One fix you can try is soaking the crud out of the thing with a hose. Poking holes will help.
 
#21 ·
Thanks for your comments. This provides insight, but Im still not sure where I went wrong...

The temp in my fish room is 72, with 40% humidity. I shook the cans well and seriously used such a small thin layer, maybe an inch at most in the thickets areas. (excess was carved out.) I let it sit for a week, dry as a bone.

You are spot on with all the places i could have gone wrong, but when I put that up against how I built the tank, it doesn't add up. Either I missed something, or the product, despite my efforts, cured improperly due to some factor I could not account for.

My wife and brother can smell it also, so It not super human smelling powers :)

I can report that I ran 2 fans on the tank all night, one blowing in and one blowing out. There was ZERO smell at all. I hope I am making progress...
 
#30 ·
In the summer I wait ~4 hours for the GS to cure before I work with it. Plenty of time in warm humid weather.

During the winter I wait 24 hours due to the lower temp and humidity.

Its all dependent on all the various factors I stated in the posts above but in most cases 24 hours is PLENTY of time.

Good to hear that the smell is going down. Hmm, the temps and humidity seem fine, so I'm thinking bad batches or some unknown variable.
 
#31 ·
The first principle to know is that EVERYTHING is toxic. The amount is what makes the difference and determines if something will cause health effects. The spray foams have a polymerizing agent called an isocyanate. Hexamethyl Diisocyanante or Toluene Diisocyanate are two common ones. They are very, very toxic! However, they react very quickly and polymerize into long chains with decreasing toxicity right away. It is highly unlikely that you have much of that after a few hours. Also, you will not smell these. Both the foam and silicone will have various volatile organic solvents of some sort. Likely Toluene or something similar. They are toxic, but we are pretty good at detecting (smelling) most of these. Usually the strong smell will let you know when something has cured. If you still smell it then there are still volatiles coming off of it. I would almost bet that this same set up, left in the sun in Yuma Az for a week, would likely have the volatiles "bake" off. The rate at which they do so is dependent on what type of volatile it is. They each have a different vapor pressure which determines the rate at which the will "evaporate". But, if you still smell it then they are still there and if volatilizing in an enclosed area "like an aquarium interior" could easily hit levels that would cause adverse biological effects. Bottom line; if it still has a "strong" smell then there is still a significant amount of vaporization occuring and you should wait and/or bake it some more. It will likely have some smell for quite a while but it should be minimal before you enclose some frogs with it.
 
#32 ·
UPDATE:<br /><br />So I had a second opinion on the smell. He said he doesn't smell Great Stuff, but he does smell what I am referring to.<br /><br />So I did a test. I sprayed some GS on some paper and smelt it. Its not the same smell... I let it cure, and I made sure some didn't fully cure. Still, not the same smell. I guess I was assuming it was the GS and not something else.<br /><br />I also read on the GS can that water misting helps cure GS. So at this point im positive its not the GS.<br /><br />My only other option is it is the Silicone. I used GE 100% silicone. The typical vinegar smell is long gone, but another smell remains. <br /><br />If I had more I would test it, but I'm currently out... I'm wondering if some of the silicon near the top is being heat up by the light and is causing some sort of smell to leach out. I know that when you heat up plastic or other materials they often have a smell to them...
 
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