Who can tell me if “two part urethane” and “polyurethane” mean the same thing when it applies to spray foam.
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Greetings Marson,
This post, in response to your question, will bump the thread through the 'recent discussion' listing again which will increase it's viewing.
Perhaps it will catch someone's attention that can help you with advice.
Cheers
94969.19 In the beginning there was Breaktime...
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Probably in practical use, but not necessarily technically correct. I'd want to read the context to know what claim is being made.
two part refers to the fact that applied on site foams use a curing agent / catalyust which is added at time of application.
here's more
http://wapedia.mobi/en/Polyurethanes
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It comes up because I am getting ready to put a commercial remodel out for bids. The archy has "two part urethane" on the drawings but "polyurethane" on the specifications.
Sounds like a typical commercial spec job to me. They put in every vague option and muddy the clarity in a document that is supposed to specify, just to cover their arse. Mike
Small wheel turn by the fire and rod, big wheel turn by the grace of god.
ask himIt should be speced as for instance, 2# sprayed in place polyurethene closed cell insulation 3" deep to provide a continuous R-20 min insulative barrier.That's a lot of words to put on a drawing, which is why spec sheets are used, anbd genrally a note someplace that tells us that the specifications will always supercede the drawing notes unless otherwise noted.Lot of arch offices will use 'typical' details on drawings or junior draftsmen to do the drawings or stock standard spec sheets and nobody in charge of proofreading to be sure it all agrees from one to the other.So in this case, I don't think there is a conflict. It just looks like careless use of different denominations for the same insulation faith.
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Yeah, pretty sure this is a canned spec sheet which is why they didn't catch the difference. I'm going to have them change it. This is my first experience with this sort of spec sheet. It's about 90 percent CYA boilerplate, with an occasional nugget of needed detail.
microscopic font size?;)
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I know of no spray foam that isn't two parts..
rattle can ?
And you can get the one part in the large froth packs also from places like Tiger foam.The terms ureathane and poly-ureathane are commonly used interchangable.The 2 part you mix 2 chemicals together and they react and cure.The one part reacts with moisture in the air.Gorrillia glue is a one part moisture cure poly foam. Just specialized for adhesive use and not insulation.
.
William the Geezer, the sequel to Billy the Kid - Shoe
The finished product is still a two part. The second being the moisture catalyst instead of a machine added catalyst at the tip
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Keeping you up to date. Tiger Foam is a two part spray foam.
I am not sure about that brand.But the last time I look some of the suppliers, might have been FOMOCO (sp?) had both.IIRC, though, they where focusing mostly on the 2 part and the larger packs where 2 part..
William the Geezer, the sequel to Billy the Kid - Shoe
FoMo Foam may be still making a one part spray, but last I knew that was in the small cans for windows & doors. I know that Tiger Foam only has 2 part because when someone calls and orders kits and wants an installer I am the one that they call.
I just did some looking.Tigger and sprayfoamdirect only have the large 2 part kits.Likewise FOMO only has the 2 part, but the brand that they sell is HandiFoam.And Foam Power also sells HandiFoam in the 2 part kits.But they also 1 part. But only in the small cans that screw on the applicator..
William the Geezer, the sequel to Billy the Kid - Shoe
What about the three part stuff?
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No, they are not the same beast. Whether there is any applical performance difference I do not know. Any mass spray foaming we have done has been two part. We use the one-part (can) for windows, doors, and small gap filling.
I would say ask the architect/ designer for clarification.
I've heard "one part foam" used to describe low-expansion canned foam for filling around windows. I'm pretty sure it's not really one part though. Gotta have a catalyst of some sort.
Hi Mike_Maines,
I've heard "one part foam" used to describe low-expansion canned foam for filling around windows. I'm pretty sure it's not really one part though. Gotta have a catalyst of some sort.
You're right that "one part foams" can be designed for low expansion but one part foams can be high expansion too. The typical "Great Stuff" cans provide various formulas for various expansion rates in a one part dispensary. Moisture in the air is the catalyst thus the reason Great Stuff only recommends layering their foam. If you were to fill a cubic foot cavity with their foam, the outside would cure at its normal rate and the inside would theoretically never get any moisture to the inside to cure thus its insulating properties would be diminished and without proper curing I've found it to be more flammable.
Pedro the Mule - And keep that sticky stuff out of my fur
the outside would cure at its normal rate and the inside would theoretically never get any moisture to the inside to cure
That makes sense. I knew that's how PL Premium and Gorilla Glue cured, but thought that canned foam must need more than just the moisture in the air to expand that much. Learn something new every day.
There's a concise description on this website http://www.positive-energy.com/sealing/polyfoams.html that says one-part lays a bead of foam, two-part sprays the foam. Not sure if that fits with your experience.
I've sprayed enough canned foam to know that it stays sticky when it's too thick. Definitely want to keep that stuff out of your fur. Don't know how many shirts and dropcloths I've ruined with foam.
Hi Mike_Maines,<!----><!----><!---->
says one-part lays a bead of foam, two-part sprays the foam. Not sure if that fits with your experience<!----><!---->
That's it...the two part foam pretty much puts out a drop for drop match thus the catalyst is always in contact with the cure. When moisture is the catalyst, it has to integrate with the one part foam. Laying down a bead leaves it thin enough in the application to fully cure. In theory I recon you could pressurize the contents of the foam and water to create a similar effect but the water has a slower react time thus it wouldn't be like the video's you may have seen when the two part stuff is applied. One part with water should fully cure but would probably be so slow that it would roll out of the cavity before curing.
<!---->Just for personal experience I tried something that I knew was somewhat of a waste of $.....rare for me but got a good education and at least got a little value for the $....I took an empty stud bay, sprayed cooking oil on a 2' x 2' piece of 3/4" plywood and used six drywall screws to mount it to the studs. I then stuck the Great Stuff red can down towards the bottom and started slowly filling up the cavity. I misted a little water from a spray bottle after each layer and waited a few minutes for the cure. Once I was near the top I removed the board and continued moving it up the wall, respraying the cooking oil on the board as a release agent until I reached the top. The whole process worked perfect but I forget, I think it took something like 7 cans to fill it up.....too costly to do an entire room/house.<!---->
<!---->A neighbor did end up doing something similar and more affordable to fix his insulation problem. He had a thermal imaging reading of his early 1900's house done. He new the previous owner had blown in rockwool 30 or 40 years back and he discovered what he imagined.....the material had settled over the years and there was about a 4" gap of no insulation at the top of the leaky walls. He simply popped a tiny hole down about 3" below the ceiling in the walls and went around and squirted a whole can of Great Stuff in each hole. He then ran a lovely crown molding around each room to cover the holes. No more air leaks and the rockwool is not likely to settle any more.<!---->
Pedro the Mule - That stuff will sure stick to horse shoes