Closed or open cell foam?
BrianWL
| Posted in General Questions on
Is Great Stuff (in the can from Lowe’s or Home Depot) open or closed cell foam? A google search said closed cell but I recall a GBA article on adding water vapor increases it’s expansion during curing so that implies open cell, doesn’t it? Thanks. (brand new to GBA subscription). Brian Lengel, Austin, TX
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Brian,
To the best of my knowledge, many moisture-cured one-component spray foams (including Great Stuff) are closed-cell when fully cured.
Here is a link to a document that declares that at least one Great Stuff product -- a canned spray foam called Great Stuff Pond and Stone Filler -- is both moisture-cured and closed-cell: Great Stuff Pond and Stone Filler.
I don't think the fact that a foam produce is moisture-cured has anything to do with whether or not the cured foam is open-cell or closed-cell.
Some advice, the cans with a straw aren't that easy to use. It's absolutely worth getting a dispensing gun for anything more than very small projects:
http://www.amazon.com/GREAT-STUFF-PRO-Dispensing-Gun/dp/B0002YOMJE/
Thanks. I wish I could find the GBA article about can spray foams because I do not understand the economics:
The foam dispensing gun costs $49.95. The 24 oz of Great Stuff PRO costs $12.47. Half as much, the 12 oz can with the straw, costs $4.25....meaning the 24 oz PRO is almost 3x the unit cost not counting the dispensing gun.
I've became very adept at using (being a DIYer) of using drip irrigation tubing in lieu of the straw (must wire it at the nozzle tho) so as to get the can upside down in every circumstance. Alternatively, with foresight, a straw nozzle fits nicely into some 3/8" OD potable water white tubing (caulk applied to "glue" the arrangement so the straw won't 'blow out' under pressure). One has to be careful about application of the foam, of course, and not merely window dress it like paint...the nozzle end needs to get into/inside the crack and crevices and holes.
What am I missing here? Seems like the cheaper way is can way, especially before the big box stores increased the 12 oz price by a dollar. Granted, more cans to waste but I recycle those.
The gun also lets you use the cab multiple times. The little cans with straws are a one-time deal — you have to use the entire can in one quick job or it seals itself and has to be trashed.
I think the most important thing with the gun is to wipe the tip thoroughly with acetone every time you’re going to stop using it for more than maybe 10-15 seconds or so. I use a bit of paper towel with some acetone to keep the tip clean. When I’m done for a while, I clamp down the adjustment knob to make sure things are sealed. Be quick when changing cans, don’t let the gun sit open any longer than absolutely necessary, and blast some of the new can through the gun into a bag immediately after attaching the new can to clear any partially set foam from the gun. If you need to leave the gun disconnected from the can for a while, run gun cleaner through it until it runs clean.
It’s vitally important that the foam is never allowed to set up and cure anywhere in the gun mechanism. As long as you’re careful about that, the gun will last a long time and is MUCH nicer to use than the one-time use straw cans.
Bill
Brian,
I'm with you. My $99 gun got irreparably clogged. I went back to the $4 cans from the hardware store.
Adding my two cents...four years later! (just in case any new visitors find it helpful...
I was wondering the same thing about the cost of the 24oz can vs. the smaller cans with a straw....but after viewing a few videos on the pro gun...and even though I'm only using this thing for my own personal one-time project, I splurged on the gun after trying one can of "windows and doors" foam in the plastic straw version with disappointing results (little control...have to use it quickly or trash it... and I got very little coverage from one standard sized can of it. So....I went and bought the Pro 14 gun and four 24.0z cans of "gaps & cracks" to air seal my 215 square foot addition. It only took me 2 cans to seal all penetrations (electrical..vents...plumbing vents... all eight (corners?/ joints?) of each and every stud bay...plus various other gaps found in other areas where existing drywall had to be cut out. I think part of why the pro-guns are so awesome is that you can adjust the amount you're letting out of the gun and use no more than you need (for example in stud bay joints) This also allows for far more control and far less over-spray where you don't want it. It's many times "cleaner"....and like I said.... for some reason the can went way farther than 3 cans of the other would have. As I said, I've used a total of two 24 oz. cans of gaps & cracks with the gun so far....followed all of the instructions and it's working perfectly...not curing inside the gun. The much better job it's allowed me to do is totally worth the cost to me...and I can clean it out with the cleaner and pass it on to someone who can use it when I'm finished with it (maybe even sell it at, say, 1/2 price to someone who could use it)